2010-06-15 Marek Safar <marek.safar@gmail.com>
[mono.git] / mcs / mcs / constant.cs
index cc3f6983805a06b04ef977cfb50b102dfc74495a..c04ad0246df1417ee4d111d3245a9f5e4e2370c1 100644 (file)
@@ -5,14 +5,14 @@
 //   Miguel de Icaza (miguel@ximian.com)
 //   Marek Safar (marek.safar@seznam.cz)
 //
-// (C) 2001 Ximian, Inc.
-//
+// Copyright 2001-2003 Ximian, Inc.
+// Copyright 2003-2008 Novell, Inc.
 //
 
-namespace Mono.CSharp {
+using System;
+using System.Reflection.Emit;
 
-       using System;
-       using System.Reflection.Emit;
+namespace Mono.CSharp {
 
        /// <summary>
        ///   Base class for constants and literals.
@@ -39,18 +39,6 @@ namespace Mono.CSharp {
                        return this.GetType ().Name + " (" + AsString () + ")";
                }
 
-               public override bool GetAttributableValue (Type valueType, out object value)
-               {
-                       Constant c = ToType (valueType, loc);
-                       if (c == null) {
-                               value = null;
-                               return false;
-                       }
-
-                       value = c.GetTypedValue ();
-                       return true;
-               }
-
                /// <summary>
                ///  This is used to obtain the actual value of the literal
                ///  cast into an object.
@@ -62,289 +50,171 @@ namespace Mono.CSharp {
                        return GetValue ();
                }
 
-               /// <summary>
-               ///   Constants are always born in a fully resolved state
-               /// </summary>
-               public override Expression DoResolve (EmitContext ec)
-               {
-                       return this;
-               }
-
-               //
-               // The various ToXXXX conversion functions are used by the constant
-               // folding evaluator.   A null value is returned if the conversion is
-               // not possible.   
-               //
-               // Note: not all the patterns for catching `implicit_conv' are the same.
-               // some implicit conversions can never be performed between two types
-               // even if the conversion would be lossless (for example short to uint),
-               // but some conversions are explicitly permitted by the standard provided
-               // that there will be no loss of information (for example, int to uint).
-               //
-               public DoubleConstant ToDouble (Location loc)
-               {
-                       DoubleConstant c = ConvertToDouble ();
-
-                       if (c == null)
-                               Error_ValueCannotBeConverted (loc, TypeManager.double_type, false);
-
-                       return c;
-               }
-
-               public FloatConstant ToFloat (Location loc)
-               {
-                       FloatConstant c = ConvertToFloat ();
-
-                       if (c == null)
-                               Error_ValueCannotBeConverted (loc, TypeManager.float_type, false);
-
-                       return c;
-               }
-
-               public ULongConstant ToULong (Location loc)
+               public override void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, TypeSpec target, bool expl)
                {
-                       ULongConstant c = ConvertToULong ();
-
-                       if (c == null)
-                               Error_ValueCannotBeConverted (loc, TypeManager.uint64_type, false);
-
-                       return c;
-               }
-
-               public LongConstant ToLong (Location loc)
-               {
-                       LongConstant c = ConvertToLong ();
-
-                       if (c == null)
-                               Error_ValueCannotBeConverted (loc, TypeManager.int64_type, false);
-
-                       return c;
-               }
-               
-               public UIntConstant ToUInt (Location loc)
-               {
-                       UIntConstant c = ConvertToUInt ();
-
-                       if (c == null)
-                               Error_ValueCannotBeConverted (loc, TypeManager.uint32_type, false);
-
-                       return c;
-               }
-
-               public IntConstant ToInt (Location loc)
-               {
-                       IntConstant c = ConvertToInt ();
-
-                       if (c == null)
-                               Error_ValueCannotBeConverted (loc, TypeManager.int32_type, false);
-
-                       return c;
+                       if (!expl && IsLiteral && 
+                               (TypeManager.IsPrimitiveType (target) || type == TypeManager.decimal_type) &&
+                               (TypeManager.IsPrimitiveType (type) || type == TypeManager.decimal_type)) {
+                               ec.Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
+                                       AsString (), TypeManager.CSharpName (target));
+                       } else {
+                               base.Error_ValueCannotBeConverted (ec, loc, target, expl);
+                       }
                }
 
-               public DecimalConstant ToDecimal (Location loc)
+               public Constant ImplicitConversionRequired (ResolveContext ec, TypeSpec type, Location loc)
                {
-                       DecimalConstant c = ConvertToDecimal ();
-
+                       Constant c = ConvertImplicitly (ec, type);
                        if (c == null)
-                               Error_ValueCannotBeConverted (loc, TypeManager.decimal_type, false);
+                               Error_ValueCannotBeConverted (ec, loc, type, false);
 
                        return c;
                }
 
-               public virtual Constant ToType (Type type, Location loc)
+               public virtual Constant ConvertImplicitly (ResolveContext rc, TypeSpec type)
                {
-                       if (Type == type)
-                               return this;
-
-                       if (type == TypeManager.object_type)
+                       if (this.type == type)
                                return this;
 
-                       if (!Convert.ImplicitStandardConversionExists (this, type)){
-                               Error_ValueCannotBeConverted (loc, type, false);
+                       if (Convert.ImplicitNumericConversion (this, type) == null) 
                                return null;
-                       }
-
-                       // Special-case: The 0 literal can be converted to an enum value,
-                       // and ImplicitStandardConversionExists will return true in that case.
-                       if (IsZeroInteger && Type == TypeManager.int32_type && TypeManager.IsEnumType (type)) {
-                               return new EnumConstant (this, type);
-                       }
 
                        bool fail;                      
                        object constant_value = TypeManager.ChangeType (GetValue (), type, out fail);
                        if (fail){
-                               Error_ValueCannotBeConverted (loc, type, false);
-                               
                                //
                                // We should always catch the error before this is ever
                                // reached, by calling Convert.ImplicitStandardConversionExists
                                //
-                               throw new Exception (
-                                       String.Format ("LookupConstantValue: This should never be reached {0} {1}", Type, type));
-                       }
-
-                       Constant retval;
-                       if (type == TypeManager.int32_type)
-                               retval = new IntConstant ((int) constant_value, loc);
-                       else if (type == TypeManager.uint32_type)
-                               retval = new UIntConstant ((uint) constant_value, loc);
-                       else if (type == TypeManager.int64_type)
-                               retval = new LongConstant ((long) constant_value, loc);
-                       else if (type == TypeManager.uint64_type)
-                               retval = new ULongConstant ((ulong) constant_value, loc);
-                       else if (type == TypeManager.float_type)
-                               retval = new FloatConstant ((float) constant_value, loc);
-                       else if (type == TypeManager.double_type)
-                               retval = new DoubleConstant ((double) constant_value, loc);
-                       else if (type == TypeManager.string_type)
-                               retval = new StringConstant ((string) constant_value, loc);
-                       else if (type == TypeManager.short_type)
-                               retval = new ShortConstant ((short) constant_value, loc);
-                       else if (type == TypeManager.ushort_type)
-                               retval = new UShortConstant ((ushort) constant_value, loc);
-                       else if (type == TypeManager.sbyte_type)
-                               retval = new SByteConstant ((sbyte) constant_value, loc);
-                       else if (type == TypeManager.byte_type)
-                               retval = new ByteConstant ((byte) constant_value, loc);
-                       else if (type == TypeManager.char_type)
-                               retval = new CharConstant ((char) constant_value, loc);
-                       else if (type == TypeManager.bool_type)
-                               retval = new BoolConstant ((bool) constant_value, loc);
-                       else if (type == TypeManager.decimal_type)
-                               retval = new DecimalConstant ((decimal) constant_value, loc);
-                       else
-                               throw new Exception ("LookupConstantValue: Unhandled constant type: " + type);
-                       
-                       return retval;
-               }
-
-               protected static void CheckRange (bool inCheckedContext, ulong value, ulong max)
-               {
-                       if (!inCheckedContext)
-                               return;
+                               throw new InternalErrorException ("Missing constant conversion between `{0}' and `{1}'",
+                                 TypeManager.CSharpName (Type), TypeManager.CSharpName (type));
+                       }
 
-                       if (value > max)
-                               throw new OverflowException ();
+                       return CreateConstant (rc, type, constant_value, loc);
                }
 
-               protected static void CheckRange (bool inCheckedContext, double value, long min, long max)
+               //
+               //  Returns a constant instance based on Type
+               //
+               public static Constant CreateConstant (ResolveContext rc, TypeSpec t, object v, Location loc)
                {
-                       if (!inCheckedContext)
-                               return;
-
-                       if (((value < min) || (value > max)))
-                               throw new OverflowException ();
-
-                       if (double.IsNaN (value))
-                               throw new OverflowException ();
+                       return CreateConstantFromValue (t, v, loc).Resolve (rc);
                }
 
-               protected static void CheckRange (bool inCheckedContext, double value, ulong min, ulong max)
+               public static Constant CreateConstantFromValue (TypeSpec t, object v, Location loc)
                {
-                       if (!inCheckedContext)
-                               return;
+                       if (t == TypeManager.int32_type)
+                               return new IntConstant ((int) v, loc);
+                       if (t == TypeManager.string_type)
+                               return new StringConstant ((string) v, loc);
+                       if (t == TypeManager.uint32_type)
+                               return new UIntConstant ((uint) v, loc);
+                       if (t == TypeManager.int64_type)
+                               return new LongConstant ((long) v, loc);
+                       if (t == TypeManager.uint64_type)
+                               return new ULongConstant ((ulong) v, loc);
+                       if (t == TypeManager.float_type)
+                               return new FloatConstant ((float) v, loc);
+                       if (t == TypeManager.double_type)
+                               return new DoubleConstant ((double) v, loc);
+                       if (t == TypeManager.short_type)
+                               return new ShortConstant ((short)v, loc);
+                       if (t == TypeManager.ushort_type)
+                               return new UShortConstant ((ushort)v, loc);
+                       if (t == TypeManager.sbyte_type)
+                               return new SByteConstant ((sbyte)v, loc);
+                       if (t == TypeManager.byte_type)
+                               return new ByteConstant ((byte)v, loc);
+                       if (t == TypeManager.char_type)
+                               return new CharConstant ((char)v, loc);
+                       if (t == TypeManager.bool_type)
+                               return new BoolConstant ((bool) v, loc);
+                       if (t == TypeManager.decimal_type)
+                               return new DecimalConstant ((decimal) v, loc);
+                       if (TypeManager.IsEnumType (t)) {
+                               var real_type = EnumSpec.GetUnderlyingType (t);
+                               return new EnumConstant (CreateConstantFromValue (real_type, v, loc).Resolve (null), t);
+                       }
+                       if (v == null) {
+                               if (TypeManager.IsNullableType (t))
+                                       return Nullable.LiftedNull.Create (t, loc);
 
-                       if (((value < min) || (value > max)))
-                               throw new OverflowException ();
+                               if (TypeManager.IsReferenceType (t))
+                                       return new NullConstant (t, loc);
+                       }
 
-                       if (double.IsNaN (value))
-                               throw new OverflowException ();
+                       throw new InternalErrorException ("Constant value `{0}' has unexpected underlying type `{1}'",
+                               v, TypeManager.CSharpName (t));
                }
 
-               protected static void CheckUnsigned (bool inCheckedContext, long value)
+               public override Expression CreateExpressionTree (ResolveContext ec)
                {
-                       if (!inCheckedContext)
-                               return;
+                       Arguments args = new Arguments (2);
+                       args.Add (new Argument (this));
+                       args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 
-                       if (value < 0)
-                               throw new OverflowException ();
+                       return CreateExpressionFactoryCall (ec, "Constant", args);
                }
 
+
                /// <summary>
                /// Maybe ConvertTo name is better. It tries to convert `this' constant to target_type.
                /// It throws OverflowException 
                /// </summary>
-               public abstract Constant Reduce (bool inCheckedContext, Type target_type);
+               // DON'T CALL THIS METHOD DIRECTLY AS IT DOES NOT HANDLE ENUMS
+               public abstract Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type);
 
                /// <summary>
                ///   Attempts to do a compile-time folding of a constant cast.
                /// </summary>
-               public Constant TryReduce (EmitContext ec, Type target_type, Location loc)
+               public Constant TryReduce (ResolveContext ec, TypeSpec target_type, Location loc)
                {
                        try {
-                               return  TryReduce (ec, target_type);
+                               return TryReduce (ec, target_type);
                        }
                        catch (OverflowException) {
-                               Report.Error (221, loc, "Constant value `{0}' cannot be converted to a `{1}' (use `unchecked' syntax to override)",
-                                       GetValue ().ToString (), TypeManager.CSharpName (target_type));
-                               throw;
+                               if (ec.ConstantCheckState) {                            
+                                       ec.Report.Error (221, loc, "Constant value `{0}' cannot be converted to a `{1}' (use `unchecked' syntax to override)",
+                                               GetValue ().ToString (), TypeManager.CSharpName (target_type));
+                               } else {
+                                       Error_ValueCannotBeConverted (ec, loc, target_type, false);
+                               }
+
+                               return New.Constantify (target_type).Resolve (ec);
                        }
                }
 
-               Constant TryReduce (EmitContext ec, Type target_type)
+               Constant TryReduce (ResolveContext ec, TypeSpec target_type)
                {
                        if (Type == target_type)
                                return this;
 
+                       Constant c;
                        if (TypeManager.IsEnumType (target_type)) {
-                               Constant c = TryReduce (ec, TypeManager.EnumToUnderlying (target_type));
+                               c = TryReduce (ec, EnumSpec.GetUnderlyingType (target_type));
                                if (c == null)
                                        return null;
 
-                               return new EnumConstant (c, target_type);
+                               return new EnumConstant (c, target_type).Resolve (ec);
                        }
 
-                       return Reduce (ec.ConstantCheckState, target_type);
-               }
-
-
-               public virtual DecimalConstant ConvertToDecimal ()
-               {
-                       return null;
-               }
-               
-               public virtual DoubleConstant ConvertToDouble ()
-               {
-                       return null;
-               }
-
-               public virtual FloatConstant ConvertToFloat ()
-               {
-                       return null;
-               }
-
-               public virtual ULongConstant ConvertToULong ()
-               {
-                       return null;
-               }
-
-               public virtual LongConstant ConvertToLong ()
-               {
-                       return null;
-               }
-
-               public virtual UIntConstant ConvertToUInt ()
-               {
-                       return null;
-               }
+                       c = ConvertExplicitly (ec.ConstantCheckState, target_type);
+                       if (c != null)
+                               c = c.Resolve (ec);
 
-               public virtual IntConstant ConvertToInt ()
-               {
-                       return null;
+                       return c;
                }
 
-               public abstract Constant Increment ();
-               
                /// <summary>
                /// Need to pass type as the constant can require a boxing
                /// and in such case no optimization is possible
                /// </summary>
-               public bool IsDefaultInitializer (Type type)
+               public bool IsDefaultInitializer (TypeSpec type)
                {
                        if (type == Type)
                                return IsDefaultValue;
 
-                       return Type == TypeManager.null_type;
+                       return this is NullLiteral;
                }
 
                public abstract bool IsDefaultValue {
@@ -355,6 +225,17 @@ namespace Mono.CSharp {
                        get;
                }
 
+               //
+               // When constant is declared as literal
+               //
+               public virtual bool IsLiteral {
+                       get { return false; }
+               }
+               
+               public virtual bool IsOneInteger {
+                       get { return false; }
+               }               
+
                //
                // Returns true iff 1) the stack type of this is one of Object, 
                // int32, int64 and 2) this == 0 or this == null.
@@ -362,6 +243,42 @@ namespace Mono.CSharp {
                public virtual bool IsZeroInteger {
                        get { return false; }
                }
+
+               public override void EmitSideEffect (EmitContext ec)
+               {
+                       // do nothing
+               }
+
+               protected override void CloneTo (CloneContext clonectx, Expression target)
+               {
+                       // CloneTo: Nothing, we do not keep any state on this expression
+               }
+
+               public override System.Linq.Expressions.Expression MakeExpression (BuilderContext ctx)
+               {
+                       return System.Linq.Expressions.Expression.Constant (GetTypedValue (), type.GetMetaInfo ());
+               }
+
+               public new Constant Resolve (ResolveContext rc)
+               {
+                       if (eclass != ExprClass.Unresolved)
+                               return this;
+
+                       // Resolved constant has to be still a constant
+                       Constant c = (Constant) DoResolve (rc);
+                       if (c == null)
+                               return null;
+
+                       if ((c.eclass & ExprClass.Value) == 0) {
+                               c.Error_UnexpectedKind (rc, ResolveFlags.VariableOrValue, loc);
+                               return null;
+                       }
+
+                       if (c.type == null)
+                               throw new InternalErrorException ("Expression `{0}' did not set its type after Resolve", c.GetType ());
+
+                       return c;
+               }
        }
 
        public abstract class IntegralConstant : Constant {
@@ -370,18 +287,20 @@ namespace Mono.CSharp {
                {
                }
 
-               public override void Error_ValueCannotBeConverted (Location loc, Type target, bool expl)
+               public override void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, TypeSpec target, bool expl)
                {
                        try {
-                               Reduce (true, target);
-                               base.Error_ValueCannotBeConverted (loc, target, expl);
+                               ConvertExplicitly (true, target);
+                               base.Error_ValueCannotBeConverted (ec, loc, target, expl);
                        }
-                       catch 
+                       catch
                        {
-                               Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
+                               ec.Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
                                        GetValue ().ToString (), TypeManager.CSharpName (target));
                        }
                }
+               
+               public abstract Constant Increment ();
        }
        
        public class BoolConstant : Constant {
@@ -390,9 +309,6 @@ namespace Mono.CSharp {
                public BoolConstant (bool val, Location loc):
                        base (loc)
                {
-                       type = TypeManager.bool_type;
-                       eclass = ExprClass.Value;
-
                        Value = val;
                }
 
@@ -401,25 +317,31 @@ namespace Mono.CSharp {
                        return Value ? "true" : "false";
                }
 
+               protected override Expression DoResolve (ResolveContext ec)
+               {
+                       type = TypeManager.bool_type;
+                       eclass = ExprClass.Value;
+                       return this;
+               }
+
                public override object GetValue ()
                {
                        return (object) Value;
                }
-                               
+
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
+               {
+                       enc.Stream.Write (Value);
+               }
                
                public override void Emit (EmitContext ec)
                {
                        if (Value)
-                               ec.ig.Emit (OpCodes.Ldc_I4_1);
+                               ec.Emit (OpCodes.Ldc_I4_1);
                        else
-                               ec.ig.Emit (OpCodes.Ldc_I4_0);
+                               ec.Emit (OpCodes.Ldc_I4_0);
                }
 
-               public override Constant Increment ()
-               {
-                       throw new NotSupportedException ();
-               }
-       
                public override bool IsDefaultValue {
                        get {
                                return !Value;
@@ -436,7 +358,7 @@ namespace Mono.CSharp {
                        get { return Value == false; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        return null;
                }
@@ -449,54 +371,34 @@ namespace Mono.CSharp {
                public ByteConstant (byte v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.byte_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               public override void Emit (EmitContext ec)
-               {
-                       IntLiteral.EmitInt (ec.ig, Value);
-               }
-
-               public override string AsString ()
-               {
-                       return Value.ToString ();
-               }
-
-               public override object GetValue ()
-               {
-                       return Value;
-               }
-
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       return new FloatConstant (Value, loc);
+                       enc.Stream.Write (Value);
                }
 
-               public override ULongConstant ConvertToULong ()
+               public override void Emit (EmitContext ec)
                {
-                       return new ULongConstant (Value, loc);
+                       ec.EmitInt (Value);
                }
 
-               public override LongConstant ConvertToLong ()
+               public override string AsString ()
                {
-                       return new LongConstant (Value, loc);
+                       return Value.ToString ();
                }
 
-               public override UIntConstant ConvertToUInt ()
+               protected override Expression DoResolve (ResolveContext ec)
                {
-                       return new UIntConstant (Value, loc);
+                       type = TypeManager.byte_type;
+                       eclass = ExprClass.Value;
+                       return this;
                }
 
-               public override IntConstant ConvertToInt ()
+               public override object GetValue ()
                {
-                       return new IntConstant (Value, loc);
+                       return Value;
                }
 
                public override Constant Increment ()
@@ -510,6 +412,12 @@ namespace Mono.CSharp {
                        }
                }
 
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
+
                public override bool IsNegative {
                        get {
                                return false;
@@ -520,10 +428,13 @@ namespace Mono.CSharp {
                        get { return Value == 0; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > SByte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type)
@@ -557,18 +468,28 @@ namespace Mono.CSharp {
 
                public CharConstant (char v, Location loc):
                        base (loc)
+               {
+                       Value = v;
+               }
+
+               protected override Expression DoResolve (ResolveContext rc)
                {
                        type = TypeManager.char_type;
                        eclass = ExprClass.Value;
-                       Value = v;
+                       return this;
+               }
+
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
+               {
+                       enc.Stream.Write ((ushort) Value);
                }
 
                public override void Emit (EmitContext ec)
                {
-                       IntLiteral.EmitInt (ec.ig, Value);
+                       ec.EmitInt (Value);
                }
 
-               static public string descape (char c)
+               static string descape (char c)
                {
                        switch (c){
                        case '\a':
@@ -607,41 +528,6 @@ namespace Mono.CSharp {
                        return Value;
                }
 
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
-               {
-                       return new FloatConstant (Value, loc);
-               }
-
-               public override ULongConstant ConvertToULong ()
-               {
-                       return new ULongConstant (Value, loc);
-               }
-
-               public override LongConstant ConvertToLong ()
-               {
-                       return new LongConstant (Value, loc);
-               }
-
-               public override UIntConstant ConvertToUInt ()
-               {
-                       return new UIntConstant (Value, loc);
-               }
-
-               public override IntConstant ConvertToInt ()
-               {
-                       return new IntConstant (Value, loc);
-               }
-
-               public override Constant Increment ()
-               {
-                       return new CharConstant (checked ((char)(Value + 1)), loc);
-               }
-               
                public override bool IsDefaultValue {
                        get {
                                return Value == 0;
@@ -658,18 +544,27 @@ namespace Mono.CSharp {
                        get { return Value == '\0'; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Byte.MinValue, Byte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Byte.MinValue || Value > Byte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > SByte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, Int16.MinValue, Int16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > Int16.MaxValue)
+                                               throw new OverflowException ();
+                               }                                       
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type)
@@ -698,57 +593,34 @@ namespace Mono.CSharp {
                public SByteConstant (sbyte v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.sbyte_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               public override void Emit (EmitContext ec)
-               {
-                       IntLiteral.EmitInt (ec.ig, Value);
-               }
-
-               public override string AsString ()
-               {
-                       return Value.ToString ();
-               }
-
-               public override object GetValue ()
-               {
-                       return Value;
-               }
-
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
+               protected override Expression DoResolve (ResolveContext rc)
                {
-                       return new FloatConstant (Value, loc);
+                       type = TypeManager.sbyte_type;
+                       eclass = ExprClass.Value;
+                       return this;
                }
 
-               public override ULongConstant ConvertToULong ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       if (Value >= 0)
-                               return new ULongConstant ((ulong) Value, loc);
-                       
-                       return null;
+                       enc.Stream.Write (Value);
                }
 
-               public override LongConstant ConvertToLong ()
+               public override void Emit (EmitContext ec)
                {
-                       return new LongConstant (Value, loc);
+                       ec.EmitInt (Value);
                }
 
-               public override UIntConstant ConvertToUInt ()
+               public override string AsString ()
                {
-                       return null;
+                       return Value.ToString ();
                }
 
-               public override IntConstant ConvertToInt ()
+               public override object GetValue ()
                {
-                       return new IntConstant (Value, loc);
+                       return Value;
                }
 
                public override Constant Increment ()
@@ -768,30 +640,40 @@ namespace Mono.CSharp {
                        }
                }
                
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
+               
                public override bool IsZeroInteger {
                        get { return Value == 0; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type)
                                return new ShortConstant ((short) Value, Location);
                        if (target_type == TypeManager.ushort_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new UShortConstant ((ushort) Value, Location);
                        } if (target_type == TypeManager.int32_type)
                                  return new IntConstant ((int) Value, Location);
                        if (target_type == TypeManager.uint32_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new UIntConstant ((uint) Value, Location);
                        } if (target_type == TypeManager.int64_type)
                                  return new LongConstant ((long) Value, Location);
                        if (target_type == TypeManager.uint64_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new ULongConstant ((ulong) Value, Location);
                        }
                        if (target_type == TypeManager.float_type)
@@ -799,7 +681,8 @@ namespace Mono.CSharp {
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -816,54 +699,34 @@ namespace Mono.CSharp {
                public ShortConstant (short v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.short_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               public override void Emit (EmitContext ec)
-               {
-                       IntLiteral.EmitInt (ec.ig, Value);
-               }
-
-               public override string AsString ()
+               protected override Expression DoResolve (ResolveContext rc)
                {
-                       return Value.ToString ();
-               }
-
-               public override object GetValue ()
-               {
-                       return Value;
-               }
-
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
-               {
-                       return new FloatConstant (Value, loc);
+                       type = TypeManager.short_type;
+                       eclass = ExprClass.Value;
+                       return this;
                }
 
-               public override ULongConstant ConvertToULong ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       return null;
+                       enc.Stream.Write (Value);
                }
 
-               public override LongConstant ConvertToLong ()
+               public override void Emit (EmitContext ec)
                {
-                       return new LongConstant (Value, loc);
+                       ec.EmitInt (Value);
                }
 
-               public override UIntConstant ConvertToUInt ()
+               public override string AsString ()
                {
-                       return null;
+                       return Value.ToString ();
                }
 
-               public override IntConstant ConvertToInt ()
+               public override object GetValue ()
                {
-                       return new IntConstant (Value, loc);
+                       return Value;
                }
 
                public override Constant Increment ()
@@ -886,31 +749,47 @@ namespace Mono.CSharp {
                                return Value < 0;
                        }
                }
+               
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Byte.MinValue, Byte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Byte.MinValue || Value > Byte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < SByte.MinValue || Value > SByte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.ushort_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
+                               
                                return new UShortConstant ((ushort) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type)
                                return new IntConstant ((int) Value, Location);
                        if (target_type == TypeManager.uint32_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new UIntConstant ((uint) Value, Location);
                        }
                        if (target_type == TypeManager.int64_type)
                                return new LongConstant ((long) Value, Location);
                        if (target_type == TypeManager.uint64_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new ULongConstant ((ulong) Value, Location);
                        }
                        if (target_type == TypeManager.float_type)
@@ -918,7 +797,10 @@ namespace Mono.CSharp {
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, Char.MinValue, Char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Char.MinValue)
+                                               throw new OverflowException ();
+                               }
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -935,54 +817,34 @@ namespace Mono.CSharp {
                public UShortConstant (ushort v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.ushort_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               public override void Emit (EmitContext ec)
-               {
-                       IntLiteral.EmitInt (ec.ig, Value);
-               }
-
-               public override string AsString ()
-               {
-                       return Value.ToString ();
-               }
-
-               public override object GetValue ()
-               {
-                       return Value;
-               }
-
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
+               protected override Expression DoResolve (ResolveContext rc)
                {
-                       return new FloatConstant (Value, loc);
+                       type = TypeManager.ushort_type;
+                       eclass = ExprClass.Value;
+                       return this;
                }
 
-               public override ULongConstant ConvertToULong ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       return new ULongConstant (Value, loc);
+                       enc.Stream.Write (Value);
                }
 
-               public override LongConstant ConvertToLong ()
+               public override void Emit (EmitContext ec)
                {
-                       return new LongConstant (Value, loc);
+                       ec.EmitInt (Value);
                }
 
-               public override UIntConstant ConvertToUInt ()
+               public override string AsString ()
                {
-                       return new UIntConstant (Value, loc);
+                       return Value.ToString ();
                }
 
-               public override IntConstant ConvertToInt ()
+               public override object GetValue ()
                {
-                       return new IntConstant (Value, loc);
+                       return Value;
                }
        
                public override Constant Increment ()
@@ -1001,23 +863,38 @@ namespace Mono.CSharp {
                                return false;
                        }
                }
+               
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
        
                public override bool IsZeroInteger {
                        get { return Value == 0; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Byte.MinValue, Byte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > Byte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > SByte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, Int16.MinValue, Int16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > Int16.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type)
@@ -1033,7 +910,10 @@ namespace Mono.CSharp {
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, Char.MinValue, Char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > Char.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -1049,66 +929,24 @@ namespace Mono.CSharp {
                public IntConstant (int v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.int32_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               static public void EmitInt (ILGenerator ig, int i)
+               protected override Expression DoResolve (ResolveContext rc)
                {
-                       switch (i){
-                       case -1:
-                               ig.Emit (OpCodes.Ldc_I4_M1);
-                               break;
-                               
-                       case 0:
-                               ig.Emit (OpCodes.Ldc_I4_0);
-                               break;
-                               
-                       case 1:
-                               ig.Emit (OpCodes.Ldc_I4_1);
-                               break;
-                               
-                       case 2:
-                               ig.Emit (OpCodes.Ldc_I4_2);
-                               break;
-                               
-                       case 3:
-                               ig.Emit (OpCodes.Ldc_I4_3);
-                               break;
-                               
-                       case 4:
-                               ig.Emit (OpCodes.Ldc_I4_4);
-                               break;
-                               
-                       case 5:
-                               ig.Emit (OpCodes.Ldc_I4_5);
-                               break;
-                               
-                       case 6:
-                               ig.Emit (OpCodes.Ldc_I4_6);
-                               break;
-                               
-                       case 7:
-                               ig.Emit (OpCodes.Ldc_I4_7);
-                               break;
-                               
-                       case 8:
-                               ig.Emit (OpCodes.Ldc_I4_8);
-                               break;
+                       type = TypeManager.int32_type;
+                       eclass = ExprClass.Value;
+                       return this;
+               }
 
-                       default:
-                               if (i >= -128 && i <= 127){
-                                       ig.Emit (OpCodes.Ldc_I4_S, (sbyte) i);
-                               } else
-                                       ig.Emit (OpCodes.Ldc_I4, i);
-                               break;
-                       }
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
+               {
+                       enc.Stream.Write (Value);
                }
 
                public override void Emit (EmitContext ec)
                {
-                       EmitInt (ec.ig, Value);
+                       ec.EmitInt (Value);
                }
 
                public override string AsString ()
@@ -1121,47 +959,6 @@ namespace Mono.CSharp {
                        return Value;
                }
 
-               public override DecimalConstant ConvertToDecimal()
-               {
-                       return new DecimalConstant (Value, loc);
-               }
-
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
-               {
-                       return new FloatConstant (Value, loc);
-               }
-
-               public override ULongConstant ConvertToULong ()
-               {
-                       if (Value < 0)
-                               return null;
-
-                       return new ULongConstant ((ulong) Value, loc);
-               }
-
-               public override LongConstant ConvertToLong ()
-               {
-                       return new LongConstant (Value, loc);
-               }
-
-               public override UIntConstant ConvertToUInt ()
-               {
-                       if (Value < 0)
-                               return null;
-
-                       return new UIntConstant ((uint) Value, loc);
-               }
-
-               public override IntConstant ConvertToInt ()
-               {
-                       return this;
-               }
-
                public override Constant Increment ()
                {
                        return new IntConstant (checked(Value + 1), loc);
@@ -1178,37 +975,59 @@ namespace Mono.CSharp {
                                return Value < 0;
                        }
                }
+               
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
 
                public override bool IsZeroInteger {
                        get { return Value == 0; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Byte.MinValue, Byte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Byte.MinValue || Value > Byte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < SByte.MinValue || Value > SByte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, Int16.MinValue, Int16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Int16.MinValue || Value > Int16.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.ushort_type) {
-                               CheckRange (inCheckedContext, Value, UInt16.MinValue, UInt16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < UInt16.MinValue || Value > UInt16.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new UShortConstant ((ushort) Value, Location);
                        }
                        if (target_type == TypeManager.uint32_type) {
-                               CheckRange (inCheckedContext, Value, UInt32.MinValue, UInt32.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < UInt32.MinValue)
+                                               throw new OverflowException ();
+                               }
                                return new UIntConstant ((uint) Value, Location);
                        }
                        if (target_type == TypeManager.int64_type)
                                return new LongConstant ((long) Value, Location);
                        if (target_type == TypeManager.uint64_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new ULongConstant ((ulong) Value, Location);
                        }
                        if (target_type == TypeManager.float_type)
@@ -1216,7 +1035,10 @@ namespace Mono.CSharp {
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, Char.MinValue, Char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Char.MinValue || Value > Char.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -1224,64 +1046,100 @@ namespace Mono.CSharp {
 
                        return null;
                }
-       }
 
-       public class UIntConstant : IntegralConstant {
-               public readonly uint Value;
-
-               public UIntConstant (uint v, Location loc):
-                       base (loc)
+               public override Constant ConvertImplicitly (ResolveContext rc, TypeSpec type)
                {
-                       type = TypeManager.uint32_type;
-                       eclass = ExprClass.Value;
-                       Value = v;
-               }
+                       if (this.type == type)
+                               return this;
 
-               public override void Emit (EmitContext ec)
-               {
-                       IntLiteral.EmitInt (ec.ig, unchecked ((int) Value));
-               }
+                       Constant c = TryImplicitIntConversion (type);
+                       if (c != null)
+                               return c.Resolve (rc);
 
-               public override string AsString ()
-               {
-                       return Value.ToString ();
+                       return base.ConvertImplicitly (rc, type);
                }
 
-               public override object GetValue ()
+               /// <summary>
+               ///   Attempts to perform an implicit constant conversion of the IntConstant
+               ///   into a different data type using casts (See Implicit Constant
+               ///   Expression Conversions)
+               /// </summary>
+               Constant TryImplicitIntConversion (TypeSpec target_type)
                {
-                       return Value;
+                       if (target_type == TypeManager.sbyte_type) {
+                               if (Value >= SByte.MinValue && Value <= SByte.MaxValue)
+                                       return new SByteConstant ((sbyte) Value, loc);
+                       } 
+                       else if (target_type == TypeManager.byte_type) {
+                               if (Value >= Byte.MinValue && Value <= Byte.MaxValue)
+                                       return new ByteConstant ((byte) Value, loc);
+                       } 
+                       else if (target_type == TypeManager.short_type) {
+                               if (Value >= Int16.MinValue && Value <= Int16.MaxValue)
+                                       return new ShortConstant ((short) Value, loc);
+                       } 
+                       else if (target_type == TypeManager.ushort_type) {
+                               if (Value >= UInt16.MinValue && Value <= UInt16.MaxValue)
+                                       return new UShortConstant ((ushort) Value, loc);
+                       } 
+                       else if (target_type == TypeManager.uint32_type) {
+                               if (Value >= 0)
+                                       return new UIntConstant ((uint) Value, loc);
+                       } 
+                       else if (target_type == TypeManager.uint64_type) {
+                               //
+                               // we can optimize this case: a positive int32
+                               // always fits on a uint64.  But we need an opcode
+                               // to do it.
+                               //
+                               if (Value >= 0)
+                                       return new ULongConstant ((ulong) Value, loc);
+                       } 
+                       else if (target_type == TypeManager.double_type)
+                               return new DoubleConstant ((double) Value, loc);
+                       else if (target_type == TypeManager.float_type)
+                               return new FloatConstant ((float) Value, loc);
+
+                       return null;
                }
+       }
+
+       public class UIntConstant : IntegralConstant {
+               public readonly uint Value;
 
-               public override DoubleConstant ConvertToDouble ()
+               public UIntConstant (uint v, Location loc):
+                       base (loc)
                {
-                       return new DoubleConstant (Value, loc);
+                       Value = v;
                }
 
-               public override FloatConstant ConvertToFloat ()
+               protected override Expression DoResolve (ResolveContext rc)
                {
-                       return new FloatConstant (Value, loc);
+                       type = TypeManager.uint32_type;
+                       eclass = ExprClass.Value;
+                       return this;
                }
 
-               public override ULongConstant ConvertToULong ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       return new ULongConstant (Value, loc);
+                       enc.Stream.Write (Value);
                }
 
-               public override LongConstant ConvertToLong ()
+               public override void Emit (EmitContext ec)
                {
-                       return new LongConstant (Value, loc);
+                       ec.EmitInt (unchecked ((int) Value));
                }
 
-               public override UIntConstant ConvertToUInt ()
+               public override string AsString ()
                {
-                       return this;
+                       return Value.ToString ();
                }
 
-               public override IntConstant ConvertToInt ()
+               public override object GetValue ()
                {
-                       return null;
+                       return Value;
                }
-       
+
                public override Constant Increment ()
                {
                        return new UIntConstant (checked(Value + 1), loc);
@@ -1298,31 +1156,52 @@ namespace Mono.CSharp {
                                return false;
                        }
                }
+               
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
 
                public override bool IsZeroInteger {
                        get { return Value == 0; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Char.MinValue, Char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Char.MinValue || Value > Char.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > SByte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, Int16.MinValue, Int16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > Int16.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.ushort_type) {
-                               CheckRange (inCheckedContext, Value, UInt16.MinValue, UInt16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < UInt16.MinValue || Value > UInt16.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new UShortConstant ((ushort) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type) {
-                               CheckRange (inCheckedContext, Value, Int32.MinValue, Int32.MaxValue);
+                               if (in_checked_context){
+                                       if (Value > Int32.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new IntConstant ((int) Value, Location);
                        }
                        if (target_type == TypeManager.int64_type)
@@ -1334,7 +1213,10 @@ namespace Mono.CSharp {
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, Char.MinValue, Char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Char.MinValue || Value > Char.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -1350,25 +1232,25 @@ namespace Mono.CSharp {
 
                public LongConstant (long v, Location loc):
                        base (loc)
+               {
+                       Value = v;
+               }
+
+               protected override Expression DoResolve (ResolveContext rc)
                {
                        type = TypeManager.int64_type;
                        eclass = ExprClass.Value;
-                       Value = v;
+                       return this;
                }
 
-               public override void Emit (EmitContext ec)
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       EmitLong (ec.ig, Value);
+                       enc.Stream.Write (Value);
                }
 
-               static public void EmitLong (ILGenerator ig, long l)
+               public override void Emit (EmitContext ec)
                {
-                       if (l >= int.MinValue && l <= int.MaxValue) {
-                               IntLiteral.EmitInt (ig, unchecked ((int) l));
-                               ig.Emit (OpCodes.Conv_I8);
-                               return;
-                       }
-                       ig.Emit (OpCodes.Ldc_I8, l);
+                       ec.EmitLong (Value);
                }
 
                public override string AsString ()
@@ -1381,39 +1263,6 @@ namespace Mono.CSharp {
                        return Value;
                }
 
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
-               {
-                       return new FloatConstant (Value, loc);
-               }
-
-               public override ULongConstant ConvertToULong ()
-               {
-                       if (Value < 0)
-                               return null;
-                       
-                       return new ULongConstant ((ulong) Value, loc);
-               }
-
-               public override LongConstant ConvertToLong ()
-               {
-                       return this;
-               }
-
-               public override UIntConstant ConvertToUInt ()
-               {
-                       return null;
-               }
-
-               public override IntConstant ConvertToInt ()
-               {
-                       return null;
-               }
-
                public override Constant Increment ()
                {
                        return new LongConstant (checked(Value + 1), loc);
@@ -1430,39 +1279,64 @@ namespace Mono.CSharp {
                                return Value < 0;
                        }
                }
+               
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
 
                public override bool IsZeroInteger {
                        get { return Value == 0; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Byte.MinValue, Byte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Byte.MinValue || Value > Byte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < SByte.MinValue || Value > SByte.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, Int16.MinValue, Int16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Int16.MinValue || Value > Int16.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.ushort_type) {
-                               CheckRange (inCheckedContext, Value, UInt16.MinValue, UInt16.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < UInt16.MinValue || Value > UInt16.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new UShortConstant ((ushort) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type) {
-                               CheckRange (inCheckedContext, Value, Int32.MinValue, Int32.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Int32.MinValue || Value > Int32.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new IntConstant ((int) Value, Location);
                        }
                        if (target_type == TypeManager.uint32_type) {
-                               CheckRange (inCheckedContext, Value, UInt32.MinValue, UInt32.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < UInt32.MinValue || Value > UInt32.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new UIntConstant ((uint) Value, Location);
                        }
                        if (target_type == TypeManager.uint64_type) {
-                               CheckUnsigned (inCheckedContext, Value);
+                               if (in_checked_context && Value < 0)
+                                       throw new OverflowException ();
                                return new ULongConstant ((ulong) Value, Location);
                        }
                        if (target_type == TypeManager.float_type)
@@ -1470,7 +1344,10 @@ namespace Mono.CSharp {
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, Char.MinValue, Char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Char.MinValue || Value > Char.MaxValue)
+                                               throw new OverflowException ();
+                               }
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -1479,6 +1356,14 @@ namespace Mono.CSharp {
                        return null;
                }
 
+               public override Constant ConvertImplicitly (ResolveContext rc, TypeSpec type)
+               {
+                       if (Value >= 0 && type == TypeManager.uint64_type) {
+                               return new ULongConstant ((ulong) Value, loc).Resolve (rc);
+                       }
+
+                       return base.ConvertImplicitly (rc, type);
+               }
        }
 
        public class ULongConstant : IntegralConstant {
@@ -1487,56 +1372,34 @@ namespace Mono.CSharp {
                public ULongConstant (ulong v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.uint64_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               public override void Emit (EmitContext ec)
-               {
-                       ILGenerator ig = ec.ig;
-
-                       LongLiteral.EmitLong (ig, unchecked ((long) Value));
-               }
-
-               public override string AsString ()
-               {
-                       return Value.ToString ();
-               }
-
-               public override object GetValue ()
-               {
-                       return Value;
-               }
-
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
+               protected override Expression DoResolve (ResolveContext rc)
                {
-                       return new FloatConstant (Value, loc);
+                       type = TypeManager.uint64_type;
+                       eclass = ExprClass.Value;
+                       return this;
                }
 
-               public override ULongConstant ConvertToULong ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       return this;
+                       enc.Stream.Write (Value);
                }
 
-               public override LongConstant ConvertToLong ()
+               public override void Emit (EmitContext ec)
                {
-                       return null;
+                       ec.EmitLong (unchecked ((long) Value));
                }
 
-               public override UIntConstant ConvertToUInt ()
+               public override string AsString ()
                {
-                       return null;
+                       return Value.ToString ();
                }
 
-               public override IntConstant ConvertToInt ()
+               public override object GetValue ()
                {
-                       return null;
+                       return Value;
                }
 
                public override Constant Increment ()
@@ -1555,39 +1418,52 @@ namespace Mono.CSharp {
                                return false;
                        }
                }
+               
+               public override bool IsOneInteger {
+                       get {
+                               return Value == 1;
+                       }
+               }               
 
                public override bool IsZeroInteger {
                        get { return Value == 0; }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Byte.MaxValue);
+                               if (in_checked_context && Value > Byte.MaxValue)
+                                       throw new OverflowException ();
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, (ulong) SByte.MaxValue);
+                               if (in_checked_context && Value > ((ulong) SByte.MaxValue))
+                                       throw new OverflowException ();
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, (ulong) Int16.MaxValue);
+                               if (in_checked_context && Value > ((ulong) Int16.MaxValue))
+                                       throw new OverflowException ();
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.ushort_type) {
-                               CheckRange (inCheckedContext, Value, UInt16.MaxValue);
+                               if (in_checked_context && Value > UInt16.MaxValue)
+                                       throw new OverflowException ();
                                return new UShortConstant ((ushort) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type) {
-                               CheckRange (inCheckedContext, Value, Int32.MaxValue);
+                               if (in_checked_context && Value > UInt32.MaxValue)
+                                       throw new OverflowException ();
                                return new IntConstant ((int) Value, Location);
                        }
                        if (target_type == TypeManager.uint32_type) {
-                               CheckRange (inCheckedContext, Value, UInt32.MaxValue);
+                               if  (in_checked_context && Value > UInt32.MaxValue)
+                                       throw new OverflowException ();
                                return new UIntConstant ((uint) Value, Location);
                        }
                        if (target_type == TypeManager.int64_type) {
-                               CheckRange (inCheckedContext, Value, (ulong) Int64.MaxValue);
+                               if (in_checked_context && Value > Int64.MaxValue)
+                                       throw new OverflowException ();
                                return new LongConstant ((long) Value, Location);
                        }
                        if (target_type == TypeManager.float_type)
@@ -1595,7 +1471,8 @@ namespace Mono.CSharp {
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, Char.MaxValue);
+                               if (in_checked_context && Value > Char.MaxValue)
+                                       throw new OverflowException ();
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -1607,59 +1484,39 @@ namespace Mono.CSharp {
        }
 
        public class FloatConstant : Constant {
-               public readonly float Value;
+               public float Value;
 
                public FloatConstant (float v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.float_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               public override void Emit (EmitContext ec)
-               {
-                       ec.ig.Emit (OpCodes.Ldc_R4, Value);
-               }
-
-               public override string AsString ()
-               {
-                       return Value.ToString ();
-               }
-
-               public override object GetValue ()
-               {
-                       return Value;
-               }
-
-               public override DoubleConstant ConvertToDouble ()
-               {
-                       return new DoubleConstant (Value, loc);
-               }
-
-               public override FloatConstant ConvertToFloat ()
+               protected override Expression DoResolve (ResolveContext rc)
                {
+                       type = TypeManager.float_type;
+                       eclass = ExprClass.Value;
                        return this;
                }
 
-               public override LongConstant ConvertToLong ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       return null;
+                       enc.Stream.Write (Value);
                }
 
-               public override UIntConstant ConvertToUInt ()
+               public override void Emit (EmitContext ec)
                {
-                       return null;
+                       ec.Emit (OpCodes.Ldc_R4, Value);
                }
 
-               public override IntConstant ConvertToInt ()
+               public override string AsString ()
                {
-                       return null;
+                       return Value.ToString ();
                }
 
-               public override Constant Increment ()
+               public override object GetValue ()
                {
-                       return new FloatConstant (checked(Value + 1), loc);
+                       return Value;
                }
 
                public override bool IsDefaultValue {
@@ -1674,44 +1531,71 @@ namespace Mono.CSharp {
                        }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, byte.MinValue, byte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < byte.MinValue || Value > byte.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value,  sbyte.MinValue, sbyte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < sbyte.MinValue || Value > sbyte.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, short.MinValue, short.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < short.MinValue || Value > short.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.ushort_type) {
-                               CheckRange (inCheckedContext, Value, ushort.MinValue, ushort.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < ushort.MinValue || Value > ushort.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new UShortConstant ((ushort) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type) {
-                               CheckRange (inCheckedContext, Value, int.MinValue, int.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < int.MinValue || Value > int.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new IntConstant ((int) Value, Location);
                        }
                        if (target_type == TypeManager.uint32_type) {
-                               CheckRange (inCheckedContext, Value, uint.MinValue, uint.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < uint.MinValue || Value > uint.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new UIntConstant ((uint) Value, Location);
                        }
                        if (target_type == TypeManager.int64_type) {
-                               CheckRange (inCheckedContext, Value, long.MinValue, long.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < long.MinValue || Value > long.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new LongConstant ((long) Value, Location);
                        }
                        if (target_type == TypeManager.uint64_type) {
-                               CheckRange (inCheckedContext, Value, ulong.MinValue, ulong.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < ulong.MinValue || Value > ulong.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new ULongConstant ((ulong) Value, Location);
                        }
                        if (target_type == TypeManager.double_type)
                                return new DoubleConstant ((double) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, char.MinValue, char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < (float) char.MinValue || Value > (float) char.MaxValue || float.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -1723,64 +1607,39 @@ namespace Mono.CSharp {
        }
 
        public class DoubleConstant : Constant {
-               public readonly double Value;
+               public double Value;
 
                public DoubleConstant (double v, Location loc):
                        base (loc)
                {
-                       type = TypeManager.double_type;
-                       eclass = ExprClass.Value;
                        Value = v;
                }
 
-               public override void Emit (EmitContext ec)
-               {
-                       ec.ig.Emit (OpCodes.Ldc_R8, Value);
-               }
-
-               public override string AsString ()
-               {
-                       return Value.ToString ();
-               }
-
-               public override object GetValue ()
-               {
-                       return Value;
-               }
-
-               public override DoubleConstant ConvertToDouble ()
+               protected override Expression DoResolve (ResolveContext rc)
                {
+                       type = TypeManager.double_type;
+                       eclass = ExprClass.Value;
                        return this;
                }
 
-               public override FloatConstant ConvertToFloat ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       return null;
+                       enc.Stream.Write (Value);
                }
 
-               public override ULongConstant ConvertToULong ()
-               {
-                       return null;
-               }
-
-               public override LongConstant ConvertToLong ()
-               {
-                       return null;
-               }
-
-               public override UIntConstant ConvertToUInt ()
+               public override void Emit (EmitContext ec)
                {
-                       return null;
+                       ec.Emit (OpCodes.Ldc_R8, Value);
                }
 
-               public override IntConstant ConvertToInt ()
+               public override string AsString ()
                {
-                       return null;
+                       return Value.ToString ();
                }
 
-               public override Constant Increment ()
+               public override object GetValue ()
                {
-                       return new DoubleConstant (checked(Value + 1), loc);
+                       return Value;
                }
 
                public override bool IsDefaultValue {
@@ -1795,44 +1654,71 @@ namespace Mono.CSharp {
                        }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.byte_type) {
-                               CheckRange (inCheckedContext, Value, Byte.MinValue, Byte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < Byte.MinValue || Value > Byte.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new ByteConstant ((byte) Value, Location);
                        }
                        if (target_type == TypeManager.sbyte_type) {
-                               CheckRange (inCheckedContext, Value, SByte.MinValue, SByte.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < SByte.MinValue || Value > SByte.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new SByteConstant ((sbyte) Value, Location);
                        }
                        if (target_type == TypeManager.short_type) {
-                               CheckRange (inCheckedContext, Value, short.MinValue, short.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < short.MinValue || Value > short.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new ShortConstant ((short) Value, Location);
                        }
                        if (target_type == TypeManager.ushort_type) {
-                               CheckRange (inCheckedContext, Value, ushort.MinValue, ushort.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < ushort.MinValue || Value > ushort.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new UShortConstant ((ushort) Value, Location);
                        }
                        if (target_type == TypeManager.int32_type) {
-                               CheckRange (inCheckedContext, Value, int.MinValue, int.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < int.MinValue || Value > int.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new IntConstant ((int) Value, Location);
                        }
                        if (target_type == TypeManager.uint32_type) {
-                               CheckRange (inCheckedContext, Value, uint.MinValue, uint.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < uint.MinValue || Value > uint.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new UIntConstant ((uint) Value, Location);
                        }
                        if (target_type == TypeManager.int64_type) {
-                               CheckRange (inCheckedContext, Value, long.MinValue, long.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < long.MinValue || Value > long.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new LongConstant ((long) Value, Location);
                        }
                        if (target_type == TypeManager.uint64_type) {
-                               CheckRange (inCheckedContext, Value, ulong.MinValue, ulong.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < ulong.MinValue || Value > ulong.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new ULongConstant ((ulong) Value, Location);
                        }
                        if (target_type == TypeManager.float_type)
                                return new FloatConstant ((float) Value, Location);
                        if (target_type == TypeManager.char_type) {
-                               CheckRange (inCheckedContext, Value, char.MinValue, char.MaxValue);
+                               if (in_checked_context){
+                                       if (Value < (double) char.MinValue || Value > (double) char.MaxValue || double.IsNaN (Value))
+                                               throw new OverflowException ();
+                               }
                                return new CharConstant ((char) Value, Location);
                        }
                        if (target_type == TypeManager.decimal_type)
@@ -1849,14 +1735,19 @@ namespace Mono.CSharp {
                public DecimalConstant (decimal d, Location loc):
                        base (loc)
                {
-                       type = TypeManager.decimal_type;
-                       eclass = ExprClass.Value;
                        Value = d;
                }
 
                override public string AsString ()
                {
-                       return Value.ToString ();
+                       return Value.ToString () + "M";
+               }
+
+               protected override Expression DoResolve (ResolveContext rc)
+               {
+                       type = TypeManager.decimal_type;
+                       eclass = ExprClass.Value;
+                       return this;
                }
 
                public override object GetValue ()
@@ -1866,40 +1757,59 @@ namespace Mono.CSharp {
 
                public override void Emit (EmitContext ec)
                {
-                       ILGenerator ig = ec.ig;
-
-                       int [] words = Decimal.GetBits (Value);
+                       int [] words = decimal.GetBits (Value);
                        int power = (words [3] >> 16) & 0xff;
 
-                       if (power == 0 && Value <= int.MaxValue && Value >= int.MinValue)
-                       {
-                               IntConstant.EmitInt (ig, (int)Value);
-                               ig.Emit (OpCodes.Newobj, TypeManager.void_decimal_ctor_int_arg);
-                               return;
-                       }
+                       if (power == 0) {
+                               if (Value <= int.MaxValue && Value >= int.MinValue) {
+                                       if (TypeManager.void_decimal_ctor_int_arg == null) {
+                                               TypeManager.void_decimal_ctor_int_arg = TypeManager.GetPredefinedConstructor (
+                                                       TypeManager.decimal_type, loc, TypeManager.int32_type);
 
-                       
-                       //
-                       // FIXME: we could optimize this, and call a better 
-                       // constructor
-                       //
+                                               if (TypeManager.void_decimal_ctor_int_arg == null)
+                                                       return;
+                                       }
+
+                                       ec.EmitInt ((int) Value);
+                                       ec.Emit (OpCodes.Newobj, TypeManager.void_decimal_ctor_int_arg);
+                                       return;
+                               }
+
+                               if (Value <= long.MaxValue && Value >= long.MinValue) {
+                                       if (TypeManager.void_decimal_ctor_long_arg == null) {
+                                               TypeManager.void_decimal_ctor_long_arg = TypeManager.GetPredefinedConstructor (
+                                                       TypeManager.decimal_type, loc, TypeManager.int64_type);
 
-                       IntConstant.EmitInt (ig, words [0]);
-                       IntConstant.EmitInt (ig, words [1]);
-                       IntConstant.EmitInt (ig, words [2]);
+                                               if (TypeManager.void_decimal_ctor_long_arg == null)
+                                                       return;
+                                       }
+
+                                       ec.EmitLong ((long) Value);
+                                       ec.Emit (OpCodes.Newobj, TypeManager.void_decimal_ctor_long_arg);
+                                       return;
+                               }
+                       }
+
+                       ec.EmitInt (words [0]);
+                       ec.EmitInt (words [1]);
+                       ec.EmitInt (words [2]);
 
                        // sign
-                       IntConstant.EmitInt (ig, words [3] >> 31);
+                       ec.EmitInt (words [3] >> 31);
 
                        // power
-                       IntConstant.EmitInt (ig, power);
+                       ec.EmitInt (power);
 
-                       ig.Emit (OpCodes.Newobj, TypeManager.void_decimal_ctor_five_args);
-               }
+                       if (TypeManager.void_decimal_ctor_five_args == null) {
+                               TypeManager.void_decimal_ctor_five_args = TypeManager.GetPredefinedConstructor (
+                                       TypeManager.decimal_type, loc, TypeManager.int32_type, TypeManager.int32_type,
+                                       TypeManager.int32_type, TypeManager.bool_type, TypeManager.byte_type);
 
-               public override Constant Increment ()
-               {
-                       return new DecimalConstant (checked (Value + 1), loc);
+                               if (TypeManager.void_decimal_ctor_five_args == null)
+                                       return;
+                       }
+
+                       ec.Emit (OpCodes.Newobj, TypeManager.void_decimal_ctor_five_args);
                }
 
                public override bool IsDefaultValue {
@@ -1914,7 +1824,7 @@ namespace Mono.CSharp {
                        }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        if (target_type == TypeManager.sbyte_type)
                                return new SByteConstant ((sbyte)Value, loc);
@@ -1950,8 +1860,6 @@ namespace Mono.CSharp {
                public StringConstant (string s, Location loc):
                        base (loc)
                {
-                       type = TypeManager.string_type;
-                       eclass = ExprClass.Value;
                        Value = s;
                }
 
@@ -1961,6 +1869,13 @@ namespace Mono.CSharp {
                        return "\"" + Value + "\"";
                }
 
+               protected override Expression DoResolve (ResolveContext rc)
+               {
+                       type = TypeManager.string_type;
+                       eclass = ExprClass.Value;
+                       return this;
+               }
+
                public override object GetValue ()
                {
                        return Value;
@@ -1968,15 +1883,35 @@ namespace Mono.CSharp {
                
                public override void Emit (EmitContext ec)
                {
-                       if (Value == null)
-                               ec.ig.Emit (OpCodes.Ldnull);
-                       else
-                               ec.ig.Emit (OpCodes.Ldstr, Value);
+                       if (Value == null) {
+                               ec.Emit (OpCodes.Ldnull);
+                               return;
+                       }
+
+                       //
+                       // Use string.Empty for both literals and constants even if
+                       // it's not allowed at language level
+                       //
+                       if (Value.Length == 0 && RootContext.Optimize && !TypeManager.IsEqual (ec.CurrentType, TypeManager.string_type)) {
+                               if (TypeManager.string_empty == null)
+                                       TypeManager.string_empty = TypeManager.GetPredefinedField (TypeManager.string_type, "Empty", loc, TypeManager.string_type);
+
+                               if (TypeManager.string_empty != null) {
+                                       ec.Emit (OpCodes.Ldsfld, TypeManager.string_empty);
+                                       return;
+                               }
+                       }
+
+                       ec.Emit (OpCodes.Ldstr, Value);
                }
 
-               public override Constant Increment ()
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
                {
-                       throw new NotSupportedException ();
+                       // cast to object
+                       if (type != targetType)
+                               enc.Encode (type);
+
+                       enc.Encode (Value);
                }
 
                public override bool IsDefaultValue {
@@ -1991,12 +1926,205 @@ namespace Mono.CSharp {
                        }
                }
 
-               public override Constant Reduce (bool inCheckedContext, Type target_type)
+               public override bool IsNull {
+                       get {
+                               return IsDefaultValue;
+                       }
+               }
+
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
                {
                        return null;
                }
        }
 
-}
+       //
+       // Null constant can have its own type, think of `default (Foo)'
+       //
+       public class NullConstant : Constant
+       {
+               public NullConstant (TypeSpec type, Location loc)
+                       : base (loc)
+               {
+                       eclass = ExprClass.Value;
+                       this.type = type;
+               }
+
+               public override string AsString ()
+               {
+                       return GetSignatureForError ();
+               }
+
+               public override Expression CreateExpressionTree (ResolveContext ec)
+               {
+                       if (type == InternalType.Null || type == TypeManager.object_type) {
+                               // Optimized version, also avoids referencing literal internal type
+                               Arguments args = new Arguments (1);
+                               args.Add (new Argument (this));
+                               return CreateExpressionFactoryCall (ec, "Constant", args);
+                       }
+
+                       return base.CreateExpressionTree (ec);
+               }
+
+               protected override Expression DoResolve (ResolveContext ec)
+               {
+                       return this;
+               }
+
+               public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
+               {
+                       // Type it as string cast
+                       if (targetType == TypeManager.object_type || targetType == TypeManager.null_type)
+                               enc.Encode (TypeManager.string_type);
+
+                       var ac = targetType as ArrayContainer;
+                       if (ac != null) {
+                               if (ac.Rank != 1)
+                                       base.EncodeAttributeValue (rc, enc, targetType);
+                               else
+                                       enc.Stream.Write (uint.MaxValue);
+                       } else {
+                               enc.Stream.Write (byte.MaxValue);
+                       }
+               }
+
+               public override void Emit (EmitContext ec)
+               {
+                       ec.Emit (OpCodes.Ldnull);
+
+                       // Only to make verifier happy
+                       if (TypeManager.IsGenericParameter (type))
+                               ec.Emit (OpCodes.Unbox_Any, type);
+               }
+
+               public override string ExprClassName {
+                       get {
+                               return GetSignatureForError ();
+                       }
+               }
+
+               public override string GetSignatureForError ()
+               {
+                       return "null";
+               }
+
+               public override Constant ConvertExplicitly (bool inCheckedContext, TypeSpec targetType)
+               {
+                       if (targetType.IsPointer) {
+                               if (IsLiteral || this is NullPointer)
+                                       return new EmptyConstantCast (new NullPointer (loc), targetType);
+
+                               return null;
+                       }
+
+                       // Exlude internal compiler types
+                       if (targetType == InternalType.AnonymousMethod)
+                               return null;
+
+                       if (!IsLiteral && !Convert.ImplicitStandardConversionExists (this, targetType))
+                               return null;
+
+                       if (TypeManager.IsReferenceType (targetType))
+                               return new NullConstant (targetType, loc);
+
+                       if (TypeManager.IsNullableType (targetType))
+                               return Nullable.LiftedNull.Create (targetType, loc);
+
+                       return null;
+               }
+
+               public override Constant ConvertImplicitly (ResolveContext rc, TypeSpec targetType)
+               {
+                       return ConvertExplicitly (false, targetType);
+               }
+
+               public override object GetValue ()
+               {
+                       return null;
+               }
+
+               public override bool IsDefaultValue {
+                       get { return true; }
+               }
+
+               public override bool IsNegative {
+                       get { return false; }
+               }
+
+               public override bool IsNull {
+                       get { return true; }
+               }
+
+               public override bool IsZeroInteger {
+                       get { return true; }
+               }
+       }
+
+       /// <summary>
+       ///   The value is constant, but when emitted has a side effect.  This is
+       ///   used by BitwiseAnd to ensure that the second expression is invoked
+       ///   regardless of the value of the left side.  
+       /// </summary>
+       public class SideEffectConstant : Constant {
+               public Constant value;
+               Expression side_effect;
+               
+               public SideEffectConstant (Constant value, Expression side_effect, Location loc) : base (loc)
+               {
+                       this.value = value;
+                       while (side_effect is SideEffectConstant)
+                               side_effect = ((SideEffectConstant) side_effect).side_effect;
+                       this.side_effect = side_effect;
+               }
+
+               public override string AsString ()
+               {
+                       return value.AsString ();
+               }
+
+               protected override Expression DoResolve (ResolveContext rc)
+               {
+                       value = value.Resolve (rc);
+
+                       type = value.Type;
+                       eclass = ExprClass.Value;
+                       return this;
+               }
+
+               public override object GetValue ()
+               {
+                       return value.GetValue ();
+               }
+
+               public override void Emit (EmitContext ec)
+               {
+                       side_effect.EmitSideEffect (ec);
+                       value.Emit (ec);
+               }
+
+               public override void EmitSideEffect (EmitContext ec)
+               {
+                       side_effect.EmitSideEffect (ec);
+                       value.EmitSideEffect (ec);
+               }
+
+               public override bool IsDefaultValue {
+                       get { return value.IsDefaultValue; }
+               }
+
+               public override bool IsNegative {
+                       get { return value.IsNegative; }
+               }
 
+               public override bool IsZeroInteger {
+                       get { return value.IsZeroInteger; }
+               }
 
+               public override Constant ConvertExplicitly (bool in_checked_context, TypeSpec target_type)
+               {
+                       Constant new_value = value.ConvertExplicitly (in_checked_context, target_type);
+                       return new_value == null ? null : new SideEffectConstant (new_value, side_effect, new_value.Location);
+               }
+       }
+}