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 {
23 // This is used to prettify the code: a null argument is allowed
24 // for ImplicitStandardConversion as long as it is known that
25 // no anonymous method will play a role.
27 // FIXME: renamed from `const' to `static' to allow bootstraping from older
28 // versions of the compiler that could not cope with this construct.
30 public static EmitContext ConstantEC = null;
32 static public void Error_CannotConvertType (Location loc, Type source, Type target)
34 Report.Error (30, loc, "Cannot convert type '" +
35 TypeManager.CSharpName (source) + "' to '" +
36 TypeManager.CSharpName (target) + "'");
39 static EmptyExpression MyEmptyExpr;
40 static public Expression ImplicitReferenceConversion (Expression expr, Type target_type)
42 Type expr_type = expr.Type;
44 if (expr_type == null && expr.eclass == ExprClass.MethodGroup){
45 // if we are a method group, emit a warning
50 if (expr_type == TypeManager.void_type)
54 // notice that it is possible to write "ValueType v = 1", the ValueType here
55 // is an abstract class, and not really a value type, so we apply the same rules.
57 if (target_type == TypeManager.object_type) {
59 // A pointer type cannot be converted to object
61 if (expr_type.IsPointer)
64 if (expr_type.IsValueType)
65 return new BoxedCast (expr);
66 if (expr_type.IsClass || expr_type.IsInterface || expr_type == TypeManager.enum_type){
67 if (expr_type == TypeManager.anonymous_method_type)
69 return new EmptyCast (expr, target_type);
73 } else if (target_type == TypeManager.value_type) {
74 if (expr_type.IsValueType)
75 return new BoxedCast (expr);
76 if (expr_type == TypeManager.null_type)
77 return new NullCast (expr, target_type);
80 } else if (expr_type.IsSubclassOf (target_type)) {
82 // Special case: enumeration to System.Enum.
83 // System.Enum is not a value type, it is a class, so we need
84 // a boxing conversion
87 return new BoxedCast (expr);
89 return new EmptyCast (expr, target_type);
92 // This code is kind of mirrored inside ImplicitStandardConversionExists
93 // with the small distinction that we only probe there
95 // Always ensure that the code here and there is in sync
97 // from the null type to any reference-type.
98 if (expr_type == TypeManager.null_type){
99 if (target_type.IsPointer)
100 return new EmptyCast (expr, target_type);
102 if (!target_type.IsValueType)
103 return new NullCast (expr, target_type);
106 // from any class-type S to any interface-type T.
107 if (target_type.IsInterface) {
108 if (target_type != TypeManager.iconvertible_type &&
109 expr_type.IsValueType && (expr is Constant) &&
110 !(expr is IntLiteral || expr is BoolLiteral ||
111 expr is FloatLiteral || expr is DoubleLiteral ||
112 expr is LongLiteral || expr is CharLiteral ||
113 expr is StringLiteral || expr is DecimalLiteral ||
114 expr is UIntLiteral || expr is ULongLiteral)) {
118 if (TypeManager.ImplementsInterface (expr_type, target_type)){
119 if (expr_type.IsClass)
120 return new EmptyCast (expr, target_type);
121 else if (expr_type.IsValueType)
122 return new BoxedCast (expr, target_type);
124 return new EmptyCast (expr, target_type);
128 // from any interface type S to interface-type T.
129 if (expr_type.IsInterface && target_type.IsInterface) {
130 if (TypeManager.ImplementsInterface (expr_type, target_type))
131 return new EmptyCast (expr, target_type);
136 // from an array-type S to an array-type of type T
137 if (expr_type.IsArray && target_type.IsArray) {
138 if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
140 Type expr_element_type = TypeManager.GetElementType (expr_type);
142 if (MyEmptyExpr == null)
143 MyEmptyExpr = new EmptyExpression ();
145 MyEmptyExpr.SetType (expr_element_type);
146 Type target_element_type = TypeManager.GetElementType (target_type);
148 if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
149 if (ImplicitStandardConversionExists (ConstantEC, MyEmptyExpr,
150 target_element_type))
151 return new EmptyCast (expr, target_type);
155 // from an array-type to System.Array
156 if (expr_type.IsArray && target_type == TypeManager.array_type)
157 return new EmptyCast (expr, target_type);
159 // from any delegate type to System.Delegate
160 if ((expr_type == TypeManager.delegate_type ||
161 expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
162 target_type == TypeManager.delegate_type)
163 return new EmptyCast (expr, target_type);
165 // from any array-type or delegate type into System.ICloneable.
166 if (expr_type.IsArray ||
167 expr_type == TypeManager.delegate_type ||
168 expr_type.IsSubclassOf (TypeManager.delegate_type))
169 if (target_type == TypeManager.icloneable_type)
170 return new EmptyCast (expr, target_type);
176 // Tests whether an implicit reference conversion exists between expr_type
179 public static bool ImplicitReferenceConversionExists (Expression expr, Type target_type)
181 Type expr_type = expr.Type;
184 // This is the boxed case.
186 if (target_type == TypeManager.object_type) {
187 if (expr_type.IsClass || expr_type.IsValueType ||
188 expr_type.IsInterface || expr_type == TypeManager.enum_type)
189 if (target_type != TypeManager.anonymous_method_type)
193 } else if (expr_type.IsSubclassOf (target_type))
196 // Please remember that all code below actually comes
197 // from ImplicitReferenceConversion so make sure code remains in sync
199 // from any class-type S to any interface-type T.
200 if (target_type.IsInterface) {
201 if (target_type != TypeManager.iconvertible_type &&
202 expr_type.IsValueType && (expr is Constant) &&
203 !(expr is IntLiteral || expr is BoolLiteral ||
204 expr is FloatLiteral || expr is DoubleLiteral ||
205 expr is LongLiteral || expr is CharLiteral ||
206 expr is StringLiteral || expr is DecimalLiteral ||
207 expr is UIntLiteral || expr is ULongLiteral)) {
211 if (TypeManager.ImplementsInterface (expr_type, target_type))
215 // from any interface type S to interface-type T.
216 if (expr_type.IsInterface && target_type.IsInterface)
217 if (TypeManager.ImplementsInterface (expr_type, target_type))
220 // from an array-type S to an array-type of type T
221 if (expr_type.IsArray && target_type.IsArray) {
222 if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
224 Type expr_element_type = expr_type.GetElementType ();
226 if (MyEmptyExpr == null)
227 MyEmptyExpr = new EmptyExpression ();
229 MyEmptyExpr.SetType (expr_element_type);
230 Type target_element_type = TypeManager.GetElementType (target_type);
232 if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
233 if (ImplicitStandardConversionExists (ConstantEC, MyEmptyExpr,
234 target_element_type))
239 // from an array-type to System.Array
240 if (expr_type.IsArray && (target_type == TypeManager.array_type))
243 // from any delegate type to System.Delegate
244 if ((expr_type == TypeManager.delegate_type ||
245 expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
246 target_type == TypeManager.delegate_type)
247 if (target_type.IsAssignableFrom (expr_type))
250 // from any array-type or delegate type into System.ICloneable.
251 if (expr_type.IsArray ||
252 expr_type == TypeManager.delegate_type ||
253 expr_type.IsSubclassOf (TypeManager.delegate_type))
254 if (target_type == TypeManager.icloneable_type)
257 // from the null type to any reference-type.
258 if (expr_type == TypeManager.null_type){
259 if (target_type.IsPointer)
262 if (!target_type.IsValueType)
269 /// Implicit Numeric Conversions.
271 /// expr is the expression to convert, returns a new expression of type
272 /// target_type or null if an implicit conversion is not possible.
274 static public Expression ImplicitNumericConversion (EmitContext ec, Expression expr,
275 Type target_type, Location loc)
277 Type expr_type = expr.Type;
280 // Attempt to do the implicit constant expression conversions
282 if (expr is Constant){
283 if (expr is IntConstant){
286 e = TryImplicitIntConversion (target_type, (IntConstant) expr);
290 } else if (expr is LongConstant && target_type == TypeManager.uint64_type){
292 // Try the implicit constant expression conversion
293 // from long to ulong, instead of a nice routine,
296 long v = ((LongConstant) expr).Value;
298 return new ULongConstant ((ulong) v);
302 Type real_target_type = target_type;
304 if (expr_type == TypeManager.sbyte_type){
306 // From sbyte to short, int, long, float, double.
308 if (real_target_type == TypeManager.int32_type)
309 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
310 if (real_target_type == TypeManager.int64_type)
311 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
312 if (real_target_type == TypeManager.double_type)
313 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
314 if (real_target_type == TypeManager.float_type)
315 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
316 if (real_target_type == TypeManager.short_type)
317 return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
318 } else if (expr_type == TypeManager.byte_type){
320 // From byte to short, ushort, int, uint, long, ulong, float, double
322 if ((real_target_type == TypeManager.short_type) ||
323 (real_target_type == TypeManager.ushort_type) ||
324 (real_target_type == TypeManager.int32_type) ||
325 (real_target_type == TypeManager.uint32_type))
326 return new EmptyCast (expr, target_type);
328 if (real_target_type == TypeManager.uint64_type)
329 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
330 if (real_target_type == TypeManager.int64_type)
331 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
332 if (real_target_type == TypeManager.float_type)
333 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
334 if (real_target_type == TypeManager.double_type)
335 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
336 } else if (expr_type == TypeManager.short_type){
338 // From short to int, long, float, double
340 if (real_target_type == TypeManager.int32_type)
341 return new EmptyCast (expr, target_type);
342 if (real_target_type == TypeManager.int64_type)
343 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
344 if (real_target_type == TypeManager.double_type)
345 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
346 if (real_target_type == TypeManager.float_type)
347 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
348 } else if (expr_type == TypeManager.ushort_type){
350 // From ushort to int, uint, long, ulong, float, double
352 if (real_target_type == TypeManager.uint32_type)
353 return new EmptyCast (expr, target_type);
355 if (real_target_type == TypeManager.uint64_type)
356 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
357 if (real_target_type == TypeManager.int32_type)
358 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
359 if (real_target_type == TypeManager.int64_type)
360 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
361 if (real_target_type == TypeManager.double_type)
362 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
363 if (real_target_type == TypeManager.float_type)
364 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
365 } else if (expr_type == TypeManager.int32_type){
367 // From int to long, float, double
369 if (real_target_type == TypeManager.int64_type)
370 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
371 if (real_target_type == TypeManager.double_type)
372 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
373 if (real_target_type == TypeManager.float_type)
374 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
375 } else if (expr_type == TypeManager.uint32_type){
377 // From uint to long, ulong, float, double
379 if (real_target_type == TypeManager.int64_type)
380 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
381 if (real_target_type == TypeManager.uint64_type)
382 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
383 if (real_target_type == TypeManager.double_type)
384 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
386 if (real_target_type == TypeManager.float_type)
387 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
389 } else if (expr_type == TypeManager.int64_type){
391 // From long/ulong to float, double
393 if (real_target_type == TypeManager.double_type)
394 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
395 if (real_target_type == TypeManager.float_type)
396 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
397 } else if (expr_type == TypeManager.uint64_type){
399 // From ulong to float, double
401 if (real_target_type == TypeManager.double_type)
402 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
404 if (real_target_type == TypeManager.float_type)
405 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
407 } else if (expr_type == TypeManager.char_type){
409 // From char to ushort, int, uint, long, ulong, float, double
411 if ((real_target_type == TypeManager.ushort_type) ||
412 (real_target_type == TypeManager.int32_type) ||
413 (real_target_type == TypeManager.uint32_type))
414 return new EmptyCast (expr, target_type);
415 if (real_target_type == TypeManager.uint64_type)
416 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
417 if (real_target_type == TypeManager.int64_type)
418 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
419 if (real_target_type == TypeManager.float_type)
420 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
421 if (real_target_type == TypeManager.double_type)
422 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
423 } else if (expr_type == TypeManager.float_type){
427 if (real_target_type == TypeManager.double_type)
428 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
436 /// Same as ImplicitStandardConversionExists except that it also looks at
437 /// implicit user defined conversions - needed for overload resolution
439 public static bool ImplicitConversionExists (EmitContext ec, Expression expr, Type target_type)
441 if (ImplicitStandardConversionExists (ec, expr, target_type))
444 Expression dummy = ImplicitUserConversion (ec, expr, target_type, Location.Null);
452 public static bool ImplicitUserConversionExists (EmitContext ec, Type source, Type target)
454 Expression dummy = ImplicitUserConversion (
455 ec, new EmptyExpression (source), target, Location.Null);
456 return dummy != null;
460 /// Determines if a standard implicit conversion exists from
461 /// expr_type to target_type
463 /// ec should point to a real EmitContext if expr.Type is TypeManager.anonymous_method_type.
465 public static bool ImplicitStandardConversionExists (EmitContext ec, Expression expr, Type target_type)
467 Type expr_type = expr.Type;
469 if (expr_type == TypeManager.void_type)
472 if (expr_type == target_type)
475 // First numeric conversions
477 if (expr_type == TypeManager.sbyte_type){
479 // From sbyte to short, int, long, float, double.
481 if ((target_type == TypeManager.int32_type) ||
482 (target_type == TypeManager.int64_type) ||
483 (target_type == TypeManager.double_type) ||
484 (target_type == TypeManager.float_type) ||
485 (target_type == TypeManager.short_type) ||
486 (target_type == TypeManager.decimal_type))
489 } else if (expr_type == TypeManager.byte_type){
491 // From byte to short, ushort, int, uint, long, ulong, float, double
493 if ((target_type == TypeManager.short_type) ||
494 (target_type == TypeManager.ushort_type) ||
495 (target_type == TypeManager.int32_type) ||
496 (target_type == TypeManager.uint32_type) ||
497 (target_type == TypeManager.uint64_type) ||
498 (target_type == TypeManager.int64_type) ||
499 (target_type == TypeManager.float_type) ||
500 (target_type == TypeManager.double_type) ||
501 (target_type == TypeManager.decimal_type))
504 } else if (expr_type == TypeManager.short_type){
506 // From short to int, long, float, double
508 if ((target_type == TypeManager.int32_type) ||
509 (target_type == TypeManager.int64_type) ||
510 (target_type == TypeManager.double_type) ||
511 (target_type == TypeManager.float_type) ||
512 (target_type == TypeManager.decimal_type))
515 } else if (expr_type == TypeManager.ushort_type){
517 // From ushort to int, uint, long, ulong, float, double
519 if ((target_type == TypeManager.uint32_type) ||
520 (target_type == TypeManager.uint64_type) ||
521 (target_type == TypeManager.int32_type) ||
522 (target_type == TypeManager.int64_type) ||
523 (target_type == TypeManager.double_type) ||
524 (target_type == TypeManager.float_type) ||
525 (target_type == TypeManager.decimal_type))
528 } else if (expr_type == TypeManager.int32_type){
530 // From int to long, float, double
532 if ((target_type == TypeManager.int64_type) ||
533 (target_type == TypeManager.double_type) ||
534 (target_type == TypeManager.float_type) ||
535 (target_type == TypeManager.decimal_type))
538 } else if (expr_type == TypeManager.uint32_type){
540 // From uint to long, ulong, float, double
542 if ((target_type == TypeManager.int64_type) ||
543 (target_type == TypeManager.uint64_type) ||
544 (target_type == TypeManager.double_type) ||
545 (target_type == TypeManager.float_type) ||
546 (target_type == TypeManager.decimal_type))
549 } else if ((expr_type == TypeManager.uint64_type) ||
550 (expr_type == TypeManager.int64_type)) {
552 // From long/ulong to float, double
554 if ((target_type == TypeManager.double_type) ||
555 (target_type == TypeManager.float_type) ||
556 (target_type == TypeManager.decimal_type))
559 } else if (expr_type == TypeManager.char_type){
561 // From char to ushort, int, uint, long, ulong, float, double
563 if ((target_type == TypeManager.ushort_type) ||
564 (target_type == TypeManager.int32_type) ||
565 (target_type == TypeManager.uint32_type) ||
566 (target_type == TypeManager.uint64_type) ||
567 (target_type == TypeManager.int64_type) ||
568 (target_type == TypeManager.float_type) ||
569 (target_type == TypeManager.double_type) ||
570 (target_type == TypeManager.decimal_type))
573 } else if (expr_type == TypeManager.float_type){
577 if (target_type == TypeManager.double_type)
581 if (ImplicitReferenceConversionExists (expr, target_type))
585 // Implicit Constant Expression Conversions
587 if (expr is IntConstant){
588 int value = ((IntConstant) expr).Value;
590 if (target_type == TypeManager.sbyte_type){
591 if (value >= SByte.MinValue && value <= SByte.MaxValue)
593 } else if (target_type == TypeManager.byte_type){
594 if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
596 } else if (target_type == TypeManager.short_type){
597 if (value >= Int16.MinValue && value <= Int16.MaxValue)
599 } else if (target_type == TypeManager.ushort_type){
600 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
602 } else if (target_type == TypeManager.uint32_type){
605 } else if (target_type == TypeManager.uint64_type){
607 // we can optimize this case: a positive int32
608 // always fits on a uint64. But we need an opcode
615 if (value == 0 && expr is IntLiteral && TypeManager.IsEnumType (target_type))
619 if (expr is LongConstant && target_type == TypeManager.uint64_type){
621 // Try the implicit constant expression conversion
622 // from long to ulong, instead of a nice routine,
625 long v = ((LongConstant) expr).Value;
630 if ((target_type == TypeManager.enum_type ||
631 target_type.IsSubclassOf (TypeManager.enum_type)) &&
633 IntLiteral i = (IntLiteral) expr;
640 // If `expr_type' implements `target_type' (which is an iface)
641 // see TryImplicitIntConversion
643 if (target_type.IsInterface && target_type.IsAssignableFrom (expr_type))
646 if (target_type == TypeManager.void_ptr_type && expr_type.IsPointer)
649 if (expr_type == TypeManager.anonymous_method_type){
650 if (!TypeManager.IsDelegateType (target_type))
653 AnonymousMethod am = (AnonymousMethod) expr;
655 Expression conv = am.Compatible (ec, target_type, true);
664 // Used internally by FindMostEncompassedType, this is used
665 // to avoid creating lots of objects in the tight loop inside
666 // FindMostEncompassedType
668 static EmptyExpression priv_fmet_param;
671 /// Finds "most encompassed type" according to the spec (13.4.2)
672 /// amongst the methods in the MethodGroupExpr
674 static Type FindMostEncompassedType (EmitContext ec, ArrayList types)
678 if (priv_fmet_param == null)
679 priv_fmet_param = new EmptyExpression ();
681 foreach (Type t in types){
682 priv_fmet_param.SetType (t);
689 if (ImplicitStandardConversionExists (ec, priv_fmet_param, best))
697 // Used internally by FindMostEncompassingType, this is used
698 // to avoid creating lots of objects in the tight loop inside
699 // FindMostEncompassingType
701 static EmptyExpression priv_fmee_ret;
704 /// Finds "most encompassing type" according to the spec (13.4.2)
705 /// amongst the types in the given set
707 static Type FindMostEncompassingType (EmitContext ec, ArrayList types)
711 if (priv_fmee_ret == null)
712 priv_fmee_ret = new EmptyExpression ();
714 foreach (Type t in types){
715 priv_fmee_ret.SetType (best);
722 if (ImplicitStandardConversionExists (ec, priv_fmee_ret, t))
730 // Used to avoid creating too many objects
732 static EmptyExpression priv_fms_expr;
735 /// Finds the most specific source Sx according to the rules of the spec (13.4.4)
736 /// by making use of FindMostEncomp* methods. Applies the correct rules separately
737 /// for explicit and implicit conversion operators.
739 static public Type FindMostSpecificSource (EmitContext ec, MethodGroupExpr me,
740 Expression source, bool apply_explicit_conv_rules,
743 ArrayList src_types_set = new ArrayList ();
745 if (priv_fms_expr == null)
746 priv_fms_expr = new EmptyExpression ();
749 // If any operator converts from S then Sx = S
751 Type source_type = source.Type;
752 foreach (MethodBase mb in me.Methods){
753 ParameterData pd = Invocation.GetParameterData (mb);
754 Type param_type = pd.ParameterType (0);
756 if (param_type == source_type)
759 if (apply_explicit_conv_rules) {
762 // Find the set of applicable user-defined conversion operators, U. This set
764 // user-defined implicit or explicit conversion operators declared by
765 // the classes or structs in D that convert from a type encompassing
766 // or encompassed by S to a type encompassing or encompassed by T
768 priv_fms_expr.SetType (param_type);
769 if (ImplicitStandardConversionExists (ec, priv_fms_expr, source_type))
770 src_types_set.Add (param_type);
772 if (ImplicitStandardConversionExists (ec, source, param_type))
773 src_types_set.Add (param_type);
777 // Only if S is encompassed by param_type
779 if (ImplicitStandardConversionExists (ec, source, param_type))
780 src_types_set.Add (param_type);
785 // Explicit Conv rules
787 if (apply_explicit_conv_rules) {
788 ArrayList candidate_set = new ArrayList ();
790 foreach (Type param_type in src_types_set){
791 if (ImplicitStandardConversionExists (ec, source, param_type))
792 candidate_set.Add (param_type);
795 if (candidate_set.Count != 0)
796 return FindMostEncompassedType (ec, candidate_set);
802 if (apply_explicit_conv_rules)
803 return FindMostEncompassingType (ec, src_types_set);
805 return FindMostEncompassedType (ec, src_types_set);
809 // Useful in avoiding proliferation of objects
811 static EmptyExpression priv_fmt_expr;
814 /// Finds the most specific target Tx according to section 13.4.4
816 static public Type FindMostSpecificTarget (EmitContext ec, MethodGroupExpr me,
817 Type target, bool apply_explicit_conv_rules,
820 ArrayList tgt_types_set = new ArrayList ();
822 if (priv_fmt_expr == null)
823 priv_fmt_expr = new EmptyExpression ();
826 // If any operator converts to T then Tx = T
828 foreach (MethodInfo mi in me.Methods){
829 Type ret_type = mi.ReturnType;
831 if (ret_type == target)
834 if (apply_explicit_conv_rules) {
837 // Find the set of applicable user-defined conversion operators, U.
839 // This set consists of the
840 // user-defined implicit or explicit conversion operators declared by
841 // the classes or structs in D that convert from a type encompassing
842 // or encompassed by S to a type encompassing or encompassed by T
844 priv_fms_expr.SetType (ret_type);
845 if (ImplicitStandardConversionExists (ec, priv_fms_expr, target))
846 tgt_types_set.Add (ret_type);
848 priv_fms_expr.SetType (target);
849 if (ImplicitStandardConversionExists (ec, priv_fms_expr, ret_type))
850 tgt_types_set.Add (ret_type);
854 // Only if T is encompassed by param_type
856 priv_fms_expr.SetType (ret_type);
857 if (ImplicitStandardConversionExists (ec, priv_fms_expr, target))
858 tgt_types_set.Add (ret_type);
863 // Explicit conv rules
865 if (apply_explicit_conv_rules) {
866 ArrayList candidate_set = new ArrayList ();
868 foreach (Type ret_type in tgt_types_set){
869 priv_fmt_expr.SetType (ret_type);
871 if (ImplicitStandardConversionExists (ec, priv_fmt_expr, target))
872 candidate_set.Add (ret_type);
875 if (candidate_set.Count != 0)
876 return FindMostEncompassingType (ec, candidate_set);
880 // Okay, final case !
882 if (apply_explicit_conv_rules)
883 return FindMostEncompassedType (ec, tgt_types_set);
885 return FindMostEncompassingType (ec, tgt_types_set);
889 /// User-defined Implicit conversions
891 static public Expression ImplicitUserConversion (EmitContext ec, Expression source,
892 Type target, Location loc)
894 return UserDefinedConversion (ec, source, target, loc, false);
898 /// User-defined Explicit conversions
900 static public Expression ExplicitUserConversion (EmitContext ec, Expression source,
901 Type target, Location loc)
903 return UserDefinedConversion (ec, source, target, loc, true);
906 static DoubleHash explicit_conv = new DoubleHash (100);
907 static DoubleHash implicit_conv = new DoubleHash (100);
909 /// Computes the MethodGroup for the user-defined conversion
910 /// operators from source_type to target_type. `look_for_explicit'
911 /// controls whether we should also include the list of explicit
914 static MethodGroupExpr GetConversionOperators (EmitContext ec,
915 Type source_type, Type target_type,
916 Location loc, bool look_for_explicit)
918 Expression mg1 = null, mg2 = null;
919 Expression mg5 = null, mg6 = null, mg7 = null, mg8 = null;
922 op_name = "op_Implicit";
924 MethodGroupExpr union3;
926 if ((look_for_explicit ? explicit_conv : implicit_conv).Lookup (source_type, target_type, out r))
927 return (MethodGroupExpr) r;
929 mg1 = Expression.MethodLookup (ec, source_type, op_name, loc);
930 if (source_type.BaseType != null)
931 mg2 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
934 union3 = (MethodGroupExpr) mg2;
935 else if (mg2 == null)
936 union3 = (MethodGroupExpr) mg1;
938 union3 = Invocation.MakeUnionSet (mg1, mg2, loc);
940 mg1 = Expression.MethodLookup (ec, target_type, op_name, loc);
943 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
945 union3 = (MethodGroupExpr) mg1;
948 if (target_type.BaseType != null)
949 mg1 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
953 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
955 union3 = (MethodGroupExpr) mg1;
958 MethodGroupExpr union4 = null;
960 if (look_for_explicit) {
961 op_name = "op_Explicit";
963 mg5 = Expression.MemberLookup (ec, source_type, op_name, loc);
964 if (source_type.BaseType != null)
965 mg6 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
967 mg7 = Expression.MemberLookup (ec, target_type, op_name, loc);
968 if (target_type.BaseType != null)
969 mg8 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
971 MethodGroupExpr union5 = Invocation.MakeUnionSet (mg5, mg6, loc);
972 MethodGroupExpr union6 = Invocation.MakeUnionSet (mg7, mg8, loc);
974 union4 = Invocation.MakeUnionSet (union5, union6, loc);
977 MethodGroupExpr ret = Invocation.MakeUnionSet (union3, union4, loc);
978 (look_for_explicit ? explicit_conv : implicit_conv).Insert (source_type, target_type, ret);
983 /// User-defined conversions
985 static public Expression UserDefinedConversion (EmitContext ec, Expression source,
986 Type target, Location loc,
987 bool look_for_explicit)
989 MethodGroupExpr union;
990 Type source_type = source.Type;
991 MethodBase method = null;
993 union = GetConversionOperators (ec, source_type, target, loc, look_for_explicit);
997 Type most_specific_source, most_specific_target;
999 most_specific_source = FindMostSpecificSource (ec, union, source, look_for_explicit, loc);
1000 if (most_specific_source == null)
1003 most_specific_target = FindMostSpecificTarget (ec, union, target, look_for_explicit, loc);
1004 if (most_specific_target == null)
1010 foreach (MethodBase mb in union.Methods){
1011 ParameterData pd = Invocation.GetParameterData (mb);
1012 MethodInfo mi = (MethodInfo) mb;
1014 if (pd.ParameterType (0) == most_specific_source &&
1015 mi.ReturnType == most_specific_target) {
1021 if (method == null || count > 1)
1026 // This will do the conversion to the best match that we
1027 // found. Now we need to perform an implict standard conversion
1028 // if the best match was not the type that we were requested
1031 if (look_for_explicit)
1032 source = ExplicitConversionStandard (ec, source, most_specific_source, loc);
1034 source = ImplicitConversionStandard (ec, source, most_specific_source, loc);
1040 e = new UserCast ((MethodInfo) method, source, loc);
1041 if (e.Type != target){
1042 if (!look_for_explicit)
1043 e = ImplicitConversionStandard (ec, e, target, loc);
1045 e = ExplicitConversionStandard (ec, e, target, loc);
1052 /// Converts implicitly the resolved expression `expr' into the
1053 /// `target_type'. It returns a new expression that can be used
1054 /// in a context that expects a `target_type'.
1056 static public Expression ImplicitConversion (EmitContext ec, Expression expr,
1057 Type target_type, Location loc)
1061 if (target_type == null)
1062 throw new Exception ("Target type is null");
1064 e = ImplicitConversionStandard (ec, expr, target_type, loc);
1068 e = ImplicitUserConversion (ec, expr, target_type, loc);
1077 /// Attempts to apply the `Standard Implicit
1078 /// Conversion' rules to the expression `expr' into
1079 /// the `target_type'. It returns a new expression
1080 /// that can be used in a context that expects a
1083 /// This is different from `ImplicitConversion' in that the
1084 /// user defined implicit conversions are excluded.
1086 static public Expression ImplicitConversionStandard (EmitContext ec, Expression expr,
1087 Type target_type, Location loc)
1089 Type expr_type = expr.Type;
1092 if (expr.eclass == ExprClass.MethodGroup){
1093 if (!TypeManager.IsDelegateType (target_type)){
1098 // Only allow anonymous method conversions on post ISO_1
1100 if (RootContext.Version != LanguageVersion.ISO_1){
1101 MethodGroupExpr mg = expr as MethodGroupExpr;
1103 return ImplicitDelegateCreation.Create (ec, mg, target_type, loc);
1107 if (expr_type == target_type && expr_type != TypeManager.null_type)
1110 e = ImplicitNumericConversion (ec, expr, target_type, loc);
1114 e = ImplicitReferenceConversion (expr, target_type);
1118 if ((target_type == TypeManager.enum_type ||
1119 target_type.IsSubclassOf (TypeManager.enum_type)) &&
1120 expr is IntLiteral){
1121 IntLiteral i = (IntLiteral) expr;
1124 return new EnumConstant ((Constant) expr, target_type);
1128 if (expr_type.IsPointer){
1129 if (target_type == TypeManager.void_ptr_type)
1130 return new EmptyCast (expr, target_type);
1133 // yep, comparing pointer types cant be done with
1134 // t1 == t2, we have to compare their element types.
1136 if (target_type.IsPointer){
1137 if (TypeManager.GetElementType(target_type) == TypeManager.GetElementType(expr_type))
1142 if (target_type.IsPointer) {
1143 if (expr_type == TypeManager.null_type)
1144 return new EmptyCast (expr, target_type);
1146 if (expr_type == TypeManager.void_ptr_type)
1147 return new EmptyCast (expr, target_type);
1151 if (expr_type == TypeManager.anonymous_method_type){
1152 if (!TypeManager.IsDelegateType (target_type)){
1153 Report.Error (1660, loc,
1154 "Cannot convert anonymous method to `{0}', since it is not a delegate",
1155 TypeManager.CSharpName (target_type));
1159 AnonymousMethod am = (AnonymousMethod) expr;
1160 int errors = Report.Errors;
1162 Expression conv = am.Compatible (ec, target_type, false);
1167 // We return something instead of null, to avoid
1168 // the duplicate error, since am.Compatible would have
1169 // reported that already
1171 if (errors != Report.Errors)
1172 return new EmptyCast (expr, target_type);
1179 /// Attempts to perform an implicit constant conversion of the IntConstant
1180 /// into a different data type using casts (See Implicit Constant
1181 /// Expression Conversions)
1183 static public Expression TryImplicitIntConversion (Type target_type, IntConstant ic)
1185 int value = ic.Value;
1187 if (target_type == TypeManager.sbyte_type){
1188 if (value >= SByte.MinValue && value <= SByte.MaxValue)
1189 return new SByteConstant ((sbyte) value);
1190 } else if (target_type == TypeManager.byte_type){
1191 if (value >= Byte.MinValue && value <= Byte.MaxValue)
1192 return new ByteConstant ((byte) value);
1193 } else if (target_type == TypeManager.short_type){
1194 if (value >= Int16.MinValue && value <= Int16.MaxValue)
1195 return new ShortConstant ((short) value);
1196 } else if (target_type == TypeManager.ushort_type){
1197 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
1198 return new UShortConstant ((ushort) value);
1199 } else if (target_type == TypeManager.uint32_type){
1201 return new UIntConstant ((uint) value);
1202 } else if (target_type == TypeManager.uint64_type){
1204 // we can optimize this case: a positive int32
1205 // always fits on a uint64. But we need an opcode
1209 return new ULongConstant ((ulong) value);
1210 } else if (target_type == TypeManager.double_type)
1211 return new DoubleConstant ((double) value);
1212 else if (target_type == TypeManager.float_type)
1213 return new FloatConstant ((float) value);
1215 if (value == 0 && ic is IntLiteral && TypeManager.IsEnumType (target_type)){
1216 Type underlying = TypeManager.EnumToUnderlying (target_type);
1217 Constant e = (Constant) ic;
1220 // Possibly, we need to create a different 0 literal before passing
1223 if (underlying == TypeManager.int64_type)
1224 e = new LongLiteral (0);
1225 else if (underlying == TypeManager.uint64_type)
1226 e = new ULongLiteral (0);
1228 return new EnumConstant (e, target_type);
1232 // If `target_type' is an interface and the type of `ic' implements the interface
1233 // e.g. target_type is IComparable, IConvertible, IFormattable
1235 if (target_type.IsInterface && target_type.IsAssignableFrom (ic.Type))
1236 return new BoxedCast (ic);
1241 static public void Error_CannotImplicitConversion (Location loc, Type source, Type target)
1243 if (source.Name == target.Name){
1244 Report.ExtraInformation (loc,
1246 "The type {0} has two conflicting definitons, one comes from {0} and the other from {1}",
1247 source.Assembly.FullName, target.Assembly.FullName));
1250 Report.Error (29, loc, "Cannot convert implicitly from {0} to `{1}'",
1251 source == TypeManager.anonymous_method_type ?
1252 "anonymous method" : "`" + TypeManager.CSharpName (source) + "'",
1253 TypeManager.CSharpName (target));
1257 /// Attempts to implicitly convert `source' into `target_type', using
1258 /// ImplicitConversion. If there is no implicit conversion, then
1259 /// an error is signaled
1261 static public Expression ImplicitConversionRequired (EmitContext ec, Expression source,
1262 Type target_type, Location loc)
1266 e = ImplicitConversion (ec, source, target_type, loc);
1270 if (source is DoubleLiteral) {
1271 if (target_type == TypeManager.float_type) {
1272 Error_664 (loc, "float", "f");
1275 if (target_type == TypeManager.decimal_type) {
1276 Error_664 (loc, "decimal", "m");
1281 if (source is Constant){
1282 Constant c = (Constant) source;
1284 Expression.Error_ConstantValueCannotBeConverted (loc, c.AsString (), target_type);
1288 Error_CannotImplicitConversion (loc, source.Type, target_type);
1293 static void Error_664 (Location loc, string type, string suffix) {
1294 Report.Error (664, loc,
1295 "Literal of type double cannot be implicitly converted to type '{0}'. Add suffix '{1}' to create a literal of this type",
1300 /// Performs the explicit numeric conversions
1302 static Expression ExplicitNumericConversion (EmitContext ec, Expression expr, Type target_type, Location loc)
1304 Type expr_type = expr.Type;
1307 // If we have an enumeration, extract the underlying type,
1308 // use this during the comparison, but wrap around the original
1311 Type real_target_type = target_type;
1313 if (TypeManager.IsEnumType (real_target_type))
1314 real_target_type = TypeManager.EnumToUnderlying (real_target_type);
1316 if (ImplicitStandardConversionExists (ec, expr, real_target_type)){
1317 Expression ce = ImplicitConversionStandard (ec, expr, real_target_type, loc);
1319 if (real_target_type != target_type)
1320 return new EmptyCast (ce, target_type);
1324 if (expr_type == TypeManager.sbyte_type){
1326 // From sbyte to byte, ushort, uint, ulong, char
1328 if (real_target_type == TypeManager.byte_type)
1329 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U1);
1330 if (real_target_type == TypeManager.ushort_type)
1331 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U2);
1332 if (real_target_type == TypeManager.uint32_type)
1333 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U4);
1334 if (real_target_type == TypeManager.uint64_type)
1335 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U8);
1336 if (real_target_type == TypeManager.char_type)
1337 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_CH);
1338 } else if (expr_type == TypeManager.byte_type){
1340 // From byte to sbyte and char
1342 if (real_target_type == TypeManager.sbyte_type)
1343 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_I1);
1344 if (real_target_type == TypeManager.char_type)
1345 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_CH);
1346 } else if (expr_type == TypeManager.short_type){
1348 // From short to sbyte, byte, ushort, uint, ulong, char
1350 if (real_target_type == TypeManager.sbyte_type)
1351 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_I1);
1352 if (real_target_type == TypeManager.byte_type)
1353 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U1);
1354 if (real_target_type == TypeManager.ushort_type)
1355 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U2);
1356 if (real_target_type == TypeManager.uint32_type)
1357 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U4);
1358 if (real_target_type == TypeManager.uint64_type)
1359 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U8);
1360 if (real_target_type == TypeManager.char_type)
1361 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_CH);
1362 } else if (expr_type == TypeManager.ushort_type){
1364 // From ushort to sbyte, byte, short, char
1366 if (real_target_type == TypeManager.sbyte_type)
1367 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I1);
1368 if (real_target_type == TypeManager.byte_type)
1369 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_U1);
1370 if (real_target_type == TypeManager.short_type)
1371 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I2);
1372 if (real_target_type == TypeManager.char_type)
1373 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_CH);
1374 } else if (expr_type == TypeManager.int32_type){
1376 // From int to sbyte, byte, short, ushort, uint, ulong, char
1378 if (real_target_type == TypeManager.sbyte_type)
1379 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I1);
1380 if (real_target_type == TypeManager.byte_type)
1381 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U1);
1382 if (real_target_type == TypeManager.short_type)
1383 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I2);
1384 if (real_target_type == TypeManager.ushort_type)
1385 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U2);
1386 if (real_target_type == TypeManager.uint32_type)
1387 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U4);
1388 if (real_target_type == TypeManager.uint64_type)
1389 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U8);
1390 if (real_target_type == TypeManager.char_type)
1391 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_CH);
1392 } else if (expr_type == TypeManager.uint32_type){
1394 // From uint to sbyte, byte, short, ushort, int, char
1396 if (real_target_type == TypeManager.sbyte_type)
1397 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I1);
1398 if (real_target_type == TypeManager.byte_type)
1399 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U1);
1400 if (real_target_type == TypeManager.short_type)
1401 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I2);
1402 if (real_target_type == TypeManager.ushort_type)
1403 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U2);
1404 if (real_target_type == TypeManager.int32_type)
1405 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I4);
1406 if (real_target_type == TypeManager.char_type)
1407 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_CH);
1408 } else if (expr_type == TypeManager.int64_type){
1410 // From long to sbyte, byte, short, ushort, int, uint, ulong, char
1412 if (real_target_type == TypeManager.sbyte_type)
1413 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I1);
1414 if (real_target_type == TypeManager.byte_type)
1415 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U1);
1416 if (real_target_type == TypeManager.short_type)
1417 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I2);
1418 if (real_target_type == TypeManager.ushort_type)
1419 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U2);
1420 if (real_target_type == TypeManager.int32_type)
1421 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I4);
1422 if (real_target_type == TypeManager.uint32_type)
1423 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U4);
1424 if (real_target_type == TypeManager.uint64_type)
1425 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U8);
1426 if (real_target_type == TypeManager.char_type)
1427 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_CH);
1428 } else if (expr_type == TypeManager.uint64_type){
1430 // From ulong to sbyte, byte, short, ushort, int, uint, long, char
1432 if (real_target_type == TypeManager.sbyte_type)
1433 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I1);
1434 if (real_target_type == TypeManager.byte_type)
1435 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U1);
1436 if (real_target_type == TypeManager.short_type)
1437 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I2);
1438 if (real_target_type == TypeManager.ushort_type)
1439 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U2);
1440 if (real_target_type == TypeManager.int32_type)
1441 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I4);
1442 if (real_target_type == TypeManager.uint32_type)
1443 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U4);
1444 if (real_target_type == TypeManager.int64_type)
1445 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I8);
1446 if (real_target_type == TypeManager.char_type)
1447 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_CH);
1448 } else if (expr_type == TypeManager.char_type){
1450 // From char to sbyte, byte, short
1452 if (real_target_type == TypeManager.sbyte_type)
1453 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I1);
1454 if (real_target_type == TypeManager.byte_type)
1455 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_U1);
1456 if (real_target_type == TypeManager.short_type)
1457 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I2);
1458 } else if (expr_type == TypeManager.float_type){
1460 // From float to sbyte, byte, short,
1461 // ushort, int, uint, long, ulong, char
1464 if (real_target_type == TypeManager.sbyte_type)
1465 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I1);
1466 if (real_target_type == TypeManager.byte_type)
1467 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U1);
1468 if (real_target_type == TypeManager.short_type)
1469 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I2);
1470 if (real_target_type == TypeManager.ushort_type)
1471 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U2);
1472 if (real_target_type == TypeManager.int32_type)
1473 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I4);
1474 if (real_target_type == TypeManager.uint32_type)
1475 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U4);
1476 if (real_target_type == TypeManager.int64_type)
1477 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I8);
1478 if (real_target_type == TypeManager.uint64_type)
1479 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U8);
1480 if (real_target_type == TypeManager.char_type)
1481 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_CH);
1482 } else if (expr_type == TypeManager.double_type){
1484 // From double to byte, byte, short,
1485 // ushort, int, uint, long, ulong,
1486 // char, float or decimal
1488 if (real_target_type == TypeManager.sbyte_type)
1489 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I1);
1490 if (real_target_type == TypeManager.byte_type)
1491 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U1);
1492 if (real_target_type == TypeManager.short_type)
1493 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I2);
1494 if (real_target_type == TypeManager.ushort_type)
1495 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U2);
1496 if (real_target_type == TypeManager.int32_type)
1497 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I4);
1498 if (real_target_type == TypeManager.uint32_type)
1499 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U4);
1500 if (real_target_type == TypeManager.int64_type)
1501 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I8);
1502 if (real_target_type == TypeManager.uint64_type)
1503 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U8);
1504 if (real_target_type == TypeManager.char_type)
1505 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_CH);
1506 if (real_target_type == TypeManager.float_type)
1507 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_R4);
1510 // decimal is taken care of by the op_Explicit methods.
1516 /// Returns whether an explicit reference conversion can be performed
1517 /// from source_type to target_type
1519 public static bool ExplicitReferenceConversionExists (Type source_type, Type target_type)
1521 bool target_is_value_type = target_type.IsValueType;
1523 if (source_type == target_type)
1527 // From object to any reference type
1529 if (source_type == TypeManager.object_type && !target_is_value_type)
1533 // From any class S to any class-type T, provided S is a base class of T
1535 if (target_type.IsSubclassOf (source_type))
1539 // From any interface type S to any interface T provided S is not derived from T
1541 if (source_type.IsInterface && target_type.IsInterface){
1542 if (!target_type.IsSubclassOf (source_type))
1547 // From any class type S to any interface T, provided S is not sealed
1548 // and provided S does not implement T.
1550 if (target_type.IsInterface && !source_type.IsSealed &&
1551 !TypeManager.ImplementsInterface (source_type, target_type))
1555 // From any interface-type S to to any class type T, provided T is not
1556 // sealed, or provided T implements S.
1558 if (source_type.IsInterface &&
1559 (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)))
1563 // From an array type S with an element type Se to an array type T with an
1564 // element type Te provided all the following are true:
1565 // * S and T differe only in element type, in other words, S and T
1566 // have the same number of dimensions.
1567 // * Both Se and Te are reference types
1568 // * An explicit referenc conversions exist from Se to Te
1570 if (source_type.IsArray && target_type.IsArray) {
1571 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1573 Type source_element_type = TypeManager.GetElementType (source_type);
1574 Type target_element_type = TypeManager.GetElementType (target_type);
1576 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1577 if (ExplicitReferenceConversionExists (source_element_type,
1578 target_element_type))
1584 // From System.Array to any array-type
1585 if (source_type == TypeManager.array_type &&
1586 target_type.IsArray){
1591 // From System delegate to any delegate-type
1593 if (source_type == TypeManager.delegate_type &&
1594 target_type.IsSubclassOf (TypeManager.delegate_type))
1598 // From ICloneable to Array or Delegate types
1600 if (source_type == TypeManager.icloneable_type &&
1601 (target_type == TypeManager.array_type ||
1602 target_type == TypeManager.delegate_type))
1609 /// Implements Explicit Reference conversions
1611 static Expression ExplicitReferenceConversion (Expression source, Type target_type)
1613 Type source_type = source.Type;
1614 bool target_is_value_type = target_type.IsValueType;
1617 // From object to any reference type
1619 if (source_type == TypeManager.object_type && !target_is_value_type)
1620 return new ClassCast (source, target_type);
1623 // Unboxing conversion.
1625 if (((source_type == TypeManager.enum_type &&
1626 !(source is EmptyCast)) ||
1627 source_type == TypeManager.value_type) && target_is_value_type)
1628 return new UnboxCast (source, target_type);
1631 // From any class S to any class-type T, provided S is a base class of T
1633 if (target_type.IsSubclassOf (source_type))
1634 return new ClassCast (source, target_type);
1637 // From any interface type S to any interface T provided S is not derived from T
1639 if (source_type.IsInterface && target_type.IsInterface){
1640 if (TypeManager.ImplementsInterface (source_type, target_type))
1643 return new ClassCast (source, target_type);
1647 // From any class type S to any interface T, provides S is not sealed
1648 // and provided S does not implement T.
1650 if (target_type.IsInterface && !source_type.IsSealed) {
1651 if (TypeManager.ImplementsInterface (source_type, target_type))
1654 return new ClassCast (source, target_type);
1659 // From any interface-type S to to any class type T, provided T is not
1660 // sealed, or provided T implements S.
1662 if (source_type.IsInterface) {
1663 if (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)) {
1664 if (target_type.IsClass)
1665 return new ClassCast (source, target_type);
1667 return new UnboxCast (source, target_type);
1673 // From an array type S with an element type Se to an array type T with an
1674 // element type Te provided all the following are true:
1675 // * S and T differe only in element type, in other words, S and T
1676 // have the same number of dimensions.
1677 // * Both Se and Te are reference types
1678 // * An explicit referenc conversions exist from Se to Te
1680 if (source_type.IsArray && target_type.IsArray) {
1681 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1683 Type source_element_type = TypeManager.GetElementType (source_type);
1684 Type target_element_type = TypeManager.GetElementType (target_type);
1686 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1687 if (ExplicitReferenceConversionExists (source_element_type,
1688 target_element_type))
1689 return new ClassCast (source, target_type);
1694 // From System.Array to any array-type
1695 if (source_type == TypeManager.array_type &&
1696 target_type.IsArray) {
1697 return new ClassCast (source, target_type);
1701 // From System delegate to any delegate-type
1703 if (source_type == TypeManager.delegate_type &&
1704 target_type.IsSubclassOf (TypeManager.delegate_type))
1705 return new ClassCast (source, target_type);
1708 // From ICloneable to Array or Delegate types
1710 if (source_type == TypeManager.icloneable_type &&
1711 (target_type == TypeManager.array_type ||
1712 target_type == TypeManager.delegate_type))
1713 return new ClassCast (source, target_type);
1719 /// Performs an explicit conversion of the expression `expr' whose
1720 /// type is expr.Type to `target_type'.
1722 static public Expression ExplicitConversion (EmitContext ec, Expression expr,
1723 Type target_type, Location loc)
1725 Type expr_type = expr.Type;
1726 Type original_expr_type = expr_type;
1728 if (expr_type.IsSubclassOf (TypeManager.enum_type)){
1729 if (target_type == TypeManager.enum_type ||
1730 target_type == TypeManager.object_type) {
1731 if (expr is EnumConstant)
1732 expr = ((EnumConstant) expr).Child;
1733 // We really need all these casts here .... :-(
1734 expr = new BoxedCast (new EmptyCast (expr, expr_type));
1735 return new EmptyCast (expr, target_type);
1736 } else if ((expr_type == TypeManager.enum_type) && target_type.IsValueType &&
1737 target_type.IsSubclassOf (TypeManager.enum_type))
1738 return new UnboxCast (expr, target_type);
1741 // Notice that we have kept the expr_type unmodified, which is only
1743 if (expr is EnumConstant)
1744 expr = ((EnumConstant) expr).Child;
1746 expr = new EmptyCast (expr, TypeManager.EnumToUnderlying (expr_type));
1747 expr_type = expr.Type;
1750 Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc);
1755 ne = ExplicitNumericConversion (ec, expr, target_type, loc);
1760 // Unboxing conversion.
1762 if (expr_type == TypeManager.object_type && target_type.IsValueType)
1763 return new UnboxCast (expr, target_type);
1766 // Skip the ExplicitReferenceConversion because we can not convert
1767 // from Null to a ValueType, and ExplicitReference wont check against
1768 // null literal explicitly
1770 if (expr_type != TypeManager.null_type){
1771 ne = ExplicitReferenceConversion (expr, target_type);
1778 if (target_type.IsPointer){
1779 if (expr_type.IsPointer)
1780 return new EmptyCast (expr, target_type);
1782 if (expr_type == TypeManager.sbyte_type ||
1783 expr_type == TypeManager.byte_type ||
1784 expr_type == TypeManager.short_type ||
1785 expr_type == TypeManager.ushort_type ||
1786 expr_type == TypeManager.int32_type ||
1787 expr_type == TypeManager.uint32_type ||
1788 expr_type == TypeManager.uint64_type ||
1789 expr_type == TypeManager.int64_type)
1790 return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
1792 if (expr_type.IsPointer){
1793 Expression e = null;
1795 if (target_type == TypeManager.sbyte_type)
1796 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
1797 else if (target_type == TypeManager.byte_type)
1798 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
1799 else if (target_type == TypeManager.short_type)
1800 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
1801 else if (target_type == TypeManager.ushort_type)
1802 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
1803 else if (target_type == TypeManager.int32_type)
1804 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
1805 else if (target_type == TypeManager.uint32_type)
1806 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
1807 else if (target_type == TypeManager.uint64_type)
1808 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
1809 else if (target_type == TypeManager.int64_type){
1810 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
1816 ci = ImplicitConversionStandard (ec, e, target_type, loc);
1821 ce = ExplicitNumericConversion (ec, e, target_type, loc);
1825 // We should always be able to go from an uint32
1826 // implicitly or explicitly to the other integral
1829 throw new Exception ("Internal compiler error");
1834 ne = ExplicitUserConversion (ec, expr, target_type, loc);
1838 if (expr is NullLiteral){
1839 Report.Error (37, loc, "Cannot convert null to value type `" +
1840 TypeManager.CSharpName (target_type) + "'");
1844 Error_CannotConvertType (loc, original_expr_type, target_type);
1849 /// Same as ExplicitConversion, only it doesn't include user defined conversions
1851 static public Expression ExplicitConversionStandard (EmitContext ec, Expression expr,
1852 Type target_type, Location l)
1854 Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
1859 ne = ExplicitNumericConversion (ec, expr, target_type, l);
1863 ne = ExplicitReferenceConversion (expr, target_type);
1867 Error_CannotConvertType (l, expr.Type, target_type);