2 // conversion.cs: various routines for implementing conversions.
5 // Miguel de Icaza (miguel@ximian.com)
6 // Ravi Pratap (ravi@ximian.com)
7 // Marek Safar (marek.safar@gmail.com)
9 // Copyright 2001, 2002, 2003 Ximian, Inc.
10 // Copyright 2003-2008 Novell, Inc.
11 // Copyright 2011 Xamarin Inc (http://www.xamarin.com)
15 using System.Collections.Generic;
18 using IKVM.Reflection.Emit;
20 using System.Reflection.Emit;
23 namespace Mono.CSharp {
26 // A container class for all the conversion operations
31 // From a one-dimensional array-type S[] to System.Collections.IList<T> and base
32 // interfaces of this interface, provided there is an implicit reference conversion
35 static bool ArrayToIList (ArrayContainer array, TypeSpec list, bool isExplicit)
37 if (array.Rank != 1 || !list.IsGenericIterateInterface)
40 var arg_type = list.TypeArguments[0];
41 if (array.Element == arg_type)
45 // Reject conversion from T[] to IList<U> even if T has U dependency
47 if (arg_type.IsGenericParameter)
51 return ExplicitReferenceConversionExists (array.Element, arg_type);
53 return ImplicitReferenceConversionExists (array.Element, arg_type);
56 static bool IList_To_Array(TypeSpec list, ArrayContainer array)
58 if (array.Rank != 1 || !list.IsGenericIterateInterface)
61 var arg_type = list.TypeArguments[0];
62 if (array.Element == arg_type)
65 return ImplicitReferenceConversionExists (array.Element, arg_type) || ExplicitReferenceConversionExists (array.Element, arg_type);
68 public static Expression ImplicitTypeParameterConversion (Expression expr, TypeParameterSpec expr_type, TypeSpec target_type)
71 // From T to a type parameter U, provided T depends on U
73 if (target_type.IsGenericParameter) {
74 if (expr_type.TypeArguments != null) {
75 foreach (var targ in expr_type.TypeArguments) {
76 if (!TypeSpecComparer.Override.IsEqual (target_type, targ))
80 return EmptyExpression.Null;
82 if (expr_type.IsReferenceType && !((TypeParameterSpec)target_type).IsReferenceType)
83 return new BoxedCast (expr, target_type);
85 return new ClassCast (expr, target_type);
93 // LAMESPEC: From T to dynamic type because it's like T to object
95 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
97 return EmptyExpression.Null;
99 if (expr_type.IsReferenceType)
100 return new ClassCast (expr, target_type);
102 return new BoxedCast (expr, target_type);
106 // From T to its effective base class C
107 // From T to any base class of C (it cannot contain dynamic or be of dynamic type)
108 // From T to any interface implemented by C
110 var base_type = expr_type.GetEffectiveBase ();
111 if (base_type == target_type || TypeSpec.IsBaseClass (base_type, target_type, false) || base_type.ImplementsInterface (target_type, true)) {
113 return EmptyExpression.Null;
115 if (expr_type.IsReferenceType)
116 return new ClassCast (expr, target_type);
118 return new BoxedCast (expr, target_type);
121 if (target_type.IsInterface && expr_type.IsConvertibleToInterface (target_type)) {
123 return EmptyExpression.Null;
125 if (expr_type.IsReferenceType)
126 return new ClassCast (expr, target_type);
128 return new BoxedCast (expr, target_type);
134 static Expression ExplicitTypeParameterConversion (Expression source, TypeSpec source_type, TypeSpec target_type)
136 var target_tp = target_type as TypeParameterSpec;
137 if (target_tp != null) {
138 if (target_tp.TypeArguments != null) {
139 foreach (var targ in target_tp.TypeArguments) {
140 if (!TypeSpecComparer.Override.IsEqual (source_type, targ))
143 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
147 if (target_tp.Interfaces != null) {
148 foreach (TypeSpec iface in target_tp.Interfaces) {
149 if (!TypeManager.IsGenericParameter (iface))
152 if (TypeManager.IsSubclassOf (source_type, iface))
153 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type, true);
160 if (target_type.IsInterface)
161 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type, true);
166 public static Expression ImplicitReferenceConversion (Expression expr, TypeSpec target_type, bool explicit_cast)
168 TypeSpec expr_type = expr.Type;
170 if (expr_type.Kind == MemberKind.TypeParameter)
171 return ImplicitTypeParameterConversion (expr, (TypeParameterSpec) expr.Type, target_type);
174 // from the null type to any reference-type.
176 NullLiteral nl = expr as NullLiteral;
178 return nl.ConvertImplicitly (target_type);
181 if (ImplicitReferenceConversionExists (expr_type, target_type)) {
183 // Avoid wrapping implicitly convertible reference type
188 return EmptyCast.Create (expr, target_type);
195 // Implicit reference conversions
197 public static bool ImplicitReferenceConversionExists (TypeSpec expr_type, TypeSpec target_type)
199 return ImplicitReferenceConversionExists (expr_type, target_type, true);
202 public static bool ImplicitReferenceConversionExists (TypeSpec expr_type, TypeSpec target_type, bool refOnlyTypeParameter)
204 // It's here only to speed things up
205 if (target_type.IsStruct)
208 switch (expr_type.Kind) {
209 case MemberKind.TypeParameter:
210 return ImplicitTypeParameterConversion (null, (TypeParameterSpec) expr_type, target_type) != null &&
211 (!refOnlyTypeParameter || TypeSpec.IsReferenceType (expr_type));
213 case MemberKind.Class:
215 // From any class-type to dynamic (+object to speed up common path)
217 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Object || target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
220 if (target_type.IsClass) {
222 // Identity conversion, including dynamic erasure
224 if (TypeSpecComparer.IsEqual (expr_type, target_type))
228 // From any class-type S to any class-type T, provided S is derived from T
230 return TypeSpec.IsBaseClass (expr_type, target_type, true);
234 // From any class-type S to any interface-type T, provided S implements T
236 if (target_type.IsInterface)
237 return expr_type.ImplementsInterface (target_type, true);
241 case MemberKind.ArrayType:
243 // Identity array conversion
245 if (expr_type == target_type)
249 // From any array-type to System.Array
251 switch (target_type.BuiltinType) {
252 case BuiltinTypeSpec.Type.Array:
253 case BuiltinTypeSpec.Type.Object:
254 case BuiltinTypeSpec.Type.Dynamic:
258 var expr_type_array = (ArrayContainer) expr_type;
259 var target_type_array = target_type as ArrayContainer;
262 // From an array-type S to an array-type of type T
264 if (target_type_array != null && expr_type_array.Rank == target_type_array.Rank) {
267 // Both SE and TE are reference-types. TE check is defered
268 // to ImplicitReferenceConversionExists
270 TypeSpec expr_element_type = expr_type_array.Element;
271 if (!TypeSpec.IsReferenceType (expr_element_type))
275 // An implicit reference conversion exists from SE to TE
277 return ImplicitReferenceConversionExists (expr_element_type, target_type_array.Element);
281 // From any array-type to the interfaces it implements
283 if (target_type.IsInterface) {
284 if (expr_type.ImplementsInterface (target_type, false))
287 // from an array-type of type T to IList<T>
288 if (ArrayToIList (expr_type_array, target_type, false))
294 case MemberKind.Delegate:
296 // From any delegate-type to System.Delegate (and its base types)
298 switch (target_type.BuiltinType) {
299 case BuiltinTypeSpec.Type.Delegate:
300 case BuiltinTypeSpec.Type.MulticastDelegate:
301 case BuiltinTypeSpec.Type.Object:
302 case BuiltinTypeSpec.Type.Dynamic:
307 // Identity conversion, including dynamic erasure
309 if (TypeSpecComparer.IsEqual (expr_type, target_type))
313 // From any delegate-type to the interfaces it implements
314 // From any reference-type to an delegate type if is variance-convertible
316 return expr_type.ImplementsInterface (target_type, false) || TypeSpecComparer.Variant.IsEqual (expr_type, target_type);
318 case MemberKind.Interface:
320 // Identity conversion, including dynamic erasure
322 if (TypeSpecComparer.IsEqual (expr_type, target_type))
326 // From any interface type S to interface-type T
327 // From any reference-type to an interface if is variance-convertible
329 if (target_type.IsInterface)
330 return TypeSpecComparer.Variant.IsEqual (expr_type, target_type) || expr_type.ImplementsInterface (target_type, true);
332 return target_type.BuiltinType == BuiltinTypeSpec.Type.Object || target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
334 case MemberKind.InternalCompilerType:
336 // from the null literal to any reference-type.
338 if (expr_type == InternalType.NullLiteral) {
339 // Exlude internal compiler types
340 if (target_type.Kind == MemberKind.InternalCompilerType)
341 return target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
343 return TypeSpec.IsReferenceType (target_type);
347 // Implicit dynamic conversion
349 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
350 switch (target_type.Kind) {
351 case MemberKind.ArrayType:
352 case MemberKind.Class:
353 case MemberKind.Delegate:
354 case MemberKind.Interface:
355 case MemberKind.TypeParameter:
359 // dynamic to __arglist
360 if (target_type == InternalType.Arglist)
372 public static Expression ImplicitBoxingConversion (Expression expr, TypeSpec expr_type, TypeSpec target_type)
374 switch (target_type.BuiltinType) {
376 // From any non-nullable-value-type to the type object and dynamic
378 case BuiltinTypeSpec.Type.Object:
379 case BuiltinTypeSpec.Type.Dynamic:
381 // From any non-nullable-value-type to the type System.ValueType
383 case BuiltinTypeSpec.Type.ValueType:
385 // No ned to check for nullable type as underlying type is always convertible
387 if (!TypeSpec.IsValueType (expr_type))
390 return expr == null ? EmptyExpression.Null : new BoxedCast (expr, target_type);
392 case BuiltinTypeSpec.Type.Enum:
394 // From any enum-type to the type System.Enum.
396 if (expr_type.IsEnum)
397 return expr == null ? EmptyExpression.Null : new BoxedCast (expr, target_type);
403 // From a nullable-type to a reference type, if a boxing conversion exists from
404 // the underlying type to the reference type
406 if (expr_type.IsNullableType) {
407 if (!TypeSpec.IsReferenceType (target_type))
410 var res = ImplicitBoxingConversion (expr, Nullable.NullableInfo.GetUnderlyingType (expr_type), target_type);
412 // "cast" underlying type to target type to emit correct InvalidCastException when
413 // underlying hierarchy changes without recompilation
414 if (res != null && expr != null)
415 res = new UnboxCast (res, target_type);
421 // A value type has a boxing conversion to an interface type I if it has a boxing conversion
422 // to an interface or delegate type I0 and I0 is variance-convertible to I
424 if (target_type.IsInterface && TypeSpec.IsValueType (expr_type) && expr_type.ImplementsInterface (target_type, true)) {
425 return expr == null ? EmptyExpression.Null : new BoxedCast (expr, target_type);
431 public static Expression ImplicitNulableConversion (ResolveContext ec, Expression expr, TypeSpec target_type)
433 TypeSpec expr_type = expr.Type;
436 // From null to any nullable type
438 if (expr_type == InternalType.NullLiteral)
439 return ec == null ? EmptyExpression.Null : Nullable.LiftedNull.Create (target_type, expr.Location);
442 TypeSpec t_el = Nullable.NullableInfo.GetUnderlyingType (target_type);
445 if (expr_type.IsNullableType)
446 expr_type = Nullable.NullableInfo.GetUnderlyingType (expr_type);
449 // Predefined implicit identity or implicit numeric conversion
450 // has to exist between underlying type S and underlying type T
453 // conversion exists only mode
455 if (TypeSpecComparer.IsEqual (expr_type, t_el))
456 return EmptyExpression.Null;
458 if (expr is Constant)
459 return ((Constant) expr).ConvertImplicitly (t_el);
461 return ImplicitNumericConversion (null, expr_type, t_el);
465 if (expr_type != expr.Type)
466 unwrap = Nullable.Unwrap.Create (expr);
470 Expression conv = unwrap;
471 if (!TypeSpecComparer.IsEqual (expr_type, t_el)) {
472 if (conv is Constant)
473 conv = ((Constant)conv).ConvertImplicitly (t_el);
475 conv = ImplicitNumericConversion (conv, expr_type, t_el);
481 if (expr_type != expr.Type)
482 return new Nullable.Lifted (conv, unwrap, target_type).Resolve (ec);
484 return Nullable.Wrap.Create (conv, target_type);
488 /// Implicit Numeric Conversions.
490 /// expr is the expression to convert, returns a new expression of type
491 /// target_type or null if an implicit conversion is not possible.
493 public static Expression ImplicitNumericConversion (Expression expr, TypeSpec target_type)
495 return ImplicitNumericConversion (expr, expr.Type, target_type);
498 public static bool ImplicitNumericConversionExists (TypeSpec expr_type, TypeSpec target_type)
500 return ImplicitNumericConversion (null, expr_type, target_type) != null;
503 static Expression ImplicitNumericConversion (Expression expr, TypeSpec expr_type, TypeSpec target_type)
505 switch (expr_type.BuiltinType) {
506 case BuiltinTypeSpec.Type.SByte:
508 // From sbyte to short, int, long, float, double, decimal
510 switch (target_type.BuiltinType) {
511 case BuiltinTypeSpec.Type.Int:
512 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
513 case BuiltinTypeSpec.Type.Long:
514 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
515 case BuiltinTypeSpec.Type.Double:
516 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
517 case BuiltinTypeSpec.Type.Float:
518 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
519 case BuiltinTypeSpec.Type.Short:
520 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
521 case BuiltinTypeSpec.Type.Decimal:
522 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
527 case BuiltinTypeSpec.Type.Byte:
529 // From byte to short, ushort, int, uint, long, ulong, float, double, decimal
531 switch (target_type.BuiltinType) {
532 case BuiltinTypeSpec.Type.Int:
533 case BuiltinTypeSpec.Type.UInt:
534 case BuiltinTypeSpec.Type.Short:
535 case BuiltinTypeSpec.Type.UShort:
536 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
537 case BuiltinTypeSpec.Type.ULong:
538 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
539 case BuiltinTypeSpec.Type.Long:
540 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
541 case BuiltinTypeSpec.Type.Float:
542 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
543 case BuiltinTypeSpec.Type.Double:
544 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
545 case BuiltinTypeSpec.Type.Decimal:
546 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
549 case BuiltinTypeSpec.Type.Short:
551 // From short to int, long, float, double, decimal
553 switch (target_type.BuiltinType) {
554 case BuiltinTypeSpec.Type.Int:
555 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
556 case BuiltinTypeSpec.Type.Long:
557 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
558 case BuiltinTypeSpec.Type.Double:
559 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
560 case BuiltinTypeSpec.Type.Float:
561 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
562 case BuiltinTypeSpec.Type.Decimal:
563 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
566 case BuiltinTypeSpec.Type.UShort:
568 // From ushort to int, uint, long, ulong, float, double, decimal
570 switch (target_type.BuiltinType) {
571 case BuiltinTypeSpec.Type.Int:
572 case BuiltinTypeSpec.Type.UInt:
573 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
574 case BuiltinTypeSpec.Type.ULong:
575 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
576 case BuiltinTypeSpec.Type.Long:
577 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
578 case BuiltinTypeSpec.Type.Double:
579 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
580 case BuiltinTypeSpec.Type.Float:
581 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
582 case BuiltinTypeSpec.Type.Decimal:
583 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
586 case BuiltinTypeSpec.Type.Int:
588 // From int to long, float, double, decimal
590 switch (target_type.BuiltinType) {
591 case BuiltinTypeSpec.Type.Long:
592 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
593 case BuiltinTypeSpec.Type.Double:
594 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
595 case BuiltinTypeSpec.Type.Float:
596 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
597 case BuiltinTypeSpec.Type.Decimal:
598 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
601 case BuiltinTypeSpec.Type.UInt:
603 // From uint to long, ulong, float, double, decimal
605 switch (target_type.BuiltinType) {
606 case BuiltinTypeSpec.Type.Long:
607 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
608 case BuiltinTypeSpec.Type.ULong:
609 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
610 case BuiltinTypeSpec.Type.Double:
611 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R8);
612 case BuiltinTypeSpec.Type.Float:
613 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R4);
614 case BuiltinTypeSpec.Type.Decimal:
615 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
618 case BuiltinTypeSpec.Type.Long:
620 // From long to float, double, decimal
622 switch (target_type.BuiltinType) {
623 case BuiltinTypeSpec.Type.Double:
624 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
625 case BuiltinTypeSpec.Type.Float:
626 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
627 case BuiltinTypeSpec.Type.Decimal:
628 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
631 case BuiltinTypeSpec.Type.ULong:
633 // From ulong to float, double, decimal
635 switch (target_type.BuiltinType) {
636 case BuiltinTypeSpec.Type.Double:
637 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R8);
638 case BuiltinTypeSpec.Type.Float:
639 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R4);
640 case BuiltinTypeSpec.Type.Decimal:
641 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
644 case BuiltinTypeSpec.Type.Char:
646 // From char to ushort, int, uint, long, ulong, float, double, decimal
648 switch (target_type.BuiltinType) {
649 case BuiltinTypeSpec.Type.UShort:
650 case BuiltinTypeSpec.Type.Int:
651 case BuiltinTypeSpec.Type.UInt:
652 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
653 case BuiltinTypeSpec.Type.ULong:
654 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
655 case BuiltinTypeSpec.Type.Long:
656 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
657 case BuiltinTypeSpec.Type.Float:
658 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
659 case BuiltinTypeSpec.Type.Double:
660 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
661 case BuiltinTypeSpec.Type.Decimal:
662 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
665 case BuiltinTypeSpec.Type.Float:
669 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Double)
670 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
678 // Full version of implicit conversion
680 public static bool ImplicitConversionExists (ResolveContext ec, Expression expr, TypeSpec target_type)
682 if (ImplicitStandardConversionExists (expr, target_type))
685 if (expr.Type == InternalType.AnonymousMethod) {
686 if (!target_type.IsDelegate && !target_type.IsExpressionTreeType)
689 AnonymousMethodExpression ame = (AnonymousMethodExpression) expr;
690 return ame.ImplicitStandardConversionExists (ec, target_type);
693 if (expr.eclass == ExprClass.MethodGroup) {
694 if (target_type.IsDelegate && ec.Module.Compiler.Settings.Version != LanguageVersion.ISO_1) {
695 MethodGroupExpr mg = expr as MethodGroupExpr;
697 return DelegateCreation.ImplicitStandardConversionExists (ec, mg, target_type);
703 // Conversion from __arglist to System.ArgIterator
704 if (expr.Type == InternalType.Arglist)
705 return target_type == ec.Module.PredefinedTypes.ArgIterator.TypeSpec;
707 return UserDefinedConversion (ec, expr, target_type, true, true, Location.Null) != null;
711 // Implicit standard conversion (only core conversions are used here)
713 public static bool ImplicitStandardConversionExists (Expression expr, TypeSpec target_type)
716 // Identity conversions
717 // Implicit numeric conversions
718 // Implicit nullable conversions
719 // Implicit reference conversions
720 // Boxing conversions
721 // Implicit constant expression conversions
722 // Implicit conversions involving type parameters
725 TypeSpec expr_type = expr.Type;
727 if (expr_type == target_type)
730 if (target_type.IsNullableType)
731 return ImplicitNulableConversion (null, expr, target_type) != null;
733 if (ImplicitNumericConversion (null, expr_type, target_type) != null)
736 if (ImplicitReferenceConversionExists (expr_type, target_type, false))
739 if (ImplicitBoxingConversion (null, expr_type, target_type) != null)
743 // Implicit Constant Expression Conversions
745 if (expr is IntConstant){
746 int value = ((IntConstant) expr).Value;
747 switch (target_type.BuiltinType) {
748 case BuiltinTypeSpec.Type.SByte:
749 if (value >= SByte.MinValue && value <= SByte.MaxValue)
752 case BuiltinTypeSpec.Type.Byte:
753 if (value >= 0 && value <= Byte.MaxValue)
756 case BuiltinTypeSpec.Type.Short:
757 if (value >= Int16.MinValue && value <= Int16.MaxValue)
760 case BuiltinTypeSpec.Type.UShort:
761 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
764 case BuiltinTypeSpec.Type.UInt:
768 case BuiltinTypeSpec.Type.ULong:
770 // we can optimize this case: a positive int32
771 // always fits on a uint64. But we need an opcode
781 if (expr is LongConstant && target_type.BuiltinType == BuiltinTypeSpec.Type.ULong){
783 // Try the implicit constant expression conversion
784 // from long to ulong, instead of a nice routine,
787 long v = ((LongConstant) expr).Value;
792 if (expr is IntegralConstant && target_type.IsEnum) {
793 var i = (IntegralConstant) expr;
795 // LAMESPEC: csc allows any constant like 0 values to be converted, including const float f = 0.0
797 // An implicit enumeration conversion permits the decimal-integer-literal 0
798 // to be converted to any enum-type and to any nullable-type whose underlying
799 // type is an enum-type
801 return i.IsZeroInteger;
805 // Implicit dynamic conversion for remaining value types. It should probably
808 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
809 switch (target_type.Kind) {
810 case MemberKind.Struct:
811 case MemberKind.Enum:
819 // In an unsafe context implicit conversions is extended to include
821 // From any pointer-type to the type void*
822 // From the null literal to any pointer-type.
824 // LAMESPEC: The specification claims this conversion is allowed in implicit conversion but
825 // in reality implicit standard conversion uses it
827 if (target_type.IsPointer && expr.Type.IsPointer && ((PointerContainer) target_type).Element.Kind == MemberKind.Void)
831 // Struct identity conversion, including dynamic erasure
833 if (expr_type.IsStruct && TypeSpecComparer.IsEqual (expr_type, target_type))
840 /// Finds "most encompassed type" according to the spec (13.4.2)
841 /// amongst the methods in the MethodGroupExpr
843 public static TypeSpec FindMostEncompassedType (IList<TypeSpec> types)
845 TypeSpec best = null;
846 EmptyExpression expr;
848 foreach (TypeSpec t in types) {
854 expr = new EmptyExpression (t);
855 if (ImplicitStandardConversionExists (expr, best))
859 expr = new EmptyExpression (best);
860 foreach (TypeSpec t in types) {
863 if (!ImplicitStandardConversionExists (expr, t)) {
873 // Finds the most encompassing type (type into which all other
874 // types can convert to) amongst the types in the given set
876 static TypeSpec FindMostEncompassingType (IList<TypeSpec> types)
878 if (types.Count == 0)
881 if (types.Count == 1)
884 TypeSpec best = null;
885 for (int i = 0; i < types.Count; ++i) {
887 for (; ii < types.Count; ++ii) {
891 var expr = new EmptyExpression (types[ii]);
892 if (!ImplicitStandardConversionExists (expr, types [i])) {
906 // Indicates multiple best types
907 return InternalType.FakeInternalType;
914 // Finds the most specific source Sx according to the rules of the spec (13.4.4)
915 // by making use of FindMostEncomp* methods. Applies the correct rules separately
916 // for explicit and implicit conversion operators.
918 static TypeSpec FindMostSpecificSource (List<MethodSpec> list, TypeSpec sourceType, Expression source, bool apply_explicit_conv_rules)
920 TypeSpec[] src_types_set = null;
923 // Try exact match first, if any operator converts from S then Sx = S
925 for (int i = 0; i < list.Count; ++i) {
926 TypeSpec param_type = list [i].Parameters.Types [0];
928 if (param_type == sourceType)
931 if (src_types_set == null)
932 src_types_set = new TypeSpec [list.Count];
934 src_types_set [i] = param_type;
938 // Explicit Conv rules
940 if (apply_explicit_conv_rules) {
941 var candidate_set = new List<TypeSpec> ();
943 foreach (TypeSpec param_type in src_types_set){
944 if (ImplicitStandardConversionExists (source, param_type))
945 candidate_set.Add (param_type);
948 if (candidate_set.Count != 0)
949 return FindMostEncompassedType (candidate_set);
955 if (apply_explicit_conv_rules)
956 return FindMostEncompassingType (src_types_set);
958 return FindMostEncompassedType (src_types_set);
962 /// Finds the most specific target Tx according to section 13.4.4
964 static public TypeSpec FindMostSpecificTarget (IList<MethodSpec> list,
965 TypeSpec target, bool apply_explicit_conv_rules)
967 List<TypeSpec> tgt_types_set = null;
970 // If any operator converts to T then Tx = T
972 foreach (var mi in list){
973 TypeSpec ret_type = mi.ReturnType;
974 if (ret_type == target)
977 if (tgt_types_set == null) {
978 tgt_types_set = new List<TypeSpec> (list.Count);
979 } else if (tgt_types_set.Contains (ret_type)) {
983 tgt_types_set.Add (ret_type);
987 // Explicit conv rules
989 if (apply_explicit_conv_rules) {
990 var candidate_set = new List<TypeSpec> ();
992 foreach (TypeSpec ret_type in tgt_types_set) {
993 var expr = new EmptyExpression (ret_type);
995 if (ImplicitStandardConversionExists (expr, target))
996 candidate_set.Add (ret_type);
999 if (candidate_set.Count != 0)
1000 return FindMostEncompassingType (candidate_set);
1004 // Okay, final case !
1006 if (apply_explicit_conv_rules)
1007 return FindMostEncompassedType (tgt_types_set);
1009 return FindMostEncompassingType (tgt_types_set);
1013 /// User-defined Implicit conversions
1015 static public Expression ImplicitUserConversion (ResolveContext ec, Expression source, TypeSpec target, Location loc)
1017 return UserDefinedConversion (ec, source, target, true, false, loc);
1021 /// User-defined Explicit conversions
1023 static Expression ExplicitUserConversion (ResolveContext ec, Expression source, TypeSpec target, Location loc)
1025 return UserDefinedConversion (ec, source, target, false, false, loc);
1028 static void FindApplicableUserDefinedConversionOperators (IList<MemberSpec> operators, Expression source, TypeSpec target, bool implicitOnly, ref List<MethodSpec> candidates)
1030 if (source.Type.IsInterface) {
1031 // Neither A nor B are interface-types
1035 // For a conversion operator to be applicable, it must be possible
1036 // to perform a standard conversion from the source type to
1037 // the operand type of the operator, and it must be possible
1038 // to perform a standard conversion from the result type of
1039 // the operator to the target type.
1041 Expression texpr = null;
1043 foreach (MethodSpec op in operators) {
1045 // Can be null because MemberCache.GetUserOperator does not resize the array
1049 var t = op.Parameters.Types[0];
1050 if (source.Type != t && !ImplicitStandardConversionExists (source, t)) {
1054 if (!ImplicitStandardConversionExists (new EmptyExpression (t), source.Type))
1064 if (t.IsNullableType)
1065 t = Nullable.NullableInfo.GetUnderlyingType (t);
1067 if (!ImplicitStandardConversionExists (new EmptyExpression (t), target)) {
1072 texpr = new EmptyExpression (target);
1074 if (!ImplicitStandardConversionExists (texpr, t))
1079 if (candidates == null)
1080 candidates = new List<MethodSpec> ();
1082 candidates.Add (op);
1087 // User-defined conversions
1089 static Expression UserDefinedConversion (ResolveContext ec, Expression source, TypeSpec target, bool implicitOnly, bool probingOnly, Location loc)
1091 List<MethodSpec> candidates = null;
1094 // If S or T are nullable types, source_type and target_type are their underlying types
1095 // otherwise source_type and target_type are equal to S and T respectively.
1097 TypeSpec source_type = source.Type;
1098 TypeSpec target_type = target;
1099 Expression source_type_expr;
1101 if (source_type.IsNullableType) {
1102 // No unwrapping conversion S? -> T for non-reference types
1103 if (implicitOnly && !TypeSpec.IsReferenceType (target_type) && !target_type.IsNullableType) {
1104 source_type_expr = source;
1106 source_type_expr = Nullable.Unwrap.Create (source);
1107 source_type = source_type_expr.Type;
1110 source_type_expr = source;
1113 if (target_type.IsNullableType)
1114 target_type = Nullable.NullableInfo.GetUnderlyingType (target_type);
1116 // Only these containers can contain a user defined implicit or explicit operators
1117 const MemberKind user_conversion_kinds = MemberKind.Class | MemberKind.Struct | MemberKind.TypeParameter;
1119 if ((source_type.Kind & user_conversion_kinds) != 0 && source_type.BuiltinType != BuiltinTypeSpec.Type.Decimal) {
1120 bool declared_only = source_type.IsStruct;
1122 var operators = MemberCache.GetUserOperator (source_type, Operator.OpType.Implicit, declared_only);
1123 if (operators != null) {
1124 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, implicitOnly, ref candidates);
1127 if (!implicitOnly) {
1128 operators = MemberCache.GetUserOperator (source_type, Operator.OpType.Explicit, declared_only);
1129 if (operators != null) {
1130 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, false, ref candidates);
1135 if ((target.Kind & user_conversion_kinds) != 0 && target_type.BuiltinType != BuiltinTypeSpec.Type.Decimal) {
1136 bool declared_only = target.IsStruct || implicitOnly;
1138 var operators = MemberCache.GetUserOperator (target_type, Operator.OpType.Implicit, declared_only);
1139 if (operators != null) {
1140 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, implicitOnly, ref candidates);
1143 if (!implicitOnly) {
1144 operators = MemberCache.GetUserOperator (target_type, Operator.OpType.Explicit, declared_only);
1145 if (operators != null) {
1146 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, false, ref candidates);
1151 if (candidates == null)
1155 // Find the most specific conversion operator
1157 MethodSpec most_specific_operator;
1159 if (candidates.Count == 1) {
1160 most_specific_operator = candidates[0];
1161 s_x = most_specific_operator.Parameters.Types[0];
1162 t_x = most_specific_operator.ReturnType;
1165 // Pass original source type to find the best match against input type and
1166 // not the unwrapped expression
1168 s_x = FindMostSpecificSource (candidates, source.Type, source_type_expr, !implicitOnly);
1172 t_x = FindMostSpecificTarget (candidates, target, !implicitOnly);
1176 most_specific_operator = null;
1177 for (int i = 0; i < candidates.Count; ++i) {
1178 if (candidates[i].ReturnType == t_x && candidates[i].Parameters.Types[0] == s_x) {
1179 most_specific_operator = candidates[i];
1184 if (most_specific_operator == null) {
1186 // Unless running in probing more
1189 MethodSpec ambig_arg = null;
1190 foreach (var candidate in candidates) {
1191 if (candidate.ReturnType == t_x)
1192 most_specific_operator = candidate;
1193 else if (candidate.Parameters.Types[0] == s_x)
1194 ambig_arg = candidate;
1197 ec.Report.Error (457, loc,
1198 "Ambiguous user defined operators `{0}' and `{1}' when converting from `{2}' to `{3}'",
1199 ambig_arg.GetSignatureForError (), most_specific_operator.GetSignatureForError (),
1200 source.Type.GetSignatureForError (), target.GetSignatureForError ());
1203 return ErrorExpression.Instance;
1208 // Convert input type when it's different to best operator argument
1210 if (s_x != source_type) {
1211 var c = source as Constant;
1213 source = c.Reduce (ec, s_x);
1219 source = implicitOnly ?
1220 ImplicitConversionStandard (ec, source_type_expr, s_x, loc) :
1221 ExplicitConversionStandard (ec, source_type_expr, s_x, loc);
1224 source = source_type_expr;
1227 source = new UserCast (most_specific_operator, source, loc).Resolve (ec);
1230 // Convert result type when it's different to best operator return type
1232 if (t_x != target_type) {
1234 // User operator is of T?, no need to lift it
1236 if (t_x == target && t_x.IsNullableType)
1239 source = implicitOnly ?
1240 ImplicitConversionStandard (ec, source, target_type, loc) :
1241 ExplicitConversionStandard (ec, source, target_type, loc);
1248 // Source expression is of nullable type, lift the result in the case it's null and
1249 // not nullable/lifted user operator is used
1251 if (source_type_expr is Nullable.Unwrap && !s_x.IsNullableType && (TypeSpec.IsReferenceType (target) || target_type != target))
1252 source = new Nullable.Lifted (source, source_type_expr, target).Resolve (ec);
1253 else if (target_type != target)
1254 source = Nullable.Wrap.Create (source, target);
1260 /// Converts implicitly the resolved expression `expr' into the
1261 /// `target_type'. It returns a new expression that can be used
1262 /// in a context that expects a `target_type'.
1264 static public Expression ImplicitConversion (ResolveContext ec, Expression expr,
1265 TypeSpec target_type, Location loc)
1269 if (target_type == null)
1270 throw new Exception ("Target type is null");
1272 e = ImplicitConversionStandard (ec, expr, target_type, loc);
1276 e = ImplicitUserConversion (ec, expr, target_type, loc);
1285 /// Attempts to apply the `Standard Implicit
1286 /// Conversion' rules to the expression `expr' into
1287 /// the `target_type'. It returns a new expression
1288 /// that can be used in a context that expects a
1291 /// This is different from `ImplicitConversion' in that the
1292 /// user defined implicit conversions are excluded.
1294 static public Expression ImplicitConversionStandard (ResolveContext ec, Expression expr,
1295 TypeSpec target_type, Location loc)
1297 return ImplicitConversionStandard (ec, expr, target_type, loc, false);
1300 static Expression ImplicitConversionStandard (ResolveContext ec, Expression expr, TypeSpec target_type, Location loc, bool explicit_cast)
1302 if (expr.eclass == ExprClass.MethodGroup){
1303 if (!target_type.IsDelegate){
1308 // Only allow anonymous method conversions on post ISO_1
1310 if (ec.Module.Compiler.Settings.Version != LanguageVersion.ISO_1){
1311 MethodGroupExpr mg = expr as MethodGroupExpr;
1313 return ImplicitDelegateCreation.Create (
1314 ec, mg, target_type, loc);
1318 TypeSpec expr_type = expr.Type;
1321 if (expr_type == target_type) {
1322 if (expr_type != InternalType.NullLiteral && expr_type != InternalType.AnonymousMethod)
1327 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1328 switch (target_type.Kind) {
1329 case MemberKind.ArrayType:
1330 case MemberKind.Class:
1331 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Object)
1332 return EmptyCast.Create (expr, target_type);
1334 goto case MemberKind.Struct;
1335 case MemberKind.Struct:
1336 case MemberKind.Delegate:
1337 case MemberKind.Enum:
1338 case MemberKind.Interface:
1339 case MemberKind.TypeParameter:
1340 Arguments args = new Arguments (1);
1341 args.Add (new Argument (expr));
1342 return new DynamicConversion (target_type, explicit_cast ? CSharpBinderFlags.ConvertExplicit : 0, args, loc).Resolve (ec);
1348 if (target_type.IsNullableType)
1349 return ImplicitNulableConversion (ec, expr, target_type);
1352 // Attempt to do the implicit constant expression conversions
1354 Constant c = expr as Constant;
1357 c = c.ConvertImplicitly (target_type);
1359 throw new InternalErrorException ("Conversion error", loc);
1365 e = ImplicitNumericConversion (expr, expr_type, target_type);
1369 e = ImplicitReferenceConversion (expr, target_type, explicit_cast);
1373 e = ImplicitBoxingConversion (expr, expr_type, target_type);
1377 if (expr is IntegralConstant && target_type.IsEnum){
1378 var i = (IntegralConstant) expr;
1380 // LAMESPEC: csc allows any constant like 0 values to be converted, including const float f = 0.0
1382 // An implicit enumeration conversion permits the decimal-integer-literal 0
1383 // to be converted to any enum-type and to any nullable-type whose underlying
1384 // type is an enum-type
1386 if (i.IsZeroInteger) {
1387 // Recreate 0 literal to remove any collected conversions
1388 return new EnumConstant (new IntLiteral (ec.BuiltinTypes, 0, i.Location), target_type);
1393 var target_pc = target_type as PointerContainer;
1394 if (target_pc != null) {
1395 if (expr_type.IsPointer) {
1397 // Pointer types are same when they have same element types
1399 if (expr_type == target_pc)
1402 if (target_pc.Element.Kind == MemberKind.Void)
1403 return EmptyCast.Create (expr, target_type);
1408 if (expr_type == InternalType.NullLiteral)
1409 return new NullPointer (target_type, loc);
1413 if (expr_type == InternalType.AnonymousMethod){
1414 AnonymousMethodExpression ame = (AnonymousMethodExpression) expr;
1415 Expression am = ame.Compatible (ec, target_type);
1417 return am.Resolve (ec);
1420 if (expr_type == InternalType.Arglist && target_type == ec.Module.PredefinedTypes.ArgIterator.TypeSpec)
1424 // dynamic erasure conversion on value types
1426 if (expr_type.IsStruct && TypeSpecComparer.IsEqual (expr_type, target_type))
1427 return expr_type == target_type ? expr : EmptyCast.Create (expr, target_type);
1433 /// Attempts to implicitly convert `source' into `target_type', using
1434 /// ImplicitConversion. If there is no implicit conversion, then
1435 /// an error is signaled
1437 static public Expression ImplicitConversionRequired (ResolveContext ec, Expression source,
1438 TypeSpec target_type, Location loc)
1440 Expression e = ImplicitConversion (ec, source, target_type, loc);
1444 source.Error_ValueCannotBeConverted (ec, target_type, false);
1449 /// Performs the explicit numeric conversions
1451 /// There are a few conversions that are not part of the C# standard,
1452 /// they were interim hacks in the C# compiler that were supposed to
1453 /// become explicit operators in the UIntPtr class and IntPtr class,
1454 /// but for historical reasons it did not happen, so the C# compiler
1455 /// ended up with these special hacks.
1457 /// See bug 59800 for details.
1459 /// The conversion are:
1469 public static Expression ExplicitNumericConversion (ResolveContext rc, Expression expr, TypeSpec target_type)
1471 // Not all predefined explicit numeric conversion are
1472 // defined here, for some of them (mostly IntPtr/UIntPtr) we
1473 // defer to user-operator handling which is now perfect but
1476 // LAMESPEC: Undocumented IntPtr/UIntPtr conversions
1477 // IntPtr -> uint uses int
1478 // UIntPtr -> long uses ulong
1481 switch (expr.Type.BuiltinType) {
1482 case BuiltinTypeSpec.Type.SByte:
1484 // From sbyte to byte, ushort, uint, ulong, char, uintptr
1486 switch (target_type.BuiltinType) {
1487 case BuiltinTypeSpec.Type.Byte:
1488 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U1);
1489 case BuiltinTypeSpec.Type.UShort:
1490 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U2);
1491 case BuiltinTypeSpec.Type.UInt:
1492 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U4);
1493 case BuiltinTypeSpec.Type.ULong:
1494 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U8);
1495 case BuiltinTypeSpec.Type.Char:
1496 return new ConvCast (expr, target_type, ConvCast.Mode.I1_CH);
1498 // One of the built-in conversions that belonged in the class library
1499 case BuiltinTypeSpec.Type.UIntPtr:
1500 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I1_U8), target_type, target_type, true);
1503 case BuiltinTypeSpec.Type.Byte:
1505 // From byte to sbyte and char
1507 switch (target_type.BuiltinType) {
1508 case BuiltinTypeSpec.Type.SByte:
1509 return new ConvCast (expr, target_type, ConvCast.Mode.U1_I1);
1510 case BuiltinTypeSpec.Type.Char:
1511 return new ConvCast (expr, target_type, ConvCast.Mode.U1_CH);
1514 case BuiltinTypeSpec.Type.Short:
1516 // From short to sbyte, byte, ushort, uint, ulong, char, uintptr
1518 switch (target_type.BuiltinType) {
1519 case BuiltinTypeSpec.Type.SByte:
1520 return new ConvCast (expr, target_type, ConvCast.Mode.I2_I1);
1521 case BuiltinTypeSpec.Type.Byte:
1522 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U1);
1523 case BuiltinTypeSpec.Type.UShort:
1524 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U2);
1525 case BuiltinTypeSpec.Type.UInt:
1526 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U4);
1527 case BuiltinTypeSpec.Type.ULong:
1528 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U8);
1529 case BuiltinTypeSpec.Type.Char:
1530 return new ConvCast (expr, target_type, ConvCast.Mode.I2_CH);
1532 // One of the built-in conversions that belonged in the class library
1533 case BuiltinTypeSpec.Type.UIntPtr:
1534 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I2_U8), target_type, target_type, true);
1537 case BuiltinTypeSpec.Type.UShort:
1539 // From ushort to sbyte, byte, short, char
1541 switch (target_type.BuiltinType) {
1542 case BuiltinTypeSpec.Type.SByte:
1543 return new ConvCast (expr, target_type, ConvCast.Mode.U2_I1);
1544 case BuiltinTypeSpec.Type.Byte:
1545 return new ConvCast (expr, target_type, ConvCast.Mode.U2_U1);
1546 case BuiltinTypeSpec.Type.Short:
1547 return new ConvCast (expr, target_type, ConvCast.Mode.U2_I2);
1548 case BuiltinTypeSpec.Type.Char:
1549 return new ConvCast (expr, target_type, ConvCast.Mode.U2_CH);
1552 case BuiltinTypeSpec.Type.Int:
1554 // From int to sbyte, byte, short, ushort, uint, ulong, char, uintptr
1556 switch (target_type.BuiltinType) {
1557 case BuiltinTypeSpec.Type.SByte:
1558 return new ConvCast (expr, target_type, ConvCast.Mode.I4_I1);
1559 case BuiltinTypeSpec.Type.Byte:
1560 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U1);
1561 case BuiltinTypeSpec.Type.Short:
1562 return new ConvCast (expr, target_type, ConvCast.Mode.I4_I2);
1563 case BuiltinTypeSpec.Type.UShort:
1564 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U2);
1565 case BuiltinTypeSpec.Type.UInt:
1566 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U4);
1567 case BuiltinTypeSpec.Type.ULong:
1568 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U8);
1569 case BuiltinTypeSpec.Type.Char:
1570 return new ConvCast (expr, target_type, ConvCast.Mode.I4_CH);
1572 // One of the built-in conversions that belonged in the class library
1573 case BuiltinTypeSpec.Type.UIntPtr:
1574 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I2_U8), target_type, target_type, true);
1577 case BuiltinTypeSpec.Type.UInt:
1579 // From uint to sbyte, byte, short, ushort, int, char
1581 switch (target_type.BuiltinType) {
1582 case BuiltinTypeSpec.Type.SByte:
1583 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I1);
1584 case BuiltinTypeSpec.Type.Byte:
1585 return new ConvCast (expr, target_type, ConvCast.Mode.U4_U1);
1586 case BuiltinTypeSpec.Type.Short:
1587 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I2);
1588 case BuiltinTypeSpec.Type.UShort:
1589 return new ConvCast (expr, target_type, ConvCast.Mode.U4_U2);
1590 case BuiltinTypeSpec.Type.Int:
1591 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I4);
1592 case BuiltinTypeSpec.Type.Char:
1593 return new ConvCast (expr, target_type, ConvCast.Mode.U4_CH);
1596 case BuiltinTypeSpec.Type.Long:
1598 // From long to sbyte, byte, short, ushort, int, uint, ulong, char
1600 switch (target_type.BuiltinType) {
1601 case BuiltinTypeSpec.Type.SByte:
1602 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I1);
1603 case BuiltinTypeSpec.Type.Byte:
1604 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U1);
1605 case BuiltinTypeSpec.Type.Short:
1606 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I2);
1607 case BuiltinTypeSpec.Type.UShort:
1608 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U2);
1609 case BuiltinTypeSpec.Type.Int:
1610 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I4);
1611 case BuiltinTypeSpec.Type.UInt:
1612 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U4);
1613 case BuiltinTypeSpec.Type.ULong:
1614 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U8);
1615 case BuiltinTypeSpec.Type.Char:
1616 return new ConvCast (expr, target_type, ConvCast.Mode.I8_CH);
1619 case BuiltinTypeSpec.Type.ULong:
1621 // From ulong to sbyte, byte, short, ushort, int, uint, long, char
1623 switch (target_type.BuiltinType) {
1624 case BuiltinTypeSpec.Type.SByte:
1625 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I1);
1626 case BuiltinTypeSpec.Type.Byte:
1627 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U1);
1628 case BuiltinTypeSpec.Type.Short:
1629 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I2);
1630 case BuiltinTypeSpec.Type.UShort:
1631 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U2);
1632 case BuiltinTypeSpec.Type.Int:
1633 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I4);
1634 case BuiltinTypeSpec.Type.UInt:
1635 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U4);
1636 case BuiltinTypeSpec.Type.Long:
1637 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I8);
1638 case BuiltinTypeSpec.Type.Char:
1639 return new ConvCast (expr, target_type, ConvCast.Mode.U8_CH);
1641 // One of the built-in conversions that belonged in the class library
1642 case BuiltinTypeSpec.Type.IntPtr:
1643 return new OperatorCast (EmptyCast.Create (expr, rc.BuiltinTypes.Long), target_type, true);
1646 case BuiltinTypeSpec.Type.Char:
1648 // From char to sbyte, byte, short
1650 switch (target_type.BuiltinType) {
1651 case BuiltinTypeSpec.Type.SByte:
1652 return new ConvCast (expr, target_type, ConvCast.Mode.CH_I1);
1653 case BuiltinTypeSpec.Type.Byte:
1654 return new ConvCast (expr, target_type, ConvCast.Mode.CH_U1);
1655 case BuiltinTypeSpec.Type.Short:
1656 return new ConvCast (expr, target_type, ConvCast.Mode.CH_I2);
1659 case BuiltinTypeSpec.Type.Float:
1661 // From float to sbyte, byte, short,
1662 // ushort, int, uint, long, ulong, char
1665 switch (target_type.BuiltinType) {
1666 case BuiltinTypeSpec.Type.SByte:
1667 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I1);
1668 case BuiltinTypeSpec.Type.Byte:
1669 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U1);
1670 case BuiltinTypeSpec.Type.Short:
1671 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I2);
1672 case BuiltinTypeSpec.Type.UShort:
1673 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U2);
1674 case BuiltinTypeSpec.Type.Int:
1675 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I4);
1676 case BuiltinTypeSpec.Type.UInt:
1677 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U4);
1678 case BuiltinTypeSpec.Type.Long:
1679 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I8);
1680 case BuiltinTypeSpec.Type.ULong:
1681 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U8);
1682 case BuiltinTypeSpec.Type.Char:
1683 return new ConvCast (expr, target_type, ConvCast.Mode.R4_CH);
1684 case BuiltinTypeSpec.Type.Decimal:
1685 return new OperatorCast (expr, target_type, true);
1688 case BuiltinTypeSpec.Type.Double:
1690 // From double to sbyte, byte, short,
1691 // ushort, int, uint, long, ulong,
1692 // char, float or decimal
1694 switch (target_type.BuiltinType) {
1695 case BuiltinTypeSpec.Type.SByte:
1696 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I1);
1697 case BuiltinTypeSpec.Type.Byte:
1698 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U1);
1699 case BuiltinTypeSpec.Type.Short:
1700 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I2);
1701 case BuiltinTypeSpec.Type.UShort:
1702 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U2);
1703 case BuiltinTypeSpec.Type.Int:
1704 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I4);
1705 case BuiltinTypeSpec.Type.UInt:
1706 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U4);
1707 case BuiltinTypeSpec.Type.Long:
1708 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I8);
1709 case BuiltinTypeSpec.Type.ULong:
1710 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U8);
1711 case BuiltinTypeSpec.Type.Char:
1712 return new ConvCast (expr, target_type, ConvCast.Mode.R8_CH);
1713 case BuiltinTypeSpec.Type.Float:
1714 return new ConvCast (expr, target_type, ConvCast.Mode.R8_R4);
1715 case BuiltinTypeSpec.Type.Decimal:
1716 return new OperatorCast (expr, target_type, true);
1719 case BuiltinTypeSpec.Type.UIntPtr:
1721 // Various built-in conversions that belonged in the class library
1723 // from uintptr to sbyte, short, int32
1725 switch (target_type.BuiltinType) {
1726 case BuiltinTypeSpec.Type.SByte:
1727 return new ConvCast (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type, ConvCast.Mode.U4_I1);
1728 case BuiltinTypeSpec.Type.Short:
1729 return new ConvCast (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type, ConvCast.Mode.U4_I2);
1730 case BuiltinTypeSpec.Type.Int:
1731 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type);
1732 case BuiltinTypeSpec.Type.UInt:
1733 return new OperatorCast (expr, expr.Type, target_type, true);
1734 case BuiltinTypeSpec.Type.Long:
1735 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.ULong, true), target_type);
1738 case BuiltinTypeSpec.Type.IntPtr:
1739 if (target_type.BuiltinType == BuiltinTypeSpec.Type.UInt)
1740 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.Int, true), target_type);
1741 if (target_type.BuiltinType == BuiltinTypeSpec.Type.ULong)
1742 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.Long, true), target_type);
1745 case BuiltinTypeSpec.Type.Decimal:
1746 // From decimal to sbyte, byte, short,
1747 // ushort, int, uint, long, ulong, char,
1749 switch (target_type.BuiltinType) {
1750 case BuiltinTypeSpec.Type.SByte:
1751 case BuiltinTypeSpec.Type.Byte:
1752 case BuiltinTypeSpec.Type.Short:
1753 case BuiltinTypeSpec.Type.UShort:
1754 case BuiltinTypeSpec.Type.Int:
1755 case BuiltinTypeSpec.Type.UInt:
1756 case BuiltinTypeSpec.Type.Long:
1757 case BuiltinTypeSpec.Type.ULong:
1758 case BuiltinTypeSpec.Type.Char:
1759 case BuiltinTypeSpec.Type.Float:
1760 case BuiltinTypeSpec.Type.Double:
1761 return new OperatorCast (expr, expr.Type, target_type, true);
1771 /// Returns whether an explicit reference conversion can be performed
1772 /// from source_type to target_type
1774 public static bool ExplicitReferenceConversionExists (TypeSpec source_type, TypeSpec target_type)
1776 Expression e = ExplicitReferenceConversion (null, source_type, target_type);
1780 if (e == EmptyExpression.Null)
1783 throw new InternalErrorException ("Invalid probing conversion result");
1787 /// Implements Explicit Reference conversions
1789 static Expression ExplicitReferenceConversion (Expression source, TypeSpec source_type, TypeSpec target_type)
1792 // From object to a generic parameter
1794 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Object && TypeManager.IsGenericParameter (target_type))
1795 return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
1798 // Explicit type parameter conversion.
1800 if (source_type.Kind == MemberKind.TypeParameter)
1801 return ExplicitTypeParameterConversion (source, source_type, target_type);
1803 bool target_is_value_type = target_type.Kind == MemberKind.Struct || target_type.Kind == MemberKind.Enum;
1806 // Unboxing conversion from System.ValueType to any non-nullable-value-type
1808 if (source_type.BuiltinType == BuiltinTypeSpec.Type.ValueType && target_is_value_type)
1809 return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
1812 // From object or dynamic to any reference type or value type (unboxing)
1814 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Object || source_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1815 if (target_type.IsPointer)
1819 source == null ? EmptyExpression.Null :
1820 target_is_value_type ? new UnboxCast (source, target_type) :
1821 source is Constant ? (Expression) new EmptyConstantCast ((Constant) source, target_type) :
1822 new ClassCast (source, target_type);
1826 // From any class S to any class-type T, provided S is a base class of T
1828 if (source_type.Kind == MemberKind.Class && TypeSpec.IsBaseClass (target_type, source_type, true))
1829 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1832 // From any interface-type S to to any class type T, provided T is not
1833 // sealed, or provided T implements S.
1835 if (source_type.Kind == MemberKind.Interface) {
1836 if (!target_type.IsSealed || target_type.ImplementsInterface (source_type, true)) {
1838 return EmptyExpression.Null;
1841 // Unboxing conversion from any interface-type to any non-nullable-value-type that
1842 // implements the interface-type
1844 return target_is_value_type ? new UnboxCast (source, target_type) : (Expression) new ClassCast (source, target_type);
1848 // From System.Collections.Generic.IList<T> and its base interfaces to a one-dimensional
1849 // array type S[], provided there is an implicit or explicit reference conversion from S to T.
1851 var target_array = target_type as ArrayContainer;
1852 if (target_array != null && IList_To_Array (source_type, target_array))
1853 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1858 var source_array = source_type as ArrayContainer;
1859 if (source_array != null) {
1860 var target_array = target_type as ArrayContainer;
1861 if (target_array != null) {
1863 // From System.Array to any array-type
1865 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Array)
1866 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1869 // From an array type S with an element type Se to an array type T with an
1870 // element type Te provided all the following are true:
1871 // * S and T differe only in element type, in other words, S and T
1872 // have the same number of dimensions.
1873 // * Both Se and Te are reference types
1874 // * An explicit reference conversions exist from Se to Te
1876 if (source_array.Rank == target_array.Rank) {
1878 source_type = source_array.Element;
1879 if (!TypeSpec.IsReferenceType (source_type))
1882 var target_element = target_array.Element;
1883 if (!TypeSpec.IsReferenceType (target_element))
1886 if (ExplicitReferenceConversionExists (source_type, target_element))
1887 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1894 // From a single-dimensional array type S[] to System.Collections.Generic.IList<T> and its base interfaces,
1895 // provided that there is an explicit reference conversion from S to T
1897 if (ArrayToIList (source_array, target_type, true))
1898 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1904 // From any class type S to any interface T, provides S is not sealed
1905 // and provided S does not implement T.
1907 if (target_type.IsInterface && !source_type.IsSealed && !source_type.ImplementsInterface (target_type, true)) {
1908 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1912 // From System delegate to any delegate-type
1914 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Delegate && target_type.IsDelegate)
1915 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1918 // From variant generic delegate to same variant generic delegate type
1920 if (source_type.IsDelegate && target_type.IsDelegate && source_type.MemberDefinition == target_type.MemberDefinition) {
1921 var tparams = source_type.MemberDefinition.TypeParameters;
1922 var targs_src = source_type.TypeArguments;
1923 var targs_dst = target_type.TypeArguments;
1925 for (i = 0; i < tparams.Length; ++i) {
1927 // If TP is invariant, types have to be identical
1929 if (TypeSpecComparer.IsEqual (targs_src[i], targs_dst[i]))
1932 if (tparams[i].Variance == Variance.Covariant) {
1934 //If TP is covariant, an implicit or explicit identity or reference conversion is required
1936 if (ImplicitReferenceConversionExists (targs_src[i], targs_dst[i]))
1939 if (ExplicitReferenceConversionExists (targs_src[i], targs_dst[i]))
1942 } else if (tparams[i].Variance == Variance.Contravariant) {
1944 //If TP is contravariant, both are either identical or reference types
1946 if (TypeSpec.IsReferenceType (targs_src[i]) && TypeSpec.IsReferenceType (targs_dst[i]))
1953 if (i == tparams.Length)
1954 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1961 /// Performs an explicit conversion of the expression `expr' whose
1962 /// type is expr.Type to `target_type'.
1964 static public Expression ExplicitConversionCore (ResolveContext ec, Expression expr,
1965 TypeSpec target_type, Location loc)
1967 TypeSpec expr_type = expr.Type;
1969 // Explicit conversion includes implicit conversion and it used for enum underlying types too
1970 Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc, true);
1974 if (expr_type.IsEnum) {
1975 TypeSpec real_target = target_type.IsEnum ? EnumSpec.GetUnderlyingType (target_type) : target_type;
1976 Expression underlying = EmptyCast.Create (expr, EnumSpec.GetUnderlyingType (expr_type));
1977 if (underlying.Type == real_target)
1981 ne = ImplicitNumericConversion (underlying, real_target);
1984 ne = ExplicitNumericConversion (ec, underlying, real_target);
1987 // LAMESPEC: IntPtr and UIntPtr conversion to any Enum is allowed
1989 if (ne == null && (real_target.BuiltinType == BuiltinTypeSpec.Type.IntPtr || real_target.BuiltinType == BuiltinTypeSpec.Type.UIntPtr))
1990 ne = ExplicitUserConversion (ec, underlying, real_target, loc);
1992 return ne != null ? EmptyCast.Create (ne, target_type) : null;
1995 if (target_type.IsEnum) {
1997 // System.Enum can be unboxed to any enum-type
1999 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Enum)
2000 return new UnboxCast (expr, target_type);
2002 TypeSpec real_target = target_type.IsEnum ? EnumSpec.GetUnderlyingType (target_type) : target_type;
2004 if (expr_type == real_target)
2005 return EmptyCast.Create (expr, target_type);
2007 Constant c = expr as Constant;
2009 c = c.TryReduce (ec, real_target);
2013 ne = ImplicitNumericConversion (expr, real_target);
2015 return EmptyCast.Create (ne, target_type);
2017 ne = ExplicitNumericConversion (ec, expr, real_target);
2019 return EmptyCast.Create (ne, target_type);
2022 // LAMESPEC: IntPtr and UIntPtr conversion to any Enum is allowed
2024 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.IntPtr || expr_type.BuiltinType == BuiltinTypeSpec.Type.UIntPtr) {
2025 ne = ExplicitUserConversion (ec, expr, real_target, loc);
2027 return ExplicitConversionCore (ec, ne, target_type, loc);
2031 ne = ExplicitNumericConversion (ec, expr, target_type);
2037 // Skip the ExplicitReferenceConversion because we can not convert
2038 // from Null to a ValueType, and ExplicitReference wont check against
2039 // null literal explicitly
2041 if (expr_type != InternalType.NullLiteral) {
2042 ne = ExplicitReferenceConversion (expr, expr_type, target_type);
2048 ne = ExplicitUnsafe (expr, target_type);
2056 public static Expression ExplicitUnsafe (Expression expr, TypeSpec target_type)
2058 TypeSpec expr_type = expr.Type;
2060 if (target_type.IsPointer){
2061 if (expr_type.IsPointer)
2062 return EmptyCast.Create (expr, target_type);
2064 switch (expr_type.BuiltinType) {
2065 case BuiltinTypeSpec.Type.SByte:
2066 case BuiltinTypeSpec.Type.Short:
2067 case BuiltinTypeSpec.Type.Int:
2068 return new OpcodeCast (expr, target_type, OpCodes.Conv_I);
2070 case BuiltinTypeSpec.Type.UShort:
2071 case BuiltinTypeSpec.Type.UInt:
2072 case BuiltinTypeSpec.Type.Byte:
2073 return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
2075 case BuiltinTypeSpec.Type.Long:
2076 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I);
2078 case BuiltinTypeSpec.Type.ULong:
2079 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I);
2083 if (expr_type.IsPointer){
2084 switch (target_type.BuiltinType) {
2085 case BuiltinTypeSpec.Type.SByte:
2086 return new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
2087 case BuiltinTypeSpec.Type.Byte:
2088 return new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
2089 case BuiltinTypeSpec.Type.Short:
2090 return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
2091 case BuiltinTypeSpec.Type.UShort:
2092 return new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
2093 case BuiltinTypeSpec.Type.Int:
2094 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
2095 case BuiltinTypeSpec.Type.UInt:
2096 return new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
2097 case BuiltinTypeSpec.Type.Long:
2098 return new ConvCast (expr, target_type, ConvCast.Mode.I_I8);
2099 case BuiltinTypeSpec.Type.ULong:
2100 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
2107 /// Same as ExplicitConversion, only it doesn't include user defined conversions
2109 static public Expression ExplicitConversionStandard (ResolveContext ec, Expression expr,
2110 TypeSpec target_type, Location l)
2112 int errors = ec.Report.Errors;
2113 Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
2114 if (ec.Report.Errors > errors)
2120 ne = ExplicitNumericConversion (ec, expr, target_type);
2124 ne = ExplicitReferenceConversion (expr, expr.Type, target_type);
2128 if (ec.IsUnsafe && expr.Type.IsPointer && target_type.IsPointer && ((PointerContainer)expr.Type).Element.Kind == MemberKind.Void)
2129 return EmptyCast.Create (expr, target_type);
2131 expr.Error_ValueCannotBeConverted (ec, target_type, true);
2136 /// Performs an explicit conversion of the expression `expr' whose
2137 /// type is expr.Type to `target_type'.
2139 static public Expression ExplicitConversion (ResolveContext ec, Expression expr,
2140 TypeSpec target_type, Location loc)
2142 Expression e = ExplicitConversionCore (ec, expr, target_type, loc);
2145 // Don't eliminate explicit precission casts
2148 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Float)
2149 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
2151 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Double)
2152 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
2158 TypeSpec expr_type = expr.Type;
2159 if (target_type.IsNullableType) {
2162 if (expr_type.IsNullableType) {
2163 target = Nullable.NullableInfo.GetUnderlyingType (target_type);
2164 Expression unwrap = Nullable.Unwrap.Create (expr);
2165 e = ExplicitConversion (ec, unwrap, target, expr.Location);
2169 return new Nullable.Lifted (e, unwrap, target_type).Resolve (ec);
2171 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
2172 return new UnboxCast (expr, target_type);
2175 target = TypeManager.GetTypeArguments (target_type) [0];
2176 e = ExplicitConversionCore (ec, expr, target, loc);
2178 return Nullable.Wrap.Create (e, target_type);
2179 } else if (expr_type.IsNullableType) {
2180 e = ImplicitBoxingConversion (expr, Nullable.NullableInfo.GetUnderlyingType (expr_type), target_type);
2184 e = Nullable.Unwrap.Create (expr, false);
2185 e = ExplicitConversionCore (ec, e, target_type, loc);
2187 return EmptyCast.Create (e, target_type);
2190 e = ExplicitUserConversion (ec, expr, target_type, loc);
2194 expr.Error_ValueCannotBeConverted (ec, target_type, true);