X-Git-Url: http://wien.tomnetworks.com/gitweb/?a=blobdiff_plain;f=mcs%2Fmcs%2Fcfold.cs;h=9e8a5a1a6293a1de740c20cb86e3fc3ef0ebbc6d;hb=a4c049eb2217fb63d763181b7a1280b2190ebe31;hp=ecc3fa20718a44c73356dced57f3fbeed9fd5848;hpb=c987b196d9d3d64635778b90662e4fad89c914fd;p=mono.git

diff --git a/mcs/mcs/cfold.cs b/mcs/mcs/cfold.cs
old mode 100755
new mode 100644
index ecc3fa20718..9e8a5a1a629
--- a/mcs/mcs/cfold.cs
+++ b/mcs/mcs/cfold.cs
@@ -4,7 +4,7 @@
 // Author:
 //   Miguel de Icaza (miguel@ximian.com)
 //
-// (C) 2002 Ximian, Inc.
+// (C) 2002, 2003 Ximian, Inc.
 //
 
 using System;
@@ -26,8 +26,10 @@ namespace Mono.CSharp {
 		//   (long, long)
 		//   (uint, uint)
 		//   (int, int)
+		//   (short, short)   (Happens with enumerations with underlying short type)
+		//   (ushort, ushort) (Happens with enumerations with underlying short type)
 		//
-		static void DoConstantNumericPromotions (Binary.Operator oper,
+		static void DoConstantNumericPromotions (EmitContext ec, Binary.Operator oper,
 							 ref Constant left, ref Constant right,
 							 Location loc)
 		{
@@ -50,23 +52,29 @@ namespace Mono.CSharp {
 
 				if (!(right is FloatConstant))
 					right = right.ToFloat (loc);
-				return;
+;				return;
 			} else if (left is ULongConstant || right is ULongConstant){
 				//
 				// If either operand is of type ulong, the other operand is
 				// converted to type ulong.  or an error ocurrs if the other
 				// operand is of type sbyte, short, int or long
 				//
+#if WRONG
 				Constant match, other;
+#endif
 					
 				if (left is ULongConstant){
+#if WRONG
 					other = right;
 					match = left;
+#endif
 					if (!(right is ULongConstant))
 						right = right.ToULong (loc);
 				} else {
+#if WRONG
 					other = left;
 					match = right;
+#endif
 					left = left.ToULong (loc);
 				}
 
@@ -93,14 +101,54 @@ namespace Mono.CSharp {
 			} else if (left is UIntConstant || right is UIntConstant){
 				//
 				// If either operand is of type uint, and the other
-				// operand is of type sbyte, short or int, othe operands are
+				// operand is of type sbyte, short or int, the operands are
 				// converted to type long.
 				//
-				if (!(left is UIntConstant))
+				Constant other;
+				if (left is UIntConstant)
+					other = right;
+				else
+					other = left;
+
+				// Nothing to do.
+				if (other is UIntConstant)
+					return;
+
+				IntConstant ic = other as IntConstant;
+				if (ic != null){
+					if (ic.Value >= 0){
+						if (left == other)
+							left = new UIntConstant ((uint) ic.Value, ic.Location);
+						else
+							right = new UIntConstant ((uint) ic.Value, ic.Location);
+						return;
+					}
+				}
+				
+				if (other is SByteConstant || other is ShortConstant || ic != null){
+					left = left.ToLong (loc);
+					right = right.ToLong (loc);
+				} else {
 					left = left.ToUInt (loc);
-				else if (!(right is UIntConstant))
-					right = right.ToUInt (loc);
+					right = left.ToUInt (loc);
+				}
+
+				return;
+			} else if (left is DecimalConstant || right is DecimalConstant) {
+				if (!(left is DecimalConstant))
+					left = left.ToDecimal (loc);
+				else if (!(right is DecimalConstant))
+					right = right.ToDecimal (loc);
 				return;
+			} else if (left is EnumConstant || right is EnumConstant){
+				if (left is EnumConstant)
+					left = ((EnumConstant) left).Child;
+				if (right is EnumConstant)
+					right = ((EnumConstant) right).Child;
+
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
+				return;
+
 			} else {
 				//
 				// Force conversions to int32
@@ -130,24 +178,37 @@ namespace Mono.CSharp {
 			Type rt = right.Type;
 			Type result_type = null;
 			bool bool_res;
-			
+
 			//
 			// Enumerator folding
 			//
 			if (rt == lt && left is EnumConstant)
 				result_type = lt;
 
+			//
+			// During an enum evaluation, we need to unwrap enumerations
+			//
+			if (ec.InEnumContext){
+				if (left is EnumConstant)
+					left = ((EnumConstant) left).Child;
+				
+				if (right is EnumConstant)
+					right = ((EnumConstant) right).Child;
+			}
+
+			Type wrap_as;
+			Constant result = null;
 			switch (oper){
 			case Binary.Operator.BitwiseOr:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
-				
+
 				if (left is IntConstant){
 					IntConstant v;
 					int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 					
-					v = new IntConstant (res);
+					v = new IntConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -156,7 +217,7 @@ namespace Mono.CSharp {
 					UIntConstant v;
 					uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 					
-					v = new UIntConstant (res);
+					v = new UIntConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -165,7 +226,7 @@ namespace Mono.CSharp {
 					LongConstant v;
 					long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 					
-					v = new LongConstant (res);
+					v = new LongConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -175,7 +236,27 @@ namespace Mono.CSharp {
 					ulong res = ((ULongConstant)left).Value |
 						((ULongConstant)right).Value;
 					
-					v = new ULongConstant (res);
+					v = new ULongConstant (res, left.Location);
+					if (result_type == null)
+						return v;
+					else
+						return new EnumConstant (v, result_type);
+				} else if (left is UShortConstant){
+					UShortConstant v;
+					ushort res = (ushort) (((UShortConstant)left).Value |
+							       ((UShortConstant)right).Value);
+					
+					v = new UShortConstant (res, left.Location);
+					if (result_type == null)
+						return v;
+					else
+						return new EnumConstant (v, result_type);
+				} else if (left is ShortConstant){
+					ShortConstant v;
+					short res = (short) (((ShortConstant)left).Value |
+							     ((ShortConstant)right).Value);
+					
+					v = new ShortConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -184,7 +265,7 @@ namespace Mono.CSharp {
 				break;
 				
 			case Binary.Operator.BitwiseAnd:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 				
@@ -192,7 +273,7 @@ namespace Mono.CSharp {
 					IntConstant v;
 					int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 					
-					v = new IntConstant (res);
+					v = new IntConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -201,7 +282,7 @@ namespace Mono.CSharp {
 					UIntConstant v;
 					uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 					
-					v = new UIntConstant (res);
+					v = new UIntConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -210,7 +291,7 @@ namespace Mono.CSharp {
 					LongConstant v;
 					long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 					
-					v = new LongConstant (res);
+					v = new LongConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -220,7 +301,27 @@ namespace Mono.CSharp {
 					ulong res = ((ULongConstant)left).Value &
 						((ULongConstant)right).Value;
 					
-					v = new ULongConstant (res);
+					v = new ULongConstant (res, left.Location);
+					if (result_type == null)
+						return v;
+					else
+						return new EnumConstant (v, result_type);
+				} else if (left is UShortConstant){
+					UShortConstant v;
+					ushort res = (ushort) (((UShortConstant)left).Value &
+							       ((UShortConstant)right).Value);
+					
+					v = new UShortConstant (res, left.Location);
+					if (result_type == null)
+						return v;
+					else
+						return new EnumConstant (v, result_type);
+				} else if (left is ShortConstant){
+					ShortConstant v;
+					short res = (short) (((ShortConstant)left).Value &
+							     ((ShortConstant)right).Value);
+					
+					v = new ShortConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -229,7 +330,7 @@ namespace Mono.CSharp {
 				break;
 
 			case Binary.Operator.ExclusiveOr:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 				
@@ -237,7 +338,7 @@ namespace Mono.CSharp {
 					IntConstant v;
 					int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 					
-					v = new IntConstant (res);
+					v = new IntConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -246,7 +347,7 @@ namespace Mono.CSharp {
 					UIntConstant v;
 					uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 					
-					v = new UIntConstant (res);
+					v = new UIntConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -255,7 +356,7 @@ namespace Mono.CSharp {
 					LongConstant v;
 					long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 					
-					v = new LongConstant (res);
+					v = new LongConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -265,7 +366,27 @@ namespace Mono.CSharp {
 					ulong res = ((ULongConstant)left).Value ^
 						((ULongConstant)right).Value;
 					
-					v = new ULongConstant (res);
+					v = new ULongConstant (res, left.Location);
+					if (result_type == null)
+						return v;
+					else
+						return new EnumConstant (v, result_type);
+				} else if (left is UShortConstant){
+					UShortConstant v;
+					ushort res = (ushort) (((UShortConstant)left).Value ^
+							       ((UShortConstant)right).Value);
+					
+					v = new UShortConstant (res, left.Location);
+					if (result_type == null)
+						return v;
+					else
+						return new EnumConstant (v, result_type);
+				} else if (left is ShortConstant){
+					ShortConstant v;
+					short res = (short)(((ShortConstant)left).Value ^
+							    ((ShortConstant)right).Value);
+					
+					v = new ShortConstant (res, left.Location);
 					if (result_type == null)
 						return v;
 					else
@@ -282,16 +403,42 @@ namespace Mono.CSharp {
 				// one is a string, and the other is not, then defer
 				// to runtime concatenation
 				//
+				wrap_as = null;
 				if (left_is_string || right_is_string){
 					if (left_is_string && right_is_string)
 						return new StringConstant (
 							((StringConstant) left).Value +
-							((StringConstant) right).Value);
+							((StringConstant) right).Value, left.Location);
 					
 					return null;
 				}
 
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				//
+				// handle "E operator + (E x, U y)"
+				// handle "E operator + (Y y, E x)"
+				//
+				// note that E operator + (E x, E y) is invalid
+				//
+				if (left is EnumConstant){
+					if (right is EnumConstant){
+						return null;
+					}
+
+					right = right.ToType (((EnumConstant) left).Child.Type, loc);
+					if (right == null)
+						return null;
+
+					wrap_as = left.Type;
+				} else if (right is EnumConstant){
+					left = left.ToType (((EnumConstant) right).Child.Type, loc);
+					if (left == null)
+						return null;
+
+					wrap_as = right.Type;
+				}
+
+				result = null;
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -306,7 +453,7 @@ namespace Mono.CSharp {
 							res = unchecked (((DoubleConstant) left).Value +
 									 ((DoubleConstant) right).Value);
 						
-						return new DoubleConstant (res);
+						result = new DoubleConstant (res, left.Location);
 					} else if (left is FloatConstant){
 						float res;
 						
@@ -317,7 +464,7 @@ namespace Mono.CSharp {
 							res = unchecked (((FloatConstant) left).Value +
 									 ((FloatConstant) right).Value);
 						
-						return new FloatConstant (res);
+						result = new FloatConstant (res, left.Location);
 					} else if (left is ULongConstant){
 						ulong res;
 						
@@ -327,8 +474,8 @@ namespace Mono.CSharp {
 						else
 							res = unchecked (((ULongConstant) left).Value +
 									 ((ULongConstant) right).Value);
-						
-						return new ULongConstant (res);
+
+						result = new ULongConstant (res, left.Location);
 					} else if (left is LongConstant){
 						long res;
 						
@@ -339,7 +486,7 @@ namespace Mono.CSharp {
 							res = unchecked (((LongConstant) left).Value +
 									 ((LongConstant) right).Value);
 						
-						return new LongConstant (res);
+						result = new LongConstant (res, left.Location);
 					} else if (left is UIntConstant){
 						uint res;
 						
@@ -350,7 +497,7 @@ namespace Mono.CSharp {
 							res = unchecked (((UIntConstant) left).Value +
 									 ((UIntConstant) right).Value);
 						
-						return new UIntConstant (res);
+						result = new UIntConstant (res, left.Location);
 					} else if (left is IntConstant){
 						int res;
 
@@ -361,17 +508,69 @@ namespace Mono.CSharp {
 							res = unchecked (((IntConstant) left).Value +
 									 ((IntConstant) right).Value);
 
-						return new IntConstant (res);
+						result = new IntConstant (res, left.Location);
+					} else if (left is DecimalConstant) {
+						decimal res;
+
+						if (ec.ConstantCheckState)
+							res = checked (((DecimalConstant) left).Value +
+								((DecimalConstant) right).Value);
+						else
+							res = unchecked (((DecimalConstant) left).Value +
+								((DecimalConstant) right).Value);
+
+						result = new DecimalConstant (res, left.Location);
 					} else {
-						throw new Exception ( "Unexepected input: " + left);
+						throw new Exception ( "Unexepected addition input: " + left);
 					}
 				} catch (OverflowException){
 					Error_CompileTimeOverflow (loc);
 				}
-				break;
+
+				if (wrap_as != null)
+					return result.TryReduce (ec, wrap_as, loc);
+				else
+					return result;
 
 			case Binary.Operator.Subtraction:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				//
+				// handle "E operator - (E x, U y)"
+				// handle "E operator - (Y y, E x)"
+				// handle "U operator - (E x, E y)"
+				//
+				wrap_as = null;
+				if (left is EnumConstant){
+					if (right is EnumConstant){
+						if (left.Type != right.Type) {
+							Binary.Error_OperatorCannotBeApplied (loc, "-", left.Type, right.Type);
+							return null;
+						}
+
+						wrap_as = TypeManager.EnumToUnderlying (left.Type);
+						right = ((EnumConstant) right).Child.ToType (wrap_as, loc);
+						if (right == null)
+							return null;
+
+						left = ((EnumConstant) left).Child.ToType (wrap_as, loc);
+						if (left == null)
+							return null;
+					}
+					else {
+						right = right.ToType (((EnumConstant) left).Child.Type, loc);
+						if (right == null)
+							return null;
+
+						wrap_as = left.Type;
+					}
+				} else if (right is EnumConstant){
+					left = left.ToType (((EnumConstant) right).Child.Type, loc);
+					if (left == null)
+						return null;
+
+					wrap_as = right.Type;
+				}
+
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -386,7 +585,7 @@ namespace Mono.CSharp {
 							res = unchecked (((DoubleConstant) left).Value -
 									 ((DoubleConstant) right).Value);
 						
-						return new DoubleConstant (res);
+						result = new DoubleConstant (res, left.Location);
 					} else if (left is FloatConstant){
 						float res;
 						
@@ -397,7 +596,7 @@ namespace Mono.CSharp {
 							res = unchecked (((FloatConstant) left).Value -
 									 ((FloatConstant) right).Value);
 						
-						return new FloatConstant (res);
+						result = new FloatConstant (res, left.Location);
 					} else if (left is ULongConstant){
 						ulong res;
 						
@@ -408,7 +607,7 @@ namespace Mono.CSharp {
 							res = unchecked (((ULongConstant) left).Value -
 									 ((ULongConstant) right).Value);
 						
-						return new ULongConstant (res);
+						result = new ULongConstant (res, left.Location);
 					} else if (left is LongConstant){
 						long res;
 						
@@ -419,7 +618,7 @@ namespace Mono.CSharp {
 							res = unchecked (((LongConstant) left).Value -
 									 ((LongConstant) right).Value);
 						
-						return new LongConstant (res);
+						result = new LongConstant (res, left.Location);
 					} else if (left is UIntConstant){
 						uint res;
 						
@@ -430,7 +629,7 @@ namespace Mono.CSharp {
 							res = unchecked (((UIntConstant) left).Value -
 									 ((UIntConstant) right).Value);
 						
-						return new UIntConstant (res);
+						result = new UIntConstant (res, left.Location);
 					} else if (left is IntConstant){
 						int res;
 
@@ -441,17 +640,32 @@ namespace Mono.CSharp {
 							res = unchecked (((IntConstant) left).Value -
 									 ((IntConstant) right).Value);
 
-						return new IntConstant (res);
+						result = new IntConstant (res, left.Location);
+					} else if (left is DecimalConstant) {
+						decimal res;
+
+						if (ec.ConstantCheckState)
+							res = checked (((DecimalConstant) left).Value -
+								((DecimalConstant) right).Value);
+						else
+							res = unchecked (((DecimalConstant) left).Value -
+								((DecimalConstant) right).Value);
+
+						return new DecimalConstant (res, left.Location);
 					} else {
-						throw new Exception ( "Unexepected input: " + left);
+						throw new Exception ( "Unexepected subtraction input: " + left);
 					}
 				} catch (OverflowException){
 					Error_CompileTimeOverflow (loc);
 				}
-				break;
+
+				if (wrap_as != null)
+					return result.TryReduce (ec, wrap_as, loc);
+
+				return result;
 				
 			case Binary.Operator.Multiply:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -461,69 +675,80 @@ namespace Mono.CSharp {
 						
 						if (ec.ConstantCheckState)
 							res = checked (((DoubleConstant) left).Value *
-								       ((DoubleConstant) right).Value);
+								((DoubleConstant) right).Value);
 						else
 							res = unchecked (((DoubleConstant) left).Value *
-									 ((DoubleConstant) right).Value);
+								((DoubleConstant) right).Value);
 						
-						return new DoubleConstant (res);
+						return new DoubleConstant (res, left.Location);
 					} else if (left is FloatConstant){
 						float res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((FloatConstant) left).Value *
-								       ((FloatConstant) right).Value);
+								((FloatConstant) right).Value);
 						else
 							res = unchecked (((FloatConstant) left).Value *
-									 ((FloatConstant) right).Value);
+								((FloatConstant) right).Value);
 						
-						return new FloatConstant (res);
+						return new FloatConstant (res, left.Location);
 					} else if (left is ULongConstant){
 						ulong res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((ULongConstant) left).Value *
-								       ((ULongConstant) right).Value);
+								((ULongConstant) right).Value);
 						else
 							res = unchecked (((ULongConstant) left).Value *
-									 ((ULongConstant) right).Value);
+								((ULongConstant) right).Value);
 						
-						return new ULongConstant (res);
+						return new ULongConstant (res, left.Location);
 					} else if (left is LongConstant){
 						long res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((LongConstant) left).Value *
-								       ((LongConstant) right).Value);
+								((LongConstant) right).Value);
 						else
 							res = unchecked (((LongConstant) left).Value *
-									 ((LongConstant) right).Value);
+								((LongConstant) right).Value);
 						
-						return new LongConstant (res);
+						return new LongConstant (res, left.Location);
 					} else if (left is UIntConstant){
 						uint res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((UIntConstant) left).Value *
-								       ((UIntConstant) right).Value);
+								((UIntConstant) right).Value);
 						else
 							res = unchecked (((UIntConstant) left).Value *
-									 ((UIntConstant) right).Value);
+								((UIntConstant) right).Value);
 						
-						return new UIntConstant (res);
+						return new UIntConstant (res, left.Location);
 					} else if (left is IntConstant){
 						int res;
 
 						if (ec.ConstantCheckState)
 							res = checked (((IntConstant) left).Value *
-								       ((IntConstant) right).Value);
+								((IntConstant) right).Value);
 						else
 							res = unchecked (((IntConstant) left).Value *
-									 ((IntConstant) right).Value);
+								((IntConstant) right).Value);
+
+						return new IntConstant (res, left.Location);
+					} else if (left is DecimalConstant) {
+						decimal res;
 
-						return new IntConstant (res);
+						if (ec.ConstantCheckState)
+							res = checked (((DecimalConstant) left).Value *
+								((DecimalConstant) right).Value);
+						else
+							res = unchecked (((DecimalConstant) left).Value *
+								((DecimalConstant) right).Value);
+
+						return new DecimalConstant (res, left.Location);
 					} else {
-						throw new Exception ( "Unexepected input: " + left);
+						throw new Exception ( "Unexepected multiply input: " + left);
 					}
 				} catch (OverflowException){
 					Error_CompileTimeOverflow (loc);
@@ -531,7 +756,7 @@ namespace Mono.CSharp {
 				break;
 
 			case Binary.Operator.Division:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -541,77 +766,92 @@ namespace Mono.CSharp {
 						
 						if (ec.ConstantCheckState)
 							res = checked (((DoubleConstant) left).Value /
-								       ((DoubleConstant) right).Value);
+								((DoubleConstant) right).Value);
 						else
 							res = unchecked (((DoubleConstant) left).Value /
-									 ((DoubleConstant) right).Value);
+								((DoubleConstant) right).Value);
 						
-						return new DoubleConstant (res);
+						return new DoubleConstant (res, left.Location);
 					} else if (left is FloatConstant){
 						float res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((FloatConstant) left).Value /
-								       ((FloatConstant) right).Value);
+								((FloatConstant) right).Value);
 						else
 							res = unchecked (((FloatConstant) left).Value /
-									 ((FloatConstant) right).Value);
+								((FloatConstant) right).Value);
 						
-						return new FloatConstant (res);
+						return new FloatConstant (res, left.Location);
 					} else if (left is ULongConstant){
 						ulong res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((ULongConstant) left).Value /
-								       ((ULongConstant) right).Value);
+								((ULongConstant) right).Value);
 						else
 							res = unchecked (((ULongConstant) left).Value /
-									 ((ULongConstant) right).Value);
+								((ULongConstant) right).Value);
 						
-						return new ULongConstant (res);
+						return new ULongConstant (res, left.Location);
 					} else if (left is LongConstant){
 						long res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((LongConstant) left).Value /
-								       ((LongConstant) right).Value);
+								((LongConstant) right).Value);
 						else
 							res = unchecked (((LongConstant) left).Value /
-									 ((LongConstant) right).Value);
+								((LongConstant) right).Value);
 						
-						return new LongConstant (res);
+						return new LongConstant (res, left.Location);
 					} else if (left is UIntConstant){
 						uint res;
 						
 						if (ec.ConstantCheckState)
 							res = checked (((UIntConstant) left).Value /
-								       ((UIntConstant) right).Value);
+								((UIntConstant) right).Value);
 						else
 							res = unchecked (((UIntConstant) left).Value /
-									 ((UIntConstant) right).Value);
+								((UIntConstant) right).Value);
 						
-						return new UIntConstant (res);
+						return new UIntConstant (res, left.Location);
 					} else if (left is IntConstant){
 						int res;
 
 						if (ec.ConstantCheckState)
 							res = checked (((IntConstant) left).Value /
-								       ((IntConstant) right).Value);
+								((IntConstant) right).Value);
 						else
 							res = unchecked (((IntConstant) left).Value /
-									 ((IntConstant) right).Value);
+								((IntConstant) right).Value);
 
-						return new IntConstant (res);
+						return new IntConstant (res, left.Location);
+					} else if (left is DecimalConstant) {
+						decimal res;
+
+						if (ec.ConstantCheckState)
+							res = checked (((DecimalConstant) left).Value /
+								((DecimalConstant) right).Value);
+						else
+							res = unchecked (((DecimalConstant) left).Value /
+								((DecimalConstant) right).Value);
+
+						return new DecimalConstant (res, left.Location);
 					} else {
-						throw new Exception ( "Unexepected input: " + left);
+						throw new Exception ( "Unexepected division input: " + left);
 					}
 				} catch (OverflowException){
 					Error_CompileTimeOverflow (loc);
+
+				} catch (DivideByZeroException) {
+					Report.Error (020, loc, "Division by constant zero");
 				}
+				
 				break;
 				
 			case Binary.Operator.Modulus:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -626,7 +866,7 @@ namespace Mono.CSharp {
 							res = unchecked (((DoubleConstant) left).Value %
 									 ((DoubleConstant) right).Value);
 						
-						return new DoubleConstant (res);
+						return new DoubleConstant (res, left.Location);
 					} else if (left is FloatConstant){
 						float res;
 						
@@ -637,7 +877,7 @@ namespace Mono.CSharp {
 							res = unchecked (((FloatConstant) left).Value %
 									 ((FloatConstant) right).Value);
 						
-						return new FloatConstant (res);
+						return new FloatConstant (res, left.Location);
 					} else if (left is ULongConstant){
 						ulong res;
 						
@@ -648,7 +888,7 @@ namespace Mono.CSharp {
 							res = unchecked (((ULongConstant) left).Value %
 									 ((ULongConstant) right).Value);
 						
-						return new ULongConstant (res);
+						return new ULongConstant (res, left.Location);
 					} else if (left is LongConstant){
 						long res;
 						
@@ -659,7 +899,7 @@ namespace Mono.CSharp {
 							res = unchecked (((LongConstant) left).Value %
 									 ((LongConstant) right).Value);
 						
-						return new LongConstant (res);
+						return new LongConstant (res, left.Location);
 					} else if (left is UIntConstant){
 						uint res;
 						
@@ -670,7 +910,7 @@ namespace Mono.CSharp {
 							res = unchecked (((UIntConstant) left).Value %
 									 ((UIntConstant) right).Value);
 						
-						return new UIntConstant (res);
+						return new UIntConstant (res, left.Location);
 					} else if (left is IntConstant){
 						int res;
 
@@ -681,10 +921,12 @@ namespace Mono.CSharp {
 							res = unchecked (((IntConstant) left).Value %
 									 ((IntConstant) right).Value);
 
-						return new IntConstant (res);
+						return new IntConstant (res, left.Location);
 					} else {
-						throw new Exception ( "Unexepected input: " + left);
+						throw new Exception ( "Unexepected modulus input: " + left);
 					}
+				} catch (DivideByZeroException){
+					Report.Error (020, loc, "Division by constant zero");
 				} catch (OverflowException){
 					Error_CompileTimeOverflow (loc);
 				}
@@ -703,19 +945,19 @@ namespace Mono.CSharp {
 
 				IntConstant lic;
 				if ((lic = left.ConvertToInt ()) != null)
-					return new IntConstant (lic.Value << lshift_val);
+					return new IntConstant (lic.Value << lshift_val, left.Location);
 
 				UIntConstant luic;
 				if ((luic = left.ConvertToUInt ()) != null)
-					return new UIntConstant (luic.Value << lshift_val);
+					return new UIntConstant (luic.Value << lshift_val, left.Location);
 
 				LongConstant llc;
 				if ((llc = left.ConvertToLong ()) != null)
-					return new LongConstant (llc.Value << lshift_val);
+					return new LongConstant (llc.Value << lshift_val, left.Location);
 
 				ULongConstant lulc;
 				if ((lulc = left.ConvertToULong ()) != null)
-					return new ULongConstant (lulc.Value << lshift_val);
+					return new ULongConstant (lulc.Value << lshift_val, left.Location);
 
 				Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 				break;
@@ -733,19 +975,19 @@ namespace Mono.CSharp {
 
 				IntConstant ric;
 				if ((ric = left.ConvertToInt ()) != null)
-					return new IntConstant (ric.Value >> rshift_val);
+					return new IntConstant (ric.Value >> rshift_val, left.Location);
 
 				UIntConstant ruic;
 				if ((ruic = left.ConvertToUInt ()) != null)
-					return new UIntConstant (ruic.Value >> rshift_val);
+					return new UIntConstant (ruic.Value >> rshift_val, left.Location);
 
 				LongConstant rlc;
 				if ((rlc = left.ConvertToLong ()) != null)
-					return new LongConstant (rlc.Value >> rshift_val);
+					return new LongConstant (rlc.Value >> rshift_val, left.Location);
 
 				ULongConstant rulc;
 				if ((rulc = left.ConvertToULong ()) != null)
-					return new ULongConstant (rulc.Value >> rshift_val);
+					return new ULongConstant (rulc.Value >> rshift_val, left.Location);
 
 				Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 				break;
@@ -754,7 +996,7 @@ namespace Mono.CSharp {
 				if (left is BoolConstant && right is BoolConstant){
 					return new BoolConstant (
 						((BoolConstant) left).Value &&
-						((BoolConstant) right).Value);
+						((BoolConstant) right).Value, left.Location);
 				}
 				break;
 
@@ -762,7 +1004,7 @@ namespace Mono.CSharp {
 				if (left is BoolConstant && right is BoolConstant){
 					return new BoolConstant (
 						((BoolConstant) left).Value ||
-						((BoolConstant) right).Value);
+						((BoolConstant) right).Value, left.Location);
 				}
 				break;
 				
@@ -770,17 +1012,30 @@ namespace Mono.CSharp {
 				if (left is BoolConstant && right is BoolConstant){
 					return new BoolConstant (
 						((BoolConstant) left).Value ==
-						((BoolConstant) right).Value);
+						((BoolConstant) right).Value, left.Location);
 				
 				}
+				if (left is NullLiteral){
+					if (right is NullLiteral)
+						return new BoolConstant (true, left.Location);
+					else if (right is StringConstant)
+						return new BoolConstant (
+							((StringConstant) right).Value == null, left.Location);
+				} else if (right is NullLiteral){
+					if (left is NullLiteral)
+						return new BoolConstant (true, left.Location);
+					else if (left is StringConstant)
+						return new BoolConstant (
+							((StringConstant) left).Value == null, left.Location);
+				}
 				if (left is StringConstant && right is StringConstant){
 					return new BoolConstant (
 						((StringConstant) left).Value ==
-						((StringConstant) right).Value);
+						((StringConstant) right).Value, left.Location);
 					
 				}
-				
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -806,21 +1061,34 @@ namespace Mono.CSharp {
 				else
 					return null;
 
-				return new BoolConstant (bool_res);
+				return new BoolConstant (bool_res, left.Location);
 
 			case Binary.Operator.Inequality:
 				if (left is BoolConstant && right is BoolConstant){
 					return new BoolConstant (
 						((BoolConstant) left).Value !=
-						((BoolConstant) right).Value);
+						((BoolConstant) right).Value, left.Location);
+				}
+				if (left is NullLiteral){
+					if (right is NullLiteral)
+						return new BoolConstant (false, left.Location);
+					else if (right is StringConstant)
+						return new BoolConstant (
+							((StringConstant) right).Value != null, left.Location);
+				} else if (right is NullLiteral){
+					if (left is NullLiteral)
+						return new BoolConstant (false, left.Location);
+					else if (left is StringConstant)
+						return new BoolConstant (
+							((StringConstant) left).Value != null, left.Location);
 				}
 				if (left is StringConstant && right is StringConstant){
 					return new BoolConstant (
 						((StringConstant) left).Value !=
-						((StringConstant) right).Value);
+						((StringConstant) right).Value, left.Location);
 					
 				}
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -846,10 +1114,10 @@ namespace Mono.CSharp {
 				else
 					return null;
 
-				return new BoolConstant (bool_res);
+				return new BoolConstant (bool_res, left.Location);
 
 			case Binary.Operator.LessThan:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -875,10 +1143,10 @@ namespace Mono.CSharp {
 				else
 					return null;
 
-				return new BoolConstant (bool_res);
+				return new BoolConstant (bool_res, left.Location);
 				
 			case Binary.Operator.GreaterThan:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -904,10 +1172,10 @@ namespace Mono.CSharp {
 				else
 					return null;
 
-				return new BoolConstant (bool_res);
+				return new BoolConstant (bool_res, left.Location);
 
 			case Binary.Operator.GreaterThanOrEqual:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -933,10 +1201,10 @@ namespace Mono.CSharp {
 				else
 					return null;
 
-				return new BoolConstant (bool_res);
+				return new BoolConstant (bool_res, left.Location);
 
 			case Binary.Operator.LessThanOrEqual:
-				DoConstantNumericPromotions (oper, ref left, ref right, loc);
+				DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 				if (left == null || right == null)
 					return null;
 
@@ -962,7 +1230,7 @@ namespace Mono.CSharp {
 				else
 					return null;
 
-				return new BoolConstant (bool_res);
+				return new BoolConstant (bool_res, left.Location);
 			}
 					
 			return null;