Fix warning.
[mono.git] / mcs / gmcs / expression.cs
index d27285c4356f5253552cf99d7173b30b09caa76d..dad971332431f25d5370495b330041392c1775b0 100644 (file)
@@ -91,10 +91,10 @@ namespace Mono.CSharp {
        {
                public Expression Expr;
 
-               public ParenthesizedExpression (Expression expr, Location loc)
+               public ParenthesizedExpression (Expression expr)
                {
                        this.Expr = expr;
-                       this.loc = loc;
+                       this.loc = expr.Location;
                }
 
                public override Expression DoResolve (EmitContext ec)
@@ -107,6 +107,13 @@ namespace Mono.CSharp {
                {
                        throw new Exception ("Should not happen");
                }
+
+               public override Location Location
+               {
+                       get {
+                               return Expr.Location;
+                       }
+               }
        }
        
        /// <summary>
@@ -173,10 +180,8 @@ namespace Mono.CSharp {
 
                void Error23 (Type t)
                {
-                       Error (
-                               23, "Operator " + OperName (Oper) +
-                               " cannot be applied to operand of type `" +
-                               TypeManager.CSharpName (t) + "'");
+                       Report.Error (23, loc, "Operator `{0}' cannot be applied to operand of type `{1}'",
+                               OperName (Oper), TypeManager.CSharpName (t));
                }
 
                /// <remarks>
@@ -190,37 +195,37 @@ namespace Mono.CSharp {
                        Expression e = null;
 
                        if (expr is IntConstant)
-                               e = new IntConstant (-((IntConstant) expr).Value);
+                               e = new IntConstant (-((IntConstant) expr).Value, expr.Location);
                        else if (expr is UIntConstant){
                                uint value = ((UIntConstant) expr).Value;
 
                                if (value < 2147483649)
-                                       return new IntConstant (-(int)value);
+                                       return new IntConstant (-(int)value, expr.Location);
                                else
-                                       e = new LongConstant (-value);
+                                       e = new LongConstant (-value, expr.Location);
                        }
                        else if (expr is LongConstant)
-                               e = new LongConstant (-((LongConstant) expr).Value);
+                               e = new LongConstant (-((LongConstant) expr).Value, expr.Location);
                        else if (expr is ULongConstant){
                                ulong value = ((ULongConstant) expr).Value;
 
                                if (value < 9223372036854775809)
-                                       return new LongConstant(-(long)value);
+                                       return new LongConstant(-(long)value, expr.Location);
                        }
                        else if (expr is FloatConstant)
-                               e = new FloatConstant (-((FloatConstant) expr).Value);
+                               e = new FloatConstant (-((FloatConstant) expr).Value, expr.Location);
                        else if (expr is DoubleConstant)
-                               e = new DoubleConstant (-((DoubleConstant) expr).Value);
+                               e = new DoubleConstant (-((DoubleConstant) expr).Value, expr.Location);
                        else if (expr is DecimalConstant)
-                               e = new DecimalConstant (-((DecimalConstant) expr).Value);
+                               e = new DecimalConstant (-((DecimalConstant) expr).Value, expr.Location);
                        else if (expr is ShortConstant)
-                               e = new IntConstant (-((ShortConstant) expr).Value);
+                               e = new IntConstant (-((ShortConstant) expr).Value, expr.Location);
                        else if (expr is UShortConstant)
-                               e = new IntConstant (-((UShortConstant) expr).Value);
+                               e = new IntConstant (-((UShortConstant) expr).Value, expr.Location);
                        else if (expr is SByteConstant)
-                               e = new IntConstant (-((SByteConstant) expr).Value);
+                               e = new IntConstant (-((SByteConstant) expr).Value, expr.Location);
                        else if (expr is ByteConstant)
-                               e = new IntConstant (-((ByteConstant) expr).Value);
+                               e = new IntConstant (-((ByteConstant) expr).Value, expr.Location);
                        return e;
                }
 
@@ -236,6 +241,12 @@ namespace Mono.CSharp {
                        
                        switch (Oper){
                        case Operator.UnaryPlus:
+                               if (expr_type == TypeManager.bool_type){
+                                       result = null;
+                                       Error23 (expr_type);
+                                       return false;
+                               }
+                               
                                result = e;
                                return true;
                                
@@ -251,7 +262,7 @@ namespace Mono.CSharp {
                                }
                                
                                BoolConstant b = (BoolConstant) e;
-                               result = new BoolConstant (!(b.Value));
+                               result = new BoolConstant (!(b.Value), b.Location);
                                return true;
                                
                        case Operator.OnesComplement:
@@ -300,13 +311,13 @@ namespace Mono.CSharp {
                                }
 
                                if (expr_type == TypeManager.int32_type){
-                                       result = new IntConstant (~ ((IntConstant) e).Value);
+                                       result = new IntConstant (~ ((IntConstant) e).Value, e.Location);
                                } else if (expr_type == TypeManager.uint32_type){
-                                       result = new UIntConstant (~ ((UIntConstant) e).Value);
+                                       result = new UIntConstant (~ ((UIntConstant) e).Value, e.Location);
                                } else if (expr_type == TypeManager.int64_type){
-                                       result = new LongConstant (~ ((LongConstant) e).Value);
+                                       result = new LongConstant (~ ((LongConstant) e).Value, e.Location);
                                } else if (expr_type == TypeManager.uint64_type){
-                                       result = new ULongConstant (~ ((ULongConstant) e).Value);
+                                       result = new ULongConstant (~ ((ULongConstant) e).Value, e.Location);
                                } else {
                                        result = null;
                                        Error23 (expr_type);
@@ -390,28 +401,24 @@ namespace Mono.CSharp {
                                        Expression e;
 
                                        e = Convert.ImplicitConversion (ec, Expr, TypeManager.int32_type, loc);
-                                       if (e != null){
-                                               type = TypeManager.int32_type;
-                                               return this;
-                                       }
+                                       if (e != null)
+                                               goto ok;
                                        e = Convert.ImplicitConversion (ec, Expr, TypeManager.uint32_type, loc);
-                                       if (e != null){
-                                               type = TypeManager.uint32_type;
-                                               return this;
-                                       }
+                                       if (e != null)
+                                               goto ok;
                                        e = Convert.ImplicitConversion (ec, Expr, TypeManager.int64_type, loc);
-                                       if (e != null){
-                                               type = TypeManager.int64_type;
-                                               return this;
-                                       }
+                                       if (e != null)
+                                               goto ok;
                                        e = Convert.ImplicitConversion (ec, Expr, TypeManager.uint64_type, loc);
-                                       if (e != null){
-                                               type = TypeManager.uint64_type;
-                                               return this;
-                                       }
+                                       if (e != null)
+                                               goto ok;
                                        Error23 (expr_type);
                                        return null;
+                               ok:
+                                       Expr = e;
+                                       expr_type = e.Type;
                                }
+
                                type = expr_type;
                                return this;
 
@@ -426,16 +433,16 @@ namespace Mono.CSharp {
                                }
 
                                IVariable variable = Expr as IVariable;
-                               bool is_fixed = variable != null && variable.VerifyFixed (false);
+                               bool is_fixed = variable != null && variable.VerifyFixed ();
 
                                if (!ec.InFixedInitializer && !is_fixed) {
-                                       Error (212, "You can only take the address of an unfixed expression inside " +
+                                       Error (212, "You can only take the address of unfixed expression inside " +
                                               "of a fixed statement initializer");
                                        return null;
                                }
 
                                if (ec.InFixedInitializer && is_fixed) {
-                                       Error (213, "You can not fix an already fixed expression");
+                                       Error (213, "You cannot use the fixed statement to take the address of an already fixed expression");
                                        return null;
                                }
 
@@ -464,7 +471,7 @@ namespace Mono.CSharp {
                                }
                                
                                if (!expr_type.IsPointer){
-                                       Error (193, "The * or -> operator can only be applied to pointers");
+                                       Error (193, "The * or -> operator must be applied to a pointer");
                                        return null;
                                }
                                
@@ -574,7 +581,7 @@ namespace Mono.CSharp {
                                Expr = Expr.DoResolveLValue (ec, new EmptyExpression ());
 
                                if (Expr == null || Expr.eclass != ExprClass.Variable){
-                                       Error (211, "Cannot take the address of non-variables");
+                                       Error (211, "Cannot take the address of the given expression");
                                        return null;
                                }
                        }
@@ -674,10 +681,6 @@ namespace Mono.CSharp {
                        eclass = ExprClass.Variable;
                        loc = l;
                }
-
-               void LoadExprValue (EmitContext ec)
-               {
-               }
                
                public override void Emit (EmitContext ec)
                {
@@ -750,8 +753,9 @@ namespace Mono.CSharp {
                        }
                }
 
-               public bool VerifyFixed (bool is_expression)
+               public bool VerifyFixed ()
                {
+                       // A pointer-indirection is always fixed.
                        return true;
                }
 
@@ -810,14 +814,6 @@ namespace Mono.CSharp {
                                "++" : "--";
                }
                
-               void Error23 (Type t)
-               {
-                       Error (
-                               23, "Operator " + OperName (mode) + 
-                               " cannot be applied to operand of type `" +
-                               TypeManager.CSharpName (t) + "'");
-               }
-
                /// <summary>
                ///   Returns whether an object of type `t' can be incremented
                ///   or decremented with add/sub (ie, basically whether we can
@@ -882,11 +878,11 @@ namespace Mono.CSharp {
                                        return null;
                                }
                        } else if (expr.eclass == ExprClass.IndexerAccess || expr.eclass == ExprClass.PropertyAccess){
-                               expr = expr.ResolveLValue (ec, this);
+                               expr = expr.ResolveLValue (ec, this, Location);
                                if (expr == null)
                                        return null;
                        } else {
-                               expr.Error_UnexpectedKind ("variable, indexer or property access", loc);
+                               expr.Error_UnexpectedKind (ec, "variable, indexer or property access", loc);
                                return null;
                        }
 
@@ -1038,7 +1034,7 @@ namespace Mono.CSharp {
        public abstract class Probe : Expression {
                public Expression ProbeType;
                protected Expression expr;
-               protected Type probe_type;
+               protected TypeExpr probe_type_expr;
                
                public Probe (Expression expr, Expression probe_type, Location l)
                {
@@ -1055,12 +1051,11 @@ namespace Mono.CSharp {
 
                public override Expression DoResolve (EmitContext ec)
                {
-                       TypeExpr texpr = ProbeType.ResolveAsTypeTerminal (ec);
-                       if (texpr == null)
+                       probe_type_expr = ProbeType.ResolveAsTypeTerminal (ec);
+                       if (probe_type_expr == null)
+                               return null;
+                       if (probe_type_expr.ResolveType (ec) == null)
                                return null;
-                       probe_type = texpr.Type;
-
-                       CheckObsoleteAttribute (probe_type);
 
                        expr = expr.Resolve (ec);
                        if (expr == null)
@@ -1112,7 +1107,7 @@ namespace Mono.CSharp {
                                ig.Emit (OpCodes.Ceq);
                                return;
                        case Action.Probe:
-                               ig.Emit (OpCodes.Isinst, probe_type);
+                               ig.Emit (OpCodes.Isinst, probe_type_expr.Type);
                                ig.Emit (OpCodes.Ldnull);
                                ig.Emit (OpCodes.Cgt_Un);
                                return;
@@ -1142,7 +1137,7 @@ namespace Mono.CSharp {
                                return;
                        case Action.Probe:
                                expr.Emit (ec);
-                               ig.Emit (OpCodes.Isinst, probe_type);
+                               ig.Emit (OpCodes.Isinst, probe_type_expr.Type);
                                ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
                                return;
                        }
@@ -1167,8 +1162,9 @@ namespace Mono.CSharp {
                        // First case, if at compile time, there is an implicit conversion
                        // then e != null (objects) or true (value types)
                        //
+                       Type probe_type = probe_type_expr.Type;
                        e = Convert.ImplicitConversionStandard (ec, expr, probe_type, loc);
-                       if (e != null){
+                       if (e != null && !(e is NullCast)){
                                expr = e;
                                if (etype.IsValueType)
                                        action = Action.AlwaysTrue;
@@ -1193,10 +1189,10 @@ namespace Mono.CSharp {
                        }
                        
                        if (warning_always_matches)
-                               Warning (183, "The given expression is always of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
+                               Report.Warning (183, 1, loc, "The given expression is always of the provided (`{0}') type", TypeManager.CSharpName (probe_type));
                        else if (warning_never_matches){
                                if (!(probe_type.IsInterface || expr.Type.IsInterface))
-                                       Warning (184, "The given expression is never of the provided ('{0}') type", TypeManager.CSharpName (probe_type));
+                                       Report.Warning (184, 1, loc, "The given expression is never of the provided (`{0}') type", TypeManager.CSharpName (probe_type));
                        }
 
                        return this;
@@ -1213,6 +1209,7 @@ namespace Mono.CSharp {
                }
 
                bool do_isinst = false;
+               Expression resolved_type;
                
                public override void Emit (EmitContext ec)
                {
@@ -1221,43 +1218,68 @@ namespace Mono.CSharp {
                        expr.Emit (ec);
 
                        if (do_isinst)
-                               ig.Emit (OpCodes.Isinst, probe_type);
+                               ig.Emit (OpCodes.Isinst, probe_type_expr.Type);
                }
 
                static void Error_CannotConvertType (Type source, Type target, Location loc)
                {
-                       Report.Error (
-                               39, loc, "as operator can not convert from `" +
-                               TypeManager.CSharpName (source) + "' to `" +
-                               TypeManager.CSharpName (target) + "'");
+                       Report.Error (39, loc, "Cannot convert type `{0}' to `{1}' via a built-in conversion",
+                               TypeManager.CSharpName (source),
+                               TypeManager.CSharpName (target));
                }
                
                public override Expression DoResolve (EmitContext ec)
                {
-                       Expression e = base.DoResolve (ec);
+                       if (resolved_type == null) {
+                               resolved_type = base.DoResolve (ec);
 
-                       if (e == null)
-                               return null;
+                               if (resolved_type == null)
+                                       return null;
+                       }
 
-                       type = probe_type;
+                       type = probe_type_expr.Type;
                        eclass = ExprClass.Value;
                        Type etype = expr.Type;
 
-                       if (TypeManager.IsValueType (probe_type)){
-                               Report.Error (77, loc, "The as operator should be used with a reference type only (" +
-                                             TypeManager.CSharpName (probe_type) + " is a value type)");
+                       if (type.IsValueType) {
+                               Report.Error (77, loc, "The as operator must be used with a reference type (`" +
+                                             TypeManager.CSharpName (type) + "' is a value type)");
                                return null;
                        
                        }
+
+                       //
+                       // If the type is a type parameter, ensure
+                       // that it is constrained by a class
+                       //
+                       TypeParameterExpr tpe = probe_type_expr as TypeParameterExpr;
+                       if (tpe != null){
+                               Constraints constraints = tpe.TypeParameter.Constraints;
+                               bool error = false;
+                               
+                               if (constraints == null)
+                                       error = true;
+                               else {
+                                       if (!constraints.HasClassConstraint)
+                                               if ((constraints.Attributes & GenericParameterAttributes.ReferenceTypeConstraint) == 0)
+                                                       error = true;
+                               }
+                               if (error){
+                                       Report.Error (413, loc,
+                                                     "The as operator requires that the `{0}' type parameter be constrained by a class",
+                                                     probe_type_expr);
+                                       return null;
+                               }
+                       }
                        
-                       e = Convert.ImplicitConversion (ec, expr, probe_type, loc);
+                       Expression e = Convert.ImplicitConversion (ec, expr, type, loc);
                        if (e != null){
                                expr = e;
                                do_isinst = false;
                                return this;
                        }
 
-                       if (Convert.ExplicitReferenceConversionExists (etype, probe_type)){
+                       if (Convert.ExplicitReferenceConversionExists (etype, type)){
                                if (etype.IsGenericParameter)
                                        expr = new BoxedCast (expr, etype);
 
@@ -1265,7 +1287,7 @@ namespace Mono.CSharp {
                                return this;
                        }
 
-                       Error_CannotConvertType (etype, probe_type, loc);
+                       Error_CannotConvertType (etype, type, loc);
                        return null;
                }                               
        }
@@ -1280,6 +1302,11 @@ namespace Mono.CSharp {
                Expression target_type;
                Expression expr;
                        
+               public Cast (Expression cast_type, Expression expr)
+                       : this (cast_type, expr, cast_type.Location)
+               {
+               }
+
                public Cast (Expression cast_type, Expression expr, Location loc)
                {
                        this.target_type = cast_type;
@@ -1301,496 +1328,6 @@ namespace Mono.CSharp {
                                expr = value;
                        }
                }
-
-               bool CheckRange (EmitContext ec, long value, Type type, long min, long max)
-               {
-                       if (!ec.ConstantCheckState)
-                               return true;
-
-                       if ((value < min) || (value > max)) {
-                               Error (221, "Constant value `" + value + "' cannot be converted " +
-                                      "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
-                                      "syntax to override)");
-                               return false;
-                       }
-
-                       return true;
-               }
-
-               bool CheckRange (EmitContext ec, ulong value, Type type, ulong max)
-               {
-                       if (!ec.ConstantCheckState)
-                               return true;
-
-                       if (value > max) {
-                               Error (221, "Constant value `" + value + "' cannot be converted " +
-                                      "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
-                                      "syntax to override)");
-                               return false;
-                       }
-
-                       return true;
-               }
-
-               bool CheckUnsigned (EmitContext ec, long value, Type type)
-               {
-                       if (!ec.ConstantCheckState)
-                               return true;
-
-                       if (value < 0) {
-                               Error (221, "Constant value `" + value + "' cannot be converted " +
-                                      "to a `" + TypeManager.CSharpName (type) + "' (use `unchecked' " +
-                                      "syntax to override)");
-                               return false;
-                       }
-
-                       return true;
-               }
-
-               /// <summary>
-               ///   Attempts to do a compile-time folding of a constant cast.
-               /// </summary>
-               Expression TryReduce (EmitContext ec, Type target_type)
-               {
-                       Expression real_expr = expr;
-                       if (real_expr is EnumConstant)
-                               real_expr = ((EnumConstant) real_expr).Child;
-                               
-                       if (real_expr is ByteConstant){
-                               byte v = ((ByteConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.short_type)
-                                       return new ShortConstant ((short) v);
-                               if (target_type == TypeManager.ushort_type)
-                                       return new UShortConstant ((ushort) v);
-                               if (target_type == TypeManager.int32_type)
-                                       return new IntConstant ((int) v);
-                               if (target_type == TypeManager.uint32_type)
-                                       return new UIntConstant ((uint) v);
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type)
-                                       return new ULongConstant ((ulong) v);
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type)
-                                       return new CharConstant ((char) v);
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is SByteConstant){
-                               sbyte v = ((SByteConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.short_type)
-                                       return new ShortConstant ((short) v);
-                               if (target_type == TypeManager.ushort_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new UShortConstant ((ushort) v);
-                               } if (target_type == TypeManager.int32_type)
-                                       return new IntConstant ((int) v);
-                               if (target_type == TypeManager.uint32_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new UIntConstant ((uint) v);
-                               } if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new ULongConstant ((ulong) v);
-                               }
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is ShortConstant){
-                               short v = ((ShortConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.ushort_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new UShortConstant ((ushort) v);
-                               }
-                               if (target_type == TypeManager.int32_type)
-                                       return new IntConstant ((int) v);
-                               if (target_type == TypeManager.uint32_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new UIntConstant ((uint) v);
-                               }
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new ULongConstant ((ulong) v);
-                               }
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is UShortConstant){
-                               ushort v = ((UShortConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.short_type) {
-                                       if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
-                                               return null;
-                                       return new ShortConstant ((short) v);
-                               }
-                               if (target_type == TypeManager.int32_type)
-                                       return new IntConstant ((int) v);
-                               if (target_type == TypeManager.uint32_type)
-                                       return new UIntConstant ((uint) v);
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type)
-                                       return new ULongConstant ((ulong) v);
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is IntConstant){
-                               int v = ((IntConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.short_type) {
-                                       if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
-                                               return null;
-                                       return new ShortConstant ((short) v);
-                               }
-                               if (target_type == TypeManager.ushort_type) {
-                                       if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
-                                               return null;
-                                       return new UShortConstant ((ushort) v);
-                               }
-                               if (target_type == TypeManager.uint32_type) {
-                                       if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
-                                               return null;
-                                       return new UIntConstant ((uint) v);
-                               }
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new ULongConstant ((ulong) v);
-                               }
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is UIntConstant){
-                               uint v = ((UIntConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.short_type) {
-                                       if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
-                                               return null;
-                                       return new ShortConstant ((short) v);
-                               }
-                               if (target_type == TypeManager.ushort_type) {
-                                       if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
-                                               return null;
-                                       return new UShortConstant ((ushort) v);
-                               }
-                               if (target_type == TypeManager.int32_type) {
-                                       if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
-                                               return null;
-                                       return new IntConstant ((int) v);
-                               }
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type)
-                                       return new ULongConstant ((ulong) v);
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is LongConstant){
-                               long v = ((LongConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.short_type) {
-                                       if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
-                                               return null;
-                                       return new ShortConstant ((short) v);
-                               }
-                               if (target_type == TypeManager.ushort_type) {
-                                       if (!CheckRange (ec, v, target_type, UInt16.MinValue, UInt16.MaxValue))
-                                               return null;
-                                       return new UShortConstant ((ushort) v);
-                               }
-                               if (target_type == TypeManager.int32_type) {
-                                       if (!CheckRange (ec, v, target_type, Int32.MinValue, Int32.MaxValue))
-                                               return null;
-                                       return new IntConstant ((int) v);
-                               }
-                               if (target_type == TypeManager.uint32_type) {
-                                       if (!CheckRange (ec, v, target_type, UInt32.MinValue, UInt32.MaxValue))
-                                               return null;
-                                       return new UIntConstant ((uint) v);
-                               }
-                               if (target_type == TypeManager.uint64_type) {
-                                       if (!CheckUnsigned (ec, v, target_type))
-                                               return null;
-                                       return new ULongConstant ((ulong) v);
-                               }
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is ULongConstant){
-                               ulong v = ((ULongConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckRange (ec, v, target_type, Byte.MaxValue))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, (ulong) SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.short_type) {
-                                       if (!CheckRange (ec, v, target_type, (ulong) Int16.MaxValue))
-                                               return null;
-                                       return new ShortConstant ((short) v);
-                               }
-                               if (target_type == TypeManager.ushort_type) {
-                                       if (!CheckRange (ec, v, target_type, UInt16.MaxValue))
-                                               return null;
-                                       return new UShortConstant ((ushort) v);
-                               }
-                               if (target_type == TypeManager.int32_type) {
-                                       if (!CheckRange (ec, v, target_type, Int32.MaxValue))
-                                               return null;
-                                       return new IntConstant ((int) v);
-                               }
-                               if (target_type == TypeManager.uint32_type) {
-                                       if (!CheckRange (ec, v, target_type, UInt32.MaxValue))
-                                               return null;
-                                       return new UIntConstant ((uint) v);
-                               }
-                               if (target_type == TypeManager.int64_type) {
-                                       if (!CheckRange (ec, v, target_type, (ulong) Int64.MaxValue))
-                                               return null;
-                                       return new LongConstant ((long) v);
-                               }
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MaxValue))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is FloatConstant){
-                               float v = ((FloatConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type)
-                                       return new ByteConstant ((byte) v);
-                               if (target_type == TypeManager.sbyte_type)
-                                       return new SByteConstant ((sbyte) v);
-                               if (target_type == TypeManager.short_type)
-                                       return new ShortConstant ((short) v);
-                               if (target_type == TypeManager.ushort_type)
-                                       return new UShortConstant ((ushort) v);
-                               if (target_type == TypeManager.int32_type)
-                                       return new IntConstant ((int) v);
-                               if (target_type == TypeManager.uint32_type)
-                                       return new UIntConstant ((uint) v);
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type)
-                                       return new ULongConstant ((ulong) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type)
-                                       return new CharConstant ((char) v);
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-                       if (real_expr is DoubleConstant){
-                               double v = ((DoubleConstant) real_expr).Value;
-       
-                               if (target_type == TypeManager.byte_type){
-                                       return new ByteConstant ((byte) v);
-                               } if (target_type == TypeManager.sbyte_type)
-                                       return new SByteConstant ((sbyte) v);
-                               if (target_type == TypeManager.short_type)
-                                       return new ShortConstant ((short) v);
-                               if (target_type == TypeManager.ushort_type)
-                                       return new UShortConstant ((ushort) v);
-                               if (target_type == TypeManager.int32_type)
-                                       return new IntConstant ((int) v);
-                               if (target_type == TypeManager.uint32_type)
-                                       return new UIntConstant ((uint) v);
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type)
-                                       return new ULongConstant ((ulong) v);
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.char_type)
-                                       return new CharConstant ((char) v);
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-
-                       if (real_expr is CharConstant){
-                               char v = ((CharConstant) real_expr).Value;
-                               
-                               if (target_type == TypeManager.byte_type) {
-                                       if (!CheckRange (ec, v, target_type, Byte.MinValue, Byte.MaxValue))
-                                               return null;
-                                       return new ByteConstant ((byte) v);
-                               }
-                               if (target_type == TypeManager.sbyte_type) {
-                                       if (!CheckRange (ec, v, target_type, SByte.MinValue, SByte.MaxValue))
-                                               return null;
-                                       return new SByteConstant ((sbyte) v);
-                               }
-                               if (target_type == TypeManager.short_type) {
-                                       if (!CheckRange (ec, v, target_type, Int16.MinValue, Int16.MaxValue))
-                                               return null;
-                                       return new ShortConstant ((short) v);
-                               }
-                               if (target_type == TypeManager.int32_type)
-                                       return new IntConstant ((int) v);
-                               if (target_type == TypeManager.uint32_type)
-                                       return new UIntConstant ((uint) v);
-                               if (target_type == TypeManager.int64_type)
-                                       return new LongConstant ((long) v);
-                               if (target_type == TypeManager.uint64_type)
-                                       return new ULongConstant ((ulong) v);
-                               if (target_type == TypeManager.float_type)
-                                       return new FloatConstant ((float) v);
-                               if (target_type == TypeManager.double_type)
-                                       return new DoubleConstant ((double) v);
-                               if (target_type == TypeManager.char_type) {
-                                       if (!CheckRange (ec, v, target_type, Char.MinValue, Char.MaxValue))
-                                               return null;
-                                       return new CharConstant ((char) v);
-                               }
-                               if (target_type == TypeManager.decimal_type)
-                                       return new DecimalConstant ((decimal) v);
-                       }
-
-                       return null;
-               }
                
                public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
                {
@@ -1816,22 +1353,20 @@ namespace Mono.CSharp {
                        if (target == null)
                                return null;
                        
-                       type = target.Type;
-
-                       CheckObsoleteAttribute (type);
+                       type = target.ResolveType (ec);
 
                        if (type.IsAbstract && type.IsSealed) {
-                               Report.Error (716, loc, "Cannot convert to static type '{0}'", TypeManager.CSharpName (type));
+                               Report.Error (716, loc, "Cannot convert to static type `{0}'", TypeManager.CSharpName (type));
                                return null;
                        }
 
                        eclass = ExprClass.Value;
 
-                       if (expr is Constant){
-                               Expression e = TryReduce (ec, type);
-
-                               if (e != null)
-                                       return e;
+                       Constant c = expr as Constant;
+                       if (c != null) {
+                               c = c.TryReduce (ec, type, loc);
+                               if (c != null)
+                                       return c;
                        }
 
                        if (type.IsPointer && !ec.InUnsafe) {
@@ -1899,12 +1434,12 @@ namespace Mono.CSharp {
                        oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
                }
 
-               public Binary (Operator oper, Expression left, Expression right, Location loc)
+               public Binary (Operator oper, Expression left, Expression right)
                {
                        this.oper = oper;
                        this.left = left;
                        this.right = right;
-                       this.loc = loc;
+                       this.loc = left.Location;
                }
 
                public Operator Oper {
@@ -1938,7 +1473,7 @@ namespace Mono.CSharp {
                /// <summary>
                ///   Returns a stringified representation of the Operator
                /// </summary>
-               static string OperName (Operator oper)
+               public static string OperName (Operator oper)
                {
                        switch (oper){
                        case Operator.Multiply:
@@ -2031,7 +1566,7 @@ namespace Mono.CSharp {
                // type, otherwise ConvertImplict() already finds the user-defined conversion for us,
                // so we don't explicitly check for performance reasons.
                //
-               bool DoNumericPromotions (EmitContext ec, Type l, Type r, bool check_user_conv)
+               bool DoNumericPromotions (EmitContext ec, Type l, Type r, Expression lexpr, Expression rexpr, bool check_user_conv)
                {
                        if (IsOfType (ec, l, r, TypeManager.double_type, check_user_conv)){
                                //
@@ -2074,9 +1609,9 @@ namespace Mono.CSharp {
                                                        long ll = ((LongConstant) right).Value;
 
                                                        if (ll >= 0)
-                                                               right = new ULongConstant ((ulong) ll);
+                                                               right = new ULongConstant ((ulong) ll, right.Location);
                                                } else {
-                                                       e = Convert.ImplicitNumericConversion (ec, right, l, loc);
+                                                       e = Convert.ImplicitNumericConversion (ec, right, l);
                                                        if (e != null)
                                                                right = e;
                                                }
@@ -2091,9 +1626,9 @@ namespace Mono.CSharp {
                                                long ll = ((LongConstant) left).Value;
                                                
                                                if (ll > 0)
-                                                       left = new ULongConstant ((ulong) ll);
+                                                       left = new ULongConstant ((ulong) ll, right.Location);
                                        } else {
-                                               e = Convert.ImplicitNumericConversion (ec, left, r, loc);
+                                               e = Convert.ImplicitNumericConversion (ec, left, r);
                                                if (e != null)
                                                        left = e;
                                        }
@@ -2135,7 +1670,7 @@ namespace Mono.CSharp {
                                                int val = ic.Value;
                                                
                                                if (val >= 0){
-                                                       right = new UIntConstant ((uint) val);
+                                                       right = new UIntConstant ((uint) val, ic.Location);
                                                        type = l;
                                                        
                                                        return true;
@@ -2148,7 +1683,7 @@ namespace Mono.CSharp {
                                                int val = ic.Value;
                                                
                                                if (val >= 0){
-                                                       left = new UIntConstant ((uint) val);
+                                                       left = new UIntConstant ((uint) val, ic.Location);
                                                        type = r;
                                                        return true;
                                                }
@@ -2183,6 +1718,12 @@ namespace Mono.CSharp {
                                left = ForceConversion (ec, left, TypeManager.int32_type);
                                right = ForceConversion (ec, right, TypeManager.int32_type);
 
+                               bool strConv =
+                                       Convert.ImplicitConversionExists (ec, lexpr, TypeManager.string_type) &&
+                                       Convert.ImplicitConversionExists (ec, rexpr, TypeManager.string_type);
+                               if (strConv && left != null && right != null)
+                                       Error_OperatorAmbiguous (loc, oper, l, r);
+
                                type = TypeManager.int32_type;
                        }
 
@@ -2191,15 +1732,18 @@ namespace Mono.CSharp {
 
                static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
                {
-                       Report.Error (19, loc,
-                              "Operator " + name + " cannot be applied to operands of type `" +
-                              TypeManager.CSharpName (l) + "' and `" +
-                              TypeManager.CSharpName (r) + "'");
+                       Error_OperatorCannotBeApplied (loc, name, TypeManager.CSharpName (l), TypeManager.CSharpName (r));
+               }
+
+               public static void Error_OperatorCannotBeApplied (Location loc, string name, string left, string right)
+               {
+                       Report.Error (19, loc, "Operator `{0}' cannot be applied to operands of type `{1}' and `{2}'",
+                               name, left, right);
                }
                
                void Error_OperatorCannotBeApplied ()
                {
-                       Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
+                       Error_OperatorCannotBeApplied (Location, OperName (oper), left.GetSignatureForError (), right.GetSignatureForError ());
                }
 
                static bool is_unsigned (Type t)
@@ -2258,10 +1802,10 @@ namespace Mono.CSharp {
                                type = e.Type;
 
                                if (type == TypeManager.int32_type || type == TypeManager.uint32_type){
-                                       right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (31), loc);
+                                       right = new Binary (Binary.Operator.BitwiseAnd, right, new IntConstant (31, loc));
                                        right = right.DoResolve (ec);
                                } else {
-                                       right = new Binary (Binary.Operator.BitwiseAnd, right, new IntLiteral (63), loc);
+                                       right = new Binary (Binary.Operator.BitwiseAnd, right, new IntConstant (63, loc));
                                        right = right.DoResolve (ec);
                                }
 
@@ -2271,29 +1815,36 @@ namespace Mono.CSharp {
                        return null;
                }
 
+               //
+               // This is used to check if a test 'x == null' can be optimized to a reference equals,
+               // i.e., not invoke op_Equality.
+               //
+               static bool EqualsNullIsReferenceEquals (Type t)
+               {
+                       return t == TypeManager.object_type || t == TypeManager.string_type ||
+                               t == TypeManager.delegate_type || t.IsSubclassOf (TypeManager.delegate_type);
+               }
+
+               static void Warning_UnintendedReferenceComparison (Location loc, string side, Type type)
+               {
+                       Report.Warning ((side == "left" ? 252 : 253), 2, loc,
+                               "Possible unintended reference comparison; to get a value comparison, " +
+                               "cast the {0} hand side to type `{1}'.", side, TypeManager.CSharpName (type));
+               }
+
                Expression ResolveOperator (EmitContext ec)
                {
                        Type l = left.Type;
                        Type r = right.Type;
 
-                       //
-                       // Special cases: string or type parameter comapred to null
-                       //
                        if (oper == Operator.Equality || oper == Operator.Inequality){
-                               if ((!TypeManager.IsValueType (l) && r == TypeManager.null_type) ||
-                                   (!TypeManager.IsValueType (r) && l == TypeManager.null_type)) {
-                                       Type = TypeManager.bool_type;
-                                       
-                                       return this;
-                               }
-
                                if (l.IsGenericParameter && (right is NullLiteral)) {
                                        if (l.BaseType == TypeManager.value_type) {
                                                Error_OperatorCannotBeApplied ();
                                                return null;
                                        }
 
-                                       left = new BoxedCast (left);
+                                       left = new BoxedCast (left, TypeManager.object_type);
                                        Type = TypeManager.bool_type;
                                        return this;
                                }
@@ -2304,11 +1855,21 @@ namespace Mono.CSharp {
                                                return null;
                                        }
 
-                                       right = new BoxedCast (right);
+                                       right = new BoxedCast (right, TypeManager.object_type);
                                        Type = TypeManager.bool_type;
                                        return this;
                                }
-                               
+
+                               //
+                               // Optimize out call to op_Equality in a few cases.
+                               //
+                               if ((l == TypeManager.null_type && EqualsNullIsReferenceEquals (r)) ||
+                                   (r == TypeManager.null_type && EqualsNullIsReferenceEquals (l))) {
+                                       Type = TypeManager.bool_type;
+                                       
+                                       return this;
+                               }
+
                                // IntPtr equality
                                if (l == TypeManager.intptr_type && r == TypeManager.intptr_type) {
                                        Type = TypeManager.bool_type;
@@ -2321,22 +1882,21 @@ namespace Mono.CSharp {
                        // Do not perform operator overload resolution when both sides are
                        // built-in types
                        //
-                       if (!(TypeManager.IsCLRType (l) && TypeManager.IsCLRType (r))){
+                       Expression left_operators = null, right_operators = null;
+                       if (!(TypeManager.IsPrimitiveType (l) && TypeManager.IsPrimitiveType (r))){
                                //
                                // Step 1: Perform Operator Overload location
                                //
-                               Expression left_expr, right_expr;
-                               
                                string op = oper_names [(int) oper];
                                
                                MethodGroupExpr union;
-                               left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
+                               left_operators = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
                                if (r != l){
-                                       right_expr = MemberLookup (
+                                       right_operators = MemberLookup (
                                                ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
-                                       union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
+                                       union = Invocation.MakeUnionSet (left_operators, right_operators, loc);
                                } else
-                                       union = (MethodGroupExpr) left_expr;
+                                       union = (MethodGroupExpr) left_operators;
                                
                                if (union != null) {
                                        ArrayList args = new ArrayList (2);
@@ -2364,7 +1924,7 @@ namespace Mono.CSharp {
                                
                                // Simple constant folding
                                if (left is StringConstant && right is StringConstant)
-                                       return new StringConstant (((StringConstant) left).Value + ((StringConstant) right).Value);
+                                       return new StringConstant (((StringConstant) left).Value + ((StringConstant) right).Value, left.Location);
 
                                if (l == TypeManager.string_type || r == TypeManager.string_type) {
 
@@ -2418,13 +1978,38 @@ namespace Mono.CSharp {
                                        return this;
                                }
 
-                               bool left_is_null = left is NullLiteral;
-                               bool right_is_null = right is NullLiteral;
-                               if (left_is_null || right_is_null) {
-                                       if (oper == Operator.Equality)
-                                               return new BoolLiteral (left_is_null == right_is_null);
-                                       else
-                                               return new BoolLiteral (left_is_null != right_is_null);
+                               if (l.IsPointer || r.IsPointer) {
+                                       if (l.IsPointer && r.IsPointer) {
+                                               type = TypeManager.bool_type;
+                                               return this;
+                                       }
+
+                                       if (l.IsPointer && r == TypeManager.null_type) {
+                                               right = new EmptyCast (NullPointer.Null, l);
+                                               type = TypeManager.bool_type;
+                                               return this;
+                                       }
+
+                                       if (r.IsPointer && l == TypeManager.null_type) {
+                                               left = new EmptyCast (NullPointer.Null, r);
+                                               type = TypeManager.bool_type;
+                                               return this;
+                                       }
+                               }
+
+                               if (l.IsGenericParameter && r.IsGenericParameter) {
+                                       GenericConstraints l_gc, r_gc;
+
+                                       l_gc = TypeManager.GetTypeParameterConstraints (l);
+                                       r_gc = TypeManager.GetTypeParameterConstraints (r);
+
+                                       if ((l_gc == null) || (r_gc == null) ||
+                                           !(l_gc.HasReferenceTypeConstraint || l_gc.HasClassConstraint) ||
+                                           !(r_gc.HasReferenceTypeConstraint || r_gc.HasClassConstraint)) {
+                                               Error_OperatorCannotBeApplied ();
+                                               return null;
+                                       }
+
                                }
 
                                //
@@ -2434,26 +2019,47 @@ namespace Mono.CSharp {
                                // For this to be used, both arguments have to be reference-types.
                                // Read the rationale on the spec (14.9.6)
                                //
-                               // Also, if at compile time we know that the classes do not inherit
-                               // one from the other, then we catch the error there.
-                               //
                                if (!(l.IsValueType || r.IsValueType)){
                                        type = TypeManager.bool_type;
 
                                        if (l == r)
                                                return this;
                                        
-                                       if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
-                                               return this;
-
                                        //
                                        // Also, a standard conversion must exist from either one
                                        //
-                                       if (!(Convert.ImplicitStandardConversionExists (ec, left, r) ||
-                                             Convert.ImplicitStandardConversionExists (ec, right, l))){
+                                       bool left_to_right =
+                                               Convert.ImplicitStandardConversionExists (ec, left, r);
+                                       bool right_to_left = !left_to_right &&
+                                               Convert.ImplicitStandardConversionExists (ec, right, l);
+
+                                       if (!left_to_right && !right_to_left) {
                                                Error_OperatorCannotBeApplied ();
                                                return null;
                                        }
+
+                                       if (left_to_right && left_operators != null &&
+                                           RootContext.WarningLevel >= 2) {
+                                               ArrayList args = new ArrayList (2);
+                                               args.Add (new Argument (left, Argument.AType.Expression));
+                                               args.Add (new Argument (left, Argument.AType.Expression));
+                                               MethodBase method = Invocation.OverloadResolve (
+                                                       ec, (MethodGroupExpr) left_operators, args, true, Location.Null);
+                                               if (method != null)
+                                                       Warning_UnintendedReferenceComparison (loc, "right", l);
+                                       }
+
+                                       if (right_to_left && right_operators != null &&
+                                           RootContext.WarningLevel >= 2) {
+                                               ArrayList args = new ArrayList (2);
+                                               args.Add (new Argument (right, Argument.AType.Expression));
+                                               args.Add (new Argument (right, Argument.AType.Expression));
+                                               MethodBase method = Invocation.OverloadResolve (
+                                                       ec, (MethodGroupExpr) right_operators, args, true, Location.Null);
+                                               if (method != null)
+                                                       Warning_UnintendedReferenceComparison (loc, "left", r);
+                                       }
+
                                        //
                                        // We are going to have to convert to an object to compare
                                        //
@@ -2634,6 +2240,10 @@ namespace Mono.CSharp {
                                if (oper == Operator.BitwiseAnd ||
                                    oper == Operator.BitwiseOr ||
                                    oper == Operator.ExclusiveOr){
+                                       if (left.Type != right.Type){
+                                               Error_OperatorCannotBeApplied ();
+                                               return null;
+                                       }
                                        type = l;
                                        return this;
                                }
@@ -2678,8 +2288,7 @@ namespace Mono.CSharp {
                        // Pointer comparison
                        //
                        if (l.IsPointer && r.IsPointer){
-                               if (oper == Operator.Equality || oper == Operator.Inequality ||
-                                   oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
+                               if (oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
                                    oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
                                        type = TypeManager.bool_type;
                                        return this;
@@ -2690,7 +2299,7 @@ namespace Mono.CSharp {
                        // This will leave left or right set to null if there is an error
                        //
                        bool check_user_conv = is_user_defined (l) && is_user_defined (r);
-                       DoNumericPromotions (ec, l, r, check_user_conv);
+                       DoNumericPromotions (ec, l, r, left, right, check_user_conv);
                        if (left == null || right == null){
                                Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
                                return null;
@@ -2735,6 +2344,43 @@ namespace Mono.CSharp {
                        return this;
                }
 
+               Constant EnumLiftUp (EmitContext ec, Constant left, Constant right)
+               {
+                       switch (oper) {
+                               case Operator.BitwiseOr:
+                               case Operator.BitwiseAnd:
+                               case Operator.ExclusiveOr:
+                               case Operator.Equality:
+                               case Operator.Inequality:
+                               case Operator.LessThan:
+                               case Operator.LessThanOrEqual:
+                               case Operator.GreaterThan:
+                               case Operator.GreaterThanOrEqual:
+                                       if (left is EnumConstant)
+                                               return left;
+
+                                       if (left.IsZeroInteger)
+                                               return new EnumConstant (left, right.Type);
+
+                                       break;
+
+                               case Operator.Addition:
+                               case Operator.Subtraction:
+                                       return left;
+
+                               case Operator.Multiply:
+                               case Operator.Division:
+                               case Operator.Modulus:
+                               case Operator.LeftShift:
+                               case Operator.RightShift:
+                                       if (right is EnumConstant || left is EnumConstant)
+                                               break;
+                                       return left;
+                       }
+                       Error_OperatorCannotBeApplied (loc, Binary.OperName (oper), left.Type, right.Type);
+                       return null;
+               }
+
                public override Expression DoResolve (EmitContext ec)
                {
                        if ((oper == Operator.Subtraction) && (left is ParenthesizedExpression)) {
@@ -2744,7 +2390,7 @@ namespace Mono.CSharp {
                                        return null;
 
                                if (left.eclass == ExprClass.Type) {
-                                       Error (75, "Casting a negative value needs to have the value in parentheses.");
+                                       Report.Error (75, loc, "To cast a negative value, you must enclose the value in parentheses");
                                        return null;
                                }
                        } else
@@ -2768,21 +2414,154 @@ namespace Mono.CSharp {
                                return null;
 
                        eclass = ExprClass.Value;
-
                        Constant rc = right as Constant;
-                       if (rc != null & lc != null){
+
+                       if (lc != null && rc != null && (TypeManager.IsEnumType (left.Type) || TypeManager.IsEnumType (right.Type))) {
+                               left = lc = EnumLiftUp (ec, lc, rc);
+                               if (lc == null)
+                                       return null;
+
+                               right = rc = EnumLiftUp (ec, rc, lc);
+                               if (rc == null)
+                                       return null;
+                       }
+
+                       if (oper == Operator.BitwiseAnd) {
+                               if (rc != null && rc.IsZeroInteger) {
+                                       return lc is EnumConstant ?
+                                               new EnumConstant (rc, lc.Type):
+                                               rc;
+                               }
+
+                               if (lc != null && lc.IsZeroInteger) {
+                                       return rc is EnumConstant ?
+                                               new EnumConstant (lc, rc.Type):
+                                               lc;
+                               }
+                       }
+                       else if (oper == Operator.BitwiseOr) {
+                               if (lc is EnumConstant &&
+                                   rc != null && rc.IsZeroInteger)
+                                       return lc;
+                               if (rc is EnumConstant &&
+                                   lc != null && lc.IsZeroInteger)
+                                       return rc;
+                       }
+
+                       if (rc != null && lc != null){
+                               int prev_e = Report.Errors;
                                Expression e = ConstantFold.BinaryFold (
                                        ec, oper, lc, rc, loc);
-                                       if (e != null)
-                                               return e;
+                               if (e != null || Report.Errors != prev_e)
+                                       return e;
                        }
 
                        if (TypeManager.IsNullableType (left.Type) || TypeManager.IsNullableType (right.Type))
                                return new Nullable.LiftedBinaryOperator (oper, left, right, loc).Resolve (ec);
 
+                       // Check CS0652 warning here (before resolving operator).
+                       if (oper == Operator.Equality ||
+                           oper == Operator.Inequality ||
+                           oper == Operator.LessThanOrEqual ||
+                           oper == Operator.LessThan ||
+                           oper == Operator.GreaterThanOrEqual ||
+                           oper == Operator.GreaterThan){
+                               CheckUselessComparison (left as Constant, right.Type);
+                               CheckUselessComparison (right as Constant, left.Type);
+                       }
+
                        return ResolveOperator (ec);
                }
 
+               private void CheckUselessComparison (Constant c, Type type)
+               {
+                       if (c == null || !IsTypeIntegral (type)
+                               || c is StringConstant
+                               || c is BoolConstant
+                               || c is CharConstant
+                               || c is FloatConstant
+                               || c is DoubleConstant
+                               || c is DecimalConstant
+                               )
+                               return;
+
+                       long value = 0;
+
+                       if (c is ULongConstant) {
+                               ulong uvalue = ((ULongConstant) c).Value;
+                               if (uvalue > long.MaxValue) {
+                                       if (type == TypeManager.byte_type ||
+                                           type == TypeManager.sbyte_type ||
+                                           type == TypeManager.short_type ||
+                                           type == TypeManager.ushort_type ||
+                                           type == TypeManager.int32_type ||
+                                           type == TypeManager.uint32_type ||
+                                           type == TypeManager.int64_type)
+                                               WarnUselessComparison (type);
+                                       return;
+                               }
+                               value = (long) uvalue;
+                       }
+                       else if (c is ByteConstant)
+                               value = ((ByteConstant) c).Value;
+                       else if (c is SByteConstant)
+                               value = ((SByteConstant) c).Value;
+                       else if (c is ShortConstant)
+                               value = ((ShortConstant) c).Value;
+                       else if (c is UShortConstant)
+                               value = ((UShortConstant) c).Value;
+                       else if (c is IntConstant)
+                               value = ((IntConstant) c).Value;
+                       else if (c is UIntConstant)
+                               value = ((UIntConstant) c).Value;
+                       else if (c is LongConstant)
+                               value = ((LongConstant) c).Value;
+
+                       if (value != 0) {
+                               if (IsValueOutOfRange (value, type))
+                                       WarnUselessComparison (type);
+                               return;
+                       }
+               }
+
+               private bool IsValueOutOfRange (long value, Type type)
+               {
+                       if (IsTypeUnsigned (type) && value < 0)
+                               return true;
+                       return type == TypeManager.sbyte_type && (value >= 0x80 || value < -0x80) ||
+                               type == TypeManager.byte_type && value >= 0x100 ||
+                               type == TypeManager.short_type && (value >= 0x8000 || value < -0x8000) ||
+                               type == TypeManager.ushort_type && value >= 0x10000 ||
+                               type == TypeManager.int32_type && (value >= 0x80000000 || value < -0x80000000) ||
+                               type == TypeManager.uint32_type && value >= 0x100000000;
+               }
+
+               private static bool IsTypeIntegral (Type type)
+               {
+                       return type == TypeManager.uint64_type ||
+                               type == TypeManager.int64_type ||
+                               type == TypeManager.uint32_type ||
+                               type == TypeManager.int32_type ||
+                               type == TypeManager.ushort_type ||
+                               type == TypeManager.short_type ||
+                               type == TypeManager.sbyte_type ||
+                               type == TypeManager.byte_type;
+               }
+
+               private static bool IsTypeUnsigned (Type type)
+               {
+                       return type == TypeManager.uint64_type ||
+                               type == TypeManager.uint32_type ||
+                               type == TypeManager.ushort_type ||
+                               type == TypeManager.byte_type;
+               }
+
+               private void WarnUselessComparison (Type type)
+               {
+                       Report.Warning (652, 2, loc, "Comparison to integral constant is useless; the constant is outside the range of type `{0}'",
+                               TypeManager.CSharpName (type));
+               }
+
                /// <remarks>
                ///   EmitBranchable is called from Statement.EmitBoolExpression in the
                ///   context of a conditional bool expression.  This function will return
@@ -3196,7 +2975,7 @@ namespace Mono.CSharp {
                        if (operand is StringConstant && operands.Count != 0) {
                                StringConstant last_operand = operands [operands.Count - 1] as StringConstant;
                                if (last_operand != null) {
-                                       operands [operands.Count - 1] = new StringConstant (last_operand.Value + ((StringConstant) operand).Value);
+                                       operands [operands.Count - 1] = new StringConstant (last_operand.Value + ((StringConstant) operand).Value, last_operand.Location);
                                        return;
                                }
                        }
@@ -3353,7 +3132,7 @@ namespace Mono.CSharp {
 
                protected void Error19 ()
                {
-                       Binary.Error_OperatorCannotBeApplied (loc, is_and ? "&&" : "||", type, type);
+                       Binary.Error_OperatorCannotBeApplied (loc, is_and ? "&&" : "||", left.GetSignatureForError (), right.GetSignatureForError ());
                }
 
                protected void Error218 ()
@@ -3390,7 +3169,7 @@ namespace Mono.CSharp {
                        }
 
                        if (method.ReturnType != type) {
-                               Report.Error (217, loc, "In order to be applicable as a short circuit operator a user-defined logical operator ('{0}') " +
+                               Report.Error (217, loc, "In order to be applicable as a short circuit operator a user-defined logical operator `{0}' " +
                                                "must have the same return type as the type of its 2 parameters", TypeManager.CSharpSignature (method));
                                return null;
                        }
@@ -3491,7 +3270,7 @@ namespace Mono.CSharp {
 
                                Constant right_const = right as Constant;
                                if (right_const != null && size != 0) {
-                                       Expression ex = ConstantFold.BinaryFold (ec, Binary.Operator.Multiply, new IntConstant (size), right_const, loc);
+                                       Expression ex = ConstantFold.BinaryFold (ec, Binary.Operator.Multiply, new IntConstant (size, right.Location), right_const, loc);
                                        if (ex == null)
                                                return;
                                        ex.Emit (ec);
@@ -3527,12 +3306,12 @@ namespace Mono.CSharp {
        public class Conditional : Expression {
                Expression expr, trueExpr, falseExpr;
                
-               public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
+               public Conditional (Expression expr, Expression trueExpr, Expression falseExpr)
                {
                        this.expr = expr;
                        this.trueExpr = trueExpr;
                        this.falseExpr = falseExpr;
-                       this.loc = l;
+                       this.loc = expr.Location;
                }
 
                public Expression Expr {
@@ -3571,6 +3350,11 @@ namespace Mono.CSharp {
                                        return null;
                        }
                        
+                       Assign ass = expr as Assign;
+                       if (ass != null && ass.Source is Constant) {
+                               Report.Warning (665, 3, loc, "Assignment in conditional expression is always constant; did you mean to use == instead of = ?");
+                       }
+
                        trueExpr = trueExpr.Resolve (ec);
                        falseExpr = falseExpr.Resolve (ec);
 
@@ -3608,10 +3392,8 @@ namespace Mono.CSharp {
                                        type = true_type;
                                        falseExpr = conv;
                                } else {
-                                       Error (173, "The type of the conditional expression can " +
-                                              "not be computed because there is no implicit conversion" +
-                                              " from `" + TypeManager.CSharpName (trueExpr.Type) + "'" +
-                                              " and `" + TypeManager.CSharpName (falseExpr.Type) + "'");
+                                       Report.Error (173, loc, "Type of conditional expression cannot be determined because there is no implicit conversion between `{0}' and `{1}'",
+                                               trueExpr.GetSignatureForError (), falseExpr.GetSignatureForError ());
                                        return null;
                                }
                        }
@@ -3686,6 +3468,12 @@ namespace Mono.CSharp {
                        }
                }
 
+               public bool VerifyAssigned (EmitContext ec)
+               {
+                       VariableInfo variable_info = local_info.VariableInfo;
+                       return variable_info == null || variable_info.IsAssigned (ec, loc);
+               }
+
                protected Expression DoResolveBase (EmitContext ec, Expression lvalue_right_side)
                {
                        if (local_info == null) {
@@ -3703,13 +3491,18 @@ namespace Mono.CSharp {
                        VariableInfo variable_info = local_info.VariableInfo;
                        if (lvalue_right_side != null){
                                if (is_readonly){
-                                       Error (1604, "cannot assign to `" + Name + "' because it is readonly");
+                                       if (lvalue_right_side is LocalVariableReference || lvalue_right_side == EmptyExpression.Null)
+                                               Report.Error (1657, loc, "Cannot pass `{0}' as a ref or out argument because it is a `{1}'",
+                                                       Name, local_info.GetReadOnlyContext ());
+                                       else
+                                               Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
+                                                       Name, local_info.GetReadOnlyContext ());
                                        return null;
                                }
-                               
+
                                if (variable_info != null)
                                        variable_info.SetAssigned (ec);
-               }
+                       }
                
                        Expression e = Block.GetConstantExpression (Name);
                        if (e != null) {
@@ -3718,7 +3511,7 @@ namespace Mono.CSharp {
                                return e.Resolve (ec);
                        }
 
-                       if ((variable_info != null) && !variable_info.IsAssigned (ec, loc))
+                       if (!VerifyAssigned (ec))
                                return null;
 
                        if (lvalue_right_side == null)
@@ -3729,7 +3522,9 @@ namespace Mono.CSharp {
                                // If we are referencing a variable from the external block
                                // flag it for capturing
                                //
-                               if (local_info.Block.Toplevel != ec.CurrentBlock.Toplevel){
+                               if ((local_info.Block.Toplevel != ec.CurrentBlock.Toplevel) ||
+                                   ec.CurrentAnonymousMethod.IsIterator)
+                               {
                                        if (local_info.AddressTaken){
                                                AnonymousMethod.Error_AddressOfCapturedVar (local_info.Name, loc);
                                                return null;
@@ -3748,16 +3543,13 @@ namespace Mono.CSharp {
 
                override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
                {
-                       Expression ret = DoResolveBase (ec, right_side);
-                       if (ret != null)
-                               CheckObsoleteAttribute (ret.Type);
-
-                       return ret;
+                       return DoResolveBase (ec, right_side);
                }
 
-               public bool VerifyFixed (bool is_expression)
+               public bool VerifyFixed ()
                {
-                       return !is_expression || local_info.IsFixed;
+                       // A local Variable is always fixed.
+                       return true;
                }
 
                public override int GetHashCode()
@@ -3782,7 +3574,7 @@ namespace Mono.CSharp {
                                //
                                // A local variable on the local CLR stack
                                //
-                       ig.Emit (OpCodes.Ldloc, local_info.LocalBuilder);
+                               ig.Emit (OpCodes.Ldloc, local_info.LocalBuilder);
                        } else {
                                //
                                // A local variable captured by anonymous methods.
@@ -3817,10 +3609,10 @@ namespace Mono.CSharp {
                                //
                                if (local_info.LocalBuilder == null)
                                        throw new Exception ("This should not happen: both Field and Local are null");
-                               
-                       source.Emit (ec);
-                       if (leave_copy)
-                               ec.ig.Emit (OpCodes.Dup);
+
+                               source.Emit (ec);
+                               if (leave_copy)
+                                       ec.ig.Emit (OpCodes.Dup);
                                ig.Emit (OpCodes.Stloc, local_info.LocalBuilder);
                        } else {
                                //
@@ -3903,13 +3695,18 @@ namespace Mono.CSharp {
                        eclass = ExprClass.Variable;
                }
 
+               public ParameterReference (InternalParameters pars, Block block, int idx, Location loc)
+                       : this (pars.Parameters, block, idx, pars.ParameterName (idx), loc)
+               { }
+
                public VariableInfo VariableInfo {
                        get { return vi; }
                }
 
-               public bool VerifyFixed (bool is_expression)
+               public bool VerifyFixed ()
                {
-                       return !is_expression || TypeManager.IsValueType (type);
+                       // A parameter is fixed if it's a value parameter (i.e., no modifier like out, ref, param).
+                       return mod == Parameter.Modifier.NONE;
                }
 
                public bool IsAssigned (EmitContext ec, Location loc)
@@ -3918,7 +3715,7 @@ namespace Mono.CSharp {
                                return true;
 
                        Report.Error (269, loc,
-                                     "Use of unassigned out parameter '{0}'", name);
+                                     "Use of unassigned out parameter `{0}'", name);
                        return false;
                }
 
@@ -3956,17 +3753,17 @@ namespace Mono.CSharp {
 
                        if (ec.CurrentAnonymousMethod != null){
                                if (is_ref){
-                                       Report.Error (1628, Location,
-                                                     "Can not reference a ref or out parameter in an anonymous method");
+                                       Report.Error (1628, Location, "Cannot use ref or out parameter `{0}' inside an anonymous method block",
+                                               name);
                                        return;
                                }
-                               
+
                                //
                                // If we are referencing the parameter from the external block
                                // flag it for capturing
                                //
                                //Console.WriteLine ("Is parameter `{0}' local? {1}", name, block.IsLocalParameter (name));
-                               if (!block.IsLocalParameter (name)){
+                               if (!block.Toplevel.IsLocalParameter (name)){
                                        ec.CaptureParameter (name, type, idx);
                                }
                        }
@@ -4002,12 +3799,9 @@ namespace Mono.CSharp {
                {
                        DoResolveBase (ec);
 
-                       if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
+                       if (is_out && ec.DoFlowAnalysis && (!ec.OmitStructFlowAnalysis || !vi.TypeInfo.IsStruct) && !IsAssigned (ec, loc))
                                return null;
 
-                       if (ec.RemapToProxy)
-                               return ec.RemapParameter (idx);
-                       
                        return this;
                }
 
@@ -4017,9 +3811,6 @@ namespace Mono.CSharp {
 
                        SetAssigned (ec);
 
-                       if (ec.RemapToProxy)
-                               return ec.RemapParameterLValue (idx, right_side);
-                       
                        return this;
                }
 
@@ -4051,7 +3842,6 @@ namespace Mono.CSharp {
                        if (!ec.MethodIsStatic)
                                arg_idx++;
                        
-
                        EmitLdArg (ig, arg_idx);
 
                        //
@@ -4061,11 +3851,6 @@ namespace Mono.CSharp {
                
                public override void Emit (EmitContext ec)
                {
-                       if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
-                               ec.EmitParameter (name);
-                               return;
-                       }
-                       
                        Emit (ec, false);
                }
                
@@ -4074,6 +3859,14 @@ namespace Mono.CSharp {
                        ILGenerator ig = ec.ig;
                        int arg_idx = idx;
 
+                       if (ec.HaveCaptureInfo && ec.IsParameterCaptured (name)){
+                               if (leave_copy)
+                                       throw new InternalErrorException ();
+
+                               ec.EmitParameter (name);
+                               return;
+                       }
+
                        if (!ec.MethodIsStatic)
                                arg_idx++;
 
@@ -4203,17 +3996,19 @@ namespace Mono.CSharp {
                        }
                }
 
-               public Parameter.Modifier GetParameterModifier ()
+               public Parameter.Modifier Modifier
                {
-                       switch (ArgType) {
-                       case AType.Out:
-                               return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
+                       get {
+                               switch (ArgType) {
+                                       case AType.Out:
+                                               return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
 
-                       case AType.Ref:
-                               return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
+                                       case AType.Ref:
+                                               return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
 
-                       default:
-                               return Parameter.Modifier.NONE;
+                                       default:
+                                               return Parameter.Modifier.NONE;
+                               }
                        }
                }
 
@@ -4244,66 +4039,42 @@ namespace Mono.CSharp {
                
                void Error_LValueRequired (Location loc)
                {
-                       Report.Error (1510, loc, "An lvalue is required as an argument to out or ref");
+                       Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
                }
 
                public bool Resolve (EmitContext ec, Location loc)
                {
+                       bool old_do_flow_analysis = ec.DoFlowAnalysis;
+                       ec.DoFlowAnalysis = true;
+
                        if (ArgType == AType.Ref) {
+                               ec.InRefOutArgumentResolving = true;
                                Expr = Expr.Resolve (ec);
-                               if (Expr == null)
+                               ec.InRefOutArgumentResolving = false;
+                               if (Expr == null) {
+                                       ec.DoFlowAnalysis = old_do_flow_analysis;
                                        return false;
-
-                               if (!ec.IsConstructor) {
-                                       FieldExpr fe = Expr as FieldExpr;
-                                       if (fe != null && fe.FieldInfo.IsInitOnly) {
-                                               if (fe.FieldInfo.IsStatic)
-                                                       Report.Error (199, loc, "A static readonly field cannot be passed ref or out (except in a static constructor)");
-                                               else
-                                                       Report.Error (192, loc, "A readonly field cannot be passed ref or out (except in a constructor)");
-                                               return false;
-                                       }
                                }
+
                                Expr = Expr.DoResolveLValue (ec, Expr);
                                if (Expr == null)
                                        Error_LValueRequired (loc);
                        } else if (ArgType == AType.Out) {
+                               ec.InRefOutArgumentResolving = true;
                                Expr = Expr.DoResolveLValue (ec, EmptyExpression.Null);
+                               ec.InRefOutArgumentResolving = false;
+
                                if (Expr == null)
                                        Error_LValueRequired (loc);
                        }
                        else
                                Expr = Expr.Resolve (ec);
 
+                       ec.DoFlowAnalysis = old_do_flow_analysis;
+
                        if (Expr == null)
                                return false;
 
-                       if (Expr is MemberExpr) {
-                               MemberExpr me = Expr as MemberExpr;
-
-                               //
-                               // This can happen with the following code:
-                               //
-                               //   class X {}
-                               //   class Y {
-                               //     public Y (X x) {}
-                               //   }
-                               //   class Z : Y {
-                               //     X X;
-                               //     public Z () : base (X) {}
-                               //   }
-                               //
-                               // SimpleNameResolve is conservative about flagging the X as
-                               // an error since it has identical name and type.  However,
-                               // because there's no MemberAccess, that is not really justified.
-                               // It is still simpler to fix it here, rather than in SimpleNameResolve.
-                               //
-                               if (me.IsInstance && me.InstanceExpression == null) {
-                                       SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
-                                       return false;
-                               }
-                       }
-
                        if (ArgType == AType.Expression)
                                return true;
                        else {
@@ -4318,8 +4089,9 @@ namespace Mono.CSharp {
                                        if (instance.GetType () != typeof (This)){
                                                if (fe.InstanceExpression.Type.IsSubclassOf (TypeManager.mbr_type)){
                                                        Report.SymbolRelatedToPreviousError (fe.InstanceExpression.Type);
-                                                       Report.Error (197, loc, "Cannot pass '{0}' as ref or out or take its address because it is a member of a marshal-by-reference class",
-                                                               fe.Name);
+                                                       Report.Warning (197, 1, loc,
+                                                               "Passing `{0}' as ref or out or taking its address may cause a runtime exception because it is a field of a marshal-by-reference class",
+                                                               fe.GetSignatureForError ());
                                                        return false;
                                                }
                                        }
@@ -4332,10 +4104,8 @@ namespace Mono.CSharp {
                                //
                                if (Expr.eclass == ExprClass.PropertyAccess ||
                                    Expr.eclass == ExprClass.IndexerAccess){
-                                       Report.Error (
-                                               206, loc,
-                                               "A property or indexer can not be passed as an out or ref " +
-                                               "parameter");
+                                       Report.Error (206, loc, "A property or indexer `{0}' may not be passed as an out or ref parameter",
+                                               Expr.GetSignatureForError ());
                                } else {
                                        Error_LValueRequired (loc);
                                }
@@ -4372,9 +4142,7 @@ namespace Mono.CSharp {
                                        if (Expr is IMemoryLocation)
                                                ((IMemoryLocation) Expr).AddressOf (ec, mode);
                                        else {
-                                               Report.Error (
-                                                       1510, Expr.Location,
-                                                       "An lvalue is required as an argument to out or ref");
+                                               Error_LValueRequired (Expr.Location);
                                                return;
                                        }
                                }
@@ -4399,11 +4167,11 @@ namespace Mono.CSharp {
                // FIXME: only allow expr to be a method invocation or a
                // delegate invocation (7.5.5)
                //
-               public Invocation (Expression expr, ArrayList arguments, Location l)
+               public Invocation (Expression expr, ArrayList arguments)
                {
                        this.expr = expr;
                        Arguments = arguments;
-                       loc = l;
+                       loc = expr.Location;
                }
 
                public Expression Expr {
@@ -4413,7 +4181,7 @@ namespace Mono.CSharp {
                }
 
                /// <summary>
-               ///   Determines "better conversion" as specified in 7.4.2.3
+               ///   Determines "better conversion" as specified in 14.4.2.3
                ///
                ///    Returns : p    if a->p is better,
                ///              q    if a->q is better,
@@ -4623,34 +4391,18 @@ namespace Mono.CSharp {
 
                public static string FullMethodDesc (MethodBase mb)
                {
-                       string ret_type = "";
-
-                        if (mb == null)
-                                return "";
-
-                       if (mb is MethodInfo)
-                               ret_type = TypeManager.CSharpName (((MethodInfo) mb).ReturnType);
-                       
-                       StringBuilder sb = new StringBuilder (ret_type);
-                       sb.Append (" ");
-                       sb.Append (mb.ReflectedType.ToString ());
-                       sb.Append (".");
-                       sb.Append (mb.Name);
-                       
-                       ParameterData pd = TypeManager.GetParameterData (mb);
-
-                       int count = pd.Count;
-                       sb.Append (" (");
-                       
-                       for (int i = count; i > 0; ) {
-                               i--;
+                       if (mb == null)
+                               return "";
 
-                               sb.Append (pd.ParameterDesc (count - i - 1));
-                               if (i != 0)
-                                       sb.Append (", ");
+                       StringBuilder sb;
+                       if (mb is MethodInfo) {
+                               sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
+                               sb.Append (" ");
                        }
-                       
-                       sb.Append (")");
+                       else
+                               sb = new StringBuilder ();
+
+                       sb.Append (TypeManager.CSharpSignature (mb));
                        return sb.ToString ();
                }
 
@@ -4764,7 +4516,7 @@ namespace Mono.CSharp {
 
                                Argument a = (Argument) arguments [i];
 
-                               Parameter.Modifier a_mod = a.GetParameterModifier () &
+                               Parameter.Modifier a_mod = a.Modifier & 
                                        (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
                                Parameter.Modifier p_mod = pd.ParameterModifier (i) &
                                        (unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF)));
@@ -4839,16 +4591,15 @@ namespace Mono.CSharp {
 
                                Argument a = (Argument) arguments [i];
 
-                               Parameter.Modifier a_mod = a.GetParameterModifier () &
+                               Parameter.Modifier a_mod = a.Modifier &
                                        unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
                                Parameter.Modifier p_mod = pd.ParameterModifier (i) &
                                        unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
 
-
                                if (a_mod == p_mod ||
                                    (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
                                        if (a_mod == Parameter.Modifier.NONE) {
-                                                if (!Convert.ImplicitConversionExists (ec,
+                                                if (!TypeManager.IsEqual (a.Type, pd.ParameterType (i)) && !Convert.ImplicitConversionExists (ec,
                                                                                        a.Expr,
                                                                                        pd.ParameterType (i)))
                                                        return false;
@@ -4916,27 +4667,27 @@ namespace Mono.CSharp {
                        if (Arguments != null)
                                arg_count = Arguments.Count;
   
-                        if ((me.Name == "Invoke") &&
-                           TypeManager.IsDelegateType (me.DeclaringType)) {
-                                Error_InvokeOnDelegate (loc);
-                                return null;
-                        }
+                       if ((me.Name == "Invoke") &&
+                               TypeManager.IsDelegateType (me.DeclaringType)) {
+                               Error_InvokeOnDelegate (loc);
+                               return null;
+                       }
 
                        MethodBase[] methods = me.Methods;
 
-                        //
-                        // First we construct the set of applicable methods
-                        //
+                       //
+                       // First we construct the set of applicable methods
+                       //
                        bool is_sorted = true;
                        for (int i = 0; i < methods.Length; i++){
-                                Type decl_type = methods [i].DeclaringType;
-
-                                //
-                                // If we have already found an applicable method
-                                // we eliminate all base types (Section 14.5.5.1)
-                                //
-                                if ((applicable_type != null) &&
-                                   IsAncestralType (decl_type, applicable_type))
+                               Type decl_type = methods [i].DeclaringType;
+
+                               //
+                               // If we have already found an applicable method
+                               // we eliminate all base types (Section 14.5.5.1)
+                               //
+                               if ((applicable_type != null) &&
+                                       IsAncestralType (decl_type, applicable_type))
                                        continue;
 
                                //
@@ -4946,9 +4697,7 @@ namespace Mono.CSharp {
                                // We avoid doing the 'applicable' test here, since it'll anyway be applied
                                // to the base virtual function, and IsOverride is much faster than IsApplicable.
                                //
-                               if (!me.IsBase &&
-                                   methods [i].IsVirtual &&
-                                   (methods [i].Attributes & MethodAttributes.NewSlot) == 0) {
+                               if (!me.IsBase && TypeManager.IsOverride (methods [i])) {
                                        if (candidate_overrides == null)
                                                candidate_overrides = new ArrayList ();
                                        candidate_overrides.Add (methods [i]);
@@ -4963,8 +4712,8 @@ namespace Mono.CSharp {
                                        ec, me, Arguments, arg_count, ref methods [i]);
 
                                if (!is_applicable &&
-                                   (IsParamsMethodApplicable (
-                                           ec, me, Arguments, arg_count, ref methods [i]))) {
+                                       (IsParamsMethodApplicable (
+                                       ec, me, Arguments, arg_count, ref methods [i]))) {
                                        MethodBase candidate = methods [i];
                                        if (candidate_to_form == null)
                                                candidate_to_form = new PtrHashtable ();
@@ -4994,6 +4743,7 @@ namespace Mono.CSharp {
                                // Okay so we have failed to find anything so we
                                // return by providing info about the closest match
                                //
+                               int errors = Report.Errors;
                                for (int i = 0; i < methods.Length; ++i) {
                                        MethodBase c = (MethodBase) methods [i];
                                        ParameterData pd = TypeManager.GetParameterData (c);
@@ -5005,11 +4755,17 @@ namespace Mono.CSharp {
                                                continue;
 
                                        VerifyArgumentsCompat (ec, Arguments, arg_count,
-                                                              c, false, null, may_fail, loc);
-                                        break;
+                                               c, false, null, may_fail, loc);
+
+                                       if (!may_fail && errors == Report.Errors)
+                                               throw new InternalErrorException (
+                                                       "VerifyArgumentsCompat and IsApplicable do not agree; " +
+                                                       "likely reason: ImplicitConversion and ImplicitConversionExists have gone out of sync");
+
+                                       break;
                                }
 
-                               if (!may_fail) {
+                               if (!may_fail && errors == Report.Errors) {
                                        string report_name = me.Name;
                                        if (report_name == ".ctor")
                                                report_name = me.DeclaringType.ToString ();
@@ -5032,11 +4788,9 @@ namespace Mono.CSharp {
                                                return null;
                                        }
 
-                                       Error_WrongNumArguments (
-                                               loc, report_name, arg_count);
-                                       return null;
+                                       Error_WrongNumArguments (loc, report_name, arg_count);
                                }
-
+                                
                                return null;
                        }
 
@@ -5112,12 +4866,11 @@ namespace Mono.CSharp {
                                        method_params = cand_params;
                                }
                        }
-
                        //
                        // Now check that there are no ambiguities i.e the selected method
                        // should be better than all the others
                        //
-                       bool ambiguous = false;
+                       MethodBase ambiguous = null;
                        for (int ix = 0; ix < candidate_top; ix++){
                                MethodBase candidate = (MethodBase) candidates [ix];
 
@@ -5130,13 +4883,14 @@ namespace Mono.CSharp {
                                                    candidate, cand_params,
                                                     loc)) {
                                        Report.SymbolRelatedToPreviousError (candidate);
-                                       ambiguous = true;
+                                       ambiguous = candidate;
                                }
                        }
 
-                       if (ambiguous) {
+                       if (ambiguous != null) {
                                Report.SymbolRelatedToPreviousError (method);
-                               Report.Error (121, loc, "Ambiguous call when selecting function due to implicit casts");                                        
+                               Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
+                                       TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (method));
                                return null;
                        }
 
@@ -5144,10 +4898,10 @@ namespace Mono.CSharp {
                        // If the method is a virtual function, pick an override closer to the LHS type.
                        //
                        if (!me.IsBase && method.IsVirtual) {
-                               if ((method.Attributes & MethodAttributes.NewSlot) != MethodAttributes.NewSlot)
+                               if (TypeManager.IsOverride (method))
                                        throw new InternalErrorException (
                                                "Should not happen.  An 'override' method took part in overload resolution: " + method);
-                                                                   
+
                                if (candidate_overrides != null)
                                        foreach (MethodBase candidate in candidate_overrides) {
                                                if (IsOverride (candidate, method))
@@ -5165,19 +4919,21 @@ namespace Mono.CSharp {
                                                     method_params, null, may_fail, loc))
                                return null;
 
+                       if (method != null) {
+                               MethodBase the_method = method;
+                               if (the_method.Mono_IsInflatedMethod)
+                                       the_method = the_method.GetGenericMethodDefinition ();
+                               IMethodData data = TypeManager.GetMethod (the_method);
+                               if (data != null)
+                                       data.SetMemberIsUsed ();
+                       }
                        return method;
                }
 
-               static void Error_WrongNumArguments (Location loc, String name, int arg_count)
+               public static void Error_WrongNumArguments (Location loc, String name, int arg_count)
                {
-                       if (name == "Finalize" && arg_count == 0) {
-                               Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
-                       }
-                       else {
-                               Report.Error (1501, loc,
-                                       "No overload for method `" + name + "' takes `" +
-                                       arg_count + "' arguments");
-                       }
+                       Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
+                               name, arg_count);
                }
 
                 static void Error_InvokeOnDelegate (Location loc)
@@ -5187,20 +4943,30 @@ namespace Mono.CSharp {
                 }
                         
                static void Error_InvalidArguments (Location loc, int idx, MethodBase method,
-                                                    Type delegate_type, string arg_sig, string par_desc)
+                                                    Type delegate_type, Argument a, ParameterData expected_par)
                {
                        if (delegate_type == null) 
-                               Report.Error (1502, loc,
-                                             "The best overloaded match for method '" +
-                                             FullMethodDesc (method) +
-                                             "' has some invalid arguments");
+                               Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
+                                             TypeManager.CSharpSignature (method));
                        else
-                               Report.Error (1594, loc,
-                                             "Delegate '" + delegate_type.ToString () +
-                                             "' has some invalid arguments.");
+                               Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
+                                       TypeManager.CSharpName (delegate_type));
+
+                       string par_desc = expected_par.ParameterDesc (idx);
+
+                       if (a.Modifier != expected_par.ParameterModifier (idx)) {
+                               if ((expected_par.ParameterModifier (idx) & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) == 0)
+                                       Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
+                                               idx + 1, Parameter.GetModifierSignature (a.Modifier));
+                               else
+                                       Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
+                                               idx + 1, Parameter.GetModifierSignature (expected_par.ParameterModifier (idx)));
+                               return;
+                       }
+
                        Report.Error (1503, loc,
-                                     String.Format ("Argument {0}: Cannot convert from '{1}' to '{2}'",
-                                                    idx, arg_sig, par_desc));
+                                     String.Format ("Argument {0}: Cannot convert from `{1}' to `{2}'",
+                                                    idx + 1, Argument.FullDesc (a), par_desc));
                }
                
                public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
@@ -5219,11 +4985,11 @@ namespace Mono.CSharp {
                                Parameter.Modifier pm = pd.ParameterModifier (j);
                                
                                if (pm == Parameter.Modifier.PARAMS){
-                                       if ((pm & ~Parameter.Modifier.PARAMS) != a.GetParameterModifier ()) {
+                                       if ((pm & ~Parameter.Modifier.PARAMS) != a.Modifier) {
                                                if (!may_fail)
                                                        Error_InvalidArguments (
                                                                loc, j, method, delegate_type,
-                                                               Argument.FullDesc (a), pd.ParameterDesc (j));
+                                                               a, pd);
                                                return false;
                                        }
 
@@ -5235,11 +5001,11 @@ namespace Mono.CSharp {
                                        //
                                        // Check modifiers
                                        //
-                                       if (pd.ParameterModifier (j) != a.GetParameterModifier ()){
+                                       if (pd.ParameterModifier (j) != a.Modifier){
                                                if (!may_fail)
                                                        Error_InvalidArguments (
                                                                loc, j, method, delegate_type,
-                                                               Argument.FullDesc (a), pd.ParameterDesc (j));
+                                                               a, pd);
                                                return false;
                                        }
                                }
@@ -5254,9 +5020,7 @@ namespace Mono.CSharp {
 
                                        if (conv == null) {
                                                if (!may_fail)
-                                                       Error_InvalidArguments (
-                                                               loc, j, method, delegate_type,
-                                                               Argument.FullDesc (a), pd.ParameterDesc (j));
+                                                       Error_InvalidArguments (loc, j, method, delegate_type, a, pd);
                                                return false;
                                        }
                                        
@@ -5274,7 +5038,7 @@ namespace Mono.CSharp {
                                        }
                                }
                                
-                               Parameter.Modifier a_mod = a.GetParameterModifier () &
+                               Parameter.Modifier a_mod = a.Modifier &
                                        unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
                                Parameter.Modifier p_mod = pd.ParameterModifier (j) &
                                        unchecked (~(Parameter.Modifier.OUT | Parameter.Modifier.REF));
@@ -5282,13 +5046,7 @@ namespace Mono.CSharp {
                                if (a_mod != p_mod &&
                                    pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
                                        if (!may_fail) {
-                                               Report.Error (1502, loc,
-                                                      "The best overloaded match for method '" + FullMethodDesc (method)+
-                                                      "' has some invalid arguments");
-                                               Report.Error (1503, loc,
-                                                      "Argument " + (j+1) +
-                                                      ": Cannot convert from '" + Argument.FullDesc (a) 
-                                                      + "' to '" + pd.ParameterDesc (j) + "'");
+                                               Invocation.Error_InvalidArguments (loc, j, method, null, a, pd);
                                        }
                                        
                                        return false;
@@ -5347,17 +5105,19 @@ namespace Mono.CSharp {
                        MethodInfo mi = method as MethodInfo;
                        if (mi != null) {
                                type = TypeManager.TypeToCoreType (mi.ReturnType);
-                               if (!mi.IsStatic && mg.InstanceExpression == null) {
-                                       SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
-                                       return null;
-                               }
-
                                Expression iexpr = mg.InstanceExpression;
-                               if (mi.IsStatic && (iexpr != null) && !(iexpr is This)) {
-                                       if (mg.IdenticalTypeName)
+                               if (mi.IsStatic) {
+                                       if (iexpr == null || 
+                                           iexpr is This || iexpr is EmptyExpression ||
+                                           mg.IdenticalTypeName) {
                                                mg.InstanceExpression = null;
-                                       else {
-                                               MemberExpr.error176 (loc, mi.Name);
+                                       } else {
+                                               MemberExpr.error176 (loc, TypeManager.CSharpSignature (mi));
+                                               return null;
+                                       }
+                               } else {
+                                       if (iexpr == null || iexpr is EmptyExpression) {
+                                               SimpleName.Error_ObjectRefRequired (ec, loc, TypeManager.CSharpSignature (mi));
                                                return null;
                                        }
                                }
@@ -5374,21 +5134,20 @@ namespace Mono.CSharp {
                        // Only base will allow this invocation to happen.
                        //
                        if (mg.IsBase && method.IsAbstract){
-                               Report.Error (205, loc, "Cannot call an abstract base member: " +
-                                             FullMethodDesc (method));
+                               Error_CannotCallAbstractBase (TypeManager.CSharpSignature (method));
                                return null;
                        }
 
-                       if (method.Name == "Finalize" && Arguments == null) {
-                               Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
+                       if (Arguments == null && method.Name == "Finalize") {
+                               if (mg.IsBase)
+                                       Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
+                               else
+                                       Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
                                return null;
                        }
-
-                       if ((method.Attributes & MethodAttributes.SpecialName) != 0){
-                               if (TypeManager.LookupDeclSpace (method.DeclaringType) != null || TypeManager.IsSpecialMethod (method)) {
-                                       Report.Error (571, loc, TypeManager.CSharpSignature (method) + ": can not call operator or accessor");
-                                       return null;
-                               }
+
+                       if ((method.Attributes & MethodAttributes.SpecialName) != 0 && IsSpecialMethodInvocation (method)) {
+                               return null;
                        }
                        
                        if (mg.InstanceExpression != null)
@@ -5398,6 +5157,32 @@ namespace Mono.CSharp {
                        return this;
                }
 
+               bool IsSpecialMethodInvocation (MethodBase method)
+               {
+                       IMethodData md = TypeManager.GetMethod (method);
+                       if (md != null) {
+                               if (!(md is AbstractPropertyEventMethod) && !(md is Operator))
+                                       return false;
+                       } else {
+                               if (!TypeManager.IsSpecialMethod (method))
+                                       return false;
+
+                               int args = TypeManager.GetParameterData (method).Count;
+                               if (method.Name.StartsWith ("get_") && args > 0)
+                                       return false;
+                               else if (method.Name.StartsWith ("set_") && args > 2)
+                                       return false;
+
+                               // TODO: check operators and events as well ?
+                       }
+
+                       Report.SymbolRelatedToPreviousError (method);
+                       Report.Error (571, loc, "`{0}': cannot explicitly call operator or accessor",
+                               TypeManager.CSharpSignature (method, true));
+       
+                       return true;
+               }
+
                // <summary>
                //   Emits the list of arguments as an array
                // </summary>
@@ -5448,33 +5233,12 @@ namespace Mono.CSharp {
                /// </summary>
                public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments, bool dup_args, LocalTemporary this_arg)
                {
-                       ParameterData pd;
-                       if (mb != null)
-                               pd = TypeManager.GetParameterData (mb);
-                       else
-                               pd = null;
-                       
+                       ParameterData pd = mb == null ? null : TypeManager.GetParameterData (mb);
+                       int top = arguments == null ? 0 : arguments.Count;
                        LocalTemporary [] temps = null;
                        
-                       if (dup_args)
-                               temps = new LocalTemporary [arguments.Count];
-
-                       //
-                       // If we are calling a params method with no arguments, special case it
-                       //
-                       if (arguments == null){
-                               if (pd != null && pd.Count > 0 &&
-                                   pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
-                                       ILGenerator ig = ec.ig;
-
-                                       IntConstant.EmitInt (ig, 0);
-                                       ig.Emit (OpCodes.Newarr, TypeManager.GetElementType (pd.ParameterType (0)));
-                               }
-
-                               return;
-                       }
-
-                       int top = arguments.Count;
+                       if (dup_args && top != 0)
+                               temps = new LocalTemporary [top];
 
                        for (int i = 0; i < top; i++){
                                Argument a = (Argument) arguments [i];
@@ -5628,7 +5392,12 @@ namespace Mono.CSharp {
                                return;
                        
                        if (!is_static){
-                               this_call = instance_expr == null;
+                               if (instance_expr == EmptyExpression.Null) {
+                                       SimpleName.Error_ObjectRefRequired (ec, loc, TypeManager.CSharpSignature (method));
+                                       return;
+                               }
+
+                               this_call = instance_expr is This;
                                if (decl_type.IsValueType || (!this_call && instance_expr.Type.IsValueType))
                                        struct_call = true;
 
@@ -5637,57 +5406,54 @@ namespace Mono.CSharp {
                                //
                                if (!omit_args) {
                                        Type t = null;
-                                       if (this_call) {
-                                               ig.Emit (OpCodes.Ldarg_0);
-                                               t = decl_type;
-                                       } else {
-                                               Type iexpr_type = instance_expr.Type;
+                                       Type iexpr_type = instance_expr.Type;
 
+                                       //
+                                       // Push the instance expression
+                                       //
+                                       if (TypeManager.IsValueType (iexpr_type)) {
                                                //
-                                               // Push the instance expression
-                                               //
-                                               if (TypeManager.IsValueType (iexpr_type)) {
+                                               // Special case: calls to a function declared in a 
+                                               // reference-type with a value-type argument need
+                                               // to have their value boxed.
+                                               if (decl_type.IsValueType ||
+                                                   iexpr_type.IsGenericParameter) {
                                                        //
-                                                       // Special case: calls to a function declared in a 
-                                                       // reference-type with a value-type argument need
-                                                       // to have their value boxed.
-                                                       if (decl_type.IsValueType ||
-                                                           iexpr_type.IsGenericParameter) {
-                                                               //
-                                                               // If the expression implements IMemoryLocation, then
-                                                               // we can optimize and use AddressOf on the
-                                                               // return.
-                                                               //
-                                                               // If not we have to use some temporary storage for
-                                                               // it.
-                                                               if (instance_expr is IMemoryLocation) {
-                                                                       ((IMemoryLocation)instance_expr).
-                                                                               AddressOf (ec, AddressOp.LoadStore);
-                                                               } else {
-                                                                       LocalTemporary temp = new LocalTemporary (ec, iexpr_type);
-                                                                       instance_expr.Emit (ec);
-                                                                       temp.Store (ec);
-                                                                       temp.AddressOf (ec, AddressOp.Load);
-                                                               }
-
-                                                               // avoid the overhead of doing this all the time.
-                                                               if (dup_args)
-                                                                       t = TypeManager.GetReferenceType (iexpr_type);
+                                                       // If the expression implements IMemoryLocation, then
+                                                       // we can optimize and use AddressOf on the
+                                                       // return.
+                                                       //
+                                                       // If not we have to use some temporary storage for
+                                                       // it.
+                                                       if (instance_expr is IMemoryLocation) {
+                                                               ((IMemoryLocation)instance_expr).
+                                                                       AddressOf (ec, AddressOp.LoadStore);
                                                        } else {
+                                                               LocalTemporary temp = new LocalTemporary (ec, iexpr_type);
                                                                instance_expr.Emit (ec);
-                                                               ig.Emit (OpCodes.Box, instance_expr.Type);
-                                                               t = TypeManager.object_type;
+                                                               temp.Store (ec);
+                                                               temp.AddressOf (ec, AddressOp.Load);
                                                        }
+
+                                                       // avoid the overhead of doing this all the time.
+                                                       if (dup_args)
+                                                               t = TypeManager.GetReferenceType (iexpr_type);
                                                } else {
                                                        instance_expr.Emit (ec);
-                                                       t = instance_expr.Type;
+                                                       ig.Emit (OpCodes.Box, instance_expr.Type);
+                                                       t = TypeManager.object_type;
                                                }
+                                       } else {
+                                               instance_expr.Emit (ec);
+                                               t = instance_expr.Type;
                                        }
 
                                        if (dup_args) {
-                                               this_arg = new LocalTemporary (ec, t);
                                                ig.Emit (OpCodes.Dup);
-                                               this_arg.Store (ec);
+                                               if (Arguments != null && Arguments.Count != 0) {
+                                                       this_arg = new LocalTemporary (ec, t);
+                                                       this_arg.Store (ec);
+                                               }
                                        }
                                }
                        }
@@ -5749,11 +5515,11 @@ namespace Mono.CSharp {
                Expression expr;
                Expression argument;
 
-               public InvocationOrCast (Expression expr, Expression argument, Location loc)
+               public InvocationOrCast (Expression expr, Expression argument)
                {
                        this.expr = expr;
                        this.argument = argument;
-                       this.loc = loc;
+                       this.loc = expr.Location;
                }
 
                public override Expression DoResolve (EmitContext ec)
@@ -5895,7 +5661,7 @@ namespace Mono.CSharp {
                        value_target = value;
                        value_target_set = true;
                        if (!(value_target is IMemoryLocation)){
-                               Error_UnexpectedKind ("variable", loc);
+                               Error_UnexpectedKind (null, "variable", loc);
                                return false;
                        }
                        return true;
@@ -5932,34 +5698,34 @@ namespace Mono.CSharp {
                /// <summary>
                /// Converts complex core type syntax like 'new int ()' to simple constant
                /// </summary>
-               Expression Constantify (Type t)
+               public static Constant Constantify (Type t)
                {
                        if (t == TypeManager.int32_type)
-                               return new IntConstant (0);
+                               return new IntConstant (0, Location.Null);
                        if (t == TypeManager.uint32_type)
-                               return new UIntConstant (0);
+                               return new UIntConstant (0, Location.Null);
                        if (t == TypeManager.int64_type)
-                               return new LongConstant (0);
+                               return new LongConstant (0, Location.Null);
                        if (t == TypeManager.uint64_type)
-                               return new ULongConstant (0);
+                               return new ULongConstant (0, Location.Null);
                        if (t == TypeManager.float_type)
-                               return new FloatConstant (0);
+                               return new FloatConstant (0, Location.Null);
                        if (t == TypeManager.double_type)
-                               return new DoubleConstant (0);
+                               return new DoubleConstant (0, Location.Null);
                        if (t == TypeManager.short_type)
-                               return new ShortConstant (0);
+                               return new ShortConstant (0, Location.Null);
                        if (t == TypeManager.ushort_type)
-                               return new UShortConstant (0);
+                               return new UShortConstant (0, Location.Null);
                        if (t == TypeManager.sbyte_type)
-                               return new SByteConstant (0);
+                               return new SByteConstant (0, Location.Null);
                        if (t == TypeManager.byte_type)
-                               return new ByteConstant (0);
+                               return new ByteConstant (0, Location.Null);
                        if (t == TypeManager.char_type)
-                               return new CharConstant ('\0');
+                               return new CharConstant ('\0', Location.Null);
                        if (t == TypeManager.bool_type)
-                               return new BoolConstant (false);
+                               return new BoolConstant (false, Location.Null);
                        if (t == TypeManager.decimal_type)
-                               return new DecimalConstant (0);
+                               return new DecimalConstant (0, Location.Null);
 
                        return null;
                }
@@ -5979,26 +5745,20 @@ namespace Mono.CSharp {
                                        return RequestedType;
                                return this;
                        }
-                       
+
                        TypeExpr texpr = RequestedType.ResolveAsTypeTerminal (ec);
                        if (texpr == null)
                                return null;
 
+                       type = texpr.ResolveType (ec);
+
                        if (Arguments == null) {
                                Expression c = Constantify (type);
                                if (c != null)
                                        return c;
                        }
-                       
-                       type = texpr.Type;
-                       if (type == null)
-                               return null;
-                       
-                       CheckObsoleteAttribute (type);
 
-                       bool IsDelegate = TypeManager.IsDelegateType (type);
-                       
-                       if (IsDelegate){
+                       if (TypeManager.IsDelegateType (type)) {
                                RequestedType = (new NewDelegate (type, Arguments, loc)).Resolve (ec);
                                if (RequestedType != null)
                                        if (!(RequestedType is DelegateCreation))
@@ -6007,7 +5767,9 @@ namespace Mono.CSharp {
                        }
 
                        if (type.IsGenericParameter) {
-                               if (!TypeManager.HasConstructorConstraint (type)) {
+                               GenericConstraints gc = TypeManager.GetTypeParameterConstraints (type);
+
+                               if ((gc == null) || (!gc.HasConstructorConstraint && !gc.IsValueType)) {
                                        Error (304, String.Format (
                                                       "Cannot create an instance of the " +
                                                       "variable type '{0}' because it " +
@@ -6029,13 +5791,15 @@ namespace Mono.CSharp {
                                return this;
                        }
 
-                       if (type.IsInterface || type.IsAbstract){
-                               Error (144, "It is not possible to create instances of interfaces or abstract classes");
+                       if (type.IsAbstract && type.IsSealed) {
+                               Report.SymbolRelatedToPreviousError (type);
+                               Report.Error (712, loc, "Cannot create an instance of the static class `{0}'", TypeManager.CSharpName (type));
                                return null;
                        }
 
-                       if (type.IsAbstract && type.IsSealed) {
-                               Report.Error (712, loc, "Cannot create an instance of the static class '{0}'", TypeManager.CSharpName (type));
+                       if (type.IsInterface || type.IsAbstract){
+                               Report.SymbolRelatedToPreviousError (type);
+                               Report.Error (144, loc, "Cannot create an instance of the abstract class or interface `{0}'", TypeManager.CSharpName (type));
                                return null;
                        }
 
@@ -6049,47 +5813,31 @@ namespace Mono.CSharp {
                        if (is_struct && Arguments == null)
                                return this;
 
-                       Expression ml;
-                       ml = MemberLookupFinal (ec, type, type, ".ctor",
-                                               // For member-lookup, treat 'new Foo (bar)' as call to 'foo.ctor (bar)', where 'foo' is of type 'Foo'.
-                                               MemberTypes.Constructor,
-                                               AllBindingFlags | BindingFlags.DeclaredOnly, loc);
+                       Expression ml = MemberLookupFinal (ec, type, type, ".ctor",
+                               MemberTypes.Constructor, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 
                        if (ml == null)
                                return null;
-                       
-                       if (! (ml is MethodGroupExpr)){
-                               if (!is_struct){
-                                       ml.Error_UnexpectedKind ("method group", loc);
-                                       return null;
-                               }
+
+                       MethodGroupExpr mg = ml as MethodGroupExpr;
+
+                       if (mg == null) {
+                               ml.Error_UnexpectedKind (ec, "method group", loc);
+                               return null;
                        }
 
-                       if (ml != null) {
-                               if (Arguments != null){
-                                       foreach (Argument a in Arguments){
-                                               if (!a.Resolve (ec, loc))
-                                                       return null;
-                                       }
+                       if (Arguments != null){
+                               foreach (Argument a in Arguments){
+                                       if (!a.Resolve (ec, loc))
+                                               return null;
                                }
-
-                               method = Invocation.OverloadResolve (
-                                       ec, (MethodGroupExpr) ml, Arguments, true, loc);
-                               
                        }
 
+                       method = Invocation.OverloadResolve (ec, mg, Arguments, false, loc);
                        if (method == null) {
-                               if (almostMatchedMembers.Count != 0) {
+                               if (almostMatchedMembers.Count != 0)
                                        MemberLookupFailed (ec, type, type, ".ctor", null, true, loc);
-                                       return null;
-                               }
-
-                                if (!is_struct || Arguments.Count > 0) {
-                                       Error (1501, String.Format (
-                                           "New invocation: Can not find a constructor in `{0}' for this argument list",
-                                           TypeManager.CSharpName (type)));
-                                       return null;
-                                }
+                               return null;
                        }
 
                        return this;
@@ -6308,7 +6056,7 @@ namespace Mono.CSharp {
 
                void Error_IncorrectArrayInitializer ()
                {
-                       Error (178, "Incorrectly structured array initializer");
+                       Error (178, "Invalid rank specifier: expected `,' or `]'");
                }
                
                public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
@@ -6335,9 +6083,11 @@ namespace Mono.CSharp {
                        }
 
                        int child_bounds = -1;
-                       foreach (object o in probe) {
+                       for (int i = 0; i < probe.Count; ++i) {
+                               object o = probe [i];
                                if (o is ArrayList) {
-                                       int current_bounds = ((ArrayList) o).Count;
+                                       ArrayList sub_probe = o as ArrayList;
+                                       int current_bounds = sub_probe.Count;
                                        
                                        if (child_bounds == -1) 
                                                child_bounds = current_bounds;
@@ -6347,11 +6097,11 @@ namespace Mono.CSharp {
                                                return false;
                                        }
                                        if (specified_dims && (idx + 1 >= arguments.Count)){
-                                               Error (623, "Array initializers can only be used in a variable or field initializer, try using the new expression");
+                                               Error (623, "Array initializers can only be used in a variable or field initializer. Try using a new expression instead");
                                                return false;
                                        }
                                        
-                                       bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
+                                       bool ret = CheckIndices (ec, sub_probe, idx + 1, specified_dims);
                                        if (!ret)
                                                return false;
                                } else {
@@ -6362,6 +6112,7 @@ namespace Mono.CSharp {
                                        
                                        Expression tmp = (Expression) o;
                                        tmp = tmp.Resolve (ec);
+                                       probe [i] = tmp;
                                        if (tmp == null)
                                                return false;
 
@@ -6397,7 +6148,7 @@ namespace Mono.CSharp {
                        int i = 0;
                        for (ArrayList probe = initializers; probe != null;) {
                                if (probe.Count > 0 && probe [0] is ArrayList) {
-                                       Expression e = new IntConstant (probe.Count);
+                                       Expression e = new IntConstant (probe.Count, Location.Null);
                                        arguments.Add (new Argument (e, Argument.AType.Expression));
 
                                        bounds [i++] =  probe.Count;
@@ -6405,7 +6156,7 @@ namespace Mono.CSharp {
                                        probe = (ArrayList) probe [0];
                                        
                                } else {
-                                       Expression e = new IntConstant (probe.Count);
+                                       Expression e = new IntConstant (probe.Count, Location.Null);
                                        arguments.Add (new Argument (e, Argument.AType.Expression));
 
                                        bounds [i++] = probe.Count;
@@ -6458,53 +6209,6 @@ namespace Mono.CSharp {
                        }
                }
 
-               //
-               // Converts `source' to an int, uint, long or ulong.
-               //
-               Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
-               {
-                       Expression target;
-                       
-                       bool old_checked = ec.CheckState;
-                       ec.CheckState = true;
-                       
-                       target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
-                       if (target == null){
-                               target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
-                               if (target == null){
-                                       target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
-                                       if (target == null){
-                                               target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
-                                               if (target == null)
-                                                       Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
-                                       }
-                               }
-                       } 
-                       ec.CheckState = old_checked;
-
-                       //
-                       // Only positive constants are allowed at compile time
-                       //
-                       if (target is Constant){
-                               if (target is IntConstant){
-                                       if (((IntConstant) target).Value < 0){
-                                               Expression.Error_NegativeArrayIndex (loc);
-                                               return null;
-                                       }
-                               }
-
-                               if (target is LongConstant){
-                                       if (((LongConstant) target).Value < 0){
-                                               Expression.Error_NegativeArrayIndex (loc);
-                                               return null;
-                                       }
-                               }
-                               
-                       }
-
-                       return target;
-               }
-
                //
                // Creates the type of the array
                //
@@ -6532,7 +6236,7 @@ namespace Mono.CSharp {
                        if (array_type_expr == null)
                                return false;
 
-                       type = array_type_expr.Type;
+                       type = array_type_expr.ResolveType (ec);
 
                        if (!type.IsArray) {
                                Error (622, "Can only use array initializer expressions to assign to array types. Try using a new expression instead.");
@@ -6577,7 +6281,7 @@ namespace Mono.CSharp {
                        array_element_type = TypeManager.GetElementType (type);
 
                        if (array_element_type.IsAbstract && array_element_type.IsSealed) {
-                               Report.Error (719, loc, "'{0}': array elements cannot be of static type", TypeManager.CSharpName (array_element_type));
+                               Report.Error (719, loc, "`{0}': array elements cannot be of static type", TypeManager.CSharpName (array_element_type));
                                return null;
                        }
 
@@ -6596,7 +6300,7 @@ namespace Mono.CSharp {
                                                   AllBindingFlags, loc);
                                
                                if (!(ml is MethodGroupExpr)) {
-                                       ml.Error_UnexpectedKind ("method group", loc);
+                                       ml.Error_UnexpectedKind (ec, "method group", loc);
                                        return null;
                                }
                                
@@ -6864,7 +6568,7 @@ namespace Mono.CSharp {
                                        if (e is StringConstant || e is DecimalConstant || !(e is Constant) ||
                                            num_automatic_initializers <= max_automatic_initializers) {
                                                Type etype = e.Type;
-                                               
+
                                                ig.Emit (OpCodes.Dup);
 
                                                for (int idx = 0; idx < dims; idx++) 
@@ -6874,7 +6578,8 @@ namespace Mono.CSharp {
                                                // If we are dealing with a struct, get the
                                                // address of it, so we can store it.
                                                //
-                                               if ((dims == 1) && etype.IsValueType &&
+                                               if ((dims == 1) && 
+                                                   TypeManager.IsValueType (etype) &&
                                                    (!TypeManager.IsBuiltinOrEnum (etype) ||
                                                     etype == TypeManager.decimal_type)) {
                                                        if (e is New){
@@ -7018,12 +6723,9 @@ namespace Mono.CSharp {
                        get { return variable_info; }
                }
 
-               public bool VerifyFixed (bool is_expression)
+               public bool VerifyFixed ()
                {
-                       if ((variable_info == null) || (variable_info.LocalInfo == null))
-                               return false;
-                       else
-                               return variable_info.LocalInfo.IsFixed;
+                       return !TypeManager.IsValueType (Type);
                }
 
                public bool ResolveBase (EmitContext ec)
@@ -7036,12 +6738,12 @@ namespace Mono.CSharp {
                                type = ec.ContainerType;
 
                        if (ec.IsStatic) {
-                               Error (26, "Keyword this not valid in static code");
+                               Error (26, "Keyword `this' is not valid in a static property, static method, or static field initializer");
                                return false;
                        }
 
-                       if ((block != null) && (block.ThisVariable != null))
-                               variable_info = block.ThisVariable.VariableInfo;
+                       if (block != null && block.Toplevel.ThisVariable != null)
+                               variable_info = block.Toplevel.ThisVariable.VariableInfo;
 
                        if (ec.CurrentAnonymousMethod != null)
                                ec.CaptureThis ();
@@ -7054,16 +6756,14 @@ namespace Mono.CSharp {
                        if (!ResolveBase (ec))
                                return null;
 
-                       if ((variable_info != null) && !variable_info.IsAssigned (ec)) {
-                               Error (188, "The this object cannot be used before all " +
-                                      "of its fields are assigned to");
+                       if ((variable_info != null) && !(type.IsValueType && ec.OmitStructFlowAnalysis) && !variable_info.IsAssigned (ec)) {
+                               Error (188, "The `this' object cannot be used before all of its fields are assigned to");
                                variable_info.SetAssigned (ec);
                                return this;
                        }
 
                        if (ec.IsFieldInitializer) {
-                               Error (27, "Keyword `this' can't be used outside a constructor, " +
-                                      "a method or a property.");
+                               Error (27, "Keyword `this' is not available in the current context");
                                return null;
                        }
 
@@ -7168,7 +6868,7 @@ namespace Mono.CSharp {
                        if (!ResolveBase (ec))
                                return null;
 
-                       if (ec.IsFieldInitializer || !ec.CurrentBlock.HasVarargs) {
+                       if (ec.IsFieldInitializer || !ec.CurrentBlock.Toplevel.HasVarargs) {
                                Error (190, "The __arglist construct is valid only within " +
                                       "a variable argument method.");
                                return null;
@@ -7267,11 +6967,10 @@ namespace Mono.CSharp {
                        if (texpr == null)
                                return null;
 
-                       typearg = texpr.Type;
+                       typearg = texpr.ResolveType (ec);
 
                        if (typearg == TypeManager.void_type) {
-                               Error (673, "System.Void cannot be used from C# - " +
-                                      "use typeof (void) to get the void type object");
+                               Error (673, "System.Void cannot be used from C#. Use typeof (void) to get the void type object");
                                return null;
                        }
 
@@ -7279,10 +6978,11 @@ namespace Mono.CSharp {
                                UnsafeError (loc);
                                return null;
                        }
-                       CheckObsoleteAttribute (typearg);
 
                        type = TypeManager.type_type;
-                       eclass = ExprClass.Type;
+                       // Even though what is returned is a type object, it's treated as a value by the compiler.
+                       // In particular, 'typeof (Foo).X' is something totally different from 'Foo.X'.
+                       eclass = ExprClass.Value;
                        return this;
                }
 
@@ -7310,7 +7010,8 @@ namespace Mono.CSharp {
                {
                        type = TypeManager.type_type;
                        typearg = TypeManager.void_type;
-                       eclass = ExprClass.Type;
+                       // See description in TypeOf.
+                       eclass = ExprClass.Value;
                        return this;
                }
        }
@@ -7339,23 +7040,20 @@ namespace Mono.CSharp {
                                return null;
                        }
 
-                       type_queried = texpr.Type;
+                       type_queried = texpr.ResolveType (ec);
 
                        int size_of = GetTypeSize (type_queried);
                        if (size_of > 0) {
-                               return new IntConstant (size_of);
+                               return new IntConstant (size_of, loc);
                        }
 
                        if (!ec.InUnsafe) {
-                               Report.Error (233, loc, "'{0}' does not have a predefined size, therefore sizeof can only be used in an unsafe context (consider using System.Runtime.InteropServices.Marshal.SizeOf)",
+                               Report.Error (233, loc, "`{0}' does not have a predefined size, therefore sizeof can only be used in an unsafe context (consider using System.Runtime.InteropServices.Marshal.SizeOf)",
                                         TypeManager.CSharpName (type_queried));
                                return null;
                        }
 
-                       CheckObsoleteAttribute (type_queried);
-
-                       if (!TypeManager.IsUnmanagedType (type_queried)){
-                               Report.Error (208, loc, "Cannot take the size of an unmanaged type (" + TypeManager.CSharpName (type_queried) + ")");
+                       if (!TypeManager.VerifyUnManaged (type_queried, loc)){
                                return null;
                        }
                        
@@ -7375,19 +7073,103 @@ namespace Mono.CSharp {
                }
        }
 
+       /// <summary>
+       ///   Implements the qualified-alias-member (::) expression.
+       /// </summary>
+       public class QualifiedAliasMember : Expression
+       {
+               string alias, identifier;
+
+               public QualifiedAliasMember (string alias, string identifier, Location l)
+               {
+                       this.alias = alias;
+                       this.identifier = identifier;
+                       loc = l;
+               }
+
+               public override FullNamedExpression ResolveAsTypeStep (EmitContext ec, bool silent)
+               {
+                       if (alias == "global")
+                               return new MemberAccess (Namespace.Root, identifier, loc).ResolveAsTypeStep (ec, silent);
+
+                       int errors = Report.Errors;
+                       FullNamedExpression fne = ec.DeclSpace.NamespaceEntry.LookupAlias (alias);
+                       if (fne == null) {
+                               if (errors == Report.Errors)
+                                       Report.Error (432, loc, "Alias `{0}' not found", alias);
+                               return null;
+                       }
+                       if (fne.eclass != ExprClass.Namespace) {
+                               if (!silent)
+                                       Report.Error (431, loc, "`{0}' cannot be used with '::' since it denotes a type", alias);
+                               return null;
+                       }
+                       return new MemberAccess (fne, identifier, loc).ResolveAsTypeStep (ec, silent);
+               }
+
+               public override Expression DoResolve (EmitContext ec)
+               {
+                       FullNamedExpression fne;
+                       if (alias == "global") {
+                               fne = Namespace.Root;
+                       } else {
+                               int errors = Report.Errors;
+                               fne = ec.DeclSpace.NamespaceEntry.LookupAlias (alias);
+                               if (fne == null) {
+                                       if (errors == Report.Errors)
+                                               Report.Error (432, loc, "Alias `{0}' not found", alias);
+                                       return null;
+                               }
+                       }
+
+                       Expression retval = new MemberAccess (fne, identifier, loc).DoResolve (ec);
+                       if (retval == null)
+                               return null;
+
+                       if (!(retval is FullNamedExpression)) {
+                               Report.Error (687, loc, "The expression `{0}::{1}' did not resolve to a namespace or a type", alias, identifier);
+                               return null;
+                       }
+
+                       // We defer this check till the end to match the behaviour of CSC
+                       if (fne.eclass != ExprClass.Namespace) {
+                               Report.Error (431, loc, "`{0}' cannot be used with '::' since it denotes a type", alias);
+                               return null;
+                       }
+                       return retval;
+               }
+
+               public override void Emit (EmitContext ec)
+               {
+                       throw new InternalErrorException ("QualifiedAliasMember found in resolved tree");
+               }
+
+
+               public override string ToString ()
+               {
+                       return alias + "::" + identifier;
+               }
+
+               public override string GetSignatureForError ()
+               {
+                       return ToString ();
+               }
+       }
+
        /// <summary>
        ///   Implements the member access expression
        /// </summary>
        public class MemberAccess : Expression {
-               public string Identifier;
-               protected Expression expr;
-               protected TypeArguments args;
+               public readonly string Identifier;
+               Expression expr;
+               TypeArguments args;
                
+               // TODO: Location can be removed
                public MemberAccess (Expression expr, string id, Location l)
                {
                        this.expr = expr;
                        Identifier = id;
-                       loc = l;
+                       loc = expr.Location;
                }
 
                public MemberAccess (Expression expr, string id, TypeArguments args,
@@ -7398,13 +7180,12 @@ namespace Mono.CSharp {
                }
 
                public Expression Expr {
-                       get {
-                               return expr;
-                       }
+                       get { return expr; }
                }
 
-               public virtual Expression DoResolve (EmitContext ec, Expression right_side,
-                                                    ResolveFlags flags)
+               // TODO: this method has very poor performace for Enum fields and
+               // probably for other constants as well
+               Expression DoResolve (EmitContext ec, Expression right_side)
                {
                        if (type != null)
                                throw new Exception ();
@@ -7417,73 +7198,26 @@ namespace Mono.CSharp {
                        //
 
                        SimpleName original = expr as SimpleName;
-                       expr = expr.Resolve (ec, flags | ResolveFlags.Intermediate | ResolveFlags.DisableFlowAnalysis);
-                       if (expr == null)
+                       Expression new_expr = expr.Resolve (ec,
+                               ResolveFlags.VariableOrValue | ResolveFlags.Type |
+                               ResolveFlags.Intermediate | ResolveFlags.DisableStructFlowAnalysis);
+
+                       if (new_expr == null)
                                return null;
 
-                       if (expr is Namespace) {
-                               Namespace ns = (Namespace) expr;
+                       if (new_expr is Namespace) {
+                               Namespace ns = (Namespace) new_expr;
                                string lookup_id = MemberName.MakeName (Identifier, args);
                                FullNamedExpression retval = ns.Lookup (ec.DeclSpace, lookup_id, loc);
                                if ((retval != null) && (args != null))
                                        retval = new ConstructedType (retval, args, loc).ResolveAsTypeStep (ec);
                                if (retval == null)
-                                       Report.Error (234, loc, "The type or namespace name `{0}' could not be found in namespace `{1}'", Identifier, ns.FullName);
+                                       Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
+                                               Identifier, ns.FullName);
                                return retval;
                        }
-                                       
-                       //
-                       // TODO: I mailed Ravi about this, and apparently we can get rid
-                       // of this and put it in the right place.
-                       // 
-                       // Handle enums here when they are in transit.
-                       // Note that we cannot afford to hit MemberLookup in this case because
-                       // it will fail to find any members at all
-                       //
-
-                       Type expr_type;
-                       if (expr is TypeExpr){
-                               expr_type = expr.Type;
-
-                               if (!ec.DeclSpace.CheckAccessLevel (expr_type)){
-                                       Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", expr_type);
-                                       return null;
-                               }
-
-                               if (expr_type == TypeManager.enum_type || expr_type.IsSubclassOf (TypeManager.enum_type)){
-                                       Enum en = TypeManager.LookupEnum (expr_type);
-
-                                       if (en != null) {
-                                               object value = en.LookupEnumValue (Identifier, loc);
-                                               
-                                               if (value != null){
-                                                       MemberCore mc = en.GetDefinition (Identifier);
-                                                       ObsoleteAttribute oa = mc.GetObsoleteAttribute (en);
-                                                       if (oa != null) {
-                                                               AttributeTester.Report_ObsoleteMessage (oa, mc.GetSignatureForError (), Location);
-                                                       }
-                                                       oa = en.GetObsoleteAttribute (en);
-                                                       if (oa != null) {
-                                                               AttributeTester.Report_ObsoleteMessage (oa, en.GetSignatureForError (), Location);
-                                                       }
-
-                                                       Constant c = Constantify (value, en.UnderlyingType);
-                                                       return new EnumConstant (c, expr_type);
-                                               }
-                                       } else {
-                                               CheckObsoleteAttribute (expr_type);
 
-                                               FieldInfo fi = expr_type.GetField (Identifier);
-                                               if (fi != null) {
-                                                       ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (fi);
-                                                       if (oa != null)
-                                                               AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (fi), Location);
-                                               }
-                                       }
-                               }
-                       } else
-                               expr_type = expr.Type;
-                       
+                       Type expr_type = new_expr.Type;
                        if (expr_type.IsPointer){
                                Error (23, "The `.' operator can not be applied to pointer operands (" +
                                       TypeManager.CSharpName (expr_type) + ")");
@@ -7500,23 +7234,38 @@ namespace Mono.CSharp {
                        }
                        if (member_lookup == null) {
                                MemberLookupFailed (
-                                       ec, expr_type, expr_type, Identifier, null, false, loc);
+                                       ec, expr_type, expr_type, Identifier, null, true, loc);
                                return null;
                        }
 
                        if (member_lookup is TypeExpr) {
-                               if (!(expr is TypeExpr) && 
-                                   (original == null || !original.IdenticalNameAndTypeName (ec, expr, loc))) {
-                                       Error (572, "Can't reference type `" + Identifier + "' through an expression; try `" +
-                                              member_lookup.Type + "' instead");
+                               if (!(new_expr is TypeExpr) && 
+                                   (original == null || !original.IdenticalNameAndTypeName (ec, new_expr, loc))) {
+                                       Report.Error (572, loc, "`{0}': cannot reference a type through an expression; try `{1}' instead",
+                                               Identifier, member_lookup.GetSignatureForError ());
                                        return null;
                                }
 
+                               ConstructedType ct = new_expr as ConstructedType;
+                               if (ct != null) {
+                                       //
+                                       // When looking up a nested type in a generic instance
+                                       // via reflection, we always get a generic type definition
+                                       // and not a generic instance - so we have to do this here.
+                                       //
+                                       // See gtest-172-lib.cs and gtest-172.cs for an example.
+                                       //
+                                       ct = new ConstructedType (
+                                               member_lookup.Type, ct.TypeArguments, loc);
+
+                                       return ct.ResolveAsTypeStep (ec);
+                               }
+
                                return member_lookup;
                        }
 
                        MemberExpr me = (MemberExpr) member_lookup;
-                       member_lookup = me.ResolveMemberAccess (ec, expr, loc, original, false);
+                       member_lookup = me.ResolveMemberAccess (ec, new_expr, loc, original);
                        if (member_lookup == null)
                                return null;
 
@@ -7528,38 +7277,47 @@ namespace Mono.CSharp {
                                return mg.ResolveGeneric (ec, args);
                        }
 
+                       if (original != null && !TypeManager.IsValueType (expr_type)) {
+                               me = member_lookup as MemberExpr;
+                               if (me != null && me.IsInstance) {
+                                       LocalVariableReference var = new_expr as LocalVariableReference;
+                                       if (var != null && !var.VerifyAssigned (ec))
+                                               return null;
+                               }
+                       }
+
                        // The following DoResolve/DoResolveLValue will do the definite assignment
                        // check.
 
                        if (right_side != null)
-                               member_lookup = member_lookup.DoResolveLValue (ec, right_side);
+                               return member_lookup.DoResolveLValue (ec, right_side);
                        else
-                               member_lookup = member_lookup.DoResolve (ec);
-
-                       return member_lookup;
+                               return member_lookup.DoResolve (ec);
                }
 
                public override Expression DoResolve (EmitContext ec)
                {
-                       return DoResolve (ec, null, ResolveFlags.VariableOrValue | ResolveFlags.Type);
+                       return DoResolve (ec, null);
                }
 
                public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
                {
-                       return DoResolve (ec, right_side, ResolveFlags.VariableOrValue | ResolveFlags.Type);
+                       return DoResolve (ec, right_side);
                }
 
-               public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
+               public override FullNamedExpression ResolveAsTypeStep (EmitContext ec, bool silent)
                {
-                       return ResolveNamespaceOrType (ec, false);
+                       return ResolveNamespaceOrType (ec, silent);
                }
 
                public FullNamedExpression ResolveNamespaceOrType (EmitContext ec, bool silent)
                {
-                       FullNamedExpression new_expr = expr.ResolveAsTypeStep (ec);
+                       FullNamedExpression new_expr = expr.ResolveAsTypeStep (ec, silent);
 
-                       if (new_expr == null)
+                       if (new_expr == null) {
+                               Report.Error (234, "No such name or typespace {0}", expr);
                                return null;
+                       }
 
                        string lookup_id = MemberName.MakeName (Identifier, args);
 
@@ -7569,7 +7327,8 @@ namespace Mono.CSharp {
                                if ((retval != null) && (args != null))
                                        retval = new ConstructedType (retval, args, loc).ResolveAsTypeStep (ec);
                                if (!silent && retval == null)
-                                       Report.Error (234, loc, "The type or namespace name `{0}' could not be found in namespace `{1}'", Identifier, ns.FullName);
+                                       Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
+                                               Identifier, ns.FullName);
                                return retval;
                        }
 
@@ -7577,7 +7336,7 @@ namespace Mono.CSharp {
                        if (tnew_expr == null)
                                return null;
 
-                       Type expr_type = tnew_expr.Type;
+                       Type expr_type = tnew_expr.ResolveType (ec);
 
                        if (expr_type.IsPointer){
                                Error (23, "The `.' operator can not be applied to pointer operands (" +
@@ -7585,20 +7344,22 @@ namespace Mono.CSharp {
                                return null;
                        }
 
-                       Expression member_lookup = MemberLookup (ec, expr_type, expr_type, lookup_id, loc);
+                       Expression member_lookup = MemberLookup (
+                               ec, ec.ContainerType, expr_type, expr_type, lookup_id,
+                               MemberTypes.NestedType, BindingFlags.Public | BindingFlags.NonPublic, loc);
                        if (member_lookup == null) {
                                int errors = Report.Errors;
                                MemberLookupFailed (ec, expr_type, expr_type, lookup_id, null, false, loc);
 
-                               if (!silent && errors == Report.Errors)
-                                       Report.Error (234, loc, "The type name `{0}' could not be found in type `{1}'", 
-                                                     lookup_id, new_expr.FullName);
+                               if (!silent && errors == Report.Errors) {
+                                       Report.Error (426, loc, "The nested type `{0}' does not exist in the type `{1}'",
+                                               Identifier, new_expr.GetSignatureForError ());
+                               }
                                return null;
                        }
 
                        if (!(member_lookup is TypeExpr)) {
-                               Report.Error (118, loc, "'{0}.{1}' denotes a '{2}', where a type was expected",
-                                             new_expr.FullName, lookup_id, member_lookup.ExprClassName ());
+                               new_expr.Error_UnexpectedKind (ec, "type", loc);
                                return null;
                        }
 
@@ -7637,6 +7398,11 @@ namespace Mono.CSharp {
                {
                        return expr + "." + MemberName.MakeName (Identifier, args);
                }
+
+               public override string GetSignatureForError ()
+               {
+                       return expr.GetSignatureForError () + "." + Identifier;
+               }
        }
 
        /// <summary>
@@ -7747,11 +7513,11 @@ namespace Mono.CSharp {
                public ArrayList  Arguments;
                public Expression Expr;
                
-               public ElementAccess (Expression e, ArrayList e_list, Location l)
+               public ElementAccess (Expression e, ArrayList e_list)
                {
                        Expr = e;
 
-                       loc  = l;
+                       loc  = e.Location;
                        
                        if (e_list == null)
                                return;
@@ -7783,11 +7549,11 @@ namespace Mono.CSharp {
                Expression MakePointerAccess (EmitContext ec, Type t)
                {
                        if (t == TypeManager.void_ptr_type){
-                               Error (242, "The array index operation is not valid for void pointers");
+                               Error (242, "The array index operation is not valid on void pointers");
                                return null;
                        }
                        if (Arguments.Count != 1){
-                               Error (196, "A pointer must be indexed by a single value");
+                               Error (196, "A pointer must be indexed by only one value");
                                return null;
                        }
                        Expression p;
@@ -7812,7 +7578,7 @@ namespace Mono.CSharp {
                        Type t = Expr.Type;
 
                        if (t == TypeManager.array_type){
-                               Report.Error (21, loc, "Cannot use indexer on System.Array");
+                               Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `System.Array'");
                                return null;
                        }
                        
@@ -7838,7 +7604,7 @@ namespace Mono.CSharp {
 
                        Type t = Expr.Type;
                        if (t.IsArray)
-                               return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
+                               return (new ArrayAccess (this, loc)).DoResolveLValue (ec, right_side);
 
                        if (t.IsPointer)
                                return MakePointerAccess (ec, Expr.Type);
@@ -7849,7 +7615,7 @@ namespace Mono.CSharp {
                                if (ff != null) {
                                        if (!(fe.InstanceExpression is LocalVariableReference) && 
                                                !(fe.InstanceExpression is This)) {
-                                               Error (1708, "Fixed buffers can only be accessed through locals or fields");
+                                               Report.Error (1708, loc, "Fixed size buffers can only be accessed through locals or fields");
                                                return null;
                                        }
 // TODO: not sure whether it is correct
@@ -7860,7 +7626,7 @@ namespace Mono.CSharp {
                                        return MakePointerAccess (ec, ff.ElementType);
                                }
                        }
-                       return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
+                       return (new IndexerAccess (this, loc)).DoResolveLValue (ec, right_side);
                }
                
                public override void Emit (EmitContext ec)
@@ -7908,10 +7674,8 @@ namespace Mono.CSharp {
 
                        Type t = ea.Expr.Type;
                        if (t.GetArrayRank () != ea.Arguments.Count){
-                               ea.Error (22,
-                                         "Incorrect number of indexes for array " +
-                                         " expected: " + t.GetArrayRank () + " got: " +
-                                         ea.Arguments.Count);
+                               Report.Error (22, ea.Location, "Wrong number of indexes `{0}' inside [], expected `{1}'",
+                                         ea.Arguments.Count, t.GetArrayRank ());
                                return null;
                        }
 
@@ -7930,7 +7694,7 @@ namespace Mono.CSharp {
                                    argtype == TypeManager.uint64_type) {
                                        Constant c = a.Expr as Constant;
                                        if (c != null && c.IsNegative) {
-                                               Report.Warning (251, 2, a.Expr.Location, "Indexing an array with a negative index (array indices always start at zero)");
+                                               Report.Warning (251, 2, ea.Location, "Indexing an array with a negative index (array indices always start at zero)");
                                        }
                                        continue;
                                }
@@ -7986,6 +7750,8 @@ namespace Mono.CSharp {
                                ig.Emit (OpCodes.Ldobj, type);
                        } else if (type.IsGenericParameter)
                                ig.Emit (OpCodes.Ldelem_Any, type);
+                       else if (type.IsPointer)
+                               ig.Emit (OpCodes.Ldelem_I);
                        else
                                ig.Emit (OpCodes.Ldelem_Ref);
                }
@@ -8026,7 +7792,9 @@ namespace Mono.CSharp {
                        } else if (t.IsGenericParameter) {
                                has_type_arg = true;
                                return OpCodes.Stelem_Any;
-                       } else
+                       } else if (t.IsPointer)
+                               return OpCodes.Stelem_I;
+                       else
                                return OpCodes.Stelem_Ref;
                }
 
@@ -8228,20 +7996,35 @@ namespace Mono.CSharp {
                                ig.Emit (OpCodes.Call, address);
                        }
                }
-       }
 
+               public void EmitGetLength (EmitContext ec, int dim)
+               {
+                       int rank = ea.Expr.Type.GetArrayRank ();
+                       ILGenerator ig = ec.ig;
+
+                       ea.Expr.Emit (ec);
+                       if (rank == 1) {
+                               ig.Emit (OpCodes.Ldlen);
+                               ig.Emit (OpCodes.Conv_I4);
+                       } else {
+                               IntLiteral.EmitInt (ig, dim);
+                               ig.Emit (OpCodes.Callvirt, TypeManager.int_getlength_int);
+                       }
+               }
+       }
        
        class Indexers {
-               public ArrayList Properties;
-               static Hashtable map;
+               // note that the ArrayList itself in mutable.  We just can't assign to 'Properties' again.
+               public readonly ArrayList Properties;
+               static Indexers empty;
 
                public struct Indexer {
-                       public readonly Type Type;
+                       public readonly PropertyInfo PropertyInfo;
                        public readonly MethodInfo Getter, Setter;
 
-                       public Indexer (Type type, MethodInfo get, MethodInfo set)
+                       public Indexer (PropertyInfo property_info, MethodInfo get, MethodInfo set)
                        {
-                               this.Type = type;
+                               this.PropertyInfo = property_info;
                                this.Getter = get;
                                this.Setter = set;
                        }
@@ -8249,22 +8032,33 @@ namespace Mono.CSharp {
 
                static Indexers ()
                {
-                       map = new Hashtable ();
+                       empty = new Indexers (null);
                }
 
-               Indexers ()
+               Indexers (ArrayList array)
                {
-                       Properties = new ArrayList ();
+                       Properties = array;
                }
-                               
-               void Append (MemberInfo [] mi)
+
+               static void Append (ref Indexers ix, Type caller_type, MemberInfo [] mi)
                {
+                       bool dummy;
+                       if (mi == null)
+                               return;
                        foreach (PropertyInfo property in mi){
                                MethodInfo get, set;
                                
                                get = property.GetGetMethod (true);
                                set = property.GetSetMethod (true);
-                               Properties.Add (new Indexer (property.PropertyType, get, set));
+                               if (get != null && !Expression.IsAccessorAccessible (caller_type, get, out dummy))
+                                       get = null;
+                               if (set != null && !Expression.IsAccessorAccessible (caller_type, set, out dummy))
+                                       set = null;
+                               if (get != null || set != null) {
+                                       if (ix == empty)
+                                               ix = new Indexers (new ArrayList ());
+                                       ix.Properties.Add (new Indexer (property, get, set));
+                               }
                        }
                }
 
@@ -8272,51 +8066,27 @@ namespace Mono.CSharp {
                {
                        string p_name = TypeManager.IndexerPropertyName (lookup_type);
 
-                       MemberInfo [] mi = TypeManager.MemberLookup (
+                       return TypeManager.MemberLookup (
                                caller_type, caller_type, lookup_type, MemberTypes.Property,
                                BindingFlags.Public | BindingFlags.Instance |
                                BindingFlags.DeclaredOnly, p_name, null);
-
-                       if (mi == null || mi.Length == 0)
-                               return null;
-
-                       return mi;
                }
                
                static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc) 
                {
-                       Indexers ix = (Indexers) map [lookup_type];
-
-                       if (ix != null)
-                               return ix;
+                       Indexers ix = empty;
 
                        Type copy = lookup_type;
                        while (copy != TypeManager.object_type && copy != null){
-                               MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, copy);
-
-                               if (mi != null){
-                                       if (ix == null)
-                                               ix = new Indexers ();
-
-                                       ix.Append (mi);
-                               }
-                                       
+                               Append (ref ix, caller_type, GetIndexersForTypeOrInterface (caller_type, copy));
                                copy = copy.BaseType;
                        }
 
-                       if (!lookup_type.IsInterface)
-                               return ix;
-
-                       Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
-                       if (ifaces != null) {
-                               foreach (Type itype in ifaces) {
-                                       MemberInfo [] mi = GetIndexersForTypeOrInterface (caller_type, itype);
-                                       if (mi != null){
-                                               if (ix == null)
-                                                       ix = new Indexers ();
-                                       
-                                               ix.Append (mi);
-                                       }
+                       if (lookup_type.IsInterface) {
+                               Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
+                               if (ifaces != null) {
+                                       foreach (Type itype in ifaces)
+                                               Append (ref ix, caller_type, GetIndexersForTypeOrInterface (caller_type, itype));
                                }
                        }
 
@@ -8378,15 +8148,12 @@ namespace Mono.CSharp {
                        bool found_any = false, found_any_getters = false;
                        Type lookup_type = indexer_type;
 
-                       Indexers ilist;
-                       ilist = Indexers.GetIndexersForType (current_type, lookup_type, loc);
-                       if (ilist != null) {
+                       Indexers ilist = Indexers.GetIndexersForType (current_type, lookup_type, loc);
+                       if (ilist.Properties != null) {
                                found_any = true;
-                               if (ilist.Properties != null) {
-                                       foreach (Indexers.Indexer ix in ilist.Properties) {
-                                               if (ix.Getter != null)
-                                                       AllGetters.Add(ix.Getter);
-                                       }
+                               foreach (Indexers.Indexer ix in ilist.Properties) {
+                                       if (ix.Getter != null)
+                                               AllGetters.Add (ix.Getter);
                                }
                        }
 
@@ -8398,21 +8165,19 @@ namespace Mono.CSharp {
                        }
 
                        if (!found_any) {
-                               Report.Error (21, loc,
-                                             "Type `" + TypeManager.CSharpName (indexer_type) +
-                                             "' does not have any indexers defined");
+                               Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `{0}'",
+                                             TypeManager.CSharpName (indexer_type));
                                return null;
                        }
 
                        if (!found_any_getters) {
-                               Error (154, "indexer can not be used in this context, because " +
-                                      "it lacks a `get' accessor");
+                               Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
+                                             "XXXXXXXX");
                                return null;
                        }
 
                        if (get == null) {
-                               Error (1501, "No Overload for method `this' takes `" +
-                                      arguments.Count + "' arguments");
+                               Invocation.Error_WrongNumArguments (loc, "this", arguments.Count);
                                return null;
                        }
 
@@ -8420,7 +8185,7 @@ namespace Mono.CSharp {
                        // Only base will allow this invocation to happen.
                        //
                        if (get.IsAbstract && this is BaseIndexerAccess){
-                               Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (get));
+                               Error_CannotCallAbstractBase (TypeManager.CSharpSignature (get));
                                return null;
                        }
 
@@ -8445,13 +8210,11 @@ namespace Mono.CSharp {
                        bool found_any = false, found_any_setters = false;
 
                        Indexers ilist = Indexers.GetIndexersForType (current_type, indexer_type, loc);
-                       if (ilist != null) {
+                       if (ilist.Properties != null) {
                                found_any = true;
-                               if (ilist.Properties != null) {
-                                       foreach (Indexers.Indexer ix in ilist.Properties) {
-                                               if (ix.Setter != null)
-                                                       AllSetters.Add(ix.Setter);
-                                       }
+                               foreach (Indexers.Indexer ix in ilist.Properties) {
+                                       if (ix.Setter != null)
+                                               AllSetters.Add (ix.Setter);
                                }
                        }
                        if (AllSetters.Count > 0) {
@@ -8464,9 +8227,8 @@ namespace Mono.CSharp {
                        }
 
                        if (!found_any) {
-                               Report.Error (21, loc,
-                                             "Type `" + TypeManager.CSharpName (indexer_type) +
-                                             "' does not have any indexers defined");
+                               Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `{0}'",
+                                             TypeManager.CSharpName (indexer_type));
                                return null;
                        }
 
@@ -8477,8 +8239,7 @@ namespace Mono.CSharp {
                        }
 
                        if (set == null) {
-                               Error (1501, "No Overload for method `this' takes `" +
-                                      arguments.Count + "' arguments");
+                               Invocation.Error_WrongNumArguments (loc, "this", arguments.Count);
                                return null;
                        }
 
@@ -8486,7 +8247,7 @@ namespace Mono.CSharp {
                        // Only base will allow this invocation to happen.
                        //
                        if (set.IsAbstract && this is BaseIndexerAccess){
-                               Report.Error (205, loc, "Cannot call an abstract base indexer: " + Invocation.FullMethodDesc (set));
+                               Error_CannotCallAbstractBase (TypeManager.CSharpSignature (set));
                                return null;
                        }
 
@@ -8496,11 +8257,11 @@ namespace Mono.CSharp {
                        type = TypeManager.void_type;   // default value
                        foreach (Indexers.Indexer ix in ilist.Properties){
                                if (ix.Setter == set){
-                                       type = ix.Type;
+                                       type = ix.PropertyInfo.PropertyType;
                                        break;
                                }
                        }
-                       
+
                        instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
 
                        eclass = ExprClass.IndexerAccess;
@@ -8607,12 +8368,12 @@ namespace Mono.CSharp {
                        Type base_type = current_type.BaseType;
 
                        if (ec.IsStatic){
-                               Error (1511, "Keyword base is not allowed in static method");
+                               Error (1511, "Keyword `base' is not available in a static method");
                                return null;
                        }
 
                        if (ec.IsFieldInitializer){
-                               Error (1512, "Keyword base is not available in the current context");
+                               Error (1512, "Keyword `base' is not available in the current context");
                                return null;
                        }
                        
@@ -8633,7 +8394,7 @@ namespace Mono.CSharp {
 
                        MemberExpr me = (MemberExpr) member_lookup;
                        
-                       Expression e = me.ResolveMemberAccess (ec, left, loc, null, false);
+                       Expression e = me.ResolveMemberAccess (ec, left, loc, null);
 
                        if (e is PropertyExpr) {
                                PropertyExpr pe = (PropertyExpr) e;
@@ -8694,6 +8455,23 @@ namespace Mono.CSharp {
        public class EmptyExpression : Expression {
                public static readonly EmptyExpression Null = new EmptyExpression ();
 
+               static EmptyExpression temp = new EmptyExpression ();
+               public static EmptyExpression Grab ()
+               {
+                       if (temp == null)
+                               throw new InternalErrorException ("Nested Grab");
+                       EmptyExpression retval = temp;
+                       temp = null;
+                       return retval;
+               }
+
+               public static void Release (EmptyExpression e)
+               {
+                       if (temp != null)
+                               throw new InternalErrorException ("Already released");
+                       temp = e;
+               }
+
                // TODO: should be protected
                public EmptyExpression ()
                {
@@ -8781,6 +8559,11 @@ namespace Mono.CSharp {
                Expression left;
                string dim;
                
+               public ComposedCast (Expression left, string dim)
+                       : this (left, dim, left.Location)
+               {
+               }
+
                public ComposedCast (Expression left, string dim, Location l)
                {
                        this.left = left;
@@ -8788,13 +8571,27 @@ namespace Mono.CSharp {
                        loc = l;
                }
 
+               public Expression RemoveNullable ()
+               {
+                       if (dim.EndsWith ("?")) {
+                               dim = dim.Substring (0, dim.Length - 1);
+                               if (dim == "")
+                                       return left;
+                       }
+
+                       return this;
+               }
+
                protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
                {
                        TypeExpr lexpr = left.ResolveAsTypeTerminal (ec);
                        if (lexpr == null)
                                return null;
 
-                       Type ltype = lexpr.Type;
+                       bool old = ec.TestObsoleteMethodUsage;
+                       ec.TestObsoleteMethodUsage = true;
+                       Type ltype = lexpr.ResolveType (ec);
+                       ec.TestObsoleteMethodUsage = old;
 
                        if ((ltype == TypeManager.void_type) && (dim != "*")) {
                                Report.Error (1547, Location,
@@ -8809,6 +8606,10 @@ namespace Mono.CSharp {
                                return nullable.ResolveAsTypeTerminal (ec);
                        }
 
+                       if (dim == "*" && !TypeManager.VerifyUnManaged (ltype, loc)) {
+                               return null;
+                       }
+
                        if (dim != "")
                                type = TypeManager.GetConstructedType (ltype, dim);
                        else
@@ -8825,7 +8626,7 @@ namespace Mono.CSharp {
 
                        if (type.IsArray && (type.GetElementType () == TypeManager.arg_iterator_type ||
                                type.GetElementType () == TypeManager.typed_reference_type)) {
-                               Report.Error (611, loc, "Array elements cannot be of type '{0}'", TypeManager.CSharpName (type.GetElementType ()));
+                               Report.Error (611, loc, "Array elements cannot be of type `{0}'", TypeManager.CSharpName (type.GetElementType ()));
                                return null;
                        }
                        
@@ -8846,7 +8647,7 @@ namespace Mono.CSharp {
                }
        }
 
-       public class FixedBufferPtr: Expression {
+       public class FixedBufferPtr : Expression {
                Expression array;
 
                public FixedBufferPtr (Expression array, Type array_type, Location l)
@@ -8963,10 +8764,8 @@ namespace Mono.CSharp {
                                return null;
                        }
 
-                       if (ec.CurrentBranching.InCatch () ||
-                           ec.CurrentBranching.InFinally (true)) {
-                               Error (255,
-                                             "stackalloc can not be used in a catch or finally block");
+                       if (ec.InCatch || ec.InFinally) {
+                               Error (255, "Cannot use stackalloc in finally or catch");
                                return null;
                        }
 
@@ -8974,7 +8773,7 @@ namespace Mono.CSharp {
                        if (texpr == null)
                                return null;
 
-                       otype = texpr.Type;
+                       otype = texpr.ResolveType (ec);
 
                        if (!TypeManager.VerifyUnManaged (otype, loc))
                                return null;