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 ImplicitUserConversion (ec, expr, target_type, 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 var src_types_set = new TypeSpec [list.Count];
923 // Try exact match first, if any operator converts from S then Sx = S
925 for (int i = 0; i < src_types_set.Length; ++i) {
926 TypeSpec param_type = list [i].Parameters.Types [0];
928 if (param_type == sourceType)
931 src_types_set [i] = param_type;
935 // Explicit Conv rules
937 if (apply_explicit_conv_rules) {
938 var candidate_set = new List<TypeSpec> ();
940 foreach (TypeSpec param_type in src_types_set){
941 if (ImplicitStandardConversionExists (source, param_type))
942 candidate_set.Add (param_type);
945 if (candidate_set.Count != 0)
946 return FindMostEncompassedType (candidate_set);
952 if (apply_explicit_conv_rules)
953 return FindMostEncompassingType (src_types_set);
955 return FindMostEncompassedType (src_types_set);
959 /// Finds the most specific target Tx according to section 13.4.4
961 static public TypeSpec FindMostSpecificTarget (IList<MethodSpec> list,
962 TypeSpec target, bool apply_explicit_conv_rules)
964 var tgt_types_set = new List<TypeSpec> ();
967 // If any operator converts to T then Tx = T
969 foreach (var mi in list){
970 TypeSpec ret_type = mi.ReturnType;
971 if (ret_type == target)
974 tgt_types_set.Add (ret_type);
978 // Explicit conv rules
980 if (apply_explicit_conv_rules) {
981 var candidate_set = new List<TypeSpec> ();
983 foreach (TypeSpec ret_type in tgt_types_set) {
984 var expr = new EmptyExpression (ret_type);
986 if (ImplicitStandardConversionExists (expr, target))
987 candidate_set.Add (ret_type);
990 if (candidate_set.Count != 0)
991 return FindMostEncompassingType (candidate_set);
995 // Okay, final case !
997 if (apply_explicit_conv_rules)
998 return FindMostEncompassedType (tgt_types_set);
1000 return FindMostEncompassingType (tgt_types_set);
1004 /// User-defined Implicit conversions
1006 static public Expression ImplicitUserConversion (ResolveContext ec, Expression source, TypeSpec target, Location loc)
1008 return UserDefinedConversion (ec, source, target, true, loc);
1012 /// User-defined Explicit conversions
1014 static Expression ExplicitUserConversion (ResolveContext ec, Expression source, TypeSpec target, Location loc)
1016 return UserDefinedConversion (ec, source, target, false, loc);
1019 static void FindApplicableUserDefinedConversionOperators (IList<MemberSpec> operators, Expression source, TypeSpec target, bool implicitOnly, ref List<MethodSpec> candidates)
1021 if (source.Type.IsInterface) {
1022 // Neither A nor B are interface-types
1026 // For a conversion operator to be applicable, it must be possible
1027 // to perform a standard conversion from the source type to
1028 // the operand type of the operator, and it must be possible
1029 // to perform a standard conversion from the result type of
1030 // the operator to the target type.
1032 Expression texpr = null;
1034 foreach (MethodSpec op in operators) {
1036 // Can be null because MemberCache.GetUserOperator does not resize the array
1040 var t = op.Parameters.Types[0];
1041 if (source.Type != t && !ImplicitStandardConversionExists (source, t)) {
1045 if (!ImplicitStandardConversionExists (new EmptyExpression (t), source.Type))
1055 if (t.IsNullableType)
1056 t = Nullable.NullableInfo.GetUnderlyingType (t);
1058 if (!ImplicitStandardConversionExists (new EmptyExpression (t), target)) {
1063 texpr = new EmptyExpression (target);
1065 if (!ImplicitStandardConversionExists (texpr, t))
1070 if (candidates == null)
1071 candidates = new List<MethodSpec> ();
1073 candidates.Add (op);
1078 // User-defined conversions
1080 static Expression UserDefinedConversion (ResolveContext ec, Expression source, TypeSpec target, bool implicitOnly, Location loc)
1082 List<MethodSpec> candidates = null;
1085 // If S or T are nullable types, source_type and target_type are their underlying types
1086 // otherwise source_type and target_type are equal to S and T respectively.
1088 TypeSpec source_type = source.Type;
1089 TypeSpec target_type = target;
1090 Expression source_type_expr;
1092 if (source_type.IsNullableType) {
1093 // No unwrapping conversion S? -> T for non-reference types
1094 if (implicitOnly && !TypeSpec.IsReferenceType (target_type) && !target_type.IsNullableType) {
1095 source_type_expr = source;
1097 source_type_expr = Nullable.Unwrap.Create (source);
1098 source_type = source_type_expr.Type;
1101 source_type_expr = source;
1104 if (target_type.IsNullableType)
1105 target_type = Nullable.NullableInfo.GetUnderlyingType (target_type);
1107 // Only these containers can contain a user defined implicit or explicit operators
1108 const MemberKind user_conversion_kinds = MemberKind.Class | MemberKind.Struct | MemberKind.TypeParameter;
1110 if ((source_type.Kind & user_conversion_kinds) != 0 && source_type.BuiltinType != BuiltinTypeSpec.Type.Decimal) {
1111 bool declared_only = source_type.IsStruct;
1113 var operators = MemberCache.GetUserOperator (source_type, Operator.OpType.Implicit, declared_only);
1114 if (operators != null) {
1115 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, implicitOnly, ref candidates);
1118 if (!implicitOnly) {
1119 operators = MemberCache.GetUserOperator (source_type, Operator.OpType.Explicit, declared_only);
1120 if (operators != null) {
1121 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, false, ref candidates);
1126 if ((target.Kind & user_conversion_kinds) != 0 && target_type.BuiltinType != BuiltinTypeSpec.Type.Decimal) {
1127 bool declared_only = target.IsStruct || implicitOnly;
1129 var operators = MemberCache.GetUserOperator (target_type, Operator.OpType.Implicit, declared_only);
1130 if (operators != null) {
1131 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, implicitOnly, ref candidates);
1134 if (!implicitOnly) {
1135 operators = MemberCache.GetUserOperator (target_type, Operator.OpType.Explicit, declared_only);
1136 if (operators != null) {
1137 FindApplicableUserDefinedConversionOperators (operators, source_type_expr, target_type, false, ref candidates);
1142 if (candidates == null)
1146 // Find the most specific conversion operator
1148 MethodSpec most_specific_operator;
1150 if (candidates.Count == 1) {
1151 most_specific_operator = candidates[0];
1152 s_x = most_specific_operator.Parameters.Types[0];
1153 t_x = most_specific_operator.ReturnType;
1156 // Pass original source type to find the best match against input type and
1157 // not the unwrapped expression
1159 s_x = FindMostSpecificSource (candidates, source.Type, source_type_expr, !implicitOnly);
1163 t_x = FindMostSpecificTarget (candidates, target, !implicitOnly);
1167 most_specific_operator = null;
1168 for (int i = 0; i < candidates.Count; ++i) {
1169 if (candidates[i].ReturnType == t_x && candidates[i].Parameters.Types[0] == s_x) {
1170 most_specific_operator = candidates[i];
1175 if (most_specific_operator == null) {
1176 MethodSpec ambig_arg = null;
1177 foreach (var candidate in candidates) {
1178 if (candidate.ReturnType == t_x)
1179 most_specific_operator = candidate;
1180 else if (candidate.Parameters.Types[0] == s_x)
1181 ambig_arg = candidate;
1184 ec.Report.Error (457, loc,
1185 "Ambiguous user defined operators `{0}' and `{1}' when converting from `{2}' to `{3}'",
1186 ambig_arg.GetSignatureForError (), most_specific_operator.GetSignatureForError (),
1187 source.Type.GetSignatureForError (), target.GetSignatureForError ());
1189 return ErrorExpression.Instance;
1194 // Convert input type when it's different to best operator argument
1196 if (s_x != source_type) {
1197 var c = source as Constant;
1199 source = c.TryReduce (ec, s_x);
1205 source = implicitOnly ?
1206 ImplicitConversionStandard (ec, source_type_expr, s_x, loc) :
1207 ExplicitConversionStandard (ec, source_type_expr, s_x, loc);
1210 source = source_type_expr;
1213 source = new UserCast (most_specific_operator, source, loc).Resolve (ec);
1216 // Convert result type when it's different to best operator return type
1218 if (t_x != target_type) {
1220 // User operator is of T?, no need to lift it
1222 if (t_x == target && t_x.IsNullableType)
1225 source = implicitOnly ?
1226 ImplicitConversionStandard (ec, source, target_type, loc) :
1227 ExplicitConversionStandard (ec, source, target_type, loc);
1234 // Source expression is of nullable type, lift the result in the case it's null and
1235 // not nullable/lifted user operator is used
1237 if (source_type_expr is Nullable.Unwrap && !s_x.IsNullableType && (TypeSpec.IsReferenceType (target) || target_type != target))
1238 source = new Nullable.Lifted (source, source_type_expr, target).Resolve (ec);
1239 else if (target_type != target)
1240 source = Nullable.Wrap.Create (source, target);
1246 /// Converts implicitly the resolved expression `expr' into the
1247 /// `target_type'. It returns a new expression that can be used
1248 /// in a context that expects a `target_type'.
1250 static public Expression ImplicitConversion (ResolveContext ec, Expression expr,
1251 TypeSpec target_type, Location loc)
1255 if (target_type == null)
1256 throw new Exception ("Target type is null");
1258 e = ImplicitConversionStandard (ec, expr, target_type, loc);
1262 e = ImplicitUserConversion (ec, expr, target_type, loc);
1271 /// Attempts to apply the `Standard Implicit
1272 /// Conversion' rules to the expression `expr' into
1273 /// the `target_type'. It returns a new expression
1274 /// that can be used in a context that expects a
1277 /// This is different from `ImplicitConversion' in that the
1278 /// user defined implicit conversions are excluded.
1280 static public Expression ImplicitConversionStandard (ResolveContext ec, Expression expr,
1281 TypeSpec target_type, Location loc)
1283 return ImplicitConversionStandard (ec, expr, target_type, loc, false);
1286 static Expression ImplicitConversionStandard (ResolveContext ec, Expression expr, TypeSpec target_type, Location loc, bool explicit_cast)
1288 if (expr.eclass == ExprClass.MethodGroup){
1289 if (!target_type.IsDelegate){
1294 // Only allow anonymous method conversions on post ISO_1
1296 if (ec.Module.Compiler.Settings.Version != LanguageVersion.ISO_1){
1297 MethodGroupExpr mg = expr as MethodGroupExpr;
1299 return ImplicitDelegateCreation.Create (
1300 ec, mg, target_type, loc);
1304 TypeSpec expr_type = expr.Type;
1307 if (expr_type == target_type) {
1308 if (expr_type != InternalType.NullLiteral && expr_type != InternalType.AnonymousMethod)
1313 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1314 switch (target_type.Kind) {
1315 case MemberKind.ArrayType:
1316 case MemberKind.Class:
1317 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Object)
1318 return EmptyCast.Create (expr, target_type);
1320 goto case MemberKind.Struct;
1321 case MemberKind.Struct:
1322 case MemberKind.Delegate:
1323 case MemberKind.Enum:
1324 case MemberKind.Interface:
1325 case MemberKind.TypeParameter:
1326 Arguments args = new Arguments (1);
1327 args.Add (new Argument (expr));
1328 return new DynamicConversion (target_type, explicit_cast ? CSharpBinderFlags.ConvertExplicit : 0, args, loc).Resolve (ec);
1334 if (target_type.IsNullableType)
1335 return ImplicitNulableConversion (ec, expr, target_type);
1338 // Attempt to do the implicit constant expression conversions
1340 Constant c = expr as Constant;
1343 c = c.ConvertImplicitly (target_type);
1345 throw new InternalErrorException ("Conversion error", loc);
1351 e = ImplicitNumericConversion (expr, expr_type, target_type);
1355 e = ImplicitReferenceConversion (expr, target_type, explicit_cast);
1359 e = ImplicitBoxingConversion (expr, expr_type, target_type);
1363 if (expr is IntegralConstant && target_type.IsEnum){
1364 var i = (IntegralConstant) expr;
1366 // LAMESPEC: csc allows any constant like 0 values to be converted, including const float f = 0.0
1368 // An implicit enumeration conversion permits the decimal-integer-literal 0
1369 // to be converted to any enum-type and to any nullable-type whose underlying
1370 // type is an enum-type
1372 if (i.IsZeroInteger) {
1373 // Recreate 0 literal to remove any collected conversions
1374 return new EnumConstant (new IntLiteral (ec.BuiltinTypes, 0, i.Location), target_type);
1379 var target_pc = target_type as PointerContainer;
1380 if (target_pc != null) {
1381 if (expr_type.IsPointer) {
1383 // Pointer types are same when they have same element types
1385 if (expr_type == target_pc)
1388 if (target_pc.Element.Kind == MemberKind.Void)
1389 return EmptyCast.Create (expr, target_type);
1394 if (expr_type == InternalType.NullLiteral)
1395 return new NullPointer (target_type, loc);
1399 if (expr_type == InternalType.AnonymousMethod){
1400 AnonymousMethodExpression ame = (AnonymousMethodExpression) expr;
1401 Expression am = ame.Compatible (ec, target_type);
1403 return am.Resolve (ec);
1406 if (expr_type == InternalType.Arglist && target_type == ec.Module.PredefinedTypes.ArgIterator.TypeSpec)
1410 // dynamic erasure conversion on value types
1412 if (expr_type.IsStruct && TypeSpecComparer.IsEqual (expr_type, target_type))
1413 return expr_type == target_type ? expr : EmptyCast.Create (expr, target_type);
1419 /// Attempts to implicitly convert `source' into `target_type', using
1420 /// ImplicitConversion. If there is no implicit conversion, then
1421 /// an error is signaled
1423 static public Expression ImplicitConversionRequired (ResolveContext ec, Expression source,
1424 TypeSpec target_type, Location loc)
1426 Expression e = ImplicitConversion (ec, source, target_type, loc);
1430 source.Error_ValueCannotBeConverted (ec, target_type, false);
1435 /// Performs the explicit numeric conversions
1437 /// There are a few conversions that are not part of the C# standard,
1438 /// they were interim hacks in the C# compiler that were supposed to
1439 /// become explicit operators in the UIntPtr class and IntPtr class,
1440 /// but for historical reasons it did not happen, so the C# compiler
1441 /// ended up with these special hacks.
1443 /// See bug 59800 for details.
1445 /// The conversion are:
1455 public static Expression ExplicitNumericConversion (ResolveContext rc, Expression expr, TypeSpec target_type)
1457 // Not all predefined explicit numeric conversion are
1458 // defined here, for some of them (mostly IntPtr/UIntPtr) we
1459 // defer to user-operator handling which is now perfect but
1462 // LAMESPEC: Undocumented IntPtr/UIntPtr conversions
1463 // IntPtr -> uint uses int
1464 // UIntPtr -> long uses ulong
1467 switch (expr.Type.BuiltinType) {
1468 case BuiltinTypeSpec.Type.SByte:
1470 // From sbyte to byte, ushort, uint, ulong, char, uintptr
1472 switch (target_type.BuiltinType) {
1473 case BuiltinTypeSpec.Type.Byte:
1474 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U1);
1475 case BuiltinTypeSpec.Type.UShort:
1476 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U2);
1477 case BuiltinTypeSpec.Type.UInt:
1478 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U4);
1479 case BuiltinTypeSpec.Type.ULong:
1480 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U8);
1481 case BuiltinTypeSpec.Type.Char:
1482 return new ConvCast (expr, target_type, ConvCast.Mode.I1_CH);
1484 // One of the built-in conversions that belonged in the class library
1485 case BuiltinTypeSpec.Type.UIntPtr:
1486 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I1_U8), target_type, target_type, true);
1489 case BuiltinTypeSpec.Type.Byte:
1491 // From byte to sbyte and char
1493 switch (target_type.BuiltinType) {
1494 case BuiltinTypeSpec.Type.SByte:
1495 return new ConvCast (expr, target_type, ConvCast.Mode.U1_I1);
1496 case BuiltinTypeSpec.Type.Char:
1497 return new ConvCast (expr, target_type, ConvCast.Mode.U1_CH);
1500 case BuiltinTypeSpec.Type.Short:
1502 // From short to sbyte, byte, ushort, uint, ulong, char, uintptr
1504 switch (target_type.BuiltinType) {
1505 case BuiltinTypeSpec.Type.SByte:
1506 return new ConvCast (expr, target_type, ConvCast.Mode.I2_I1);
1507 case BuiltinTypeSpec.Type.Byte:
1508 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U1);
1509 case BuiltinTypeSpec.Type.UShort:
1510 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U2);
1511 case BuiltinTypeSpec.Type.UInt:
1512 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U4);
1513 case BuiltinTypeSpec.Type.ULong:
1514 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U8);
1515 case BuiltinTypeSpec.Type.Char:
1516 return new ConvCast (expr, target_type, ConvCast.Mode.I2_CH);
1518 // One of the built-in conversions that belonged in the class library
1519 case BuiltinTypeSpec.Type.UIntPtr:
1520 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I2_U8), target_type, target_type, true);
1523 case BuiltinTypeSpec.Type.UShort:
1525 // From ushort to sbyte, byte, short, char
1527 switch (target_type.BuiltinType) {
1528 case BuiltinTypeSpec.Type.SByte:
1529 return new ConvCast (expr, target_type, ConvCast.Mode.U2_I1);
1530 case BuiltinTypeSpec.Type.Byte:
1531 return new ConvCast (expr, target_type, ConvCast.Mode.U2_U1);
1532 case BuiltinTypeSpec.Type.Short:
1533 return new ConvCast (expr, target_type, ConvCast.Mode.U2_I2);
1534 case BuiltinTypeSpec.Type.Char:
1535 return new ConvCast (expr, target_type, ConvCast.Mode.U2_CH);
1538 case BuiltinTypeSpec.Type.Int:
1540 // From int to sbyte, byte, short, ushort, uint, ulong, char, uintptr
1542 switch (target_type.BuiltinType) {
1543 case BuiltinTypeSpec.Type.SByte:
1544 return new ConvCast (expr, target_type, ConvCast.Mode.I4_I1);
1545 case BuiltinTypeSpec.Type.Byte:
1546 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U1);
1547 case BuiltinTypeSpec.Type.Short:
1548 return new ConvCast (expr, target_type, ConvCast.Mode.I4_I2);
1549 case BuiltinTypeSpec.Type.UShort:
1550 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U2);
1551 case BuiltinTypeSpec.Type.UInt:
1552 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U4);
1553 case BuiltinTypeSpec.Type.ULong:
1554 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U8);
1555 case BuiltinTypeSpec.Type.Char:
1556 return new ConvCast (expr, target_type, ConvCast.Mode.I4_CH);
1558 // One of the built-in conversions that belonged in the class library
1559 case BuiltinTypeSpec.Type.UIntPtr:
1560 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I2_U8), target_type, target_type, true);
1563 case BuiltinTypeSpec.Type.UInt:
1565 // From uint to sbyte, byte, short, ushort, int, char
1567 switch (target_type.BuiltinType) {
1568 case BuiltinTypeSpec.Type.SByte:
1569 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I1);
1570 case BuiltinTypeSpec.Type.Byte:
1571 return new ConvCast (expr, target_type, ConvCast.Mode.U4_U1);
1572 case BuiltinTypeSpec.Type.Short:
1573 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I2);
1574 case BuiltinTypeSpec.Type.UShort:
1575 return new ConvCast (expr, target_type, ConvCast.Mode.U4_U2);
1576 case BuiltinTypeSpec.Type.Int:
1577 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I4);
1578 case BuiltinTypeSpec.Type.Char:
1579 return new ConvCast (expr, target_type, ConvCast.Mode.U4_CH);
1582 case BuiltinTypeSpec.Type.Long:
1584 // From long to sbyte, byte, short, ushort, int, uint, ulong, char
1586 switch (target_type.BuiltinType) {
1587 case BuiltinTypeSpec.Type.SByte:
1588 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I1);
1589 case BuiltinTypeSpec.Type.Byte:
1590 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U1);
1591 case BuiltinTypeSpec.Type.Short:
1592 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I2);
1593 case BuiltinTypeSpec.Type.UShort:
1594 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U2);
1595 case BuiltinTypeSpec.Type.Int:
1596 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I4);
1597 case BuiltinTypeSpec.Type.UInt:
1598 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U4);
1599 case BuiltinTypeSpec.Type.ULong:
1600 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U8);
1601 case BuiltinTypeSpec.Type.Char:
1602 return new ConvCast (expr, target_type, ConvCast.Mode.I8_CH);
1605 case BuiltinTypeSpec.Type.ULong:
1607 // From ulong to sbyte, byte, short, ushort, int, uint, long, char
1609 switch (target_type.BuiltinType) {
1610 case BuiltinTypeSpec.Type.SByte:
1611 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I1);
1612 case BuiltinTypeSpec.Type.Byte:
1613 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U1);
1614 case BuiltinTypeSpec.Type.Short:
1615 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I2);
1616 case BuiltinTypeSpec.Type.UShort:
1617 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U2);
1618 case BuiltinTypeSpec.Type.Int:
1619 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I4);
1620 case BuiltinTypeSpec.Type.UInt:
1621 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U4);
1622 case BuiltinTypeSpec.Type.Long:
1623 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I8);
1624 case BuiltinTypeSpec.Type.Char:
1625 return new ConvCast (expr, target_type, ConvCast.Mode.U8_CH);
1627 // One of the built-in conversions that belonged in the class library
1628 case BuiltinTypeSpec.Type.IntPtr:
1629 return new OperatorCast (EmptyCast.Create (expr, rc.BuiltinTypes.Long), target_type, true);
1632 case BuiltinTypeSpec.Type.Char:
1634 // From char to sbyte, byte, short
1636 switch (target_type.BuiltinType) {
1637 case BuiltinTypeSpec.Type.SByte:
1638 return new ConvCast (expr, target_type, ConvCast.Mode.CH_I1);
1639 case BuiltinTypeSpec.Type.Byte:
1640 return new ConvCast (expr, target_type, ConvCast.Mode.CH_U1);
1641 case BuiltinTypeSpec.Type.Short:
1642 return new ConvCast (expr, target_type, ConvCast.Mode.CH_I2);
1645 case BuiltinTypeSpec.Type.Float:
1647 // From float to sbyte, byte, short,
1648 // ushort, int, uint, long, ulong, char
1651 switch (target_type.BuiltinType) {
1652 case BuiltinTypeSpec.Type.SByte:
1653 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I1);
1654 case BuiltinTypeSpec.Type.Byte:
1655 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U1);
1656 case BuiltinTypeSpec.Type.Short:
1657 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I2);
1658 case BuiltinTypeSpec.Type.UShort:
1659 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U2);
1660 case BuiltinTypeSpec.Type.Int:
1661 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I4);
1662 case BuiltinTypeSpec.Type.UInt:
1663 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U4);
1664 case BuiltinTypeSpec.Type.Long:
1665 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I8);
1666 case BuiltinTypeSpec.Type.ULong:
1667 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U8);
1668 case BuiltinTypeSpec.Type.Char:
1669 return new ConvCast (expr, target_type, ConvCast.Mode.R4_CH);
1670 case BuiltinTypeSpec.Type.Decimal:
1671 return new OperatorCast (expr, target_type, true);
1674 case BuiltinTypeSpec.Type.Double:
1676 // From double to sbyte, byte, short,
1677 // ushort, int, uint, long, ulong,
1678 // char, float or decimal
1680 switch (target_type.BuiltinType) {
1681 case BuiltinTypeSpec.Type.SByte:
1682 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I1);
1683 case BuiltinTypeSpec.Type.Byte:
1684 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U1);
1685 case BuiltinTypeSpec.Type.Short:
1686 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I2);
1687 case BuiltinTypeSpec.Type.UShort:
1688 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U2);
1689 case BuiltinTypeSpec.Type.Int:
1690 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I4);
1691 case BuiltinTypeSpec.Type.UInt:
1692 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U4);
1693 case BuiltinTypeSpec.Type.Long:
1694 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I8);
1695 case BuiltinTypeSpec.Type.ULong:
1696 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U8);
1697 case BuiltinTypeSpec.Type.Char:
1698 return new ConvCast (expr, target_type, ConvCast.Mode.R8_CH);
1699 case BuiltinTypeSpec.Type.Float:
1700 return new ConvCast (expr, target_type, ConvCast.Mode.R8_R4);
1701 case BuiltinTypeSpec.Type.Decimal:
1702 return new OperatorCast (expr, target_type, true);
1705 case BuiltinTypeSpec.Type.UIntPtr:
1707 // Various built-in conversions that belonged in the class library
1709 // from uintptr to sbyte, short, int32
1711 switch (target_type.BuiltinType) {
1712 case BuiltinTypeSpec.Type.SByte:
1713 return new ConvCast (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type, ConvCast.Mode.U4_I1);
1714 case BuiltinTypeSpec.Type.Short:
1715 return new ConvCast (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type, ConvCast.Mode.U4_I2);
1716 case BuiltinTypeSpec.Type.Int:
1717 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type);
1718 case BuiltinTypeSpec.Type.UInt:
1719 return new OperatorCast (expr, expr.Type, target_type, true);
1720 case BuiltinTypeSpec.Type.Long:
1721 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.ULong, true), target_type);
1724 case BuiltinTypeSpec.Type.IntPtr:
1725 if (target_type.BuiltinType == BuiltinTypeSpec.Type.UInt)
1726 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.Int, true), target_type);
1727 if (target_type.BuiltinType == BuiltinTypeSpec.Type.ULong)
1728 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.Long, true), target_type);
1731 case BuiltinTypeSpec.Type.Decimal:
1732 // From decimal to sbyte, byte, short,
1733 // ushort, int, uint, long, ulong, char,
1735 switch (target_type.BuiltinType) {
1736 case BuiltinTypeSpec.Type.SByte:
1737 case BuiltinTypeSpec.Type.Byte:
1738 case BuiltinTypeSpec.Type.Short:
1739 case BuiltinTypeSpec.Type.UShort:
1740 case BuiltinTypeSpec.Type.Int:
1741 case BuiltinTypeSpec.Type.UInt:
1742 case BuiltinTypeSpec.Type.Long:
1743 case BuiltinTypeSpec.Type.ULong:
1744 case BuiltinTypeSpec.Type.Char:
1745 case BuiltinTypeSpec.Type.Float:
1746 case BuiltinTypeSpec.Type.Double:
1747 return new OperatorCast (expr, expr.Type, target_type, true);
1757 /// Returns whether an explicit reference conversion can be performed
1758 /// from source_type to target_type
1760 public static bool ExplicitReferenceConversionExists (TypeSpec source_type, TypeSpec target_type)
1762 Expression e = ExplicitReferenceConversion (null, source_type, target_type);
1766 if (e == EmptyExpression.Null)
1769 throw new InternalErrorException ("Invalid probing conversion result");
1773 /// Implements Explicit Reference conversions
1775 static Expression ExplicitReferenceConversion (Expression source, TypeSpec source_type, TypeSpec target_type)
1778 // From object to a generic parameter
1780 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Object && TypeManager.IsGenericParameter (target_type))
1781 return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
1784 // Explicit type parameter conversion.
1786 if (source_type.Kind == MemberKind.TypeParameter)
1787 return ExplicitTypeParameterConversion (source, source_type, target_type);
1789 bool target_is_value_type = target_type.Kind == MemberKind.Struct || target_type.Kind == MemberKind.Enum;
1792 // Unboxing conversion from System.ValueType to any non-nullable-value-type
1794 if (source_type.BuiltinType == BuiltinTypeSpec.Type.ValueType && target_is_value_type)
1795 return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
1798 // From object or dynamic to any reference type or value type (unboxing)
1800 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Object || source_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1801 if (target_type.IsPointer)
1805 source == null ? EmptyExpression.Null :
1806 target_is_value_type ? new UnboxCast (source, target_type) :
1807 source is Constant ? (Expression) new EmptyConstantCast ((Constant) source, target_type) :
1808 new ClassCast (source, target_type);
1812 // From any class S to any class-type T, provided S is a base class of T
1814 if (source_type.Kind == MemberKind.Class && TypeSpec.IsBaseClass (target_type, source_type, true))
1815 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1818 // From any interface-type S to to any class type T, provided T is not
1819 // sealed, or provided T implements S.
1821 if (source_type.Kind == MemberKind.Interface) {
1822 if (!target_type.IsSealed || target_type.ImplementsInterface (source_type, true)) {
1824 return EmptyExpression.Null;
1827 // Unboxing conversion from any interface-type to any non-nullable-value-type that
1828 // implements the interface-type
1830 return target_is_value_type ? new UnboxCast (source, target_type) : (Expression) new ClassCast (source, target_type);
1834 // From System.Collections.Generic.IList<T> and its base interfaces to a one-dimensional
1835 // array type S[], provided there is an implicit or explicit reference conversion from S to T.
1837 var target_array = target_type as ArrayContainer;
1838 if (target_array != null && IList_To_Array (source_type, target_array))
1839 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1844 var source_array = source_type as ArrayContainer;
1845 if (source_array != null) {
1846 var target_array = target_type as ArrayContainer;
1847 if (target_array != null) {
1849 // From System.Array to any array-type
1851 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Array)
1852 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1855 // From an array type S with an element type Se to an array type T with an
1856 // element type Te provided all the following are true:
1857 // * S and T differe only in element type, in other words, S and T
1858 // have the same number of dimensions.
1859 // * Both Se and Te are reference types
1860 // * An explicit reference conversions exist from Se to Te
1862 if (source_array.Rank == target_array.Rank) {
1864 source_type = source_array.Element;
1865 if (!TypeSpec.IsReferenceType (source_type))
1868 var target_element = target_array.Element;
1869 if (!TypeSpec.IsReferenceType (target_element))
1872 if (ExplicitReferenceConversionExists (source_type, target_element))
1873 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1880 // From a single-dimensional array type S[] to System.Collections.Generic.IList<T> and its base interfaces,
1881 // provided that there is an explicit reference conversion from S to T
1883 if (ArrayToIList (source_array, target_type, true))
1884 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1890 // From any class type S to any interface T, provides S is not sealed
1891 // and provided S does not implement T.
1893 if (target_type.IsInterface && !source_type.IsSealed && !source_type.ImplementsInterface (target_type, true)) {
1894 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1898 // From System delegate to any delegate-type
1900 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Delegate && target_type.IsDelegate)
1901 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1904 // From variant generic delegate to same variant generic delegate type
1906 if (source_type.IsDelegate && target_type.IsDelegate && source_type.MemberDefinition == target_type.MemberDefinition) {
1907 var tparams = source_type.MemberDefinition.TypeParameters;
1908 var targs_src = source_type.TypeArguments;
1909 var targs_dst = target_type.TypeArguments;
1911 for (i = 0; i < tparams.Length; ++i) {
1913 // If TP is invariant, types have to be identical
1915 if (TypeSpecComparer.IsEqual (targs_src[i], targs_dst[i]))
1918 if (tparams[i].Variance == Variance.Covariant) {
1920 //If TP is covariant, an implicit or explicit identity or reference conversion is required
1922 if (ImplicitReferenceConversionExists (targs_src[i], targs_dst[i]))
1925 if (ExplicitReferenceConversionExists (targs_src[i], targs_dst[i]))
1928 } else if (tparams[i].Variance == Variance.Contravariant) {
1930 //If TP is contravariant, both are either identical or reference types
1932 if (TypeSpec.IsReferenceType (targs_src[i]) && TypeSpec.IsReferenceType (targs_dst[i]))
1939 if (i == tparams.Length)
1940 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1947 /// Performs an explicit conversion of the expression `expr' whose
1948 /// type is expr.Type to `target_type'.
1950 static public Expression ExplicitConversionCore (ResolveContext ec, Expression expr,
1951 TypeSpec target_type, Location loc)
1953 TypeSpec expr_type = expr.Type;
1955 // Explicit conversion includes implicit conversion and it used for enum underlying types too
1956 Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc, true);
1960 if (expr_type.IsEnum) {
1961 TypeSpec real_target = target_type.IsEnum ? EnumSpec.GetUnderlyingType (target_type) : target_type;
1962 Expression underlying = EmptyCast.Create (expr, EnumSpec.GetUnderlyingType (expr_type));
1963 if (underlying.Type == real_target)
1967 ne = ImplicitNumericConversion (underlying, real_target);
1970 ne = ExplicitNumericConversion (ec, underlying, real_target);
1973 // LAMESPEC: IntPtr and UIntPtr conversion to any Enum is allowed
1975 if (ne == null && (real_target.BuiltinType == BuiltinTypeSpec.Type.IntPtr || real_target.BuiltinType == BuiltinTypeSpec.Type.UIntPtr))
1976 ne = ExplicitUserConversion (ec, underlying, real_target, loc);
1978 return ne != null ? EmptyCast.Create (ne, target_type) : null;
1981 if (target_type.IsEnum) {
1983 // System.Enum can be unboxed to any enum-type
1985 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Enum)
1986 return new UnboxCast (expr, target_type);
1988 TypeSpec real_target = target_type.IsEnum ? EnumSpec.GetUnderlyingType (target_type) : target_type;
1990 if (expr_type == real_target)
1991 return EmptyCast.Create (expr, target_type);
1993 ne = ImplicitNumericConversion (expr, real_target);
1995 return EmptyCast.Create (ne, target_type);
1997 ne = ExplicitNumericConversion (ec, expr, real_target);
1999 return EmptyCast.Create (ne, target_type);
2002 // LAMESPEC: IntPtr and UIntPtr conversion to any Enum is allowed
2004 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.IntPtr || expr_type.BuiltinType == BuiltinTypeSpec.Type.UIntPtr) {
2005 ne = ExplicitUserConversion (ec, expr, real_target, loc);
2007 return ExplicitConversionCore (ec, ne, target_type, loc);
2010 ne = ExplicitNumericConversion (ec, expr, target_type);
2016 // Skip the ExplicitReferenceConversion because we can not convert
2017 // from Null to a ValueType, and ExplicitReference wont check against
2018 // null literal explicitly
2020 if (expr_type != InternalType.NullLiteral) {
2021 ne = ExplicitReferenceConversion (expr, expr_type, target_type);
2027 ne = ExplicitUnsafe (expr, target_type);
2035 public static Expression ExplicitUnsafe (Expression expr, TypeSpec target_type)
2037 TypeSpec expr_type = expr.Type;
2039 if (target_type.IsPointer){
2040 if (expr_type.IsPointer)
2041 return EmptyCast.Create (expr, target_type);
2043 switch (expr_type.BuiltinType) {
2044 case BuiltinTypeSpec.Type.SByte:
2045 case BuiltinTypeSpec.Type.Short:
2046 case BuiltinTypeSpec.Type.Int:
2047 return new OpcodeCast (expr, target_type, OpCodes.Conv_I);
2049 case BuiltinTypeSpec.Type.UShort:
2050 case BuiltinTypeSpec.Type.UInt:
2051 case BuiltinTypeSpec.Type.Byte:
2052 return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
2054 case BuiltinTypeSpec.Type.Long:
2055 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I);
2057 case BuiltinTypeSpec.Type.ULong:
2058 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I);
2062 if (expr_type.IsPointer){
2063 switch (target_type.BuiltinType) {
2064 case BuiltinTypeSpec.Type.SByte:
2065 return new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
2066 case BuiltinTypeSpec.Type.Byte:
2067 return new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
2068 case BuiltinTypeSpec.Type.Short:
2069 return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
2070 case BuiltinTypeSpec.Type.UShort:
2071 return new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
2072 case BuiltinTypeSpec.Type.Int:
2073 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
2074 case BuiltinTypeSpec.Type.UInt:
2075 return new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
2076 case BuiltinTypeSpec.Type.Long:
2077 return new ConvCast (expr, target_type, ConvCast.Mode.I_I8);
2078 case BuiltinTypeSpec.Type.ULong:
2079 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
2086 /// Same as ExplicitConversion, only it doesn't include user defined conversions
2088 static public Expression ExplicitConversionStandard (ResolveContext ec, Expression expr,
2089 TypeSpec target_type, Location l)
2091 int errors = ec.Report.Errors;
2092 Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
2093 if (ec.Report.Errors > errors)
2099 ne = ExplicitNumericConversion (ec, expr, target_type);
2103 ne = ExplicitReferenceConversion (expr, expr.Type, target_type);
2107 if (ec.IsUnsafe && expr.Type.IsPointer && target_type.IsPointer && ((PointerContainer)expr.Type).Element.Kind == MemberKind.Void)
2108 return EmptyCast.Create (expr, target_type);
2110 expr.Error_ValueCannotBeConverted (ec, target_type, true);
2115 /// Performs an explicit conversion of the expression `expr' whose
2116 /// type is expr.Type to `target_type'.
2118 static public Expression ExplicitConversion (ResolveContext ec, Expression expr,
2119 TypeSpec target_type, Location loc)
2121 Expression e = ExplicitConversionCore (ec, expr, target_type, loc);
2124 // Don't eliminate explicit precission casts
2127 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Float)
2128 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
2130 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Double)
2131 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
2137 TypeSpec expr_type = expr.Type;
2138 if (target_type.IsNullableType) {
2141 if (expr_type.IsNullableType) {
2142 target = Nullable.NullableInfo.GetUnderlyingType (target_type);
2143 Expression unwrap = Nullable.Unwrap.Create (expr);
2144 e = ExplicitConversion (ec, unwrap, target, expr.Location);
2148 return new Nullable.Lifted (e, unwrap, target_type).Resolve (ec);
2150 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
2151 return new UnboxCast (expr, target_type);
2154 target = TypeManager.GetTypeArguments (target_type) [0];
2155 e = ExplicitConversionCore (ec, expr, target, loc);
2157 return Nullable.Wrap.Create (e, target_type);
2158 } else if (expr_type.IsNullableType) {
2159 e = ImplicitBoxingConversion (expr, Nullable.NullableInfo.GetUnderlyingType (expr_type), target_type);
2163 e = Nullable.Unwrap.Create (expr, false);
2164 e = ExplicitConversionCore (ec, e, target_type, loc);
2166 return EmptyCast.Create (e, target_type);
2169 e = ExplicitUserConversion (ec, expr, target_type, loc);
2173 expr.Error_ValueCannotBeConverted (ec, target_type, true);