2 // conversion.cs: various routines for implementing conversions.
5 // Miguel de Icaza (miguel@ximian.com)
6 // Ravi Pratap (ravi@ximian.com)
8 // (C) 2001, 2002, 2003 Ximian, Inc.
11 namespace Mono.CSharp {
13 using System.Collections;
14 using System.Diagnostics;
15 using System.Reflection;
16 using System.Reflection.Emit;
19 // A container class for all the conversion operations
21 public class Convert {
22 static public void Error_CannotConvertType (Location loc, Type source, Type target)
24 Report.Error (30, loc, "Cannot convert type '" +
25 TypeManager.CSharpName (source) + "' to '" +
26 TypeManager.CSharpName (target) + "'");
29 static EmptyExpression MyEmptyExpr;
30 static public Expression ImplicitReferenceConversion (Expression expr, Type target_type)
32 Type expr_type = expr.Type;
34 if (expr_type == null && expr.eclass == ExprClass.MethodGroup){
35 // if we are a method group, emit a warning
40 if (expr_type == TypeManager.void_type)
44 // notice that it is possible to write "ValueType v = 1", the ValueType here
45 // is an abstract class, and not really a value type, so we apply the same rules.
47 if (target_type == TypeManager.object_type) {
49 // A pointer type cannot be converted to object
51 if (expr_type.IsPointer)
54 if (expr_type.IsValueType)
55 return new BoxedCast (expr);
56 if (expr_type.IsClass || expr_type.IsInterface || expr_type == TypeManager.enum_type)
57 return new EmptyCast (expr, target_type);
58 } else if (target_type == TypeManager.value_type) {
59 if (expr_type.IsValueType)
60 return new BoxedCast (expr);
61 if (expr is NullLiteral)
62 return new NullCast (expr, target_type);
63 } else if (expr_type.IsSubclassOf (target_type)) {
65 // Special case: enumeration to System.Enum.
66 // System.Enum is not a value type, it is a class, so we need
67 // a boxing conversion
70 return new BoxedCast (expr);
72 return new EmptyCast (expr, target_type);
75 // This code is kind of mirrored inside ImplicitStandardConversionExists
76 // with the small distinction that we only probe there
78 // Always ensure that the code here and there is in sync
80 // from the null type to any reference-type.
81 if (expr is NullLiteral){
82 if (target_type.IsPointer)
83 return NullPointer.Null;
85 if (!target_type.IsValueType)
86 return new NullCast (expr, target_type);
89 // from any class-type S to any interface-type T.
90 if (target_type.IsInterface) {
91 if (TypeManager.ImplementsInterface (expr_type, target_type)){
92 if (expr_type.IsClass)
93 return new EmptyCast (expr, target_type);
94 else if (expr_type.IsValueType || expr_type == TypeManager.enum_type)
95 return new BoxedCast (expr, target_type);
97 return new EmptyCast (expr, target_type);
101 // from any interface type S to interface-type T.
102 if (expr_type.IsInterface && target_type.IsInterface) {
103 if (TypeManager.ImplementsInterface (expr_type, target_type))
104 return new EmptyCast (expr, target_type);
109 // from an array-type S to an array-type of type T
110 if (expr_type.IsArray && target_type.IsArray) {
111 if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
113 Type expr_element_type = TypeManager.GetElementType (expr_type);
115 if (MyEmptyExpr == null)
116 MyEmptyExpr = new EmptyExpression ();
118 MyEmptyExpr.SetType (expr_element_type);
119 Type target_element_type = TypeManager.GetElementType (target_type);
121 if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
122 if (ImplicitStandardConversionExists (MyEmptyExpr,
123 target_element_type))
124 return new EmptyCast (expr, target_type);
129 // from an array-type to System.Array
130 if (expr_type.IsArray && target_type == TypeManager.array_type)
131 return new EmptyCast (expr, target_type);
133 // from any delegate type to System.Delegate
134 if ((expr_type == TypeManager.delegate_type ||
135 expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
136 target_type == TypeManager.delegate_type)
137 return new EmptyCast (expr, target_type);
139 // from any array-type or delegate type into System.ICloneable.
140 if (expr_type.IsArray ||
141 expr_type == TypeManager.delegate_type ||
142 expr_type.IsSubclassOf (TypeManager.delegate_type))
143 if (target_type == TypeManager.icloneable_type)
144 return new EmptyCast (expr, target_type);
154 // Tests whether an implicit reference conversion exists between expr_type
157 public static bool ImplicitReferenceConversionExists (Expression expr, Type target_type)
159 Type expr_type = expr.Type;
162 // This is the boxed case.
164 if (target_type == TypeManager.object_type) {
165 if (expr_type.IsClass || expr_type.IsValueType ||
166 expr_type.IsInterface || expr_type == TypeManager.enum_type)
168 } else if (expr_type.IsSubclassOf (target_type))
171 // Please remember that all code below actually comes
172 // from ImplicitReferenceConversion so make sure code remains in sync
174 // from any class-type S to any interface-type T.
175 if (target_type.IsInterface) {
176 if (TypeManager.ImplementsInterface (expr_type, target_type))
180 // from any interface type S to interface-type T.
181 if (expr_type.IsInterface && target_type.IsInterface)
182 if (TypeManager.ImplementsInterface (expr_type, target_type))
185 // from an array-type S to an array-type of type T
186 if (expr_type.IsArray && target_type.IsArray) {
187 if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
189 Type expr_element_type = expr_type.GetElementType ();
191 if (MyEmptyExpr == null)
192 MyEmptyExpr = new EmptyExpression ();
194 MyEmptyExpr.SetType (expr_element_type);
195 Type target_element_type = TypeManager.GetElementType (target_type);
197 if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
198 if (ImplicitStandardConversionExists (MyEmptyExpr,
199 target_element_type))
204 // from an array-type to System.Array
205 if (expr_type.IsArray && (target_type == TypeManager.array_type))
208 // from any delegate type to System.Delegate
209 if ((expr_type == TypeManager.delegate_type ||
210 expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
211 target_type == TypeManager.delegate_type)
212 if (target_type.IsAssignableFrom (expr_type))
215 // from any array-type or delegate type into System.ICloneable.
216 if (expr_type.IsArray ||
217 expr_type == TypeManager.delegate_type ||
218 expr_type.IsSubclassOf (TypeManager.delegate_type))
219 if (target_type == TypeManager.icloneable_type)
222 // from the null type to any reference-type.
223 if (expr is NullLiteral && !target_type.IsValueType &&
224 !TypeManager.IsEnumType (target_type))
232 /// Implicit Numeric Conversions.
234 /// expr is the expression to convert, returns a new expression of type
235 /// target_type or null if an implicit conversion is not possible.
237 static public Expression ImplicitNumericConversion (EmitContext ec, Expression expr,
238 Type target_type, Location loc)
240 Type expr_type = expr.Type;
243 // Attempt to do the implicit constant expression conversions
245 if (expr is Constant){
246 if (expr is IntConstant){
249 e = TryImplicitIntConversion (target_type, (IntConstant) expr);
253 } else if (expr is LongConstant && target_type == TypeManager.uint64_type){
255 // Try the implicit constant expression conversion
256 // from long to ulong, instead of a nice routine,
259 long v = ((LongConstant) expr).Value;
261 return new ULongConstant ((ulong) v);
265 Type real_target_type = target_type;
267 if (expr_type == TypeManager.sbyte_type){
269 // From sbyte to short, int, long, float, double.
271 if (real_target_type == TypeManager.int32_type)
272 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
273 if (real_target_type == TypeManager.int64_type)
274 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
275 if (real_target_type == TypeManager.double_type)
276 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
277 if (real_target_type == TypeManager.float_type)
278 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
279 if (real_target_type == TypeManager.short_type)
280 return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
281 } else if (expr_type == TypeManager.byte_type){
283 // From byte to short, ushort, int, uint, long, ulong, float, double
285 if ((real_target_type == TypeManager.short_type) ||
286 (real_target_type == TypeManager.ushort_type) ||
287 (real_target_type == TypeManager.int32_type) ||
288 (real_target_type == TypeManager.uint32_type))
289 return new EmptyCast (expr, target_type);
291 if (real_target_type == TypeManager.uint64_type)
292 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
293 if (real_target_type == TypeManager.int64_type)
294 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
295 if (real_target_type == TypeManager.float_type)
296 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
297 if (real_target_type == TypeManager.double_type)
298 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
299 } else if (expr_type == TypeManager.short_type){
301 // From short to int, long, float, double
303 if (real_target_type == TypeManager.int32_type)
304 return new EmptyCast (expr, target_type);
305 if (real_target_type == TypeManager.int64_type)
306 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
307 if (real_target_type == TypeManager.double_type)
308 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
309 if (real_target_type == TypeManager.float_type)
310 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
311 } else if (expr_type == TypeManager.ushort_type){
313 // From ushort to int, uint, long, ulong, float, double
315 if (real_target_type == TypeManager.uint32_type)
316 return new EmptyCast (expr, target_type);
318 if (real_target_type == TypeManager.uint64_type)
319 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
320 if (real_target_type == TypeManager.int32_type)
321 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
322 if (real_target_type == TypeManager.int64_type)
323 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
324 if (real_target_type == TypeManager.double_type)
325 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
326 if (real_target_type == TypeManager.float_type)
327 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
328 } else if (expr_type == TypeManager.int32_type){
330 // From int to long, float, double
332 if (real_target_type == TypeManager.int64_type)
333 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
334 if (real_target_type == TypeManager.double_type)
335 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
336 if (real_target_type == TypeManager.float_type)
337 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
338 } else if (expr_type == TypeManager.uint32_type){
340 // From uint to long, ulong, float, double
342 if (real_target_type == TypeManager.int64_type)
343 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
344 if (real_target_type == TypeManager.uint64_type)
345 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
346 if (real_target_type == TypeManager.double_type)
347 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
349 if (real_target_type == TypeManager.float_type)
350 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
352 } else if (expr_type == TypeManager.int64_type){
354 // From long/ulong to float, double
356 if (real_target_type == TypeManager.double_type)
357 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
358 if (real_target_type == TypeManager.float_type)
359 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
360 } else if (expr_type == TypeManager.uint64_type){
362 // From ulong to float, double
364 if (real_target_type == TypeManager.double_type)
365 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
367 if (real_target_type == TypeManager.float_type)
368 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
370 } else if (expr_type == TypeManager.char_type){
372 // From char to ushort, int, uint, long, ulong, float, double
374 if ((real_target_type == TypeManager.ushort_type) ||
375 (real_target_type == TypeManager.int32_type) ||
376 (real_target_type == TypeManager.uint32_type))
377 return new EmptyCast (expr, target_type);
378 if (real_target_type == TypeManager.uint64_type)
379 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
380 if (real_target_type == TypeManager.int64_type)
381 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
382 if (real_target_type == TypeManager.float_type)
383 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
384 if (real_target_type == TypeManager.double_type)
385 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
386 } else if (expr_type == TypeManager.float_type){
390 if (real_target_type == TypeManager.double_type)
391 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
399 /// Same as ImplicitStandardConversionExists except that it also looks at
400 /// implicit user defined conversions - needed for overload resolution
402 public static bool ImplicitConversionExists (EmitContext ec, Expression expr, Type target_type)
404 if (ImplicitStandardConversionExists (expr, target_type))
407 Expression dummy = ImplicitUserConversion (ec, expr, target_type, Location.Null);
415 public static bool ImplicitUserConversionExists (EmitContext ec, Type source, Type target)
417 Expression dummy = ImplicitUserConversion (
418 ec, new EmptyExpression (source), target, Location.Null);
419 return dummy != null;
423 /// Determines if a standard implicit conversion exists from
424 /// expr_type to target_type
426 public static bool ImplicitStandardConversionExists (Expression expr, Type target_type)
428 Type expr_type = expr.Type;
430 if (expr_type == TypeManager.void_type)
433 if (expr_type == target_type)
436 // First numeric conversions
438 if (expr_type == TypeManager.sbyte_type){
440 // From sbyte to short, int, long, float, double.
442 if ((target_type == TypeManager.int32_type) ||
443 (target_type == TypeManager.int64_type) ||
444 (target_type == TypeManager.double_type) ||
445 (target_type == TypeManager.float_type) ||
446 (target_type == TypeManager.short_type) ||
447 (target_type == TypeManager.decimal_type))
450 } else if (expr_type == TypeManager.byte_type){
452 // From byte to short, ushort, int, uint, long, ulong, float, double
454 if ((target_type == TypeManager.short_type) ||
455 (target_type == TypeManager.ushort_type) ||
456 (target_type == TypeManager.int32_type) ||
457 (target_type == TypeManager.uint32_type) ||
458 (target_type == TypeManager.uint64_type) ||
459 (target_type == TypeManager.int64_type) ||
460 (target_type == TypeManager.float_type) ||
461 (target_type == TypeManager.double_type) ||
462 (target_type == TypeManager.decimal_type))
465 } else if (expr_type == TypeManager.short_type){
467 // From short to int, long, float, double
469 if ((target_type == TypeManager.int32_type) ||
470 (target_type == TypeManager.int64_type) ||
471 (target_type == TypeManager.double_type) ||
472 (target_type == TypeManager.float_type) ||
473 (target_type == TypeManager.decimal_type))
476 } else if (expr_type == TypeManager.ushort_type){
478 // From ushort to int, uint, long, ulong, float, double
480 if ((target_type == TypeManager.uint32_type) ||
481 (target_type == TypeManager.uint64_type) ||
482 (target_type == TypeManager.int32_type) ||
483 (target_type == TypeManager.int64_type) ||
484 (target_type == TypeManager.double_type) ||
485 (target_type == TypeManager.float_type) ||
486 (target_type == TypeManager.decimal_type))
489 } else if (expr_type == TypeManager.int32_type){
491 // From int to long, float, double
493 if ((target_type == TypeManager.int64_type) ||
494 (target_type == TypeManager.double_type) ||
495 (target_type == TypeManager.float_type) ||
496 (target_type == TypeManager.decimal_type))
499 } else if (expr_type == TypeManager.uint32_type){
501 // From uint to long, ulong, float, double
503 if ((target_type == TypeManager.int64_type) ||
504 (target_type == TypeManager.uint64_type) ||
505 (target_type == TypeManager.double_type) ||
506 (target_type == TypeManager.float_type) ||
507 (target_type == TypeManager.decimal_type))
510 } else if ((expr_type == TypeManager.uint64_type) ||
511 (expr_type == TypeManager.int64_type)) {
513 // From long/ulong to float, double
515 if ((target_type == TypeManager.double_type) ||
516 (target_type == TypeManager.float_type) ||
517 (target_type == TypeManager.decimal_type))
520 } else if (expr_type == TypeManager.char_type){
522 // From char to ushort, int, uint, long, ulong, float, double
524 if ((target_type == TypeManager.ushort_type) ||
525 (target_type == TypeManager.int32_type) ||
526 (target_type == TypeManager.uint32_type) ||
527 (target_type == TypeManager.uint64_type) ||
528 (target_type == TypeManager.int64_type) ||
529 (target_type == TypeManager.float_type) ||
530 (target_type == TypeManager.double_type) ||
531 (target_type == TypeManager.decimal_type))
534 } else if (expr_type == TypeManager.float_type){
538 if (target_type == TypeManager.double_type)
542 if (ImplicitReferenceConversionExists (expr, target_type))
546 // Implicit Constant Expression Conversions
548 if (expr is IntConstant){
549 int value = ((IntConstant) expr).Value;
551 if (target_type == TypeManager.sbyte_type){
552 if (value >= SByte.MinValue && value <= SByte.MaxValue)
554 } else if (target_type == TypeManager.byte_type){
555 if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
557 } else if (target_type == TypeManager.short_type){
558 if (value >= Int16.MinValue && value <= Int16.MaxValue)
560 } else if (target_type == TypeManager.ushort_type){
561 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
563 } else if (target_type == TypeManager.uint32_type){
566 } else if (target_type == TypeManager.uint64_type){
568 // we can optimize this case: a positive int32
569 // always fits on a uint64. But we need an opcode
576 if (value == 0 && expr is IntLiteral && TypeManager.IsEnumType (target_type))
580 if (expr is LongConstant && target_type == TypeManager.uint64_type){
582 // Try the implicit constant expression conversion
583 // from long to ulong, instead of a nice routine,
586 long v = ((LongConstant) expr).Value;
591 if ((target_type == TypeManager.enum_type ||
592 target_type.IsSubclassOf (TypeManager.enum_type)) &&
594 IntLiteral i = (IntLiteral) expr;
600 if (target_type == TypeManager.void_ptr_type && expr_type.IsPointer)
607 // Used internally by FindMostEncompassedType, this is used
608 // to avoid creating lots of objects in the tight loop inside
609 // FindMostEncompassedType
611 static EmptyExpression priv_fmet_param;
614 /// Finds "most encompassed type" according to the spec (13.4.2)
615 /// amongst the methods in the MethodGroupExpr
617 static Type FindMostEncompassedType (ArrayList types)
621 if (priv_fmet_param == null)
622 priv_fmet_param = new EmptyExpression ();
624 foreach (Type t in types){
625 priv_fmet_param.SetType (t);
632 if (ImplicitStandardConversionExists (priv_fmet_param, best))
640 // Used internally by FindMostEncompassingType, this is used
641 // to avoid creating lots of objects in the tight loop inside
642 // FindMostEncompassingType
644 static EmptyExpression priv_fmee_ret;
647 /// Finds "most encompassing type" according to the spec (13.4.2)
648 /// amongst the types in the given set
650 static Type FindMostEncompassingType (ArrayList types)
654 if (priv_fmee_ret == null)
655 priv_fmee_ret = new EmptyExpression ();
657 foreach (Type t in types){
658 priv_fmee_ret.SetType (best);
665 if (ImplicitStandardConversionExists (priv_fmee_ret, t))
673 // Used to avoid creating too many objects
675 static EmptyExpression priv_fms_expr;
678 /// Finds the most specific source Sx according to the rules of the spec (13.4.4)
679 /// by making use of FindMostEncomp* methods. Applies the correct rules separately
680 /// for explicit and implicit conversion operators.
682 static public Type FindMostSpecificSource (MethodGroupExpr me, Expression source,
683 bool apply_explicit_conv_rules,
686 ArrayList src_types_set = new ArrayList ();
688 if (priv_fms_expr == null)
689 priv_fms_expr = new EmptyExpression ();
692 // If any operator converts from S then Sx = S
694 Type source_type = source.Type;
695 foreach (MethodBase mb in me.Methods){
696 ParameterData pd = Invocation.GetParameterData (mb);
697 Type param_type = pd.ParameterType (0);
699 if (param_type == source_type)
702 if (apply_explicit_conv_rules) {
705 // Find the set of applicable user-defined conversion operators, U. This set
707 // user-defined implicit or explicit conversion operators declared by
708 // the classes or structs in D that convert from a type encompassing
709 // or encompassed by S to a type encompassing or encompassed by T
711 priv_fms_expr.SetType (param_type);
712 if (ImplicitStandardConversionExists (priv_fms_expr, source_type))
713 src_types_set.Add (param_type);
715 if (ImplicitStandardConversionExists (source, param_type))
716 src_types_set.Add (param_type);
720 // Only if S is encompassed by param_type
722 if (ImplicitStandardConversionExists (source, param_type))
723 src_types_set.Add (param_type);
728 // Explicit Conv rules
730 if (apply_explicit_conv_rules) {
731 ArrayList candidate_set = new ArrayList ();
733 foreach (Type param_type in src_types_set){
734 if (ImplicitStandardConversionExists (source, param_type))
735 candidate_set.Add (param_type);
738 if (candidate_set.Count != 0)
739 return FindMostEncompassedType (candidate_set);
745 if (apply_explicit_conv_rules)
746 return FindMostEncompassingType (src_types_set);
748 return FindMostEncompassedType (src_types_set);
752 // Useful in avoiding proliferation of objects
754 static EmptyExpression priv_fmt_expr;
757 /// Finds the most specific target Tx according to section 13.4.4
759 static public Type FindMostSpecificTarget (MethodGroupExpr me, Type target,
760 bool apply_explicit_conv_rules,
763 ArrayList tgt_types_set = new ArrayList ();
765 if (priv_fmt_expr == null)
766 priv_fmt_expr = new EmptyExpression ();
769 // If any operator converts to T then Tx = T
771 foreach (MethodInfo mi in me.Methods){
772 Type ret_type = mi.ReturnType;
774 if (ret_type == target)
777 if (apply_explicit_conv_rules) {
780 // Find the set of applicable user-defined conversion operators, U.
782 // This set consists of the
783 // user-defined implicit or explicit conversion operators declared by
784 // the classes or structs in D that convert from a type encompassing
785 // or encompassed by S to a type encompassing or encompassed by T
787 priv_fms_expr.SetType (ret_type);
788 if (ImplicitStandardConversionExists (priv_fms_expr, target))
789 tgt_types_set.Add (ret_type);
791 priv_fms_expr.SetType (target);
792 if (ImplicitStandardConversionExists (priv_fms_expr, ret_type))
793 tgt_types_set.Add (ret_type);
797 // Only if T is encompassed by param_type
799 priv_fms_expr.SetType (ret_type);
800 if (ImplicitStandardConversionExists (priv_fms_expr, target))
801 tgt_types_set.Add (ret_type);
806 // Explicit conv rules
808 if (apply_explicit_conv_rules) {
809 ArrayList candidate_set = new ArrayList ();
811 foreach (Type ret_type in tgt_types_set){
812 priv_fmt_expr.SetType (ret_type);
814 if (ImplicitStandardConversionExists (priv_fmt_expr, target))
815 candidate_set.Add (ret_type);
818 if (candidate_set.Count != 0)
819 return FindMostEncompassingType (candidate_set);
823 // Okay, final case !
825 if (apply_explicit_conv_rules)
826 return FindMostEncompassedType (tgt_types_set);
828 return FindMostEncompassingType (tgt_types_set);
832 /// User-defined Implicit conversions
834 static public Expression ImplicitUserConversion (EmitContext ec, Expression source,
835 Type target, Location loc)
837 return UserDefinedConversion (ec, source, target, loc, false);
841 /// User-defined Explicit conversions
843 static public Expression ExplicitUserConversion (EmitContext ec, Expression source,
844 Type target, Location loc)
846 return UserDefinedConversion (ec, source, target, loc, true);
850 /// Computes the MethodGroup for the user-defined conversion
851 /// operators from source_type to target_type. `look_for_explicit'
852 /// controls whether we should also include the list of explicit
855 static MethodGroupExpr GetConversionOperators (EmitContext ec,
856 Type source_type, Type target_type,
857 Location loc, bool look_for_explicit)
859 Expression mg1 = null, mg2 = null;
860 Expression mg5 = null, mg6 = null, mg7 = null, mg8 = null;
863 op_name = "op_Implicit";
865 MethodGroupExpr union3;
867 mg1 = Expression.MethodLookup (ec, source_type, op_name, loc);
868 if (source_type.BaseType != null)
869 mg2 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
872 union3 = (MethodGroupExpr) mg2;
873 else if (mg2 == null)
874 union3 = (MethodGroupExpr) mg1;
876 union3 = Invocation.MakeUnionSet (mg1, mg2, loc);
878 mg1 = Expression.MethodLookup (ec, target_type, op_name, loc);
881 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
883 union3 = (MethodGroupExpr) mg1;
886 if (target_type.BaseType != null)
887 mg1 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
891 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
893 union3 = (MethodGroupExpr) mg1;
896 MethodGroupExpr union4 = null;
898 if (look_for_explicit) {
899 op_name = "op_Explicit";
901 mg5 = Expression.MemberLookup (ec, source_type, op_name, loc);
902 if (source_type.BaseType != null)
903 mg6 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
905 mg7 = Expression.MemberLookup (ec, target_type, op_name, loc);
906 if (target_type.BaseType != null)
907 mg8 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
909 MethodGroupExpr union5 = Invocation.MakeUnionSet (mg5, mg6, loc);
910 MethodGroupExpr union6 = Invocation.MakeUnionSet (mg7, mg8, loc);
912 union4 = Invocation.MakeUnionSet (union5, union6, loc);
915 return Invocation.MakeUnionSet (union3, union4, loc);
919 /// User-defined conversions
921 static public Expression UserDefinedConversion (EmitContext ec, Expression source,
922 Type target, Location loc,
923 bool look_for_explicit)
925 MethodGroupExpr union;
926 Type source_type = source.Type;
927 MethodBase method = null;
929 union = GetConversionOperators (ec, source_type, target, loc, look_for_explicit);
933 Type most_specific_source, most_specific_target;
935 most_specific_source = FindMostSpecificSource (union, source, look_for_explicit, loc);
936 if (most_specific_source == null)
939 most_specific_target = FindMostSpecificTarget (union, target, look_for_explicit, loc);
940 if (most_specific_target == null)
946 foreach (MethodBase mb in union.Methods){
947 ParameterData pd = Invocation.GetParameterData (mb);
948 MethodInfo mi = (MethodInfo) mb;
950 if (pd.ParameterType (0) == most_specific_source &&
951 mi.ReturnType == most_specific_target) {
957 if (method == null || count > 1)
962 // This will do the conversion to the best match that we
963 // found. Now we need to perform an implict standard conversion
964 // if the best match was not the type that we were requested
967 if (look_for_explicit)
968 source = ExplicitConversionStandard (ec, source, most_specific_source, loc);
970 source = ImplicitConversionStandard (ec, source, most_specific_source, loc);
976 e = new UserCast ((MethodInfo) method, source, loc);
977 if (e.Type != target){
978 if (!look_for_explicit)
979 e = ImplicitConversionStandard (ec, e, target, loc);
981 e = ExplicitConversionStandard (ec, e, target, loc);
988 /// Converts implicitly the resolved expression `expr' into the
989 /// `target_type'. It returns a new expression that can be used
990 /// in a context that expects a `target_type'.
992 static public Expression ImplicitConversion (EmitContext ec, Expression expr,
993 Type target_type, Location loc)
997 if (target_type == null)
998 throw new Exception ("Target type is null");
1000 e = ImplicitConversionStandard (ec, expr, target_type, loc);
1004 e = ImplicitUserConversion (ec, expr, target_type, loc);
1013 /// Attempts to apply the `Standard Implicit
1014 /// Conversion' rules to the expression `expr' into
1015 /// the `target_type'. It returns a new expression
1016 /// that can be used in a context that expects a
1019 /// This is different from `ImplicitConversion' in that the
1020 /// user defined implicit conversions are excluded.
1022 static public Expression ImplicitConversionStandard (EmitContext ec, Expression expr,
1023 Type target_type, Location loc)
1025 Type expr_type = expr.Type;
1028 if (expr.eclass == ExprClass.MethodGroup){
1029 if (!TypeManager.IsDelegateType (target_type)){
1030 Report.Error (428, loc,
1032 "Cannot convert method group to `{0}', since it is not a delegate",
1033 TypeManager.CSharpName (target_type)));
1037 return ImplicitDelegateCreation.Create (ec, (MethodGroupExpr) expr, target_type, loc);
1040 if (expr_type == target_type && !(expr is NullLiteral))
1043 e = ImplicitNumericConversion (ec, expr, target_type, loc);
1047 e = ImplicitReferenceConversion (expr, target_type);
1051 if ((target_type == TypeManager.enum_type ||
1052 target_type.IsSubclassOf (TypeManager.enum_type)) &&
1053 expr is IntLiteral){
1054 IntLiteral i = (IntLiteral) expr;
1057 return new EnumConstant ((Constant) expr, target_type);
1061 if (expr_type.IsPointer){
1062 if (target_type == TypeManager.void_ptr_type)
1063 return new EmptyCast (expr, target_type);
1066 // yep, comparing pointer types cant be done with
1067 // t1 == t2, we have to compare their element types.
1069 if (target_type.IsPointer){
1070 if (TypeManager.GetElementType(target_type) == TypeManager.GetElementType(expr_type))
1075 if (target_type.IsPointer) {
1076 if (expr is NullLiteral)
1077 return new EmptyCast (expr, target_type);
1079 if (expr_type == TypeManager.void_ptr_type)
1080 return new EmptyCast (expr, target_type);
1088 /// Attemps to perform an implict constant conversion of the IntConstant
1089 /// into a different data type using casts (See Implicit Constant
1090 /// Expression Conversions)
1092 static public Expression TryImplicitIntConversion (Type target_type, IntConstant ic)
1094 int value = ic.Value;
1096 if (target_type == TypeManager.sbyte_type){
1097 if (value >= SByte.MinValue && value <= SByte.MaxValue)
1098 return new SByteConstant ((sbyte) value);
1099 } else if (target_type == TypeManager.byte_type){
1100 if (value >= Byte.MinValue && value <= Byte.MaxValue)
1101 return new ByteConstant ((byte) value);
1102 } else if (target_type == TypeManager.short_type){
1103 if (value >= Int16.MinValue && value <= Int16.MaxValue)
1104 return new ShortConstant ((short) value);
1105 } else if (target_type == TypeManager.ushort_type){
1106 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
1107 return new UShortConstant ((ushort) value);
1108 } else if (target_type == TypeManager.uint32_type){
1110 return new UIntConstant ((uint) value);
1111 } else if (target_type == TypeManager.uint64_type){
1113 // we can optimize this case: a positive int32
1114 // always fits on a uint64. But we need an opcode
1118 return new ULongConstant ((ulong) value);
1119 } else if (target_type == TypeManager.double_type)
1120 return new DoubleConstant ((double) value);
1121 else if (target_type == TypeManager.float_type)
1122 return new FloatConstant ((float) value);
1124 if (value == 0 && ic is IntLiteral && TypeManager.IsEnumType (target_type)){
1125 Type underlying = TypeManager.EnumToUnderlying (target_type);
1126 Constant e = (Constant) ic;
1129 // Possibly, we need to create a different 0 literal before passing
1132 if (underlying == TypeManager.int64_type)
1133 e = new LongLiteral (0);
1134 else if (underlying == TypeManager.uint64_type)
1135 e = new ULongLiteral (0);
1137 return new EnumConstant (e, target_type);
1142 static public void Error_CannotImplicitConversion (Location loc, Type source, Type target)
1144 string msg = "Cannot convert implicitly from `"+
1145 TypeManager.CSharpName (source) + "' to `" +
1146 TypeManager.CSharpName (target) + "'";
1148 Report.Error (29, loc, msg);
1152 /// Attemptes to implicityly convert `target' into `type', using
1153 /// ImplicitConversion. If there is no implicit conversion, then
1154 /// an error is signaled
1156 static public Expression ImplicitConversionRequired (EmitContext ec, Expression source,
1157 Type target_type, Location loc)
1161 e = ImplicitConversion (ec, source, target_type, loc);
1165 if (source is DoubleLiteral && target_type == TypeManager.float_type){
1166 Report.Error (664, loc,
1167 "Double literal cannot be implicitly converted to " +
1168 "float type, use F suffix to create a float literal");
1171 if (source is Constant){
1172 Constant c = (Constant) source;
1174 Expression.Error_ConstantValueCannotBeConverted (loc, c.AsString (), target_type);
1178 Error_CannotImplicitConversion (loc, source.Type, target_type);
1184 /// Performs the explicit numeric conversions
1186 static Expression ExplicitNumericConversion (EmitContext ec, Expression expr, Type target_type, Location loc)
1188 Type expr_type = expr.Type;
1191 // If we have an enumeration, extract the underlying type,
1192 // use this during the comparison, but wrap around the original
1195 Type real_target_type = target_type;
1197 if (TypeManager.IsEnumType (real_target_type))
1198 real_target_type = TypeManager.EnumToUnderlying (real_target_type);
1200 if (ImplicitStandardConversionExists (expr, real_target_type)){
1201 Expression ce = ImplicitConversionStandard (ec, expr, real_target_type, loc);
1203 if (real_target_type != target_type)
1204 return new EmptyCast (ce, target_type);
1208 if (expr_type == TypeManager.sbyte_type){
1210 // From sbyte to byte, ushort, uint, ulong, char
1212 if (real_target_type == TypeManager.byte_type)
1213 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U1);
1214 if (real_target_type == TypeManager.ushort_type)
1215 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U2);
1216 if (real_target_type == TypeManager.uint32_type)
1217 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U4);
1218 if (real_target_type == TypeManager.uint64_type)
1219 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U8);
1220 if (real_target_type == TypeManager.char_type)
1221 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_CH);
1222 } else if (expr_type == TypeManager.byte_type){
1224 // From byte to sbyte and char
1226 if (real_target_type == TypeManager.sbyte_type)
1227 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_I1);
1228 if (real_target_type == TypeManager.char_type)
1229 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_CH);
1230 } else if (expr_type == TypeManager.short_type){
1232 // From short to sbyte, byte, ushort, uint, ulong, char
1234 if (real_target_type == TypeManager.sbyte_type)
1235 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_I1);
1236 if (real_target_type == TypeManager.byte_type)
1237 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U1);
1238 if (real_target_type == TypeManager.ushort_type)
1239 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U2);
1240 if (real_target_type == TypeManager.uint32_type)
1241 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U4);
1242 if (real_target_type == TypeManager.uint64_type)
1243 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U8);
1244 if (real_target_type == TypeManager.char_type)
1245 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_CH);
1246 } else if (expr_type == TypeManager.ushort_type){
1248 // From ushort to sbyte, byte, short, char
1250 if (real_target_type == TypeManager.sbyte_type)
1251 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I1);
1252 if (real_target_type == TypeManager.byte_type)
1253 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_U1);
1254 if (real_target_type == TypeManager.short_type)
1255 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I2);
1256 if (real_target_type == TypeManager.char_type)
1257 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_CH);
1258 } else if (expr_type == TypeManager.int32_type){
1260 // From int to sbyte, byte, short, ushort, uint, ulong, char
1262 if (real_target_type == TypeManager.sbyte_type)
1263 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I1);
1264 if (real_target_type == TypeManager.byte_type)
1265 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U1);
1266 if (real_target_type == TypeManager.short_type)
1267 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I2);
1268 if (real_target_type == TypeManager.ushort_type)
1269 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U2);
1270 if (real_target_type == TypeManager.uint32_type)
1271 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U4);
1272 if (real_target_type == TypeManager.uint64_type)
1273 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U8);
1274 if (real_target_type == TypeManager.char_type)
1275 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_CH);
1276 } else if (expr_type == TypeManager.uint32_type){
1278 // From uint to sbyte, byte, short, ushort, int, char
1280 if (real_target_type == TypeManager.sbyte_type)
1281 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I1);
1282 if (real_target_type == TypeManager.byte_type)
1283 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U1);
1284 if (real_target_type == TypeManager.short_type)
1285 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I2);
1286 if (real_target_type == TypeManager.ushort_type)
1287 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U2);
1288 if (real_target_type == TypeManager.int32_type)
1289 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I4);
1290 if (real_target_type == TypeManager.char_type)
1291 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_CH);
1292 } else if (expr_type == TypeManager.int64_type){
1294 // From long to sbyte, byte, short, ushort, int, uint, ulong, char
1296 if (real_target_type == TypeManager.sbyte_type)
1297 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I1);
1298 if (real_target_type == TypeManager.byte_type)
1299 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U1);
1300 if (real_target_type == TypeManager.short_type)
1301 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I2);
1302 if (real_target_type == TypeManager.ushort_type)
1303 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U2);
1304 if (real_target_type == TypeManager.int32_type)
1305 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I4);
1306 if (real_target_type == TypeManager.uint32_type)
1307 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U4);
1308 if (real_target_type == TypeManager.uint64_type)
1309 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U8);
1310 if (real_target_type == TypeManager.char_type)
1311 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_CH);
1312 } else if (expr_type == TypeManager.uint64_type){
1314 // From ulong to sbyte, byte, short, ushort, int, uint, long, char
1316 if (real_target_type == TypeManager.sbyte_type)
1317 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I1);
1318 if (real_target_type == TypeManager.byte_type)
1319 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U1);
1320 if (real_target_type == TypeManager.short_type)
1321 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I2);
1322 if (real_target_type == TypeManager.ushort_type)
1323 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U2);
1324 if (real_target_type == TypeManager.int32_type)
1325 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I4);
1326 if (real_target_type == TypeManager.uint32_type)
1327 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U4);
1328 if (real_target_type == TypeManager.int64_type)
1329 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I8);
1330 if (real_target_type == TypeManager.char_type)
1331 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_CH);
1332 } else if (expr_type == TypeManager.char_type){
1334 // From char to sbyte, byte, short
1336 if (real_target_type == TypeManager.sbyte_type)
1337 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I1);
1338 if (real_target_type == TypeManager.byte_type)
1339 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_U1);
1340 if (real_target_type == TypeManager.short_type)
1341 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I2);
1342 } else if (expr_type == TypeManager.float_type){
1344 // From float to sbyte, byte, short,
1345 // ushort, int, uint, long, ulong, char
1348 if (real_target_type == TypeManager.sbyte_type)
1349 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I1);
1350 if (real_target_type == TypeManager.byte_type)
1351 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U1);
1352 if (real_target_type == TypeManager.short_type)
1353 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I2);
1354 if (real_target_type == TypeManager.ushort_type)
1355 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U2);
1356 if (real_target_type == TypeManager.int32_type)
1357 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I4);
1358 if (real_target_type == TypeManager.uint32_type)
1359 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U4);
1360 if (real_target_type == TypeManager.int64_type)
1361 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I8);
1362 if (real_target_type == TypeManager.uint64_type)
1363 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U8);
1364 if (real_target_type == TypeManager.char_type)
1365 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_CH);
1366 } else if (expr_type == TypeManager.double_type){
1368 // From double to byte, byte, short,
1369 // ushort, int, uint, long, ulong,
1370 // char, float or decimal
1372 if (real_target_type == TypeManager.sbyte_type)
1373 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I1);
1374 if (real_target_type == TypeManager.byte_type)
1375 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U1);
1376 if (real_target_type == TypeManager.short_type)
1377 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I2);
1378 if (real_target_type == TypeManager.ushort_type)
1379 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U2);
1380 if (real_target_type == TypeManager.int32_type)
1381 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I4);
1382 if (real_target_type == TypeManager.uint32_type)
1383 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U4);
1384 if (real_target_type == TypeManager.int64_type)
1385 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I8);
1386 if (real_target_type == TypeManager.uint64_type)
1387 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U8);
1388 if (real_target_type == TypeManager.char_type)
1389 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_CH);
1390 if (real_target_type == TypeManager.float_type)
1391 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_R4);
1394 // decimal is taken care of by the op_Explicit methods.
1400 /// Returns whether an explicit reference conversion can be performed
1401 /// from source_type to target_type
1403 public static bool ExplicitReferenceConversionExists (Type source_type, Type target_type)
1405 bool target_is_value_type = target_type.IsValueType;
1407 if (source_type == target_type)
1411 // From object to any reference type
1413 if (source_type == TypeManager.object_type && !target_is_value_type)
1417 // From any class S to any class-type T, provided S is a base class of T
1419 if (target_type.IsSubclassOf (source_type))
1423 // From any interface type S to any interface T provided S is not derived from T
1425 if (source_type.IsInterface && target_type.IsInterface){
1426 if (!target_type.IsSubclassOf (source_type))
1431 // From any class type S to any interface T, provided S is not sealed
1432 // and provided S does not implement T.
1434 if (target_type.IsInterface && !source_type.IsSealed &&
1435 !TypeManager.ImplementsInterface (source_type, target_type))
1439 // From any interface-type S to to any class type T, provided T is not
1440 // sealed, or provided T implements S.
1442 if (source_type.IsInterface &&
1443 (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)))
1447 // From an array type S with an element type Se to an array type T with an
1448 // element type Te provided all the following are true:
1449 // * S and T differe only in element type, in other words, S and T
1450 // have the same number of dimensions.
1451 // * Both Se and Te are reference types
1452 // * An explicit referenc conversions exist from Se to Te
1454 if (source_type.IsArray && target_type.IsArray) {
1455 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1457 Type source_element_type = TypeManager.GetElementType (source_type);
1458 Type target_element_type = TypeManager.GetElementType (target_type);
1460 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1461 if (ExplicitReferenceConversionExists (source_element_type,
1462 target_element_type))
1468 // From System.Array to any array-type
1469 if (source_type == TypeManager.array_type &&
1470 target_type.IsArray){
1475 // From System delegate to any delegate-type
1477 if (source_type == TypeManager.delegate_type &&
1478 target_type.IsSubclassOf (TypeManager.delegate_type))
1482 // From ICloneable to Array or Delegate types
1484 if (source_type == TypeManager.icloneable_type &&
1485 (target_type == TypeManager.array_type ||
1486 target_type == TypeManager.delegate_type))
1493 /// Implements Explicit Reference conversions
1495 static Expression ExplicitReferenceConversion (Expression source, Type target_type)
1497 Type source_type = source.Type;
1498 bool target_is_value_type = target_type.IsValueType;
1501 // From object to any reference type
1503 if (source_type == TypeManager.object_type && !target_is_value_type)
1504 return new ClassCast (source, target_type);
1507 // Unboxing conversion.
1509 if (((source_type == TypeManager.enum_type &&
1510 !(source is EmptyCast)) ||
1511 source_type == TypeManager.value_type) && target_is_value_type)
1512 return new UnboxCast (source, target_type);
1515 // From any class S to any class-type T, provided S is a base class of T
1517 if (target_type.IsSubclassOf (source_type))
1518 return new ClassCast (source, target_type);
1521 // From any interface type S to any interface T provided S is not derived from T
1523 if (source_type.IsInterface && target_type.IsInterface){
1524 if (TypeManager.ImplementsInterface (source_type, target_type))
1527 return new ClassCast (source, target_type);
1531 // From any class type S to any interface T, provides S is not sealed
1532 // and provided S does not implement T.
1534 if (target_type.IsInterface && !source_type.IsSealed) {
1535 if (TypeManager.ImplementsInterface (source_type, target_type))
1538 return new ClassCast (source, target_type);
1543 // From any interface-type S to to any class type T, provided T is not
1544 // sealed, or provided T implements S.
1546 if (source_type.IsInterface) {
1547 if (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)) {
1548 if (target_type.IsClass)
1549 return new ClassCast (source, target_type);
1551 return new UnboxCast (source, target_type);
1557 // From an array type S with an element type Se to an array type T with an
1558 // element type Te provided all the following are true:
1559 // * S and T differe only in element type, in other words, S and T
1560 // have the same number of dimensions.
1561 // * Both Se and Te are reference types
1562 // * An explicit referenc conversions exist from Se to Te
1564 if (source_type.IsArray && target_type.IsArray) {
1565 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1567 Type source_element_type = TypeManager.GetElementType (source_type);
1568 Type target_element_type = TypeManager.GetElementType (target_type);
1570 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1571 if (ExplicitReferenceConversionExists (source_element_type,
1572 target_element_type))
1573 return new ClassCast (source, target_type);
1578 // From System.Array to any array-type
1579 if (source_type == TypeManager.array_type &&
1580 target_type.IsArray) {
1581 return new ClassCast (source, target_type);
1585 // From System delegate to any delegate-type
1587 if (source_type == TypeManager.delegate_type &&
1588 target_type.IsSubclassOf (TypeManager.delegate_type))
1589 return new ClassCast (source, target_type);
1592 // From ICloneable to Array or Delegate types
1594 if (source_type == TypeManager.icloneable_type &&
1595 (target_type == TypeManager.array_type ||
1596 target_type == TypeManager.delegate_type))
1597 return new ClassCast (source, target_type);
1603 /// Performs an explicit conversion of the expression `expr' whose
1604 /// type is expr.Type to `target_type'.
1606 static public Expression ExplicitConversion (EmitContext ec, Expression expr,
1607 Type target_type, Location loc)
1609 Type expr_type = expr.Type;
1610 Type original_expr_type = expr_type;
1612 if (expr_type.IsSubclassOf (TypeManager.enum_type)){
1613 if (target_type == TypeManager.enum_type ||
1614 target_type == TypeManager.object_type) {
1615 if (expr is EnumConstant)
1616 expr = ((EnumConstant) expr).Child;
1617 // We really need all these casts here .... :-(
1618 expr = new BoxedCast (new EmptyCast (expr, expr_type));
1619 return new EmptyCast (expr, target_type);
1620 } else if ((expr_type == TypeManager.enum_type) && target_type.IsValueType &&
1621 target_type.IsSubclassOf (TypeManager.enum_type))
1622 return new UnboxCast (expr, target_type);
1625 // Notice that we have kept the expr_type unmodified, which is only
1627 if (expr is EnumConstant)
1628 expr = ((EnumConstant) expr).Child;
1630 expr = new EmptyCast (expr, TypeManager.EnumToUnderlying (expr_type));
1631 expr_type = expr.Type;
1634 Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc);
1639 ne = ExplicitNumericConversion (ec, expr, target_type, loc);
1644 // Unboxing conversion.
1646 if (expr_type == TypeManager.object_type && target_type.IsValueType){
1647 if (expr is NullLiteral){
1649 // Skip the ExplicitReferenceConversion because we can not convert
1650 // from Null to a ValueType, and ExplicitReference wont check against
1651 // null literal explicitly
1655 return new UnboxCast (expr, target_type);
1659 ne = ExplicitReferenceConversion (expr, target_type);
1665 if (target_type.IsPointer){
1666 if (expr_type.IsPointer)
1667 return new EmptyCast (expr, target_type);
1669 if (expr_type == TypeManager.sbyte_type ||
1670 expr_type == TypeManager.byte_type ||
1671 expr_type == TypeManager.short_type ||
1672 expr_type == TypeManager.ushort_type ||
1673 expr_type == TypeManager.int32_type ||
1674 expr_type == TypeManager.uint32_type ||
1675 expr_type == TypeManager.uint64_type ||
1676 expr_type == TypeManager.int64_type)
1677 return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
1679 if (expr_type.IsPointer){
1680 Expression e = null;
1682 if (target_type == TypeManager.sbyte_type)
1683 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
1684 else if (target_type == TypeManager.byte_type)
1685 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
1686 else if (target_type == TypeManager.short_type)
1687 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
1688 else if (target_type == TypeManager.ushort_type)
1689 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
1690 else if (target_type == TypeManager.int32_type)
1691 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
1692 else if (target_type == TypeManager.uint32_type)
1693 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
1694 else if (target_type == TypeManager.uint64_type)
1695 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
1696 else if (target_type == TypeManager.int64_type){
1697 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
1703 ci = ImplicitConversionStandard (ec, e, target_type, loc);
1708 ce = ExplicitNumericConversion (ec, e, target_type, loc);
1712 // We should always be able to go from an uint32
1713 // implicitly or explicitly to the other integral
1716 throw new Exception ("Internal compiler error");
1721 ne = ExplicitUserConversion (ec, expr, target_type, loc);
1725 if (expr is NullLiteral){
1726 Report.Error (37, loc, "Cannot convert null to value type `" +
1727 TypeManager.CSharpName (target_type) + "'");
1731 Error_CannotConvertType (loc, original_expr_type, target_type);
1736 /// Same as ExplicitConversion, only it doesn't include user defined conversions
1738 static public Expression ExplicitConversionStandard (EmitContext ec, Expression expr,
1739 Type target_type, Location l)
1741 Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
1746 ne = ExplicitNumericConversion (ec, expr, target_type, l);
1750 ne = ExplicitReferenceConversion (expr, target_type);
1754 Error_CannotConvertType (l, expr.Type, target_type);