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 public enum UserConversionRestriction
36 NullableSourceOnly = 1 << 2
40 // From a one-dimensional array-type S[] to System.Collections.IList<T> and base
41 // interfaces of this interface, provided there is an implicit reference conversion
44 static bool ArrayToIList (ArrayContainer array, TypeSpec list, bool isExplicit)
46 if (array.Rank != 1 || !list.IsArrayGenericInterface)
49 var arg_type = list.TypeArguments[0];
50 if (array.Element == arg_type)
54 // Reject conversion from T[] to IList<U> even if T has U dependency
56 if (arg_type.IsGenericParameter)
60 return ExplicitReferenceConversionExists (array.Element, arg_type);
62 return ImplicitReferenceConversionExists (array.Element, arg_type);
65 static bool IList_To_Array(TypeSpec list, ArrayContainer array)
67 if (array.Rank != 1 || !list.IsArrayGenericInterface)
70 var arg_type = list.TypeArguments[0];
71 if (array.Element == arg_type)
74 return ImplicitReferenceConversionExists (array.Element, arg_type) || ExplicitReferenceConversionExists (array.Element, arg_type);
77 public static Expression ImplicitTypeParameterConversion (Expression expr, TypeParameterSpec expr_type, TypeSpec target_type)
80 // From T to a type parameter U, provided T depends on U
82 if (target_type.IsGenericParameter) {
83 if (expr_type.TypeArguments != null && expr_type.HasDependencyOn (target_type)) {
85 return EmptyExpression.Null;
87 if (expr_type.IsReferenceType && !((TypeParameterSpec) target_type).IsReferenceType)
88 return new BoxedCast (expr, target_type);
90 return new ClassCast (expr, target_type);
97 // LAMESPEC: From T to dynamic type because it's like T to object
99 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
101 return EmptyExpression.Null;
103 if (expr_type.IsReferenceType)
104 return new ClassCast (expr, target_type);
106 return new BoxedCast (expr, target_type);
110 // From T to its effective base class C
111 // From T to any base class of C (it cannot contain dynamic or be of dynamic type)
112 // From T to any interface implemented by C
114 var base_type = expr_type.GetEffectiveBase ();
115 if (base_type == target_type || TypeSpec.IsBaseClass (base_type, target_type, false) || base_type.ImplementsInterface (target_type, true)) {
117 return EmptyExpression.Null;
119 if (expr_type.IsReferenceType)
120 return new ClassCast (expr, target_type);
122 return new BoxedCast (expr, target_type);
125 if (target_type.IsInterface && expr_type.IsConvertibleToInterface (target_type)) {
127 return EmptyExpression.Null;
129 if (expr_type.IsReferenceType)
130 return new ClassCast (expr, target_type);
132 return new BoxedCast (expr, target_type);
138 static Expression ExplicitTypeParameterConversionFromT (Expression source, TypeSpec source_type, TypeSpec target_type)
140 var target_tp = target_type as TypeParameterSpec;
141 if (target_tp != null) {
143 // From a type parameter U to T, provided T depends on U
145 if (target_tp.TypeArguments != null && target_tp.HasDependencyOn (source_type)) {
146 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
151 // From T to any interface-type I provided there is not already an implicit conversion from T to I
153 if (target_type.IsInterface)
154 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type, true);
159 static Expression ExplicitTypeParameterConversionToT (Expression source, TypeSpec source_type, TypeParameterSpec target_type)
162 // From the effective base class C of T to T and from any base class of C to T
164 var effective = target_type.GetEffectiveBase ();
165 if (TypeSpecComparer.IsEqual (effective, source_type) || TypeSpec.IsBaseClass (effective, source_type, false))
166 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
171 public static Expression ImplicitReferenceConversion (Expression expr, TypeSpec target_type, bool explicit_cast)
173 TypeSpec expr_type = expr.Type;
175 if (expr_type.Kind == MemberKind.TypeParameter)
176 return ImplicitTypeParameterConversion (expr, (TypeParameterSpec) expr.Type, target_type);
179 // from the null type to any reference-type.
181 NullLiteral nl = expr as NullLiteral;
183 return nl.ConvertImplicitly (target_type);
186 if (ImplicitReferenceConversionExists (expr_type, target_type)) {
188 // Avoid wrapping implicitly convertible reference type
193 return EmptyCast.Create (expr, target_type);
200 // Implicit reference conversions
202 public static bool ImplicitReferenceConversionExists (TypeSpec expr_type, TypeSpec target_type)
204 return ImplicitReferenceConversionExists (expr_type, target_type, true);
207 public static bool ImplicitReferenceConversionExists (TypeSpec expr_type, TypeSpec target_type, bool refOnlyTypeParameter)
209 // It's here only to speed things up
210 if (target_type.IsStruct)
213 switch (expr_type.Kind) {
214 case MemberKind.TypeParameter:
215 return ImplicitTypeParameterConversion (null, (TypeParameterSpec) expr_type, target_type) != null &&
216 (!refOnlyTypeParameter || TypeSpec.IsReferenceType (expr_type));
218 case MemberKind.Class:
220 // From any class-type to dynamic (+object to speed up common path)
222 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Object || target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
225 if (target_type.IsClass) {
227 // Identity conversion, including dynamic erasure
229 if (TypeSpecComparer.IsEqual (expr_type, target_type))
233 // From any class-type S to any class-type T, provided S is derived from T
235 return TypeSpec.IsBaseClass (expr_type, target_type, true);
239 // From any class-type S to any interface-type T, provided S implements T
241 if (target_type.IsInterface)
242 return expr_type.ImplementsInterface (target_type, true);
246 case MemberKind.ArrayType:
248 // Identity array conversion
250 if (expr_type == target_type)
254 // From any array-type to System.Array
256 switch (target_type.BuiltinType) {
257 case BuiltinTypeSpec.Type.Array:
258 case BuiltinTypeSpec.Type.Object:
259 case BuiltinTypeSpec.Type.Dynamic:
263 var expr_type_array = (ArrayContainer) expr_type;
264 var target_type_array = target_type as ArrayContainer;
267 // From an array-type S to an array-type of type T
269 if (target_type_array != null && expr_type_array.Rank == target_type_array.Rank) {
272 // Both SE and TE are reference-types. TE check is defered
273 // to ImplicitReferenceConversionExists
275 TypeSpec expr_element_type = expr_type_array.Element;
276 if (!TypeSpec.IsReferenceType (expr_element_type))
280 // An implicit reference conversion exists from SE to TE
282 return ImplicitReferenceConversionExists (expr_element_type, target_type_array.Element);
286 // From any array-type to the interfaces it implements
288 if (target_type.IsInterface) {
289 if (expr_type.ImplementsInterface (target_type, false))
292 // from an array-type of type T to IList<T>
293 if (ArrayToIList (expr_type_array, target_type, false))
299 case MemberKind.Delegate:
301 // From any delegate-type to System.Delegate (and its base types)
303 switch (target_type.BuiltinType) {
304 case BuiltinTypeSpec.Type.Delegate:
305 case BuiltinTypeSpec.Type.MulticastDelegate:
306 case BuiltinTypeSpec.Type.Object:
307 case BuiltinTypeSpec.Type.Dynamic:
312 // Identity conversion, including dynamic erasure
314 if (TypeSpecComparer.IsEqual (expr_type, target_type))
318 // From any delegate-type to the interfaces it implements
319 // From any reference-type to an delegate type if is variance-convertible
321 return expr_type.ImplementsInterface (target_type, false) || TypeSpecComparer.Variant.IsEqual (expr_type, target_type);
323 case MemberKind.Interface:
325 // Identity conversion, including dynamic erasure
327 if (TypeSpecComparer.IsEqual (expr_type, target_type))
331 // From any interface type S to interface-type T
332 // From any reference-type to an interface if is variance-convertible
334 if (target_type.IsInterface)
335 return TypeSpecComparer.Variant.IsEqual (expr_type, target_type) || expr_type.ImplementsInterface (target_type, true);
337 return target_type.BuiltinType == BuiltinTypeSpec.Type.Object || target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
339 case MemberKind.InternalCompilerType:
341 // from the null literal to any reference-type.
343 if (expr_type == InternalType.NullLiteral) {
344 // Exlude internal compiler types
345 if (target_type.Kind == MemberKind.InternalCompilerType)
346 return target_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
348 return TypeSpec.IsReferenceType (target_type) || target_type.Kind == MemberKind.PointerType;
352 // Implicit dynamic conversion
354 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
355 switch (target_type.Kind) {
356 case MemberKind.ArrayType:
357 case MemberKind.Class:
358 case MemberKind.Delegate:
359 case MemberKind.Interface:
360 case MemberKind.TypeParameter:
364 // dynamic to __arglist
365 if (target_type == InternalType.Arglist)
377 public static Expression ImplicitBoxingConversion (Expression expr, TypeSpec expr_type, TypeSpec target_type)
379 switch (target_type.BuiltinType) {
381 // From any non-nullable-value-type to the type object and dynamic
383 case BuiltinTypeSpec.Type.Object:
384 case BuiltinTypeSpec.Type.Dynamic:
386 // From any non-nullable-value-type to the type System.ValueType
388 case BuiltinTypeSpec.Type.ValueType:
390 // No ned to check for nullable type as underlying type is always convertible
392 if (!TypeSpec.IsValueType (expr_type))
395 return expr == null ? EmptyExpression.Null : new BoxedCast (expr, target_type);
397 case BuiltinTypeSpec.Type.Enum:
399 // From any enum-type to the type System.Enum.
401 if (expr_type.IsEnum)
402 return expr == null ? EmptyExpression.Null : new BoxedCast (expr, target_type);
408 // From a nullable-type to a reference type, if a boxing conversion exists from
409 // the underlying type to the reference type
411 if (expr_type.IsNullableType) {
412 if (!TypeSpec.IsReferenceType (target_type))
415 var res = ImplicitBoxingConversion (expr, Nullable.NullableInfo.GetUnderlyingType (expr_type), target_type);
417 // "cast" underlying type to target type to emit correct InvalidCastException when
418 // underlying hierarchy changes without recompilation
419 if (res != null && expr != null)
420 res = new UnboxCast (res, target_type);
426 // A value type has a boxing conversion to an interface type I if it has a boxing conversion
427 // to an interface or delegate type I0 and I0 is variance-convertible to I
429 if (target_type.IsInterface && TypeSpec.IsValueType (expr_type) && expr_type.ImplementsInterface (target_type, true)) {
430 return expr == null ? EmptyExpression.Null : new BoxedCast (expr, target_type);
436 public static Expression ImplicitNulableConversion (ResolveContext ec, Expression expr, TypeSpec target_type)
438 TypeSpec expr_type = expr.Type;
441 // From null to any nullable type
443 if (expr_type == InternalType.NullLiteral)
444 return ec == null ? EmptyExpression.Null : Nullable.LiftedNull.Create (target_type, expr.Location);
447 TypeSpec t_el = Nullable.NullableInfo.GetUnderlyingType (target_type);
450 if (expr_type.IsNullableType)
451 expr_type = Nullable.NullableInfo.GetUnderlyingType (expr_type);
454 // Predefined implicit identity or implicit numeric conversion
455 // has to exist between underlying type S and underlying type T
458 // conversion exists only mode
460 if (TypeSpecComparer.IsEqual (expr_type, t_el))
461 return EmptyExpression.Null;
463 if (expr is Constant)
464 return ((Constant) expr).ConvertImplicitly (t_el);
466 return ImplicitNumericConversion (null, expr_type, t_el);
470 if (expr_type != expr.Type)
471 unwrap = Nullable.Unwrap.Create (expr);
475 Expression conv = unwrap;
476 if (!TypeSpecComparer.IsEqual (expr_type, t_el)) {
477 if (conv is Constant)
478 conv = ((Constant)conv).ConvertImplicitly (t_el);
480 conv = ImplicitNumericConversion (conv, expr_type, t_el);
486 if (expr_type != expr.Type)
487 return new Nullable.LiftedConversion (conv, unwrap, target_type).Resolve (ec);
489 return Nullable.Wrap.Create (conv, target_type);
493 /// Implicit Numeric Conversions.
495 /// expr is the expression to convert, returns a new expression of type
496 /// target_type or null if an implicit conversion is not possible.
498 public static Expression ImplicitNumericConversion (Expression expr, TypeSpec target_type)
500 return ImplicitNumericConversion (expr, expr.Type, target_type);
503 public static bool ImplicitNumericConversionExists (TypeSpec expr_type, TypeSpec target_type)
505 return ImplicitNumericConversion (null, expr_type, target_type) != null;
508 static Expression ImplicitNumericConversion (Expression expr, TypeSpec expr_type, TypeSpec target_type)
510 switch (expr_type.BuiltinType) {
511 case BuiltinTypeSpec.Type.SByte:
513 // From sbyte to short, int, long, float, double, decimal
515 switch (target_type.BuiltinType) {
516 case BuiltinTypeSpec.Type.Int:
517 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
518 case BuiltinTypeSpec.Type.Long:
519 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
520 case BuiltinTypeSpec.Type.Double:
521 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
522 case BuiltinTypeSpec.Type.Float:
523 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
524 case BuiltinTypeSpec.Type.Short:
525 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
526 case BuiltinTypeSpec.Type.Decimal:
527 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
532 case BuiltinTypeSpec.Type.Byte:
534 // From byte to short, ushort, int, uint, long, ulong, float, double, decimal
536 switch (target_type.BuiltinType) {
537 case BuiltinTypeSpec.Type.Int:
538 case BuiltinTypeSpec.Type.UInt:
539 case BuiltinTypeSpec.Type.Short:
540 case BuiltinTypeSpec.Type.UShort:
541 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
542 case BuiltinTypeSpec.Type.ULong:
543 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
544 case BuiltinTypeSpec.Type.Long:
545 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
546 case BuiltinTypeSpec.Type.Float:
547 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
548 case BuiltinTypeSpec.Type.Double:
549 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
550 case BuiltinTypeSpec.Type.Decimal:
551 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
554 case BuiltinTypeSpec.Type.Short:
556 // From short to int, long, float, double, decimal
558 switch (target_type.BuiltinType) {
559 case BuiltinTypeSpec.Type.Int:
560 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
561 case BuiltinTypeSpec.Type.Long:
562 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
563 case BuiltinTypeSpec.Type.Double:
564 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
565 case BuiltinTypeSpec.Type.Float:
566 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
567 case BuiltinTypeSpec.Type.Decimal:
568 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
571 case BuiltinTypeSpec.Type.UShort:
573 // From ushort to int, uint, long, ulong, float, double, decimal
575 switch (target_type.BuiltinType) {
576 case BuiltinTypeSpec.Type.Int:
577 case BuiltinTypeSpec.Type.UInt:
578 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
579 case BuiltinTypeSpec.Type.ULong:
580 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
581 case BuiltinTypeSpec.Type.Long:
582 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
583 case BuiltinTypeSpec.Type.Double:
584 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
585 case BuiltinTypeSpec.Type.Float:
586 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
587 case BuiltinTypeSpec.Type.Decimal:
588 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
591 case BuiltinTypeSpec.Type.Int:
593 // From int to long, float, double, decimal
595 switch (target_type.BuiltinType) {
596 case BuiltinTypeSpec.Type.Long:
597 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
598 case BuiltinTypeSpec.Type.Double:
599 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
600 case BuiltinTypeSpec.Type.Float:
601 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
602 case BuiltinTypeSpec.Type.Decimal:
603 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
606 case BuiltinTypeSpec.Type.UInt:
608 // From uint to long, ulong, float, double, decimal
610 switch (target_type.BuiltinType) {
611 case BuiltinTypeSpec.Type.Long:
612 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
613 case BuiltinTypeSpec.Type.ULong:
614 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
615 case BuiltinTypeSpec.Type.Double:
616 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R8);
617 case BuiltinTypeSpec.Type.Float:
618 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R4);
619 case BuiltinTypeSpec.Type.Decimal:
620 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
623 case BuiltinTypeSpec.Type.Long:
625 // From long to float, double, decimal
627 switch (target_type.BuiltinType) {
628 case BuiltinTypeSpec.Type.Double:
629 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
630 case BuiltinTypeSpec.Type.Float:
631 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
632 case BuiltinTypeSpec.Type.Decimal:
633 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
636 case BuiltinTypeSpec.Type.ULong:
638 // From ulong to float, double, decimal
640 switch (target_type.BuiltinType) {
641 case BuiltinTypeSpec.Type.Double:
642 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R8);
643 case BuiltinTypeSpec.Type.Float:
644 return expr == null ? EmptyExpression.Null : new OpcodeCastDuplex (expr, target_type, OpCodes.Conv_R_Un, OpCodes.Conv_R4);
645 case BuiltinTypeSpec.Type.Decimal:
646 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
649 case BuiltinTypeSpec.Type.Char:
651 // From char to ushort, int, uint, long, ulong, float, double, decimal
653 switch (target_type.BuiltinType) {
654 case BuiltinTypeSpec.Type.UShort:
655 case BuiltinTypeSpec.Type.Int:
656 case BuiltinTypeSpec.Type.UInt:
657 return expr == null ? EmptyExpression.Null : EmptyCast.Create (expr, target_type);
658 case BuiltinTypeSpec.Type.ULong:
659 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
660 case BuiltinTypeSpec.Type.Long:
661 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
662 case BuiltinTypeSpec.Type.Float:
663 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
664 case BuiltinTypeSpec.Type.Double:
665 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
666 case BuiltinTypeSpec.Type.Decimal:
667 return expr == null ? EmptyExpression.Null : new OperatorCast (expr, target_type);
670 case BuiltinTypeSpec.Type.Float:
674 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Double)
675 return expr == null ? EmptyExpression.Null : new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
683 // Full version of implicit conversion
685 public static bool ImplicitConversionExists (ResolveContext ec, Expression expr, TypeSpec target_type)
687 if (ImplicitStandardConversionExists (ec, expr, target_type))
690 if (expr.Type == InternalType.AnonymousMethod) {
691 if (!target_type.IsDelegate && !target_type.IsExpressionTreeType)
694 AnonymousMethodExpression ame = (AnonymousMethodExpression) expr;
695 return ame.ImplicitStandardConversionExists (ec, target_type);
698 // Conversion from __arglist to System.ArgIterator
699 if (expr.Type == InternalType.Arglist)
700 return target_type == ec.Module.PredefinedTypes.ArgIterator.TypeSpec;
702 return UserDefinedConversion (ec, expr, target_type,
703 UserConversionRestriction.ImplicitOnly | UserConversionRestriction.ProbingOnly, Location.Null) != null;
706 public static bool ImplicitStandardConversionExists (ResolveContext rc, Expression expr, TypeSpec target_type)
708 if (expr.eclass == ExprClass.MethodGroup) {
709 if (target_type.IsDelegate && rc.Module.Compiler.Settings.Version != LanguageVersion.ISO_1) {
710 MethodGroupExpr mg = expr as MethodGroupExpr;
712 return DelegateCreation.ImplicitStandardConversionExists (rc, mg, target_type);
718 var interpolated_string = expr as InterpolatedString;
719 if (interpolated_string != null) {
720 if (target_type == rc.Module.PredefinedTypes.IFormattable.TypeSpec || target_type == rc.Module.PredefinedTypes.FormattableString.TypeSpec)
724 return ImplicitStandardConversionExists (expr, target_type);
728 // Implicit standard conversion (only core conversions are used here)
730 public static bool ImplicitStandardConversionExists (Expression expr, TypeSpec target_type)
733 // Identity conversions
734 // Implicit numeric conversions
735 // Implicit nullable conversions
736 // Implicit reference conversions
737 // Boxing conversions
738 // Implicit constant expression conversions
739 // Implicit conversions involving type parameters
742 TypeSpec expr_type = expr.Type;
744 if (expr_type == target_type)
747 if (expr_type == InternalType.ThrowExpr)
748 return target_type.Kind != MemberKind.InternalCompilerType;
750 if (target_type.IsNullableType)
751 return ImplicitNulableConversion (null, expr, target_type) != null;
753 if (ImplicitNumericConversion (null, expr_type, target_type) != null)
756 if (ImplicitReferenceConversionExists (expr_type, target_type, false))
759 if (ImplicitBoxingConversion (null, expr_type, target_type) != null)
763 // Implicit Constant Expression Conversions
765 if (expr is IntConstant){
766 int value = ((IntConstant) expr).Value;
767 switch (target_type.BuiltinType) {
768 case BuiltinTypeSpec.Type.SByte:
769 if (value >= SByte.MinValue && value <= SByte.MaxValue)
772 case BuiltinTypeSpec.Type.Byte:
773 if (value >= 0 && value <= Byte.MaxValue)
776 case BuiltinTypeSpec.Type.Short:
777 if (value >= Int16.MinValue && value <= Int16.MaxValue)
780 case BuiltinTypeSpec.Type.UShort:
781 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
784 case BuiltinTypeSpec.Type.UInt:
788 case BuiltinTypeSpec.Type.ULong:
790 // we can optimize this case: a positive int32
791 // always fits on a uint64. But we need an opcode
801 if (expr is LongConstant && target_type.BuiltinType == BuiltinTypeSpec.Type.ULong){
803 // Try the implicit constant expression conversion
804 // from long to ulong, instead of a nice routine,
807 long v = ((LongConstant) expr).Value;
812 if (expr is IntegralConstant && target_type.IsEnum) {
813 var i = (IntegralConstant) expr;
815 // LAMESPEC: csc allows any constant like 0 values to be converted, including const float f = 0.0
817 // An implicit enumeration conversion permits the decimal-integer-literal 0
818 // to be converted to any enum-type and to any nullable-type whose underlying
819 // type is an enum-type
821 return i.IsZeroInteger;
825 // Implicit dynamic conversion for remaining value types. It should probably
828 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
829 switch (target_type.Kind) {
830 case MemberKind.Struct:
831 case MemberKind.Enum:
839 // In an unsafe context implicit conversions is extended to include
841 // From any pointer-type to the type void*
842 // From the null literal to any pointer-type.
844 // LAMESPEC: The specification claims this conversion is allowed in implicit conversion but
845 // in reality implicit standard conversion uses it
847 if (target_type.IsPointer && expr.Type.IsPointer && ((PointerContainer) target_type).Element.Kind == MemberKind.Void)
851 // Struct identity conversion, including dynamic erasure
853 if (expr_type.IsStruct && TypeSpecComparer.IsEqual (expr_type, target_type))
860 /// Finds "most encompassed type" according to the spec (13.4.2)
861 /// amongst the methods in the MethodGroupExpr
863 public static TypeSpec FindMostEncompassedType (IList<TypeSpec> types)
865 TypeSpec best = null;
866 EmptyExpression expr;
868 foreach (TypeSpec t in types) {
874 expr = new EmptyExpression (t);
875 if (ImplicitStandardConversionExists (expr, best))
879 expr = new EmptyExpression (best);
880 foreach (TypeSpec t in types) {
883 if (!ImplicitStandardConversionExists (expr, t)) {
893 // Finds the most encompassing type (type into which all other
894 // types can convert to) amongst the types in the given set
896 static TypeSpec FindMostEncompassingType (IList<TypeSpec> types)
898 if (types.Count == 0)
901 if (types.Count == 1)
904 TypeSpec best = null;
905 for (int i = 0; i < types.Count; ++i) {
907 for (; ii < types.Count; ++ii) {
911 var expr = new EmptyExpression (types[ii]);
912 if (!ImplicitStandardConversionExists (expr, types [i])) {
926 // Indicates multiple best types
927 return InternalType.FakeInternalType;
934 // Finds the most specific source Sx according to the rules of the spec (13.4.4)
935 // by making use of FindMostEncomp* methods. Applies the correct rules separately
936 // for explicit and implicit conversion operators.
938 static TypeSpec FindMostSpecificSource (ResolveContext rc, List<MethodSpec> list, TypeSpec sourceType, Expression source, bool apply_explicit_conv_rules)
940 TypeSpec[] src_types_set = null;
943 // Try exact match first, if any operator converts from S then Sx = S
945 for (int i = 0; i < list.Count; ++i) {
946 TypeSpec param_type = list [i].Parameters.Types [0];
948 if (param_type == sourceType)
951 if (src_types_set == null)
952 src_types_set = new TypeSpec [list.Count];
954 src_types_set [i] = param_type;
958 // Explicit Conv rules
960 if (apply_explicit_conv_rules) {
961 var candidate_set = new List<TypeSpec> ();
963 foreach (TypeSpec param_type in src_types_set){
964 if (ImplicitStandardConversionExists (rc, source, param_type))
965 candidate_set.Add (param_type);
968 if (candidate_set.Count != 0) {
969 if (source.eclass == ExprClass.MethodGroup)
970 return InternalType.FakeInternalType;
972 return FindMostEncompassedType (candidate_set);
979 if (apply_explicit_conv_rules)
980 return FindMostEncompassingType (src_types_set);
982 return FindMostEncompassedType (src_types_set);
986 /// Finds the most specific target Tx according to section 13.4.4
988 static public TypeSpec FindMostSpecificTarget (IList<MethodSpec> list,
989 TypeSpec target, bool apply_explicit_conv_rules)
991 List<TypeSpec> tgt_types_set = null;
994 // If any operator converts to T then Tx = T
996 foreach (var mi in list){
997 TypeSpec ret_type = mi.ReturnType;
998 if (ret_type == target)
1001 if (tgt_types_set == null) {
1002 tgt_types_set = new List<TypeSpec> (list.Count);
1003 } else if (tgt_types_set.Contains (ret_type)) {
1007 tgt_types_set.Add (ret_type);
1011 // Explicit conv rules
1013 if (apply_explicit_conv_rules) {
1014 var candidate_set = new List<TypeSpec> ();
1016 foreach (TypeSpec ret_type in tgt_types_set) {
1017 var expr = new EmptyExpression (ret_type);
1019 if (ImplicitStandardConversionExists (expr, target))
1020 candidate_set.Add (ret_type);
1023 if (candidate_set.Count != 0)
1024 return FindMostEncompassingType (candidate_set);
1028 // Okay, final case !
1030 if (apply_explicit_conv_rules)
1031 return FindMostEncompassedType (tgt_types_set);
1033 return FindMostEncompassingType (tgt_types_set);
1037 /// User-defined Implicit conversions
1039 static public Expression ImplicitUserConversion (ResolveContext ec, Expression source, TypeSpec target, Location loc)
1041 return UserDefinedConversion (ec, source, target, UserConversionRestriction.ImplicitOnly, loc);
1045 /// User-defined Explicit conversions
1047 static Expression ExplicitUserConversion (ResolveContext ec, Expression source, TypeSpec target, Location loc)
1049 return UserDefinedConversion (ec, source, target, 0, loc);
1052 static void FindApplicableUserDefinedConversionOperators (ResolveContext rc, IList<MemberSpec> operators, Expression source, TypeSpec target, UserConversionRestriction restr, ref List<MethodSpec> candidates)
1054 if (source.Type.IsInterface) {
1055 // Neither A nor B are interface-types
1059 // For a conversion operator to be applicable, it must be possible
1060 // to perform a standard conversion from the source type to
1061 // the operand type of the operator, and it must be possible
1062 // to perform a standard conversion from the result type of
1063 // the operator to the target type.
1065 Expression texpr = null;
1067 foreach (MethodSpec op in operators) {
1069 // Can be null because MemberCache.GetUserOperator does not resize the array
1073 var t = op.Parameters.Types[0];
1074 if (source.Type != t && !ImplicitStandardConversionExists (rc, source, t)) {
1075 if ((restr & UserConversionRestriction.ImplicitOnly) != 0)
1078 if (!ImplicitStandardConversionExists (new EmptyExpression (t), source.Type))
1082 if ((restr & UserConversionRestriction.NullableSourceOnly) != 0 && !t.IsNullableType)
1091 if (t.IsNullableType)
1092 t = Nullable.NullableInfo.GetUnderlyingType (t);
1094 if (!ImplicitStandardConversionExists (new EmptyExpression (t), target)) {
1095 if ((restr & UserConversionRestriction.ImplicitOnly) != 0)
1099 texpr = new EmptyExpression (target);
1101 if (!ImplicitStandardConversionExists (texpr, t))
1106 if (candidates == null)
1107 candidates = new List<MethodSpec> ();
1109 candidates.Add (op);
1114 // User-defined conversions
1116 public static Expression UserDefinedConversion (ResolveContext rc, Expression source, TypeSpec target, UserConversionRestriction restr, Location loc)
1118 List<MethodSpec> candidates = null;
1121 // If S or T are nullable types, source_type and target_type are their underlying types
1122 // otherwise source_type and target_type are equal to S and T respectively.
1124 TypeSpec source_type = source.Type;
1125 TypeSpec target_type = target;
1126 Expression source_type_expr;
1127 bool nullable_source = false;
1128 var implicitOnly = (restr & UserConversionRestriction.ImplicitOnly) != 0;
1130 if (source_type.IsNullableType) {
1131 // No unwrapping conversion S? -> T for non-reference types
1132 if (implicitOnly && !TypeSpec.IsReferenceType (target_type) && !target_type.IsNullableType) {
1133 source_type_expr = source;
1135 source_type_expr = Nullable.Unwrap.CreateUnwrapped (source);
1136 source_type = source_type_expr.Type;
1137 nullable_source = true;
1140 source_type_expr = source;
1143 if (target_type.IsNullableType)
1144 target_type = Nullable.NullableInfo.GetUnderlyingType (target_type);
1146 // Only these containers can contain a user defined implicit or explicit operators
1147 const MemberKind user_conversion_kinds = MemberKind.Class | MemberKind.Struct | MemberKind.TypeParameter;
1149 if ((source_type.Kind & user_conversion_kinds) != 0 && source_type.BuiltinType != BuiltinTypeSpec.Type.Decimal) {
1150 bool declared_only = source_type.IsStruct;
1152 var operators = MemberCache.GetUserOperator (source_type, Operator.OpType.Implicit, declared_only);
1153 if (operators != null) {
1154 FindApplicableUserDefinedConversionOperators (rc, operators, source_type_expr, target_type, restr, ref candidates);
1157 if (!implicitOnly) {
1158 operators = MemberCache.GetUserOperator (source_type, Operator.OpType.Explicit, declared_only);
1159 if (operators != null) {
1160 FindApplicableUserDefinedConversionOperators (rc, operators, source_type_expr, target_type, restr, ref candidates);
1165 if ((target.Kind & user_conversion_kinds) != 0 && target_type.BuiltinType != BuiltinTypeSpec.Type.Decimal) {
1166 bool declared_only = target.IsStruct || implicitOnly;
1168 var operators = MemberCache.GetUserOperator (target_type, Operator.OpType.Implicit, declared_only);
1169 if (operators != null) {
1170 FindApplicableUserDefinedConversionOperators (rc, operators, source_type_expr, target_type, restr, ref candidates);
1173 if (!implicitOnly) {
1174 operators = MemberCache.GetUserOperator (target_type, Operator.OpType.Explicit, declared_only);
1175 if (operators != null) {
1176 FindApplicableUserDefinedConversionOperators (rc, operators, source_type_expr, target_type, restr, ref candidates);
1181 if (candidates == null)
1185 // Find the most specific conversion operator
1187 MethodSpec most_specific_operator;
1189 if (candidates.Count == 1) {
1190 most_specific_operator = candidates[0];
1191 s_x = most_specific_operator.Parameters.Types[0];
1192 t_x = most_specific_operator.ReturnType;
1195 // Pass original source type to find the best match against input type and
1196 // not the unwrapped expression
1198 s_x = FindMostSpecificSource (rc, candidates, source.Type, source_type_expr, !implicitOnly);
1202 t_x = FindMostSpecificTarget (candidates, target, !implicitOnly);
1206 most_specific_operator = null;
1207 for (int i = 0; i < candidates.Count; ++i) {
1208 if (candidates[i].ReturnType == t_x && candidates[i].Parameters.Types[0] == s_x) {
1209 most_specific_operator = candidates[i];
1214 if (most_specific_operator == null) {
1216 // Unless running in probing more
1218 if ((restr & UserConversionRestriction.ProbingOnly) == 0) {
1219 MethodSpec ambig_arg = candidates [0];
1220 most_specific_operator = candidates [1];
1222 foreach (var candidate in candidates) {
1223 if (candidate.ReturnType == t_x)
1224 most_specific_operator = candidate;
1225 else if (candidate.Parameters.Types[0] == s_x)
1226 ambig_arg = candidate;
1229 rc.Report.Error (457, loc,
1230 "Ambiguous user defined operators `{0}' and `{1}' when converting from `{2}' to `{3}'",
1231 ambig_arg.GetSignatureForError (), most_specific_operator.GetSignatureForError (),
1232 source.Type.GetSignatureForError (), target.GetSignatureForError ());
1235 return ErrorExpression.Instance;
1240 // Convert input type when it's different to best operator argument
1242 if (s_x != source_type) {
1243 var c = source as Constant;
1245 source = c.Reduce (rc, s_x);
1251 source = implicitOnly ?
1252 ImplicitConversionStandard (rc, source_type_expr, s_x, loc) :
1253 ExplicitConversionStandard (rc, source_type_expr, s_x, loc);
1256 source = source_type_expr;
1259 source = new UserCast (most_specific_operator, source, loc).Resolve (rc);
1262 // Convert result type when it's different to best operator return type
1264 if (t_x != target_type) {
1266 // User operator is of T?
1268 if (t_x.IsNullableType && (target.IsNullableType || !implicitOnly)) {
1270 // User operator return type does not match target type we need
1271 // yet another conversion. This should happen for promoted numeric
1274 if (t_x != target) {
1275 var unwrap = Nullable.Unwrap.CreateUnwrapped (source);
1277 source = implicitOnly ?
1278 ImplicitConversionStandard (rc, unwrap, target_type, loc) :
1279 ExplicitConversionStandard (rc, unwrap, target_type, loc);
1284 if (target.IsNullableType)
1285 source = new Nullable.LiftedConversion (source, unwrap, target).Resolve (rc);
1288 source = implicitOnly ?
1289 ImplicitConversionStandard (rc, source, target_type, loc) :
1290 ExplicitConversionStandard (rc, source, target_type, loc);
1299 // Source expression is of nullable type and underlying conversion returns
1300 // only non-nullable type we need to lift it manually
1302 if (nullable_source && !s_x.IsNullableType)
1303 return new Nullable.LiftedConversion (source, source_type_expr, target).Resolve (rc);
1306 // Target is of nullable type but source type is not, wrap the result expression
1308 if (target.IsNullableType && !t_x.IsNullableType)
1309 source = Nullable.Wrap.Create (source, target);
1315 /// Converts implicitly the resolved expression `expr' into the
1316 /// `target_type'. It returns a new expression that can be used
1317 /// in a context that expects a `target_type'.
1319 static public Expression ImplicitConversion (ResolveContext ec, Expression expr,
1320 TypeSpec target_type, Location loc)
1324 if (target_type == null)
1325 throw new Exception ("Target type is null");
1327 e = ImplicitConversionStandard (ec, expr, target_type, loc);
1331 e = ImplicitUserConversion (ec, expr, target_type, loc);
1340 /// Attempts to apply the `Standard Implicit
1341 /// Conversion' rules to the expression `expr' into
1342 /// the `target_type'. It returns a new expression
1343 /// that can be used in a context that expects a
1346 /// This is different from `ImplicitConversion' in that the
1347 /// user defined implicit conversions are excluded.
1349 static public Expression ImplicitConversionStandard (ResolveContext ec, Expression expr,
1350 TypeSpec target_type, Location loc)
1352 return ImplicitConversionStandard (ec, expr, target_type, loc, false);
1355 static Expression ImplicitConversionStandard (ResolveContext ec, Expression expr, TypeSpec target_type, Location loc, bool explicit_cast)
1357 if (expr.eclass == ExprClass.MethodGroup){
1358 if (!target_type.IsDelegate){
1363 // Only allow anonymous method conversions on post ISO_1
1365 if (ec.Module.Compiler.Settings.Version != LanguageVersion.ISO_1){
1366 MethodGroupExpr mg = expr as MethodGroupExpr;
1368 return new ImplicitDelegateCreation (target_type, mg, loc).Resolve (ec);
1372 TypeSpec expr_type = expr.Type;
1375 if (expr_type == target_type) {
1376 if (expr_type != InternalType.NullLiteral && expr_type != InternalType.AnonymousMethod && expr_type != InternalType.ThrowExpr)
1381 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1382 switch (target_type.Kind) {
1383 case MemberKind.ArrayType:
1384 case MemberKind.Class:
1385 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Object)
1386 return EmptyCast.Create (expr, target_type);
1388 goto case MemberKind.Struct;
1389 case MemberKind.Struct:
1390 case MemberKind.Delegate:
1391 case MemberKind.Enum:
1392 case MemberKind.Interface:
1393 case MemberKind.TypeParameter:
1394 Arguments args = new Arguments (1);
1395 args.Add (new Argument (expr));
1396 return new DynamicConversion (target_type, explicit_cast ? CSharpBinderFlags.ConvertExplicit : 0, args, loc).Resolve (ec);
1402 if (expr_type == InternalType.ThrowExpr) {
1403 return target_type.Kind == MemberKind.InternalCompilerType ? null : EmptyCast.Create (expr, target_type);
1406 if (target_type.IsNullableType)
1407 return ImplicitNulableConversion (ec, expr, target_type);
1410 // Attempt to do the implicit constant expression conversions
1412 Constant c = expr as Constant;
1415 c = c.ConvertImplicitly (target_type);
1417 throw new InternalErrorException ("Conversion error", loc);
1423 e = ImplicitNumericConversion (expr, expr_type, target_type);
1427 e = ImplicitReferenceConversion (expr, target_type, explicit_cast);
1431 e = ImplicitBoxingConversion (expr, expr_type, target_type);
1435 if (expr is IntegralConstant && target_type.IsEnum){
1436 var i = (IntegralConstant) expr;
1438 // LAMESPEC: csc allows any constant like 0 values to be converted, including const float f = 0.0
1440 // An implicit enumeration conversion permits the decimal-integer-literal 0
1441 // to be converted to any enum-type and to any nullable-type whose underlying
1442 // type is an enum-type
1444 if (i.IsZeroInteger) {
1445 // Recreate 0 literal to remove any collected conversions
1446 return new EnumConstant (new IntLiteral (ec.BuiltinTypes, 0, i.Location), target_type);
1450 var target_pc = target_type as PointerContainer;
1451 if (target_pc != null) {
1452 if (expr_type.IsPointer) {
1454 // Pointer types are same when they have same element types
1456 if (expr_type == target_pc)
1459 if (target_pc.Element.Kind == MemberKind.Void)
1460 return EmptyCast.Create (expr, target_type);
1465 if (expr_type == InternalType.NullLiteral)
1466 return new NullPointer (target_type, loc);
1469 if (expr_type == InternalType.AnonymousMethod){
1470 AnonymousMethodExpression ame = (AnonymousMethodExpression) expr;
1471 Expression am = ame.Compatible (ec, target_type);
1473 return am.Resolve (ec);
1475 // Avoid CS1503 after CS1661
1476 return ErrorExpression.Instance;
1479 if (expr_type == InternalType.Arglist && target_type == ec.Module.PredefinedTypes.ArgIterator.TypeSpec)
1483 // dynamic erasure conversion on value types
1485 if (expr_type.IsStruct && TypeSpecComparer.IsEqual (expr_type, target_type))
1486 return expr_type == target_type ? expr : EmptyCast.Create (expr, target_type);
1488 var interpolated_string = expr as InterpolatedString;
1489 if (interpolated_string != null) {
1490 if (target_type == ec.Module.PredefinedTypes.IFormattable.TypeSpec || target_type == ec.Module.PredefinedTypes.FormattableString.TypeSpec)
1491 return interpolated_string.ConvertTo (ec, target_type);
1498 /// Attempts to implicitly convert `source' into `target_type', using
1499 /// ImplicitConversion. If there is no implicit conversion, then
1500 /// an error is signaled
1502 static public Expression ImplicitConversionRequired (ResolveContext ec, Expression source,
1503 TypeSpec target_type, Location loc)
1505 Expression e = ImplicitConversion (ec, source, target_type, loc);
1509 source.Error_ValueCannotBeConverted (ec, target_type, false);
1515 /// Performs the explicit numeric conversions
1517 /// There are a few conversions that are not part of the C# standard,
1518 /// they were interim hacks in the C# compiler that were supposed to
1519 /// become explicit operators in the UIntPtr class and IntPtr class,
1520 /// but for historical reasons it did not happen, so the C# compiler
1521 /// ended up with these special hacks.
1523 /// See bug 59800 for details.
1525 /// The conversion are:
1535 public static Expression ExplicitNumericConversion (ResolveContext rc, Expression expr, TypeSpec target_type)
1537 // Not all predefined explicit numeric conversion are
1538 // defined here, for some of them (mostly IntPtr/UIntPtr) we
1539 // defer to user-operator handling which is now perfect but
1542 // LAMESPEC: Undocumented IntPtr/UIntPtr conversions
1543 // IntPtr -> uint uses int
1544 // UIntPtr -> long uses ulong
1547 switch (expr.Type.BuiltinType) {
1548 case BuiltinTypeSpec.Type.SByte:
1550 // From sbyte to byte, ushort, uint, ulong, char, uintptr
1552 switch (target_type.BuiltinType) {
1553 case BuiltinTypeSpec.Type.Byte:
1554 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U1);
1555 case BuiltinTypeSpec.Type.UShort:
1556 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U2);
1557 case BuiltinTypeSpec.Type.UInt:
1558 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U4);
1559 case BuiltinTypeSpec.Type.ULong:
1560 return new ConvCast (expr, target_type, ConvCast.Mode.I1_U8);
1561 case BuiltinTypeSpec.Type.Char:
1562 return new ConvCast (expr, target_type, ConvCast.Mode.I1_CH);
1564 // One of the built-in conversions that belonged in the class library
1565 case BuiltinTypeSpec.Type.UIntPtr:
1566 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I1_U8), target_type, target_type, true);
1569 case BuiltinTypeSpec.Type.Byte:
1571 // From byte to sbyte and char
1573 switch (target_type.BuiltinType) {
1574 case BuiltinTypeSpec.Type.SByte:
1575 return new ConvCast (expr, target_type, ConvCast.Mode.U1_I1);
1576 case BuiltinTypeSpec.Type.Char:
1577 return new ConvCast (expr, target_type, ConvCast.Mode.U1_CH);
1580 case BuiltinTypeSpec.Type.Short:
1582 // From short to sbyte, byte, ushort, uint, ulong, char, uintptr
1584 switch (target_type.BuiltinType) {
1585 case BuiltinTypeSpec.Type.SByte:
1586 return new ConvCast (expr, target_type, ConvCast.Mode.I2_I1);
1587 case BuiltinTypeSpec.Type.Byte:
1588 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U1);
1589 case BuiltinTypeSpec.Type.UShort:
1590 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U2);
1591 case BuiltinTypeSpec.Type.UInt:
1592 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U4);
1593 case BuiltinTypeSpec.Type.ULong:
1594 return new ConvCast (expr, target_type, ConvCast.Mode.I2_U8);
1595 case BuiltinTypeSpec.Type.Char:
1596 return new ConvCast (expr, target_type, ConvCast.Mode.I2_CH);
1598 // One of the built-in conversions that belonged in the class library
1599 case BuiltinTypeSpec.Type.UIntPtr:
1600 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I2_U8), target_type, target_type, true);
1603 case BuiltinTypeSpec.Type.UShort:
1605 // From ushort to sbyte, byte, short, char
1607 switch (target_type.BuiltinType) {
1608 case BuiltinTypeSpec.Type.SByte:
1609 return new ConvCast (expr, target_type, ConvCast.Mode.U2_I1);
1610 case BuiltinTypeSpec.Type.Byte:
1611 return new ConvCast (expr, target_type, ConvCast.Mode.U2_U1);
1612 case BuiltinTypeSpec.Type.Short:
1613 return new ConvCast (expr, target_type, ConvCast.Mode.U2_I2);
1614 case BuiltinTypeSpec.Type.Char:
1615 return new ConvCast (expr, target_type, ConvCast.Mode.U2_CH);
1618 case BuiltinTypeSpec.Type.Int:
1620 // From int to sbyte, byte, short, ushort, uint, ulong, char, uintptr
1622 switch (target_type.BuiltinType) {
1623 case BuiltinTypeSpec.Type.SByte:
1624 return new ConvCast (expr, target_type, ConvCast.Mode.I4_I1);
1625 case BuiltinTypeSpec.Type.Byte:
1626 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U1);
1627 case BuiltinTypeSpec.Type.Short:
1628 return new ConvCast (expr, target_type, ConvCast.Mode.I4_I2);
1629 case BuiltinTypeSpec.Type.UShort:
1630 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U2);
1631 case BuiltinTypeSpec.Type.UInt:
1632 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U4);
1633 case BuiltinTypeSpec.Type.ULong:
1634 return new ConvCast (expr, target_type, ConvCast.Mode.I4_U8);
1635 case BuiltinTypeSpec.Type.Char:
1636 return new ConvCast (expr, target_type, ConvCast.Mode.I4_CH);
1638 // One of the built-in conversions that belonged in the class library
1639 case BuiltinTypeSpec.Type.UIntPtr:
1640 return new OperatorCast (new ConvCast (expr, rc.BuiltinTypes.ULong, ConvCast.Mode.I2_U8), target_type, target_type, true);
1643 case BuiltinTypeSpec.Type.UInt:
1645 // From uint to sbyte, byte, short, ushort, int, char
1647 switch (target_type.BuiltinType) {
1648 case BuiltinTypeSpec.Type.SByte:
1649 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I1);
1650 case BuiltinTypeSpec.Type.Byte:
1651 return new ConvCast (expr, target_type, ConvCast.Mode.U4_U1);
1652 case BuiltinTypeSpec.Type.Short:
1653 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I2);
1654 case BuiltinTypeSpec.Type.UShort:
1655 return new ConvCast (expr, target_type, ConvCast.Mode.U4_U2);
1656 case BuiltinTypeSpec.Type.Int:
1657 return new ConvCast (expr, target_type, ConvCast.Mode.U4_I4);
1658 case BuiltinTypeSpec.Type.Char:
1659 return new ConvCast (expr, target_type, ConvCast.Mode.U4_CH);
1662 case BuiltinTypeSpec.Type.Long:
1664 // From long to sbyte, byte, short, ushort, int, uint, ulong, char
1666 switch (target_type.BuiltinType) {
1667 case BuiltinTypeSpec.Type.SByte:
1668 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I1);
1669 case BuiltinTypeSpec.Type.Byte:
1670 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U1);
1671 case BuiltinTypeSpec.Type.Short:
1672 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I2);
1673 case BuiltinTypeSpec.Type.UShort:
1674 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U2);
1675 case BuiltinTypeSpec.Type.Int:
1676 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I4);
1677 case BuiltinTypeSpec.Type.UInt:
1678 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U4);
1679 case BuiltinTypeSpec.Type.ULong:
1680 return new ConvCast (expr, target_type, ConvCast.Mode.I8_U8);
1681 case BuiltinTypeSpec.Type.Char:
1682 return new ConvCast (expr, target_type, ConvCast.Mode.I8_CH);
1685 case BuiltinTypeSpec.Type.ULong:
1687 // From ulong to sbyte, byte, short, ushort, int, uint, long, char
1689 switch (target_type.BuiltinType) {
1690 case BuiltinTypeSpec.Type.SByte:
1691 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I1);
1692 case BuiltinTypeSpec.Type.Byte:
1693 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U1);
1694 case BuiltinTypeSpec.Type.Short:
1695 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I2);
1696 case BuiltinTypeSpec.Type.UShort:
1697 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U2);
1698 case BuiltinTypeSpec.Type.Int:
1699 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I4);
1700 case BuiltinTypeSpec.Type.UInt:
1701 return new ConvCast (expr, target_type, ConvCast.Mode.U8_U4);
1702 case BuiltinTypeSpec.Type.Long:
1703 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I8);
1704 case BuiltinTypeSpec.Type.Char:
1705 return new ConvCast (expr, target_type, ConvCast.Mode.U8_CH);
1707 // One of the built-in conversions that belonged in the class library
1708 case BuiltinTypeSpec.Type.IntPtr:
1709 return new OperatorCast (EmptyCast.Create (expr, rc.BuiltinTypes.Long), target_type, true);
1712 case BuiltinTypeSpec.Type.Char:
1714 // From char to sbyte, byte, short
1716 switch (target_type.BuiltinType) {
1717 case BuiltinTypeSpec.Type.SByte:
1718 return new ConvCast (expr, target_type, ConvCast.Mode.CH_I1);
1719 case BuiltinTypeSpec.Type.Byte:
1720 return new ConvCast (expr, target_type, ConvCast.Mode.CH_U1);
1721 case BuiltinTypeSpec.Type.Short:
1722 return new ConvCast (expr, target_type, ConvCast.Mode.CH_I2);
1725 case BuiltinTypeSpec.Type.Float:
1727 // From float to sbyte, byte, short,
1728 // ushort, int, uint, long, ulong, char
1731 switch (target_type.BuiltinType) {
1732 case BuiltinTypeSpec.Type.SByte:
1733 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I1);
1734 case BuiltinTypeSpec.Type.Byte:
1735 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U1);
1736 case BuiltinTypeSpec.Type.Short:
1737 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I2);
1738 case BuiltinTypeSpec.Type.UShort:
1739 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U2);
1740 case BuiltinTypeSpec.Type.Int:
1741 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I4);
1742 case BuiltinTypeSpec.Type.UInt:
1743 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U4);
1744 case BuiltinTypeSpec.Type.Long:
1745 return new ConvCast (expr, target_type, ConvCast.Mode.R4_I8);
1746 case BuiltinTypeSpec.Type.ULong:
1747 return new ConvCast (expr, target_type, ConvCast.Mode.R4_U8);
1748 case BuiltinTypeSpec.Type.Char:
1749 return new ConvCast (expr, target_type, ConvCast.Mode.R4_CH);
1750 case BuiltinTypeSpec.Type.Decimal:
1751 return new OperatorCast (expr, target_type, true);
1754 case BuiltinTypeSpec.Type.Double:
1756 // From double to sbyte, byte, short,
1757 // ushort, int, uint, long, ulong,
1758 // char, float or decimal
1760 switch (target_type.BuiltinType) {
1761 case BuiltinTypeSpec.Type.SByte:
1762 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I1);
1763 case BuiltinTypeSpec.Type.Byte:
1764 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U1);
1765 case BuiltinTypeSpec.Type.Short:
1766 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I2);
1767 case BuiltinTypeSpec.Type.UShort:
1768 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U2);
1769 case BuiltinTypeSpec.Type.Int:
1770 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I4);
1771 case BuiltinTypeSpec.Type.UInt:
1772 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U4);
1773 case BuiltinTypeSpec.Type.Long:
1774 return new ConvCast (expr, target_type, ConvCast.Mode.R8_I8);
1775 case BuiltinTypeSpec.Type.ULong:
1776 return new ConvCast (expr, target_type, ConvCast.Mode.R8_U8);
1777 case BuiltinTypeSpec.Type.Char:
1778 return new ConvCast (expr, target_type, ConvCast.Mode.R8_CH);
1779 case BuiltinTypeSpec.Type.Float:
1780 return new ConvCast (expr, target_type, ConvCast.Mode.R8_R4);
1781 case BuiltinTypeSpec.Type.Decimal:
1782 return new OperatorCast (expr, target_type, true);
1785 case BuiltinTypeSpec.Type.UIntPtr:
1787 // Various built-in conversions that belonged in the class library
1789 // from uintptr to sbyte, short, int32
1791 switch (target_type.BuiltinType) {
1792 case BuiltinTypeSpec.Type.SByte:
1793 return new ConvCast (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type, ConvCast.Mode.U4_I1);
1794 case BuiltinTypeSpec.Type.Short:
1795 return new ConvCast (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type, ConvCast.Mode.U4_I2);
1796 case BuiltinTypeSpec.Type.Int:
1797 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.UInt, true), target_type);
1798 case BuiltinTypeSpec.Type.UInt:
1799 return new OperatorCast (expr, expr.Type, target_type, true);
1800 case BuiltinTypeSpec.Type.Long:
1801 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.ULong, true), target_type);
1804 case BuiltinTypeSpec.Type.IntPtr:
1805 if (target_type.BuiltinType == BuiltinTypeSpec.Type.UInt)
1806 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.Int, true), target_type);
1807 if (target_type.BuiltinType == BuiltinTypeSpec.Type.ULong)
1808 return EmptyCast.Create (new OperatorCast (expr, expr.Type, rc.BuiltinTypes.Long, true), target_type);
1811 case BuiltinTypeSpec.Type.Decimal:
1812 // From decimal to sbyte, byte, short,
1813 // ushort, int, uint, long, ulong, char,
1815 switch (target_type.BuiltinType) {
1816 case BuiltinTypeSpec.Type.SByte:
1817 case BuiltinTypeSpec.Type.Byte:
1818 case BuiltinTypeSpec.Type.Short:
1819 case BuiltinTypeSpec.Type.UShort:
1820 case BuiltinTypeSpec.Type.Int:
1821 case BuiltinTypeSpec.Type.UInt:
1822 case BuiltinTypeSpec.Type.Long:
1823 case BuiltinTypeSpec.Type.ULong:
1824 case BuiltinTypeSpec.Type.Char:
1825 case BuiltinTypeSpec.Type.Float:
1826 case BuiltinTypeSpec.Type.Double:
1827 return new OperatorCast (expr, expr.Type, target_type, true);
1837 /// Returns whether an explicit reference conversion can be performed
1838 /// from source_type to target_type
1840 public static bool ExplicitReferenceConversionExists (TypeSpec source_type, TypeSpec target_type)
1842 Expression e = ExplicitReferenceConversion (null, source_type, target_type);
1846 if (e == EmptyExpression.Null)
1849 throw new InternalErrorException ("Invalid probing conversion result");
1853 /// Implements Explicit Reference conversions
1855 static Expression ExplicitReferenceConversion (Expression source, TypeSpec source_type, TypeSpec target_type)
1858 // From object to a generic parameter
1860 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Object && TypeManager.IsGenericParameter (target_type))
1861 return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
1864 // Explicit type parameter conversion from T
1866 if (source_type.Kind == MemberKind.TypeParameter)
1867 return ExplicitTypeParameterConversionFromT (source, source_type, target_type);
1869 bool target_is_value_type = target_type.Kind == MemberKind.Struct || target_type.Kind == MemberKind.Enum;
1872 // Unboxing conversion from System.ValueType to any non-nullable-value-type
1874 if (source_type.BuiltinType == BuiltinTypeSpec.Type.ValueType && target_is_value_type)
1875 return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
1878 // From object or dynamic to any reference type or value type (unboxing)
1880 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Object || source_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1881 if (target_type.IsPointer)
1885 source == null ? EmptyExpression.Null :
1886 target_is_value_type ? new UnboxCast (source, target_type) :
1887 source is Constant ? (Expression) new EmptyConstantCast ((Constant) source, target_type) :
1888 new ClassCast (source, target_type);
1892 // From any class S to any class-type T, provided S is a base class of T
1894 if (source_type.Kind == MemberKind.Class && TypeSpec.IsBaseClass (target_type, source_type, true))
1895 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1898 // From any interface-type S to to any class type T, provided T is not
1899 // sealed, or provided T implements S.
1901 // This also covers Explicit conversions involving type parameters
1902 // section From any interface type to T
1904 if (source_type.Kind == MemberKind.Interface) {
1905 if (!target_type.IsSealed || target_type.ImplementsInterface (source_type, true)) {
1907 return EmptyExpression.Null;
1910 // Unboxing conversion from any interface-type to any non-nullable-value-type that
1911 // implements the interface-type
1913 return target_is_value_type ? new UnboxCast (source, target_type) : (Expression) new ClassCast (source, target_type);
1917 // From System.Collections.Generic.IList<T> and its base interfaces to a one-dimensional
1918 // array type S[], provided there is an implicit or explicit reference conversion from S to T.
1920 var target_array = target_type as ArrayContainer;
1921 if (target_array != null && IList_To_Array (source_type, target_array))
1922 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1927 var source_array = source_type as ArrayContainer;
1928 if (source_array != null) {
1929 var target_array = target_type as ArrayContainer;
1930 if (target_array != null) {
1932 // From System.Array to any array-type
1934 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Array)
1935 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1938 // From an array type S with an element type Se to an array type T with an
1939 // element type Te provided all the following are true:
1940 // * S and T differe only in element type, in other words, S and T
1941 // have the same number of dimensions.
1942 // * Both Se and Te are reference types
1943 // * An explicit reference conversions exist from Se to Te
1945 if (source_array.Rank == target_array.Rank) {
1947 source_type = source_array.Element;
1948 var target_element = target_array.Element;
1951 // LAMESPEC: Type parameters are special cased somehow but
1952 // only when both source and target elements are type parameters
1954 if ((source_type.Kind & target_element.Kind & MemberKind.TypeParameter) == MemberKind.TypeParameter) {
1956 // Conversion is allowed unless source element type has struct constrain
1958 if (TypeSpec.IsValueType (source_type))
1961 if (!TypeSpec.IsReferenceType (source_type))
1965 if (!TypeSpec.IsReferenceType (target_element))
1968 if (ExplicitReferenceConversionExists (source_type, target_element))
1969 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1976 // From a single-dimensional array type S[] to System.Collections.Generic.IList<T> and its base interfaces,
1977 // provided that there is an explicit reference conversion from S to T
1979 if (ArrayToIList (source_array, target_type, true))
1980 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1986 // From any class type S to any interface T, provides S is not sealed
1987 // and provided S does not implement T.
1989 if (target_type.IsInterface && !source_type.IsSealed && !source_type.ImplementsInterface (target_type, true)) {
1990 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
1994 // From System delegate to any delegate-type
1996 if (source_type.BuiltinType == BuiltinTypeSpec.Type.Delegate && target_type.IsDelegate)
1997 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
2000 // From variant generic delegate to same variant generic delegate type
2002 if (source_type.IsDelegate && target_type.IsDelegate && source_type.MemberDefinition == target_type.MemberDefinition) {
2003 var tparams = source_type.MemberDefinition.TypeParameters;
2004 var targs_src = source_type.TypeArguments;
2005 var targs_dst = target_type.TypeArguments;
2007 for (i = 0; i < tparams.Length; ++i) {
2009 // If TP is invariant, types have to be identical
2011 if (TypeSpecComparer.IsEqual (targs_src[i], targs_dst[i]))
2014 if (tparams[i].Variance == Variance.Covariant) {
2016 //If TP is covariant, an implicit or explicit identity or reference conversion is required
2018 if (ImplicitReferenceConversionExists (targs_src[i], targs_dst[i]))
2021 if (ExplicitReferenceConversionExists (targs_src[i], targs_dst[i]))
2024 } else if (tparams[i].Variance == Variance.Contravariant) {
2026 //If TP is contravariant, both are either identical or reference types
2028 if (TypeSpec.IsReferenceType (targs_src[i]) && TypeSpec.IsReferenceType (targs_dst[i]))
2035 if (i == tparams.Length)
2036 return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
2039 var tps = target_type as TypeParameterSpec;
2041 return ExplicitTypeParameterConversionToT (source, source_type, tps);
2047 /// Performs an explicit conversion of the expression `expr' whose
2048 /// type is expr.Type to `target_type'.
2050 static public Expression ExplicitConversionCore (ResolveContext ec, Expression expr,
2051 TypeSpec target_type, Location loc)
2053 TypeSpec expr_type = expr.Type;
2055 // Explicit conversion includes implicit conversion and it used for enum underlying types too
2056 Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc, true);
2060 if (expr_type.IsEnum) {
2061 TypeSpec real_target = target_type.IsEnum ? EnumSpec.GetUnderlyingType (target_type) : target_type;
2062 Expression underlying = EmptyCast.Create (expr, EnumSpec.GetUnderlyingType (expr_type));
2063 if (underlying.Type == real_target)
2067 ne = ImplicitNumericConversion (underlying, real_target);
2070 ne = ExplicitNumericConversion (ec, underlying, real_target);
2073 // LAMESPEC: IntPtr and UIntPtr conversion to any Enum is allowed
2075 if (ne == null && (real_target.BuiltinType == BuiltinTypeSpec.Type.IntPtr || real_target.BuiltinType == BuiltinTypeSpec.Type.UIntPtr))
2076 ne = ExplicitUserConversion (ec, underlying, real_target, loc);
2078 return ne != null ? EmptyCast.Create (ne, target_type) : null;
2081 if (target_type.IsEnum) {
2083 // System.Enum can be unboxed to any enum-type
2085 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Enum)
2086 return new UnboxCast (expr, target_type);
2088 TypeSpec real_target = target_type.IsEnum ? EnumSpec.GetUnderlyingType (target_type) : target_type;
2090 if (expr_type == real_target)
2091 return EmptyCast.Create (expr, target_type);
2093 Constant c = expr as Constant;
2095 c = c.TryReduce (ec, real_target);
2099 ne = ImplicitNumericConversion (expr, real_target);
2101 return EmptyCast.Create (ne, target_type);
2103 ne = ExplicitNumericConversion (ec, expr, real_target);
2105 return EmptyCast.Create (ne, target_type);
2108 // LAMESPEC: IntPtr and UIntPtr conversion to any Enum is allowed
2110 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.IntPtr || expr_type.BuiltinType == BuiltinTypeSpec.Type.UIntPtr) {
2111 ne = ExplicitUserConversion (ec, expr, real_target, loc);
2113 return ExplicitConversionCore (ec, ne, target_type, loc);
2117 ne = ExplicitNumericConversion (ec, expr, target_type);
2123 // Skip the ExplicitReferenceConversion because we can not convert
2124 // from Null to a ValueType, and ExplicitReference wont check against
2125 // null literal explicitly
2127 if (expr_type != InternalType.NullLiteral) {
2128 ne = ExplicitReferenceConversion (expr, expr_type, target_type);
2134 ne = ExplicitUnsafe (expr, target_type);
2142 public static Expression ExplicitUnsafe (Expression expr, TypeSpec target_type)
2144 TypeSpec expr_type = expr.Type;
2146 if (target_type.IsPointer){
2147 if (expr_type.IsPointer)
2148 return EmptyCast.Create (expr, target_type);
2150 switch (expr_type.BuiltinType) {
2151 case BuiltinTypeSpec.Type.SByte:
2152 case BuiltinTypeSpec.Type.Short:
2153 case BuiltinTypeSpec.Type.Int:
2154 return new OpcodeCast (expr, target_type, OpCodes.Conv_I);
2156 case BuiltinTypeSpec.Type.UShort:
2157 case BuiltinTypeSpec.Type.UInt:
2158 case BuiltinTypeSpec.Type.Byte:
2159 return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
2161 case BuiltinTypeSpec.Type.Long:
2162 return new ConvCast (expr, target_type, ConvCast.Mode.I8_I);
2164 case BuiltinTypeSpec.Type.ULong:
2165 return new ConvCast (expr, target_type, ConvCast.Mode.U8_I);
2169 if (expr_type.IsPointer){
2170 switch (target_type.BuiltinType) {
2171 case BuiltinTypeSpec.Type.SByte:
2172 return new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
2173 case BuiltinTypeSpec.Type.Byte:
2174 return new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
2175 case BuiltinTypeSpec.Type.Short:
2176 return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
2177 case BuiltinTypeSpec.Type.UShort:
2178 return new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
2179 case BuiltinTypeSpec.Type.Int:
2180 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
2181 case BuiltinTypeSpec.Type.UInt:
2182 return new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
2183 case BuiltinTypeSpec.Type.Long:
2184 return new ConvCast (expr, target_type, ConvCast.Mode.I_I8);
2185 case BuiltinTypeSpec.Type.ULong:
2186 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
2193 /// Same as ExplicitConversion, only it doesn't include user defined conversions
2195 static public Expression ExplicitConversionStandard (ResolveContext ec, Expression expr,
2196 TypeSpec target_type, Location l)
2198 int errors = ec.Report.Errors;
2199 Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
2200 if (ec.Report.Errors > errors)
2206 ne = ExplicitNumericConversion (ec, expr, target_type);
2210 ne = ExplicitReferenceConversion (expr, expr.Type, target_type);
2214 if (ec.IsUnsafe && expr.Type.IsPointer && target_type.IsPointer && ((PointerContainer)expr.Type).Element.Kind == MemberKind.Void)
2215 return EmptyCast.Create (expr, target_type);
2217 expr.Error_ValueCannotBeConverted (ec, target_type, true);
2222 /// Performs an explicit conversion of the expression `expr' whose
2223 /// type is expr.Type to `target_type'.
2225 static public Expression ExplicitConversion (ResolveContext ec, Expression expr,
2226 TypeSpec target_type, Location loc)
2228 Expression e = ExplicitConversionCore (ec, expr, target_type, loc);
2231 // Don't eliminate explicit precission casts
2234 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Float)
2235 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
2237 if (target_type.BuiltinType == BuiltinTypeSpec.Type.Double)
2238 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
2244 TypeSpec expr_type = expr.Type;
2245 if (target_type.IsNullableType) {
2248 if (expr_type.IsNullableType) {
2249 target = Nullable.NullableInfo.GetUnderlyingType (target_type);
2250 Expression unwrap = Nullable.Unwrap.Create (expr);
2251 e = ExplicitConversion (ec, unwrap, target, expr.Location);
2255 return new Nullable.LiftedConversion (e, unwrap, target_type).Resolve (ec);
2257 if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
2258 return new UnboxCast (expr, target_type);
2261 target = TypeManager.GetTypeArguments (target_type) [0];
2262 e = ExplicitConversionCore (ec, expr, target, loc);
2264 return TypeSpec.IsReferenceType (expr.Type) ? new UnboxCast (expr, target_type) : Nullable.Wrap.Create (e, target_type);
2265 } else if (expr_type.IsNullableType) {
2266 e = ImplicitBoxingConversion (expr, Nullable.NullableInfo.GetUnderlyingType (expr_type), target_type);
2270 e = Nullable.Unwrap.Create (expr, false);
2271 e = ExplicitConversionCore (ec, e, target_type, loc);
2273 return EmptyCast.Create (e, target_type);
2276 e = ExplicitUserConversion (ec, expr, target_type, loc);
2281 expr.Error_ValueCannotBeConverted (ec, target_type, true);