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)
476 // First numeric conversions
478 if (expr_type == TypeManager.sbyte_type){
480 // From sbyte to short, int, long, float, double.
482 if ((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.short_type) ||
487 (target_type == TypeManager.decimal_type))
490 } else if (expr_type == TypeManager.byte_type){
492 // From byte to short, ushort, int, uint, long, ulong, float, double
494 if ((target_type == TypeManager.short_type) ||
495 (target_type == TypeManager.ushort_type) ||
496 (target_type == TypeManager.int32_type) ||
497 (target_type == TypeManager.uint32_type) ||
498 (target_type == TypeManager.uint64_type) ||
499 (target_type == TypeManager.int64_type) ||
500 (target_type == TypeManager.float_type) ||
501 (target_type == TypeManager.double_type) ||
502 (target_type == TypeManager.decimal_type))
505 } else if (expr_type == TypeManager.short_type){
507 // From short to int, long, float, double
509 if ((target_type == TypeManager.int32_type) ||
510 (target_type == TypeManager.int64_type) ||
511 (target_type == TypeManager.double_type) ||
512 (target_type == TypeManager.float_type) ||
513 (target_type == TypeManager.decimal_type))
516 } else if (expr_type == TypeManager.ushort_type){
518 // From ushort to int, uint, long, ulong, float, double
520 if ((target_type == TypeManager.uint32_type) ||
521 (target_type == TypeManager.uint64_type) ||
522 (target_type == TypeManager.int32_type) ||
523 (target_type == TypeManager.int64_type) ||
524 (target_type == TypeManager.double_type) ||
525 (target_type == TypeManager.float_type) ||
526 (target_type == TypeManager.decimal_type))
529 } else if (expr_type == TypeManager.int32_type){
531 // From int to long, float, double
533 if ((target_type == TypeManager.int64_type) ||
534 (target_type == TypeManager.double_type) ||
535 (target_type == TypeManager.float_type) ||
536 (target_type == TypeManager.decimal_type))
539 } else if (expr_type == TypeManager.uint32_type){
541 // From uint to long, ulong, float, double
543 if ((target_type == TypeManager.int64_type) ||
544 (target_type == TypeManager.uint64_type) ||
545 (target_type == TypeManager.double_type) ||
546 (target_type == TypeManager.float_type) ||
547 (target_type == TypeManager.decimal_type))
550 } else if ((expr_type == TypeManager.uint64_type) ||
551 (expr_type == TypeManager.int64_type)) {
553 // From long/ulong to float, double
555 if ((target_type == TypeManager.double_type) ||
556 (target_type == TypeManager.float_type) ||
557 (target_type == TypeManager.decimal_type))
560 } else if (expr_type == TypeManager.char_type){
562 // From char to ushort, int, uint, long, ulong, float, double
564 if ((target_type == TypeManager.ushort_type) ||
565 (target_type == TypeManager.int32_type) ||
566 (target_type == TypeManager.uint32_type) ||
567 (target_type == TypeManager.uint64_type) ||
568 (target_type == TypeManager.int64_type) ||
569 (target_type == TypeManager.float_type) ||
570 (target_type == TypeManager.double_type) ||
571 (target_type == TypeManager.decimal_type))
574 } else if (expr_type == TypeManager.float_type){
578 if (target_type == TypeManager.double_type)
582 if (expr.eclass == ExprClass.MethodGroup){
583 if (TypeManager.IsDelegateType (target_type) && RootContext.Version != LanguageVersion.ISO_1){
584 MethodGroupExpr mg = expr as MethodGroupExpr;
587 // This should not happen frequently, so we can create an object
588 // to test compatibility
590 Expression c = ImplicitDelegateCreation.Create (ec, mg, target_type, Location.Null);
596 if (ImplicitReferenceConversionExists (expr, target_type))
600 // Implicit Constant Expression Conversions
602 if (expr is IntConstant){
603 int value = ((IntConstant) expr).Value;
605 if (target_type == TypeManager.sbyte_type){
606 if (value >= SByte.MinValue && value <= SByte.MaxValue)
608 } else if (target_type == TypeManager.byte_type){
609 if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
611 } else if (target_type == TypeManager.short_type){
612 if (value >= Int16.MinValue && value <= Int16.MaxValue)
614 } else if (target_type == TypeManager.ushort_type){
615 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
617 } else if (target_type == TypeManager.uint32_type){
620 } else if (target_type == TypeManager.uint64_type){
622 // we can optimize this case: a positive int32
623 // always fits on a uint64. But we need an opcode
630 if (value == 0 && expr is IntLiteral && TypeManager.IsEnumType (target_type))
634 if (expr is LongConstant && target_type == TypeManager.uint64_type){
636 // Try the implicit constant expression conversion
637 // from long to ulong, instead of a nice routine,
640 long v = ((LongConstant) expr).Value;
645 if ((target_type == TypeManager.enum_type ||
646 target_type.IsSubclassOf (TypeManager.enum_type)) &&
648 IntLiteral i = (IntLiteral) expr;
655 // If `expr_type' implements `target_type' (which is an iface)
656 // see TryImplicitIntConversion
658 if (target_type.IsInterface && target_type.IsAssignableFrom (expr_type))
661 if (target_type == TypeManager.void_ptr_type && expr_type.IsPointer)
664 if (expr_type == TypeManager.anonymous_method_type){
665 if (!TypeManager.IsDelegateType (target_type))
668 AnonymousMethod am = (AnonymousMethod) expr;
670 Expression conv = am.Compatible (ec, target_type, true);
679 // Used internally by FindMostEncompassedType, this is used
680 // to avoid creating lots of objects in the tight loop inside
681 // FindMostEncompassedType
683 static EmptyExpression priv_fmet_param;
686 /// Finds "most encompassed type" according to the spec (13.4.2)
687 /// amongst the methods in the MethodGroupExpr
689 static Type FindMostEncompassedType (EmitContext ec, ArrayList types)
693 if (priv_fmet_param == null)
694 priv_fmet_param = new EmptyExpression ();
696 foreach (Type t in types){
697 priv_fmet_param.SetType (t);
704 if (ImplicitStandardConversionExists (ec, priv_fmet_param, best))
712 // Used internally by FindMostEncompassingType, this is used
713 // to avoid creating lots of objects in the tight loop inside
714 // FindMostEncompassingType
716 static EmptyExpression priv_fmee_ret;
719 /// Finds "most encompassing type" according to the spec (13.4.2)
720 /// amongst the types in the given set
722 static Type FindMostEncompassingType (EmitContext ec, ArrayList types)
726 if (priv_fmee_ret == null)
727 priv_fmee_ret = new EmptyExpression ();
729 foreach (Type t in types){
730 priv_fmee_ret.SetType (best);
737 if (ImplicitStandardConversionExists (ec, priv_fmee_ret, t))
745 // Used to avoid creating too many objects
747 static EmptyExpression priv_fms_expr;
750 /// Finds the most specific source Sx according to the rules of the spec (13.4.4)
751 /// by making use of FindMostEncomp* methods. Applies the correct rules separately
752 /// for explicit and implicit conversion operators.
754 static public Type FindMostSpecificSource (EmitContext ec, MethodGroupExpr me,
755 Expression source, bool apply_explicit_conv_rules,
758 ArrayList src_types_set = new ArrayList ();
760 if (priv_fms_expr == null)
761 priv_fms_expr = new EmptyExpression ();
764 // If any operator converts from S then Sx = S
766 Type source_type = source.Type;
767 foreach (MethodBase mb in me.Methods){
768 ParameterData pd = TypeManager.GetParameterData (mb);
769 Type param_type = pd.ParameterType (0);
771 if (param_type == source_type)
774 if (apply_explicit_conv_rules) {
777 // Find the set of applicable user-defined conversion operators, U. This set
779 // user-defined implicit or explicit conversion operators declared by
780 // the classes or structs in D that convert from a type encompassing
781 // or encompassed by S to a type encompassing or encompassed by T
783 priv_fms_expr.SetType (param_type);
784 if (ImplicitStandardConversionExists (ec, priv_fms_expr, source_type))
785 src_types_set.Add (param_type);
787 if (ImplicitStandardConversionExists (ec, source, param_type))
788 src_types_set.Add (param_type);
792 // Only if S is encompassed by param_type
794 if (ImplicitStandardConversionExists (ec, source, param_type))
795 src_types_set.Add (param_type);
800 // Explicit Conv rules
802 if (apply_explicit_conv_rules) {
803 ArrayList candidate_set = new ArrayList ();
805 foreach (Type param_type in src_types_set){
806 if (ImplicitStandardConversionExists (ec, source, param_type))
807 candidate_set.Add (param_type);
810 if (candidate_set.Count != 0)
811 return FindMostEncompassedType (ec, candidate_set);
817 if (apply_explicit_conv_rules)
818 return FindMostEncompassingType (ec, src_types_set);
820 return FindMostEncompassedType (ec, src_types_set);
824 // Useful in avoiding proliferation of objects
826 static EmptyExpression priv_fmt_expr;
829 /// Finds the most specific target Tx according to section 13.4.4
831 static public Type FindMostSpecificTarget (EmitContext ec, MethodGroupExpr me,
832 Type target, bool apply_explicit_conv_rules,
835 ArrayList tgt_types_set = new ArrayList ();
837 if (priv_fmt_expr == null)
838 priv_fmt_expr = new EmptyExpression ();
841 // If any operator converts to T then Tx = T
843 foreach (MethodInfo mi in me.Methods){
844 Type ret_type = mi.ReturnType;
846 if (ret_type == target)
849 if (apply_explicit_conv_rules) {
852 // Find the set of applicable user-defined conversion operators, U.
854 // This set consists of the
855 // user-defined implicit or explicit conversion operators declared by
856 // the classes or structs in D that convert from a type encompassing
857 // or encompassed by S to a type encompassing or encompassed by T
859 priv_fms_expr.SetType (ret_type);
860 if (ImplicitStandardConversionExists (ec, priv_fms_expr, target))
861 tgt_types_set.Add (ret_type);
863 priv_fms_expr.SetType (target);
864 if (ImplicitStandardConversionExists (ec, priv_fms_expr, ret_type))
865 tgt_types_set.Add (ret_type);
869 // Only if T is encompassed by param_type
871 priv_fms_expr.SetType (ret_type);
872 if (ImplicitStandardConversionExists (ec, priv_fms_expr, target))
873 tgt_types_set.Add (ret_type);
878 // Explicit conv rules
880 if (apply_explicit_conv_rules) {
881 ArrayList candidate_set = new ArrayList ();
883 foreach (Type ret_type in tgt_types_set){
884 priv_fmt_expr.SetType (ret_type);
886 if (ImplicitStandardConversionExists (ec, priv_fmt_expr, target))
887 candidate_set.Add (ret_type);
890 if (candidate_set.Count != 0)
891 return FindMostEncompassingType (ec, candidate_set);
895 // Okay, final case !
897 if (apply_explicit_conv_rules)
898 return FindMostEncompassedType (ec, tgt_types_set);
900 return FindMostEncompassingType (ec, tgt_types_set);
904 /// User-defined Implicit conversions
906 static public Expression ImplicitUserConversion (EmitContext ec, Expression source,
907 Type target, Location loc)
909 return UserDefinedConversion (ec, source, target, loc, false);
913 /// User-defined Explicit conversions
915 static public Expression ExplicitUserConversion (EmitContext ec, Expression source,
916 Type target, Location loc)
918 return UserDefinedConversion (ec, source, target, loc, true);
921 static DoubleHash explicit_conv = new DoubleHash (100);
922 static DoubleHash implicit_conv = new DoubleHash (100);
924 /// Computes the MethodGroup for the user-defined conversion
925 /// operators from source_type to target_type. `look_for_explicit'
926 /// controls whether we should also include the list of explicit
929 static MethodGroupExpr GetConversionOperators (EmitContext ec,
930 Type source_type, Type target_type,
931 Location loc, bool look_for_explicit)
933 Expression mg1 = null, mg2 = null;
934 Expression mg5 = null, mg6 = null, mg7 = null, mg8 = null;
937 op_name = "op_Implicit";
939 MethodGroupExpr union3;
941 if ((look_for_explicit ? explicit_conv : implicit_conv).Lookup (source_type, target_type, out r))
942 return (MethodGroupExpr) r;
944 mg1 = Expression.MethodLookup (ec, source_type, op_name, loc);
945 if (source_type.BaseType != null)
946 mg2 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
949 union3 = (MethodGroupExpr) mg2;
950 else if (mg2 == null)
951 union3 = (MethodGroupExpr) mg1;
953 union3 = Invocation.MakeUnionSet (mg1, mg2, loc);
955 mg1 = Expression.MethodLookup (ec, target_type, op_name, loc);
958 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
960 union3 = (MethodGroupExpr) mg1;
963 if (target_type.BaseType != null)
964 mg1 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
968 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
970 union3 = (MethodGroupExpr) mg1;
973 MethodGroupExpr union4 = null;
975 if (look_for_explicit) {
976 op_name = "op_Explicit";
978 mg5 = Expression.MemberLookup (ec, source_type, op_name, loc);
979 if (source_type.BaseType != null)
980 mg6 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
982 mg7 = Expression.MemberLookup (ec, target_type, op_name, loc);
983 if (target_type.BaseType != null)
984 mg8 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
986 MethodGroupExpr union5 = Invocation.MakeUnionSet (mg5, mg6, loc);
987 MethodGroupExpr union6 = Invocation.MakeUnionSet (mg7, mg8, loc);
989 union4 = Invocation.MakeUnionSet (union5, union6, loc);
992 MethodGroupExpr ret = Invocation.MakeUnionSet (union3, union4, loc);
993 (look_for_explicit ? explicit_conv : implicit_conv).Insert (source_type, target_type, ret);
998 /// User-defined conversions
1000 static public Expression UserDefinedConversion (EmitContext ec, Expression source,
1001 Type target, Location loc,
1002 bool look_for_explicit)
1004 MethodGroupExpr union;
1005 Type source_type = source.Type;
1006 MethodBase method = null;
1008 union = GetConversionOperators (ec, source_type, target, loc, look_for_explicit);
1012 Type most_specific_source, most_specific_target;
1014 most_specific_source = FindMostSpecificSource (ec, union, source, look_for_explicit, loc);
1015 if (most_specific_source == null)
1018 most_specific_target = FindMostSpecificTarget (ec, union, target, look_for_explicit, loc);
1019 if (most_specific_target == null)
1025 foreach (MethodBase mb in union.Methods){
1026 ParameterData pd = TypeManager.GetParameterData (mb);
1027 MethodInfo mi = (MethodInfo) mb;
1029 if (pd.ParameterType (0) == most_specific_source &&
1030 mi.ReturnType == most_specific_target) {
1036 if (method == null || count > 1)
1041 // This will do the conversion to the best match that we
1042 // found. Now we need to perform an implict standard conversion
1043 // if the best match was not the type that we were requested
1046 if (look_for_explicit)
1047 source = ExplicitConversionStandard (ec, source, most_specific_source, loc);
1049 source = ImplicitConversionStandard (ec, source, most_specific_source, loc);
1055 e = new UserCast ((MethodInfo) method, source, loc);
1056 if (e.Type != target){
1057 if (!look_for_explicit)
1058 e = ImplicitConversionStandard (ec, e, target, loc);
1060 e = ExplicitConversionStandard (ec, e, target, loc);
1067 /// Converts implicitly the resolved expression `expr' into the
1068 /// `target_type'. It returns a new expression that can be used
1069 /// in a context that expects a `target_type'.
1071 static public Expression ImplicitConversion (EmitContext ec, Expression expr,
1072 Type target_type, Location loc)
1076 if (target_type == null)
1077 throw new Exception ("Target type is null");
1079 e = ImplicitConversionStandard (ec, expr, target_type, loc);
1083 e = ImplicitUserConversion (ec, expr, target_type, loc);
1092 /// Attempts to apply the `Standard Implicit
1093 /// Conversion' rules to the expression `expr' into
1094 /// the `target_type'. It returns a new expression
1095 /// that can be used in a context that expects a
1098 /// This is different from `ImplicitConversion' in that the
1099 /// user defined implicit conversions are excluded.
1101 static public Expression ImplicitConversionStandard (EmitContext ec, Expression expr,
1102 Type target_type, Location loc)
1104 Type expr_type = expr.Type;
1107 if (expr.eclass == ExprClass.MethodGroup){
1108 if (!TypeManager.IsDelegateType (target_type)){
1113 // Only allow anonymous method conversions on post ISO_1
1115 if (RootContext.Version != LanguageVersion.ISO_1){
1116 MethodGroupExpr mg = expr as MethodGroupExpr;
1118 return ImplicitDelegateCreation.Create (ec, mg, target_type, loc);
1122 if (expr_type == target_type && expr_type != TypeManager.null_type)
1125 e = ImplicitNumericConversion (ec, expr, target_type, loc);
1129 e = ImplicitReferenceConversion (expr, target_type);
1133 if ((target_type == TypeManager.enum_type ||
1134 target_type.IsSubclassOf (TypeManager.enum_type)) &&
1135 expr is IntLiteral){
1136 IntLiteral i = (IntLiteral) expr;
1139 return new EnumConstant ((Constant) expr, target_type);
1143 if (expr_type.IsPointer){
1144 if (target_type == TypeManager.void_ptr_type)
1145 return new EmptyCast (expr, target_type);
1148 // yep, comparing pointer types cant be done with
1149 // t1 == t2, we have to compare their element types.
1151 if (target_type.IsPointer){
1152 if (TypeManager.GetElementType(target_type) == TypeManager.GetElementType(expr_type))
1157 if (target_type.IsPointer) {
1158 if (expr_type == TypeManager.null_type)
1159 return new EmptyCast (expr, target_type);
1161 if (expr_type == TypeManager.void_ptr_type)
1162 return new EmptyCast (expr, target_type);
1166 if (expr_type == TypeManager.anonymous_method_type){
1167 if (!TypeManager.IsDelegateType (target_type)){
1168 Report.Error (1660, loc,
1169 "Cannot convert anonymous method to `{0}', since it is not a delegate",
1170 TypeManager.CSharpName (target_type));
1174 AnonymousMethod am = (AnonymousMethod) expr;
1175 int errors = Report.Errors;
1177 Expression conv = am.Compatible (ec, target_type, false);
1182 // We return something instead of null, to avoid
1183 // the duplicate error, since am.Compatible would have
1184 // reported that already
1186 if (errors != Report.Errors)
1187 return new EmptyCast (expr, target_type);
1194 /// Attempts to perform an implicit constant conversion of the IntConstant
1195 /// into a different data type using casts (See Implicit Constant
1196 /// Expression Conversions)
1198 static public Expression TryImplicitIntConversion (Type target_type, IntConstant ic)
1200 int value = ic.Value;
1202 if (target_type == TypeManager.sbyte_type){
1203 if (value >= SByte.MinValue && value <= SByte.MaxValue)
1204 return new SByteConstant ((sbyte) value);
1205 } else if (target_type == TypeManager.byte_type){
1206 if (value >= Byte.MinValue && value <= Byte.MaxValue)
1207 return new ByteConstant ((byte) value);
1208 } else if (target_type == TypeManager.short_type){
1209 if (value >= Int16.MinValue && value <= Int16.MaxValue)
1210 return new ShortConstant ((short) value);
1211 } else if (target_type == TypeManager.ushort_type){
1212 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
1213 return new UShortConstant ((ushort) value);
1214 } else if (target_type == TypeManager.uint32_type){
1216 return new UIntConstant ((uint) value);
1217 } else if (target_type == TypeManager.uint64_type){
1219 // we can optimize this case: a positive int32
1220 // always fits on a uint64. But we need an opcode
1224 return new ULongConstant ((ulong) value);
1225 } else if (target_type == TypeManager.double_type)
1226 return new DoubleConstant ((double) value);
1227 else if (target_type == TypeManager.float_type)
1228 return new FloatConstant ((float) value);
1230 if (value == 0 && ic is IntLiteral && TypeManager.IsEnumType (target_type)){
1231 Type underlying = TypeManager.EnumToUnderlying (target_type);
1232 Constant e = (Constant) ic;
1235 // Possibly, we need to create a different 0 literal before passing
1238 if (underlying == TypeManager.int64_type)
1239 e = new LongLiteral (0);
1240 else if (underlying == TypeManager.uint64_type)
1241 e = new ULongLiteral (0);
1243 return new EnumConstant (e, target_type);
1247 // If `target_type' is an interface and the type of `ic' implements the interface
1248 // e.g. target_type is IComparable, IConvertible, IFormattable
1250 if (target_type.IsInterface && target_type.IsAssignableFrom (ic.Type))
1251 return new BoxedCast (ic);
1256 static public void Error_CannotImplicitConversion (Location loc, Type source, Type target)
1258 if (source.Name == target.Name){
1259 Report.ExtraInformation (loc,
1261 "The type {0} has two conflicting definitions, one comes from {1} and the other from {2}",
1262 source.Name, source.Assembly.FullName, target.Assembly.FullName));
1265 Report.Error (29, loc, "Cannot convert implicitly from {0} to `{1}'",
1266 source == TypeManager.anonymous_method_type ?
1267 "anonymous method" : "`" + TypeManager.CSharpName (source) + "'",
1268 TypeManager.CSharpName (target));
1272 /// Attempts to implicitly convert `source' into `target_type', using
1273 /// ImplicitConversion. If there is no implicit conversion, then
1274 /// an error is signaled
1276 static public Expression ImplicitConversionRequired (EmitContext ec, Expression source,
1277 Type target_type, Location loc)
1281 e = ImplicitConversion (ec, source, target_type, loc);
1285 if (source is DoubleLiteral) {
1286 if (target_type == TypeManager.float_type) {
1287 Error_664 (loc, "float", "f");
1290 if (target_type == TypeManager.decimal_type) {
1291 Error_664 (loc, "decimal", "m");
1296 if (source is Constant){
1297 Constant c = (Constant) source;
1299 Expression.Error_ConstantValueCannotBeConverted (loc, c.AsString (), target_type);
1303 Error_CannotImplicitConversion (loc, source.Type, target_type);
1308 static void Error_664 (Location loc, string type, string suffix) {
1309 Report.Error (664, loc,
1310 "Literal of type double cannot be implicitly converted to type '{0}'. Add suffix '{1}' to create a literal of this type",
1315 /// Performs the explicit numeric conversions
1317 static Expression ExplicitNumericConversion (EmitContext ec, Expression expr, Type target_type, Location loc)
1319 Type expr_type = expr.Type;
1322 // If we have an enumeration, extract the underlying type,
1323 // use this during the comparison, but wrap around the original
1326 Type real_target_type = target_type;
1328 if (TypeManager.IsEnumType (real_target_type))
1329 real_target_type = TypeManager.EnumToUnderlying (real_target_type);
1331 if (ImplicitStandardConversionExists (ec, expr, real_target_type)){
1332 Expression ce = ImplicitConversionStandard (ec, expr, real_target_type, loc);
1334 if (real_target_type != target_type)
1335 return new EmptyCast (ce, target_type);
1339 if (expr_type == TypeManager.sbyte_type){
1341 // From sbyte to byte, ushort, uint, ulong, char
1343 if (real_target_type == TypeManager.byte_type)
1344 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U1);
1345 if (real_target_type == TypeManager.ushort_type)
1346 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U2);
1347 if (real_target_type == TypeManager.uint32_type)
1348 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U4);
1349 if (real_target_type == TypeManager.uint64_type)
1350 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U8);
1351 if (real_target_type == TypeManager.char_type)
1352 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_CH);
1353 } else if (expr_type == TypeManager.byte_type){
1355 // From byte to sbyte and char
1357 if (real_target_type == TypeManager.sbyte_type)
1358 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_I1);
1359 if (real_target_type == TypeManager.char_type)
1360 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_CH);
1361 } else if (expr_type == TypeManager.short_type){
1363 // From short to sbyte, byte, ushort, uint, ulong, char
1365 if (real_target_type == TypeManager.sbyte_type)
1366 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_I1);
1367 if (real_target_type == TypeManager.byte_type)
1368 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U1);
1369 if (real_target_type == TypeManager.ushort_type)
1370 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U2);
1371 if (real_target_type == TypeManager.uint32_type)
1372 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U4);
1373 if (real_target_type == TypeManager.uint64_type)
1374 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U8);
1375 if (real_target_type == TypeManager.char_type)
1376 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_CH);
1377 } else if (expr_type == TypeManager.ushort_type){
1379 // From ushort to sbyte, byte, short, char
1381 if (real_target_type == TypeManager.sbyte_type)
1382 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I1);
1383 if (real_target_type == TypeManager.byte_type)
1384 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_U1);
1385 if (real_target_type == TypeManager.short_type)
1386 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I2);
1387 if (real_target_type == TypeManager.char_type)
1388 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_CH);
1389 } else if (expr_type == TypeManager.int32_type){
1391 // From int to sbyte, byte, short, ushort, uint, ulong, char
1393 if (real_target_type == TypeManager.sbyte_type)
1394 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I1);
1395 if (real_target_type == TypeManager.byte_type)
1396 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U1);
1397 if (real_target_type == TypeManager.short_type)
1398 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I2);
1399 if (real_target_type == TypeManager.ushort_type)
1400 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U2);
1401 if (real_target_type == TypeManager.uint32_type)
1402 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U4);
1403 if (real_target_type == TypeManager.uint64_type)
1404 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U8);
1405 if (real_target_type == TypeManager.char_type)
1406 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_CH);
1407 } else if (expr_type == TypeManager.uint32_type){
1409 // From uint to sbyte, byte, short, ushort, int, char
1411 if (real_target_type == TypeManager.sbyte_type)
1412 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I1);
1413 if (real_target_type == TypeManager.byte_type)
1414 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U1);
1415 if (real_target_type == TypeManager.short_type)
1416 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I2);
1417 if (real_target_type == TypeManager.ushort_type)
1418 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U2);
1419 if (real_target_type == TypeManager.int32_type)
1420 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I4);
1421 if (real_target_type == TypeManager.char_type)
1422 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_CH);
1423 } else if (expr_type == TypeManager.int64_type){
1425 // From long to sbyte, byte, short, ushort, int, uint, ulong, char
1427 if (real_target_type == TypeManager.sbyte_type)
1428 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I1);
1429 if (real_target_type == TypeManager.byte_type)
1430 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U1);
1431 if (real_target_type == TypeManager.short_type)
1432 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I2);
1433 if (real_target_type == TypeManager.ushort_type)
1434 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U2);
1435 if (real_target_type == TypeManager.int32_type)
1436 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I4);
1437 if (real_target_type == TypeManager.uint32_type)
1438 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U4);
1439 if (real_target_type == TypeManager.uint64_type)
1440 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U8);
1441 if (real_target_type == TypeManager.char_type)
1442 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_CH);
1443 } else if (expr_type == TypeManager.uint64_type){
1445 // From ulong to sbyte, byte, short, ushort, int, uint, long, char
1447 if (real_target_type == TypeManager.sbyte_type)
1448 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I1);
1449 if (real_target_type == TypeManager.byte_type)
1450 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U1);
1451 if (real_target_type == TypeManager.short_type)
1452 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I2);
1453 if (real_target_type == TypeManager.ushort_type)
1454 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U2);
1455 if (real_target_type == TypeManager.int32_type)
1456 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I4);
1457 if (real_target_type == TypeManager.uint32_type)
1458 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U4);
1459 if (real_target_type == TypeManager.int64_type)
1460 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I8);
1461 if (real_target_type == TypeManager.char_type)
1462 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_CH);
1463 } else if (expr_type == TypeManager.char_type){
1465 // From char to sbyte, byte, short
1467 if (real_target_type == TypeManager.sbyte_type)
1468 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I1);
1469 if (real_target_type == TypeManager.byte_type)
1470 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_U1);
1471 if (real_target_type == TypeManager.short_type)
1472 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I2);
1473 } else if (expr_type == TypeManager.float_type){
1475 // From float to sbyte, byte, short,
1476 // ushort, int, uint, long, ulong, char
1479 if (real_target_type == TypeManager.sbyte_type)
1480 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I1);
1481 if (real_target_type == TypeManager.byte_type)
1482 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U1);
1483 if (real_target_type == TypeManager.short_type)
1484 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I2);
1485 if (real_target_type == TypeManager.ushort_type)
1486 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U2);
1487 if (real_target_type == TypeManager.int32_type)
1488 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I4);
1489 if (real_target_type == TypeManager.uint32_type)
1490 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U4);
1491 if (real_target_type == TypeManager.int64_type)
1492 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I8);
1493 if (real_target_type == TypeManager.uint64_type)
1494 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U8);
1495 if (real_target_type == TypeManager.char_type)
1496 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_CH);
1497 } else if (expr_type == TypeManager.double_type){
1499 // From double to byte, byte, short,
1500 // ushort, int, uint, long, ulong,
1501 // char, float or decimal
1503 if (real_target_type == TypeManager.sbyte_type)
1504 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I1);
1505 if (real_target_type == TypeManager.byte_type)
1506 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U1);
1507 if (real_target_type == TypeManager.short_type)
1508 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I2);
1509 if (real_target_type == TypeManager.ushort_type)
1510 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U2);
1511 if (real_target_type == TypeManager.int32_type)
1512 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I4);
1513 if (real_target_type == TypeManager.uint32_type)
1514 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U4);
1515 if (real_target_type == TypeManager.int64_type)
1516 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I8);
1517 if (real_target_type == TypeManager.uint64_type)
1518 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U8);
1519 if (real_target_type == TypeManager.char_type)
1520 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_CH);
1521 if (real_target_type == TypeManager.float_type)
1522 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_R4);
1525 // decimal is taken care of by the op_Explicit methods.
1531 /// Returns whether an explicit reference conversion can be performed
1532 /// from source_type to target_type
1534 public static bool ExplicitReferenceConversionExists (Type source_type, Type target_type)
1536 bool target_is_value_type = target_type.IsValueType;
1538 if (source_type == target_type)
1542 // From object to any reference type
1544 if (source_type == TypeManager.object_type && !target_is_value_type)
1548 // From any class S to any class-type T, provided S is a base class of T
1550 if (target_type.IsSubclassOf (source_type))
1554 // From any interface type S to any interface T provided S is not derived from T
1556 if (source_type.IsInterface && target_type.IsInterface){
1557 if (!target_type.IsSubclassOf (source_type))
1562 // From any class type S to any interface T, provided S is not sealed
1563 // and provided S does not implement T.
1565 if (target_type.IsInterface && !source_type.IsSealed &&
1566 !TypeManager.ImplementsInterface (source_type, target_type))
1570 // From any interface-type S to to any class type T, provided T is not
1571 // sealed, or provided T implements S.
1573 if (source_type.IsInterface &&
1574 (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)))
1578 // From an array type S with an element type Se to an array type T with an
1579 // element type Te provided all the following are true:
1580 // * S and T differe only in element type, in other words, S and T
1581 // have the same number of dimensions.
1582 // * Both Se and Te are reference types
1583 // * An explicit referenc conversions exist from Se to Te
1585 if (source_type.IsArray && target_type.IsArray) {
1586 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1588 Type source_element_type = TypeManager.GetElementType (source_type);
1589 Type target_element_type = TypeManager.GetElementType (target_type);
1591 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1592 if (ExplicitReferenceConversionExists (source_element_type,
1593 target_element_type))
1599 // From System.Array to any array-type
1600 if (source_type == TypeManager.array_type &&
1601 target_type.IsArray){
1606 // From System delegate to any delegate-type
1608 if (source_type == TypeManager.delegate_type &&
1609 target_type.IsSubclassOf (TypeManager.delegate_type))
1613 // From ICloneable to Array or Delegate types
1615 if (source_type == TypeManager.icloneable_type &&
1616 (target_type == TypeManager.array_type ||
1617 target_type == TypeManager.delegate_type))
1624 /// Implements Explicit Reference conversions
1626 static Expression ExplicitReferenceConversion (Expression source, Type target_type)
1628 Type source_type = source.Type;
1629 bool target_is_value_type = target_type.IsValueType;
1632 // From object to any reference type
1634 if (source_type == TypeManager.object_type && !target_is_value_type)
1635 return new ClassCast (source, target_type);
1638 // Unboxing conversion.
1640 if (((source_type == TypeManager.enum_type &&
1641 !(source is EmptyCast)) ||
1642 source_type == TypeManager.value_type) && target_is_value_type)
1643 return new UnboxCast (source, target_type);
1646 // From any class S to any class-type T, provided S is a base class of T
1648 if (target_type.IsSubclassOf (source_type))
1649 return new ClassCast (source, target_type);
1652 // From any interface type S to any interface T provided S is not derived from T
1654 if (source_type.IsInterface && target_type.IsInterface){
1655 if (TypeManager.ImplementsInterface (source_type, target_type))
1658 return new ClassCast (source, target_type);
1662 // From any class type S to any interface T, provides S is not sealed
1663 // and provided S does not implement T.
1665 if (target_type.IsInterface && !source_type.IsSealed) {
1666 if (TypeManager.ImplementsInterface (source_type, target_type))
1669 return new ClassCast (source, target_type);
1674 // From any interface-type S to to any class type T, provided T is not
1675 // sealed, or provided T implements S.
1677 if (source_type.IsInterface) {
1678 if (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)) {
1679 if (target_type.IsClass)
1680 return new ClassCast (source, target_type);
1682 return new UnboxCast (source, target_type);
1688 // From an array type S with an element type Se to an array type T with an
1689 // element type Te provided all the following are true:
1690 // * S and T differe only in element type, in other words, S and T
1691 // have the same number of dimensions.
1692 // * Both Se and Te are reference types
1693 // * An explicit referenc conversions exist from Se to Te
1695 if (source_type.IsArray && target_type.IsArray) {
1696 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1698 Type source_element_type = TypeManager.GetElementType (source_type);
1699 Type target_element_type = TypeManager.GetElementType (target_type);
1701 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1702 if (ExplicitReferenceConversionExists (source_element_type,
1703 target_element_type))
1704 return new ClassCast (source, target_type);
1709 // From System.Array to any array-type
1710 if (source_type == TypeManager.array_type &&
1711 target_type.IsArray) {
1712 return new ClassCast (source, target_type);
1716 // From System delegate to any delegate-type
1718 if (source_type == TypeManager.delegate_type &&
1719 target_type.IsSubclassOf (TypeManager.delegate_type))
1720 return new ClassCast (source, target_type);
1723 // From ICloneable to Array or Delegate types
1725 if (source_type == TypeManager.icloneable_type &&
1726 (target_type == TypeManager.array_type ||
1727 target_type == TypeManager.delegate_type))
1728 return new ClassCast (source, target_type);
1734 /// Performs an explicit conversion of the expression `expr' whose
1735 /// type is expr.Type to `target_type'.
1737 static public Expression ExplicitConversion (EmitContext ec, Expression expr,
1738 Type target_type, Location loc)
1740 Type expr_type = expr.Type;
1741 Type original_expr_type = expr_type;
1743 if (expr_type.IsSubclassOf (TypeManager.enum_type)){
1744 if (target_type == TypeManager.enum_type ||
1745 target_type == TypeManager.object_type) {
1746 if (expr is EnumConstant)
1747 expr = ((EnumConstant) expr).Child;
1748 // We really need all these casts here .... :-(
1749 expr = new BoxedCast (new EmptyCast (expr, expr_type));
1750 return new EmptyCast (expr, target_type);
1751 } else if ((expr_type == TypeManager.enum_type) && target_type.IsValueType &&
1752 target_type.IsSubclassOf (TypeManager.enum_type))
1753 return new UnboxCast (expr, target_type);
1756 // Notice that we have kept the expr_type unmodified, which is only
1758 if (expr is EnumConstant)
1759 expr = ((EnumConstant) expr).Child;
1761 expr = new EmptyCast (expr, TypeManager.EnumToUnderlying (expr_type));
1762 expr_type = expr.Type;
1765 Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc);
1770 ne = ExplicitNumericConversion (ec, expr, target_type, loc);
1775 // Unboxing conversion.
1777 if (expr_type == TypeManager.object_type && target_type.IsValueType)
1778 return new UnboxCast (expr, target_type);
1781 // Skip the ExplicitReferenceConversion because we can not convert
1782 // from Null to a ValueType, and ExplicitReference wont check against
1783 // null literal explicitly
1785 if (expr_type != TypeManager.null_type){
1786 ne = ExplicitReferenceConversion (expr, target_type);
1793 if (target_type.IsPointer){
1794 if (expr_type.IsPointer)
1795 return new EmptyCast (expr, target_type);
1797 if (expr_type == TypeManager.sbyte_type ||
1798 expr_type == TypeManager.byte_type ||
1799 expr_type == TypeManager.short_type ||
1800 expr_type == TypeManager.ushort_type ||
1801 expr_type == TypeManager.int32_type ||
1802 expr_type == TypeManager.uint32_type ||
1803 expr_type == TypeManager.uint64_type ||
1804 expr_type == TypeManager.int64_type)
1805 return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
1807 if (expr_type.IsPointer){
1808 Expression e = null;
1810 if (target_type == TypeManager.sbyte_type)
1811 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
1812 else if (target_type == TypeManager.byte_type)
1813 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
1814 else if (target_type == TypeManager.short_type)
1815 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
1816 else if (target_type == TypeManager.ushort_type)
1817 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
1818 else if (target_type == TypeManager.int32_type)
1819 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
1820 else if (target_type == TypeManager.uint32_type)
1821 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
1822 else if (target_type == TypeManager.uint64_type)
1823 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
1824 else if (target_type == TypeManager.int64_type){
1825 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
1831 ci = ImplicitConversionStandard (ec, e, target_type, loc);
1836 ce = ExplicitNumericConversion (ec, e, target_type, loc);
1840 // We should always be able to go from an uint32
1841 // implicitly or explicitly to the other integral
1844 throw new Exception ("Internal compiler error");
1849 ne = ExplicitUserConversion (ec, expr, target_type, loc);
1853 if (expr is NullLiteral){
1854 Report.Error (37, loc, "Cannot convert null to value type `" +
1855 TypeManager.CSharpName (target_type) + "'");
1859 Error_CannotConvertType (loc, original_expr_type, target_type);
1864 /// Same as ExplicitConversion, only it doesn't include user defined conversions
1866 static public Expression ExplicitConversionStandard (EmitContext ec, Expression expr,
1867 Type target_type, Location l)
1869 Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
1874 ne = ExplicitNumericConversion (ec, expr, target_type, l);
1878 ne = ExplicitReferenceConversion (expr, target_type);
1882 Error_CannotConvertType (l, expr.Type, target_type);