Fix warning.
[mono.git] / mcs / gmcs / convert.cs
index 7ac630671a57e9ba6f032bd9bdf1449b0d02d275..c6c625d01ca228b6f539f0eb424fa568c590f285 100644 (file)
@@ -29,13 +29,6 @@ namespace Mono.CSharp {
                //
                public static EmitContext ConstantEC = null;
                
-               static public void Error_CannotConvertType (Location loc, Type source, Type target)
-               {
-                       Report.Error (30, loc, "Cannot convert type '" +
-                                     TypeManager.CSharpName (source) + "' to '" +
-                                     TypeManager.CSharpName (target) + "'");
-               }
-
                static Expression TypeParameter_to_Null (Expression expr, Type target_type,
                                                         Location loc)
                {
@@ -88,7 +81,7 @@ namespace Mono.CSharp {
 
                        if (gc == null) {
                                if (target_type == TypeManager.object_type)
-                                       return new BoxedCast (expr);
+                                       return new BoxedCast (expr, target_type);
 
                                return null;
                        }
@@ -97,15 +90,15 @@ namespace Mono.CSharp {
                        Type base_type = TypeParam_EffectiveBaseType (ec, gc);
 
                        if (TypeManager.IsSubclassOf (base_type, target_type))
-                               return new BoxedCast (expr, target_type);
+                               return new ClassCast (expr, target_type);
 
                        if (target_type.IsInterface) {
                                if (TypeManager.ImplementsInterface (base_type, target_type))
-                                       return new BoxedCast (expr, target_type);
+                                       return new ClassCast (expr, target_type);
 
                                foreach (Type t in gc.InterfaceConstraints) {
                                        if (TypeManager.IsSubclassOf (t, target_type))
-                                               return new BoxedCast (expr, target_type);
+                                               return new ClassCast (expr, target_type);
                                }
                        }
 
@@ -113,7 +106,7 @@ namespace Mono.CSharp {
                                if (!t.IsGenericParameter)
                                        continue;
                                if (TypeManager.IsSubclassOf (t, target_type))
-                                       return new BoxedCast (expr, target_type);
+                                       return new ClassCast (expr, target_type);
                        }
 
                        return null;
@@ -148,7 +141,7 @@ namespace Mono.CSharp {
                                        return null;
 
                                if (TypeManager.IsValueType (expr_type))
-                                       return new BoxedCast (expr);
+                                       return new BoxedCast (expr, target_type);
                                if (expr_type.IsClass || expr_type.IsInterface || expr_type == TypeManager.enum_type){
                                        if (expr_type == TypeManager.anonymous_method_type)
                                                return null;
@@ -158,7 +151,7 @@ namespace Mono.CSharp {
                                return null;
                        } else if (target_type == TypeManager.value_type) {
                                if (TypeManager.IsValueType (expr_type))
-                                       return new BoxedCast (expr);
+                                       return new BoxedCast (expr, target_type);
                                if (expr_type == TypeManager.null_type)
                                        return new NullCast (expr, target_type);
 
@@ -170,7 +163,7 @@ namespace Mono.CSharp {
                                // a boxing conversion
                                //
                                if (expr_type.IsEnum || expr_type.IsGenericParameter)
-                                       return new BoxedCast (expr);
+                                       return new BoxedCast (expr, target_type);
 
                                return new EmptyCast (expr, target_type);
                        }
@@ -268,6 +261,9 @@ namespace Mono.CSharp {
                //
                public static bool ImplicitReferenceConversionExists (EmitContext ec, Expression expr, Type target_type)
                {
+                       if (target_type.IsValueType)
+                               return false;
+
                        Type expr_type = expr.Type;
 
                        if (expr_type.IsGenericParameter)
@@ -372,7 +368,7 @@ namespace Mono.CSharp {
                ///   target_type or null if an implicit conversion is not possible.
                /// </summary>
                static public Expression ImplicitNumericConversion (EmitContext ec, Expression expr,
-                                                                   Type target_type, Location loc)
+                                                                   Type target_type)
                {
                        Type expr_type = expr.Type;
 
@@ -395,7 +391,7 @@ namespace Mono.CSharp {
                                        //
                                        long v = ((LongConstant) expr).Value;
                                        if (v >= 0)
-                                               return new ULongConstant ((ulong) v);
+                                               return new ULongConstant ((ulong) v, expr.Location);
                                } 
                        }
                        
@@ -416,7 +412,7 @@ namespace Mono.CSharp {
                                if (real_target_type == TypeManager.short_type)
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                        } else if (expr_type == TypeManager.byte_type){
                                //
                                // From byte to short, ushort, int, uint, long, ulong, float, double, decimal
@@ -436,7 +432,7 @@ namespace Mono.CSharp {
                                if (real_target_type == TypeManager.double_type)
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                                
                        } else if (expr_type == TypeManager.short_type){
                                //
@@ -451,7 +447,7 @@ namespace Mono.CSharp {
                                if (real_target_type == TypeManager.float_type)
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                                
                        } else if (expr_type == TypeManager.ushort_type){
                                //
@@ -471,7 +467,7 @@ namespace Mono.CSharp {
                                if (real_target_type == TypeManager.float_type)
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                        } else if (expr_type == TypeManager.int32_type){
                                //
                                // From int to long, float, double, decimal
@@ -483,7 +479,7 @@ namespace Mono.CSharp {
                                if (real_target_type == TypeManager.float_type)
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                        } else if (expr_type == TypeManager.uint32_type){
                                //
                                // From uint to long, ulong, float, double, decimal
@@ -499,7 +495,7 @@ namespace Mono.CSharp {
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
                                                               OpCodes.Conv_R4);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                        } else if (expr_type == TypeManager.int64_type){
                                //
                                // From long/ulong to float, double
@@ -509,7 +505,7 @@ namespace Mono.CSharp {
                                if (real_target_type == TypeManager.float_type)
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                        } else if (expr_type == TypeManager.uint64_type){
                                //
                                // From ulong to float, double
@@ -521,7 +517,7 @@ namespace Mono.CSharp {
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
                                                               OpCodes.Conv_R4);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                        } else if (expr_type == TypeManager.char_type){
                                //
                                // From char to ushort, int, uint, long, ulong, float, double, decimal
@@ -539,7 +535,7 @@ namespace Mono.CSharp {
                                if (real_target_type == TypeManager.double_type)
                                        return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr);
+                                       return new CastToDecimal (expr);
                        } else if (expr_type == TypeManager.float_type){
                                //
                                // float to double
@@ -551,7 +547,6 @@ namespace Mono.CSharp {
                        return null;
                }
 
-
                /// <summary>
                ///  Same as ImplicitStandardConversionExists except that it also looks at
                ///  implicit user defined conversions - needed for overload resolution
@@ -579,9 +574,7 @@ namespace Mono.CSharp {
 
                public static bool ImplicitUserConversionExists (EmitContext ec, Type source, Type target)
                {
-                       Expression dummy = ImplicitUserConversion (
-                               ec, new EmptyExpression (source), target, Location.Null);
-                       return dummy != null;
+                       return ImplicitUserConversion (ec, new EmptyExpression (source), target, Location.Null) != null;
                }
 
                /// <summary>
@@ -737,7 +730,7 @@ namespace Mono.CSharp {
                                        if (value >= SByte.MinValue && value <= SByte.MaxValue)
                                                return true;
                                } else if (target_type == TypeManager.byte_type){
-                                       if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
+                                       if (value >= 0 && value <= Byte.MaxValue)
                                                return true;
                                } else if (target_type == TypeManager.short_type){
                                        if (value >= Int16.MinValue && value <= Int16.MaxValue)
@@ -769,7 +762,7 @@ namespace Mono.CSharp {
                                // we just inline it
                                //
                                long v = ((LongConstant) expr).Value;
-                               if (v > 0)
+                               if (v >= 0)
                                        return true;
                        }
                        
@@ -899,8 +892,7 @@ namespace Mono.CSharp {
                ///   for explicit and implicit conversion operators.
                /// </summary>
                static public Type FindMostSpecificSource (EmitContext ec, IList list,
-                                                          Expression source, bool apply_explicit_conv_rules,
-                                                          Location loc)
+                                                          Expression source, bool apply_explicit_conv_rules)
                {
                        ArrayList src_types_set = new ArrayList ();
                        
@@ -946,8 +938,7 @@ namespace Mono.CSharp {
                ///  Finds the most specific target Tx according to section 13.4.4
                /// </summary>
                static public Type FindMostSpecificTarget (EmitContext ec, IList list,
-                                                          Type target, bool apply_explicit_conv_rules,
-                                                          Location loc)
+                                                          Type target, bool apply_explicit_conv_rules)
                {
                        ArrayList tgt_types_set = new ArrayList ();
                        
@@ -1053,42 +1044,60 @@ namespace Mono.CSharp {
                }
 
                /// <summary>
-               ///   Computes the list of the user-defined conversion
-               ///   operators from source_type to target_type.  `look_for_explicit'
-               ///   controls whether we should also include the list of explicit
-               ///   operators
+               ///   Compute the user-defined conversion operator from source_type to target_type. 
+               ///   `look_for_explicit' controls whether we should also include the list of explicit operators
                /// </summary>
-               static IList GetConversionOperators (EmitContext ec,
-                                                    Expression source, Type target_type,
-                                                    Location loc, bool look_for_explicit)
+               static MethodInfo GetConversionOperator (EmitContext ec, Expression source, Type target_type, bool look_for_explicit)
                {
-                       ArrayList ret = new ArrayList (4);
+                       ArrayList ops = new ArrayList (4);
 
                        Type source_type = source.Type;
 
                        if (source_type != TypeManager.decimal_type) {
-                               AddConversionOperators (ec, ret, source, target_type, look_for_explicit,
-                                       Expression.MethodLookup (
-                                               ec, source_type, "op_Implicit", loc) as MethodGroupExpr);
+                               AddConversionOperators (ec, ops, source, target_type, look_for_explicit,
+                                       Expression.MethodLookup (ec, source_type, "op_Implicit", Location.Null) as MethodGroupExpr);
                                if (look_for_explicit) {
-                                       AddConversionOperators (ec, ret, source, target_type, look_for_explicit,
+                                       AddConversionOperators (ec, ops, source, target_type, look_for_explicit,
                                                Expression.MethodLookup (
-                                                       ec, source_type, "op_Explicit", loc) as MethodGroupExpr);
+                                                       ec, source_type, "op_Explicit", Location.Null) as MethodGroupExpr);
                                }
                        }
 
                        if (target_type != TypeManager.decimal_type) {
-                               AddConversionOperators (ec, ret, source, target_type, look_for_explicit,
-                                       Expression.MethodLookup (
-                                               ec, target_type, "op_Implicit", loc) as MethodGroupExpr);
+                               AddConversionOperators (ec, ops, source, target_type, look_for_explicit,
+                                       Expression.MethodLookup (ec, target_type, "op_Implicit", Location.Null) as MethodGroupExpr);
                                if (look_for_explicit) {
-                                       AddConversionOperators (ec, ret, source, target_type, look_for_explicit,
+                                       AddConversionOperators (ec, ops, source, target_type, look_for_explicit,
                                                Expression.MethodLookup (
-                                                       ec, target_type, "op_Explicit", loc) as MethodGroupExpr);
+                                                       ec, target_type, "op_Explicit", Location.Null) as MethodGroupExpr);
                                }
                        }
 
-                       return ret;
+                       if (ops.Count == 0)
+                               return null;
+
+                       Type most_specific_source = FindMostSpecificSource (ec, ops, source, look_for_explicit);
+                       if (most_specific_source == null)
+                               return null;
+
+                       Type most_specific_target = FindMostSpecificTarget (ec, ops, target_type, look_for_explicit);
+                       if (most_specific_target == null)
+                               return null;
+
+                       MethodInfo method = null;
+
+                       foreach (MethodInfo m in ops) {
+                               if (m.ReturnType != most_specific_target)
+                                       continue;
+                               if (TypeManager.GetParameterData (m).ParameterType (0) != most_specific_source)
+                                       continue;
+                               // Ambiguous: more than one conversion operator satisfies the signature.
+                               if (method != null)
+                                       return null;
+                               method = m;
+                       }
+
+                       return method;
                }
 
                static DoubleHash explicit_conv = new DoubleHash (100);
@@ -1103,8 +1112,6 @@ namespace Mono.CSharp {
                {
                        Type source_type = source.Type;
                        MethodInfo method = null;
-                       Type most_specific_source = null;
-                       Type most_specific_target = null;
 
                        if (TypeManager.IsNullableType (source_type) && TypeManager.IsNullableType (target))
                                return new Nullable.LiftedConversion (
@@ -1115,45 +1122,8 @@ namespace Mono.CSharp {
 
                        if (!(source is Constant) && hash.Lookup (source_type, target, out o)) {
                                method = (MethodInfo) o;
-                               if (method != null) {
-                                       ParameterData pd = TypeManager.GetParameterData (method);
-                                       most_specific_source = pd.ParameterType (0);
-                                       most_specific_target = method.ReturnType;
-                               }
                        } else {
-                               IList ops = GetConversionOperators (ec, source, target, loc, look_for_explicit);
-                               if (ops == null || ops.Count == 0) {
-                                       method = null;
-                                       goto skip;
-                               }
-                                       
-                               most_specific_source = FindMostSpecificSource (ec, ops, source, look_for_explicit, loc);
-                               if (most_specific_source == null) {
-                                       method = null;
-                                       goto skip;
-                               }
-                               
-                               most_specific_target = FindMostSpecificTarget (ec, ops, target, look_for_explicit, loc);
-                               if (most_specific_target == null) {
-                                       method = null;
-                                       goto skip;
-                               }
-                               
-                               int count = 0;
-                               
-                               foreach (MethodInfo m in ops) {
-                                       ParameterData pd = TypeManager.GetParameterData (m);
-                                       
-                                       if (pd.ParameterType (0) == most_specific_source &&
-                                           m.ReturnType == most_specific_target) {
-                                               method = m;
-                                               count++;
-                                       }
-                               }
-                               if (count > 1)
-                                       method = null;
-                               
-                       skip:
+                               method = GetConversionOperator (ec, source, target, look_for_explicit);
                                if (!(source is Constant))
                                        hash.Insert (source_type, target, method);
                        }
@@ -1161,6 +1131,8 @@ namespace Mono.CSharp {
                        if (method == null)
                                return null;
                        
+                       Type most_specific_source = TypeManager.GetParameterData (method).ParameterType (0);
+
                        //
                        // This will do the conversion to the best match that we
                        // found.  Now we need to perform an implict standard conversion
@@ -1259,7 +1231,7 @@ namespace Mono.CSharp {
                        if (expr_type.Equals (target_type) && !TypeManager.IsNullType (expr_type))
                                return expr;
 
-                       e = ImplicitNumericConversion (ec, expr, target_type, loc);
+                       e = ImplicitNumericConversion (ec, expr, target_type);
                        if (e != null)
                                return e;
 
@@ -1288,16 +1260,13 @@ namespace Mono.CSharp {
                                        if (target_type.IsPointer){
                                                if (TypeManager.GetElementType(target_type) == TypeManager.GetElementType(expr_type))
                                                        return expr;
+
+                                               //return null;
                                        }
                                }
                                
-                               if (target_type.IsPointer) {
-                                       if (expr_type == TypeManager.null_type)
-                                               return new EmptyCast (NullPointer.Null, target_type);
-
-                                       if (expr_type == TypeManager.void_ptr_type)
-                                               return new EmptyCast (expr, target_type);
-                               }
+                               if (expr_type == TypeManager.null_type && target_type.IsPointer)
+                                       return new EmptyCast (NullPointer.Null, target_type);
                        }
 
                        if (expr_type == TypeManager.anonymous_method_type){
@@ -1338,19 +1307,19 @@ namespace Mono.CSharp {
 
                        if (target_type == TypeManager.sbyte_type){
                                if (value >= SByte.MinValue && value <= SByte.MaxValue)
-                                       return new SByteConstant ((sbyte) value);
+                                       return new SByteConstant ((sbyte) value, ic.Location);
                        } else if (target_type == TypeManager.byte_type){
                                if (value >= Byte.MinValue && value <= Byte.MaxValue)
-                                       return new ByteConstant ((byte) value);
+                                       return new ByteConstant ((byte) value, ic.Location);
                        } else if (target_type == TypeManager.short_type){
                                if (value >= Int16.MinValue && value <= Int16.MaxValue)
-                                       return new ShortConstant ((short) value);
+                                       return new ShortConstant ((short) value, ic.Location);
                        } else if (target_type == TypeManager.ushort_type){
                                if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
-                                       return new UShortConstant ((ushort) value);
+                                       return new UShortConstant ((ushort) value, ic.Location);
                        } else if (target_type == TypeManager.uint32_type){
                                if (value >= 0)
-                                       return new UIntConstant ((uint) value);
+                                       return new UIntConstant ((uint) value, ic.Location);
                        } else if (target_type == TypeManager.uint64_type){
                                //
                                // we can optimize this case: a positive int32
@@ -1358,11 +1327,11 @@ namespace Mono.CSharp {
                                // to do it.
                                //
                                if (value >= 0)
-                                       return new ULongConstant ((ulong) value);
+                                       return new ULongConstant ((ulong) value, ic.Location);
                        } else if (target_type == TypeManager.double_type)
-                               return new DoubleConstant ((double) value);
+                               return new DoubleConstant ((double) value, ic.Location);
                        else if (target_type == TypeManager.float_type)
-                               return new FloatConstant ((float) value);
+                               return new FloatConstant ((float) value, ic.Location);
                        
                        if (value == 0 && ic is IntLiteral && TypeManager.IsEnumType (target_type)){
                                Type underlying = TypeManager.EnumToUnderlying (target_type);
@@ -1373,9 +1342,9 @@ namespace Mono.CSharp {
                                // to EnumConstant
                                //
                                if (underlying == TypeManager.int64_type)
-                                       e = new LongLiteral (0);
+                                       e = new LongLiteral (0, ic.Location);
                                else if (underlying == TypeManager.uint64_type)
-                                       e = new ULongLiteral (0);
+                                       e = new ULongLiteral (0, ic.Location);
 
                                return new EnumConstant (e, target_type);
                        }
@@ -1385,26 +1354,11 @@ namespace Mono.CSharp {
                        // e.g. target_type is IComparable, IConvertible, IFormattable
                        //
                        if (target_type.IsInterface && target_type.IsAssignableFrom (ic.Type))
-                               return new BoxedCast (ic);
+                               return new BoxedCast (ic, target_type);
 
                        return null;
                }
 
-               static public void Error_CannotImplicitConversion (Location loc, Type source, Type target)
-               {
-                       if (source.FullName == target.FullName){
-                               Report.ExtraInformation (loc,
-                                        String.Format (
-                                               "The type {0} has two conflicting definitions, one comes from {1} and the other from {2}",
-                                               source.Name, source.Assembly.FullName, target.Assembly.FullName));
-                                                        
-                       }
-                       Report.Error (29, loc, "Cannot implicitly convert type {0} to `{1}'",
-                                     source == TypeManager.anonymous_method_type ?
-                                     "anonymous method" : "`" + TypeManager.CSharpName (source) + "'",
-                                     TypeManager.CSharpName (target));
-               }
-
                /// <summary>
                ///   Attempts to implicitly convert `source' into `target_type', using
                ///   ImplicitConversion.  If there is no implicit conversion, then
@@ -1433,15 +1387,7 @@ namespace Mono.CSharp {
                                }
                        }
 
-                       if (source is Constant){
-                               Constant c = (Constant) source;
-
-                               Expression.Error_ConstantValueCannotBeConverted (loc, c.AsString (), target_type);
-                               return null;
-                       }
-                       
-                       Error_CannotImplicitConversion (loc, source.Type, target_type);
-
+                       source.Error_ValueCannotBeConverted (loc, target_type, false);
                        return null;
                }
 
@@ -1454,162 +1400,145 @@ namespace Mono.CSharp {
                /// <summary>
                ///   Performs the explicit numeric conversions
                /// </summary>
-               static Expression ExplicitNumericConversion (EmitContext ec, Expression expr, Type target_type, Location loc)
+               public static Expression ExplicitNumericConversion (Expression expr, Type target_type)
                {
                        Type expr_type = expr.Type;
-
-                       //
-                       // If we have an enumeration, extract the underlying type,
-                       // use this during the comparison, but wrap around the original
-                       // target_type
-                       //
                        Type real_target_type = target_type;
 
-                       if (TypeManager.IsEnumType (real_target_type))
-                               real_target_type = TypeManager.EnumToUnderlying (real_target_type);
-
-                       if (ImplicitStandardConversionExists (ec, expr, real_target_type)){
-                               Expression ce = ImplicitConversionStandard (ec, expr, real_target_type, loc);
-
-                               if (real_target_type != target_type)
-                                       return new EmptyCast (ce, target_type);
-                               return ce;
-                       }
-                       
                        if (expr_type == TypeManager.sbyte_type){
                                //
                                // From sbyte to byte, ushort, uint, ulong, char
                                //
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I1_U1);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I1_U2);
                                if (real_target_type == TypeManager.uint32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I1_U4);
                                if (real_target_type == TypeManager.uint64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I1_U8);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I1_CH);
                        } else if (expr_type == TypeManager.byte_type){
                                //
                                // From byte to sbyte and char
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U1_I1);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U1_CH);
                        } else if (expr_type == TypeManager.short_type){
                                //
                                // From short to sbyte, byte, ushort, uint, ulong, char
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I2_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I2_U1);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I2_U2);
                                if (real_target_type == TypeManager.uint32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I2_U4);
                                if (real_target_type == TypeManager.uint64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I2_U8);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I2_CH);
                        } else if (expr_type == TypeManager.ushort_type){
                                //
                                // From ushort to sbyte, byte, short, char
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U2_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U2_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U2_I2);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U2_CH);
                        } else if (expr_type == TypeManager.int32_type){
                                //
                                // From int to sbyte, byte, short, ushort, uint, ulong, char
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I4_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I4_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I4_I2);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I4_U2);
                                if (real_target_type == TypeManager.uint32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I4_U4);
                                if (real_target_type == TypeManager.uint64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I4_U8);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I4_CH);
                        } else if (expr_type == TypeManager.uint32_type){
                                //
                                // From uint to sbyte, byte, short, ushort, int, char
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U4_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U4_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U4_I2);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U4_U2);
                                if (real_target_type == TypeManager.int32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U4_I4);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U4_CH);
                        } else if (expr_type == TypeManager.int64_type){
                                //
                                // From long to sbyte, byte, short, ushort, int, uint, ulong, char
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_I2);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_U2);
                                if (real_target_type == TypeManager.int32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_I4);
                                if (real_target_type == TypeManager.uint32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_U4);
                                if (real_target_type == TypeManager.uint64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_U8);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.I8_CH);
                        } else if (expr_type == TypeManager.uint64_type){
                                //
                                // From ulong to sbyte, byte, short, ushort, int, uint, long, char
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_I2);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_U2);
                                if (real_target_type == TypeManager.int32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_I4);
                                if (real_target_type == TypeManager.uint32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_U4);
                                if (real_target_type == TypeManager.int64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_I8);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.U8_CH);
                        } else if (expr_type == TypeManager.char_type){
                                //
                                // From char to sbyte, byte, short
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.CH_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.CH_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.CH_I2);
                        } else if (expr_type == TypeManager.float_type){
                                //
                                // From float to sbyte, byte, short,
@@ -1617,25 +1546,25 @@ namespace Mono.CSharp {
                                // or decimal
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_I2);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_U2);
                                if (real_target_type == TypeManager.int32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_I4);
                                if (real_target_type == TypeManager.uint32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_U4);
                                if (real_target_type == TypeManager.int64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_I8);
                                if (real_target_type == TypeManager.uint64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_U8);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R4_CH);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr, true);
+                                       return new CastToDecimal (expr, true);
                        } else if (expr_type == TypeManager.double_type){
                                //
                                // From double to sbyte, byte, short,
@@ -1643,44 +1572,29 @@ namespace Mono.CSharp {
                                // char, float or decimal
                                //
                                if (real_target_type == TypeManager.sbyte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_I1);
                                if (real_target_type == TypeManager.byte_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U1);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_U1);
                                if (real_target_type == TypeManager.short_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_I2);
                                if (real_target_type == TypeManager.ushort_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U2);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_U2);
                                if (real_target_type == TypeManager.int32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_I4);
                                if (real_target_type == TypeManager.uint32_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_U4);
                                if (real_target_type == TypeManager.int64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_I8);
                                if (real_target_type == TypeManager.uint64_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U8);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_U8);
                                if (real_target_type == TypeManager.char_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_CH);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_CH);
                                if (real_target_type == TypeManager.float_type)
-                                       return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_R4);
+                                       return new ConvCast (expr, target_type, ConvCast.Mode.R8_R4);
                                if (real_target_type == TypeManager.decimal_type)
-                                       return new CastToDecimal (ec, expr, true);
+                                       return new CastToDecimal (expr, true);
                        } else if (expr_type == TypeManager.decimal_type) {
-                               //
-                               // From decimal to sbyte, byte, short, ushort, int, uint,
-                               // long, ulong, char, double or float
-                               //
-                               if (real_target_type == TypeManager.sbyte_type ||
-                                   real_target_type == TypeManager.byte_type ||
-                                   real_target_type == TypeManager.short_type ||
-                                   real_target_type == TypeManager.ushort_type ||
-                                   real_target_type == TypeManager.int32_type ||
-                                   real_target_type == TypeManager.uint32_type ||
-                                   real_target_type == TypeManager.int64_type ||
-                                   real_target_type == TypeManager.uint64_type ||
-                                   real_target_type == TypeManager.char_type ||
-                                   real_target_type == TypeManager.double_type ||
-                                   real_target_type == TypeManager.float_type)
-                                       return new CastFromDecimal (ec, expr, target_type);
+                               return new CastFromDecimal (expr, target_type).Resolve ();
                        }
                        return null;
                }
@@ -1913,56 +1827,40 @@ namespace Mono.CSharp {
                ///   Performs an explicit conversion of the expression `expr' whose
                ///   type is expr.Type to `target_type'.
                /// </summary>
-               static public Expression ExplicitConversion (EmitContext ec, Expression expr,
+               static public Expression ExplicitConversionCore (EmitContext ec, Expression expr,
                                                             Type target_type, Location loc)
                {
                        Type expr_type = expr.Type;
-                       Type original_expr_type = expr_type;
-
-                       if (expr_type.IsSubclassOf (TypeManager.enum_type)){
-                               if (target_type == TypeManager.enum_type ||
-                                   target_type == TypeManager.object_type) {
-                                       if (expr is EnumConstant)
-                                               expr = ((EnumConstant) expr).Child;
-                                       // We really need all these casts here .... :-(
-                                       expr = new BoxedCast (new EmptyCast (expr, expr_type));
-                                       return new EmptyCast (expr, target_type);
-                               } else if ((expr_type == TypeManager.enum_type) && target_type.IsValueType &&
-                                          target_type.IsSubclassOf (TypeManager.enum_type))
-                                       return new UnboxCast (expr, target_type);
-
-                               //
-                               // Notice that we have kept the expr_type unmodified, which is only
-                               // used later on to 
-                               if (expr is EnumConstant)
-                                       expr = ((EnumConstant) expr).Child;
-                               else
-                                       expr = new EmptyCast (expr, TypeManager.EnumToUnderlying (expr_type));
-                               expr_type = expr.Type;
-                       }
 
-                       int errors = Report.Errors;
+                       // Explicit conversion includes implicit conversion and it used for enum underlying types too
                        Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc);
-                       if (Report.Errors > errors)
-                               return null;
-
                        if (ne != null)
                                return ne;
 
-                       if (TypeManager.IsNullableType (expr.Type) && TypeManager.IsNullableType (target_type))
+                       //
+                       // Unboxing conversions; only object types can be convertible to enum
+                       //
+                       if (expr_type == TypeManager.object_type && target_type.IsValueType || expr_type == TypeManager.enum_type)
+                               return new UnboxCast (expr, target_type);
+
+                       if (TypeManager.IsEnumType (expr_type)) {
+                               if (expr is EnumConstant)
+                                       return ExplicitConversionCore (ec, ((EnumConstant) expr).Child, target_type, loc);
+
+                               return ExplicitConversionCore (ec, new EmptyCast (expr, TypeManager.EnumToUnderlying (expr_type)), target_type, loc);
+                       }
+
+                       if (TypeManager.IsNullableType (expr_type) && TypeManager.IsNullableType (target_type))
                                return new Nullable.LiftedConversion (
                                        expr, target_type, false, true, loc).Resolve (ec);
 
-                       ne = ExplicitNumericConversion (ec, expr, target_type, loc);
+                       if (TypeManager.IsEnumType (target_type))
+                               return new EmptyCast (ExplicitConversionCore (ec, expr, TypeManager.EnumToUnderlying (target_type), loc), target_type);
+
+                       ne = ExplicitNumericConversion (expr, target_type);
                        if (ne != null)
                                return ne;
 
-                       //
-                       // Unboxing conversion.
-                       //
-                       if (expr_type == TypeManager.object_type && target_type.IsValueType)
-                               return new UnboxCast (expr, target_type);
-
                        //
                        // Skip the ExplicitReferenceConversion because we can not convert
                        // from Null to a ValueType, and ExplicitReference wont check against
@@ -1975,75 +1873,58 @@ namespace Mono.CSharp {
                        }
 
                        if (ec.InUnsafe){
-                               if (target_type.IsPointer){
-                                       if (expr_type.IsPointer)
-                                               return new EmptyCast (expr, target_type);
-                                       
-                                       if (expr_type == TypeManager.sbyte_type ||
-                                           expr_type == TypeManager.short_type ||
-                                           expr_type == TypeManager.int32_type ||
-                                           expr_type == TypeManager.int64_type)
-                                               return new OpcodeCast (expr, target_type, OpCodes.Conv_I);
-
-                                       if (expr_type == TypeManager.ushort_type ||
-                                           expr_type == TypeManager.uint32_type ||
-                                           expr_type == TypeManager.uint64_type ||
-                                           expr_type == TypeManager.byte_type)
-                                               return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
-                               }
-                               if (expr_type.IsPointer){
-                                       Expression e = null;
-                                       
-                                       if (target_type == TypeManager.sbyte_type)
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
-                                       else if (target_type == TypeManager.byte_type)
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
-                                       else if (target_type == TypeManager.short_type)
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
-                                       else if (target_type == TypeManager.ushort_type)
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
-                                       else if (target_type == TypeManager.int32_type)
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
-                                       else if (target_type == TypeManager.uint32_type)
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
-                                       else if (target_type == TypeManager.uint64_type)
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
-                                       else if (target_type == TypeManager.int64_type){
-                                               e = new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
-                                       }
+                               ne = ExplicitUnsafe (expr, target_type);
+                               if (ne != null)
+                                       return ne;
+                       }
 
-                                       if (e != null){
-                                               Expression ci, ce;
+                       ne = ExplicitUserConversion (ec, expr, target_type, loc);
+                       if (ne != null)
+                               return ne;
 
-                                               ci = ImplicitConversionStandard (ec, e, target_type, loc);
+                       return null;
+               }
 
-                                               if (ci != null)
-                                                       return ci;
+               public static Expression ExplicitUnsafe (Expression expr, Type target_type)
+               {
+                       Type expr_type = expr.Type;
 
-                                               ce = ExplicitNumericConversion (ec, e, target_type, loc);
-                                               if (ce != null)
-                                                       return ce;
-                                               //
-                                               // We should always be able to go from an uint32
-                                               // implicitly or explicitly to the other integral
-                                               // types
-                                               //
-                                               throw new Exception ("Internal compiler error");
-                                       }
-                               }
+                       if (target_type.IsPointer){
+                               if (expr_type.IsPointer)
+                                       return new EmptyCast (expr, target_type);
+                                       
+                               if (expr_type == TypeManager.sbyte_type ||
+                                       expr_type == TypeManager.short_type ||
+                                       expr_type == TypeManager.int32_type ||
+                                       expr_type == TypeManager.int64_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_I);
+
+                               if (expr_type == TypeManager.ushort_type ||
+                                       expr_type == TypeManager.uint32_type ||
+                                       expr_type == TypeManager.uint64_type ||
+                                       expr_type == TypeManager.byte_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
                        }
                        
-                       ne = ExplicitUserConversion (ec, expr, target_type, loc);
-                       if (ne != null)
-                               return ne;
-
-                       if (expr is NullLiteral){
-                               Report.Error (37, loc, "Cannot convert null to `{0}' because it is a value type",
-                                             TypeManager.CSharpName (target_type));
-                               return null;
+                       if (expr_type.IsPointer){
+                               if (target_type == TypeManager.sbyte_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
+                               else if (target_type == TypeManager.byte_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
+                               else if (target_type == TypeManager.short_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
+                               else if (target_type == TypeManager.ushort_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
+                               else if (target_type == TypeManager.int32_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
+                               else if (target_type == TypeManager.uint32_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
+                               else if (target_type == TypeManager.uint64_type)
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
+                               else if (target_type == TypeManager.int64_type){
+                                       return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
+                               }
                        }
-
-                       Error_CannotConvertType (loc, original_expr_type, target_type);
                        return null;
                }
 
@@ -2065,7 +1946,7 @@ namespace Mono.CSharp {
                                return new Nullable.LiftedConversion (
                                        expr, target_type, false, true, l).Resolve (ec);
 
-                       ne = ExplicitNumericConversion (ec, expr, target_type, l);
+                       ne = ExplicitNumericConversion (expr, target_type);
                        if (ne != null)
                                return ne;
 
@@ -2073,7 +1954,25 @@ namespace Mono.CSharp {
                        if (ne != null)
                                return ne;
 
-                       Error_CannotConvertType (l, expr.Type, target_type);
+                       if (ec.InUnsafe && expr.Type == TypeManager.void_ptr_type && target_type.IsPointer)
+                               return new EmptyCast (expr, target_type);
+
+                       expr.Error_ValueCannotBeConverted (l, target_type, true);
+                       return null;
+               }
+
+               /// <summary>
+               ///   Performs an explicit conversion of the expression `expr' whose
+               ///   type is expr.Type to `target_type'.
+               /// </summary>
+               static public Expression ExplicitConversion (EmitContext ec, Expression expr,
+                       Type target_type, Location loc)
+               {
+                       Expression e = ExplicitConversionCore (ec, expr, target_type, loc);
+                       if (e != null)
+                               return e;
+
+                       expr.Error_ValueCannotBeConverted (loc, target_type, true);
                        return null;
                }
        }