2 // conversion.cs: various routines for implementing conversions.
5 // Miguel de Icaza (miguel@ximian.com)
6 // Ravi Pratap (ravi@ximian.com)
8 // (C) 2001, 2002, 2003 Ximian, Inc.
11 namespace Mono.CSharp {
13 using System.Collections;
14 using System.Diagnostics;
15 using System.Reflection;
16 using System.Reflection.Emit;
19 // A container class for all the conversion operations
21 public class Convert {
22 static public void Error_CannotConvertType (Location loc, Type source, Type target)
24 Report.Error (30, loc, "Cannot convert type '" +
25 TypeManager.CSharpName (source) + "' to '" +
26 TypeManager.CSharpName (target) + "'");
29 static EmptyExpression MyEmptyExpr;
30 static public Expression ImplicitReferenceConversion (Expression expr, Type target_type)
32 Type expr_type = expr.Type;
34 if (expr_type == null && expr.eclass == ExprClass.MethodGroup){
35 // if we are a method group, emit a warning
41 // notice that it is possible to write "ValueType v = 1", the ValueType here
42 // is an abstract class, and not really a value type, so we apply the same rules.
44 if (target_type == TypeManager.object_type) {
46 // A pointer type cannot be converted to object
48 if (expr_type.IsPointer)
51 if (expr_type.IsValueType)
52 return new BoxedCast (expr);
53 if (expr_type.IsClass || expr_type.IsInterface || expr_type == TypeManager.enum_type)
54 return new EmptyCast (expr, target_type);
55 } else if (target_type == TypeManager.value_type) {
56 if (expr_type.IsValueType)
57 return new BoxedCast (expr);
58 if (expr is NullLiteral)
59 return new BoxedCast (expr);
60 } else if (expr_type.IsSubclassOf (target_type)) {
62 // Special case: enumeration to System.Enum.
63 // System.Enum is not a value type, it is a class, so we need
64 // a boxing conversion
67 return new BoxedCast (expr);
69 return new EmptyCast (expr, target_type);
72 // This code is kind of mirrored inside ImplicitStandardConversionExists
73 // with the small distinction that we only probe there
75 // Always ensure that the code here and there is in sync
77 // from the null type to any reference-type.
78 if (expr is NullLiteral){
79 if (target_type.IsPointer)
80 return NullPointer.Null;
82 if (!target_type.IsValueType)
83 return new NullCast (expr, target_type);
86 // from any class-type S to any interface-type T.
87 if (target_type.IsInterface) {
88 if (TypeManager.ImplementsInterface (expr_type, target_type)){
89 if (expr_type.IsClass)
90 return new EmptyCast (expr, target_type);
91 else if (expr_type.IsValueType)
92 return new BoxedCast (expr, target_type);
96 // from any interface type S to interface-type T.
97 if (expr_type.IsInterface && target_type.IsInterface) {
98 if (TypeManager.ImplementsInterface (expr_type, target_type))
99 return new EmptyCast (expr, target_type);
104 // from an array-type S to an array-type of type T
105 if (expr_type.IsArray && target_type.IsArray) {
106 if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
108 Type expr_element_type = TypeManager.GetElementType (expr_type);
110 if (MyEmptyExpr == null)
111 MyEmptyExpr = new EmptyExpression ();
113 MyEmptyExpr.SetType (expr_element_type);
114 Type target_element_type = TypeManager.GetElementType (target_type);
116 if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
117 if (ImplicitStandardConversionExists (MyEmptyExpr,
118 target_element_type))
119 return new EmptyCast (expr, target_type);
124 // from an array-type to System.Array
125 if (expr_type.IsArray && target_type == TypeManager.array_type)
126 return new EmptyCast (expr, target_type);
128 // from any delegate type to System.Delegate
129 if ((expr_type == TypeManager.delegate_type ||
130 expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
131 target_type == TypeManager.delegate_type)
132 return new EmptyCast (expr, target_type);
134 // from any array-type or delegate type into System.ICloneable.
135 if (expr_type.IsArray ||
136 expr_type == TypeManager.delegate_type ||
137 expr_type.IsSubclassOf (TypeManager.delegate_type))
138 if (target_type == TypeManager.icloneable_type)
139 return new EmptyCast (expr, target_type);
149 // Tests whether an implicit reference conversion exists between expr_type
152 public static bool ImplicitReferenceConversionExists (Expression expr, Type target_type)
154 Type expr_type = expr.Type;
157 // This is the boxed case.
159 if (target_type == TypeManager.object_type) {
160 if (expr_type.IsClass || expr_type.IsValueType ||
161 expr_type.IsInterface || expr_type == TypeManager.enum_type)
163 } else if (expr_type.IsSubclassOf (target_type)) {
166 // Please remember that all code below actually comes
167 // from ImplicitReferenceConversion so make sure code remains in sync
169 // from any class-type S to any interface-type T.
170 if (target_type.IsInterface) {
171 if (TypeManager.ImplementsInterface (expr_type, target_type))
175 // from any interface type S to interface-type T.
176 if (expr_type.IsInterface && target_type.IsInterface)
177 if (TypeManager.ImplementsInterface (expr_type, target_type))
180 // from an array-type S to an array-type of type T
181 if (expr_type.IsArray && target_type.IsArray) {
182 if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
184 Type expr_element_type = expr_type.GetElementType ();
186 if (MyEmptyExpr == null)
187 MyEmptyExpr = new EmptyExpression ();
189 MyEmptyExpr.SetType (expr_element_type);
190 Type target_element_type = TypeManager.GetElementType (target_type);
192 if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
193 if (ImplicitStandardConversionExists (MyEmptyExpr,
194 target_element_type))
199 // from an array-type to System.Array
200 if (expr_type.IsArray && (target_type == TypeManager.array_type))
203 // from any delegate type to System.Delegate
204 if ((expr_type == TypeManager.delegate_type ||
205 expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
206 target_type == TypeManager.delegate_type)
207 if (target_type.IsAssignableFrom (expr_type))
210 // from any array-type or delegate type into System.ICloneable.
211 if (expr_type.IsArray ||
212 expr_type == TypeManager.delegate_type ||
213 expr_type.IsSubclassOf (TypeManager.delegate_type))
214 if (target_type == TypeManager.icloneable_type)
217 // from the null type to any reference-type.
218 if (expr is NullLiteral && !target_type.IsValueType &&
219 !TypeManager.IsEnumType (target_type))
227 /// Implicit Numeric Conversions.
229 /// expr is the expression to convert, returns a new expression of type
230 /// target_type or null if an implicit conversion is not possible.
232 static public Expression ImplicitNumericConversion (EmitContext ec, Expression expr,
233 Type target_type, Location loc)
235 Type expr_type = expr.Type;
238 // Attempt to do the implicit constant expression conversions
240 if (expr is Constant){
242 if (expr is IntConstant){
245 e = TryImplicitIntConversion (target_type, (IntConstant) expr);
249 } else if (expr is LongConstant && target_type == TypeManager.uint64_type){
251 // Try the implicit constant expression conversion
252 // from long to ulong, instead of a nice routine,
255 long v = ((LongConstant) expr).Value;
257 return new ULongConstant ((ulong) v);
261 Type real_target_type = target_type;
263 if (expr_type == TypeManager.sbyte_type){
265 // From sbyte to short, int, long, float, double.
267 if (real_target_type == TypeManager.int32_type)
268 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
269 if (real_target_type == TypeManager.int64_type)
270 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
271 if (real_target_type == TypeManager.double_type)
272 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
273 if (real_target_type == TypeManager.float_type)
274 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
275 if (real_target_type == TypeManager.short_type)
276 return new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
277 } else if (expr_type == TypeManager.byte_type){
279 // From byte to short, ushort, int, uint, long, ulong, float, double
281 if ((real_target_type == TypeManager.short_type) ||
282 (real_target_type == TypeManager.ushort_type) ||
283 (real_target_type == TypeManager.int32_type) ||
284 (real_target_type == TypeManager.uint32_type))
285 return new EmptyCast (expr, target_type);
287 if (real_target_type == TypeManager.uint64_type)
288 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
289 if (real_target_type == TypeManager.int64_type)
290 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
291 if (real_target_type == TypeManager.float_type)
292 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
293 if (real_target_type == TypeManager.double_type)
294 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
295 } else if (expr_type == TypeManager.short_type){
297 // From short to int, long, float, double
299 if (real_target_type == TypeManager.int32_type)
300 return new EmptyCast (expr, target_type);
301 if (real_target_type == TypeManager.int64_type)
302 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
303 if (real_target_type == TypeManager.double_type)
304 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
305 if (real_target_type == TypeManager.float_type)
306 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
307 } else if (expr_type == TypeManager.ushort_type){
309 // From ushort to int, uint, long, ulong, float, double
311 if (real_target_type == TypeManager.uint32_type)
312 return new EmptyCast (expr, target_type);
314 if (real_target_type == TypeManager.uint64_type)
315 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
316 if (real_target_type == TypeManager.int32_type)
317 return new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
318 if (real_target_type == TypeManager.int64_type)
319 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
320 if (real_target_type == TypeManager.double_type)
321 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
322 if (real_target_type == TypeManager.float_type)
323 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
324 } else if (expr_type == TypeManager.int32_type){
326 // From int to long, float, double
328 if (real_target_type == TypeManager.int64_type)
329 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
330 if (real_target_type == TypeManager.double_type)
331 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
332 if (real_target_type == TypeManager.float_type)
333 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
334 } else if (expr_type == TypeManager.uint32_type){
336 // From uint to long, ulong, float, double
338 if (real_target_type == TypeManager.int64_type)
339 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
340 if (real_target_type == TypeManager.uint64_type)
341 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
342 if (real_target_type == TypeManager.double_type)
343 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
345 if (real_target_type == TypeManager.float_type)
346 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
348 } else if (expr_type == TypeManager.int64_type){
350 // From long/ulong to float, double
352 if (real_target_type == TypeManager.double_type)
353 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
354 if (real_target_type == TypeManager.float_type)
355 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
356 } else if (expr_type == TypeManager.uint64_type){
358 // From ulong to float, double
360 if (real_target_type == TypeManager.double_type)
361 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
363 if (real_target_type == TypeManager.float_type)
364 return new OpcodeCast (expr, target_type, OpCodes.Conv_R_Un,
366 } else if (expr_type == TypeManager.char_type){
368 // From char to ushort, int, uint, long, ulong, float, double
370 if ((real_target_type == TypeManager.ushort_type) ||
371 (real_target_type == TypeManager.int32_type) ||
372 (real_target_type == TypeManager.uint32_type))
373 return new EmptyCast (expr, target_type);
374 if (real_target_type == TypeManager.uint64_type)
375 return new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
376 if (real_target_type == TypeManager.int64_type)
377 return new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
378 if (real_target_type == TypeManager.float_type)
379 return new OpcodeCast (expr, target_type, OpCodes.Conv_R4);
380 if (real_target_type == TypeManager.double_type)
381 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
382 } else if (expr_type == TypeManager.float_type){
386 if (real_target_type == TypeManager.double_type)
387 return new OpcodeCast (expr, target_type, OpCodes.Conv_R8);
395 /// Same as ImplicitStandardConversionExists except that it also looks at
396 /// implicit user defined conversions - needed for overload resolution
398 public static bool ImplicitConversionExists (EmitContext ec, Expression expr, Type target_type)
400 if (ImplicitStandardConversionExists (expr, target_type))
403 Expression dummy = ImplicitUserConversion (ec, expr, target_type, Location.Null);
411 public static bool ImplicitUserConversionExists (EmitContext ec, Type source, Type target)
413 Expression dummy = ImplicitUserConversion (
414 ec, new EmptyExpression (source), target, Location.Null);
415 return dummy != null;
419 /// Determines if a standard implicit conversion exists from
420 /// expr_type to target_type
422 public static bool ImplicitStandardConversionExists (Expression expr, Type target_type)
424 Type expr_type = expr.Type;
426 if (expr_type == TypeManager.void_type)
429 if (expr_type == target_type)
432 // First numeric conversions
434 if (expr_type == TypeManager.sbyte_type){
436 // From sbyte to short, int, long, float, double.
438 if ((target_type == TypeManager.int32_type) ||
439 (target_type == TypeManager.int64_type) ||
440 (target_type == TypeManager.double_type) ||
441 (target_type == TypeManager.float_type) ||
442 (target_type == TypeManager.short_type) ||
443 (target_type == TypeManager.decimal_type))
446 } else if (expr_type == TypeManager.byte_type){
448 // From byte to short, ushort, int, uint, long, ulong, float, double
450 if ((target_type == TypeManager.short_type) ||
451 (target_type == TypeManager.ushort_type) ||
452 (target_type == TypeManager.int32_type) ||
453 (target_type == TypeManager.uint32_type) ||
454 (target_type == TypeManager.uint64_type) ||
455 (target_type == TypeManager.int64_type) ||
456 (target_type == TypeManager.float_type) ||
457 (target_type == TypeManager.double_type) ||
458 (target_type == TypeManager.decimal_type))
461 } else if (expr_type == TypeManager.short_type){
463 // From short to int, long, float, double
465 if ((target_type == TypeManager.int32_type) ||
466 (target_type == TypeManager.int64_type) ||
467 (target_type == TypeManager.double_type) ||
468 (target_type == TypeManager.float_type) ||
469 (target_type == TypeManager.decimal_type))
472 } else if (expr_type == TypeManager.ushort_type){
474 // From ushort to int, uint, long, ulong, float, double
476 if ((target_type == TypeManager.uint32_type) ||
477 (target_type == TypeManager.uint64_type) ||
478 (target_type == TypeManager.int32_type) ||
479 (target_type == TypeManager.int64_type) ||
480 (target_type == TypeManager.double_type) ||
481 (target_type == TypeManager.float_type) ||
482 (target_type == TypeManager.decimal_type))
485 } else if (expr_type == TypeManager.int32_type){
487 // From int to long, float, double
489 if ((target_type == TypeManager.int64_type) ||
490 (target_type == TypeManager.double_type) ||
491 (target_type == TypeManager.float_type) ||
492 (target_type == TypeManager.decimal_type))
495 } else if (expr_type == TypeManager.uint32_type){
497 // From uint to long, ulong, float, double
499 if ((target_type == TypeManager.int64_type) ||
500 (target_type == TypeManager.uint64_type) ||
501 (target_type == TypeManager.double_type) ||
502 (target_type == TypeManager.float_type) ||
503 (target_type == TypeManager.decimal_type))
506 } else if ((expr_type == TypeManager.uint64_type) ||
507 (expr_type == TypeManager.int64_type)) {
509 // From long/ulong to float, double
511 if ((target_type == TypeManager.double_type) ||
512 (target_type == TypeManager.float_type) ||
513 (target_type == TypeManager.decimal_type))
516 } else if (expr_type == TypeManager.char_type){
518 // From char to ushort, int, uint, long, ulong, float, double
520 if ((target_type == TypeManager.ushort_type) ||
521 (target_type == TypeManager.int32_type) ||
522 (target_type == TypeManager.uint32_type) ||
523 (target_type == TypeManager.uint64_type) ||
524 (target_type == TypeManager.int64_type) ||
525 (target_type == TypeManager.float_type) ||
526 (target_type == TypeManager.double_type) ||
527 (target_type == TypeManager.decimal_type))
530 } else if (expr_type == TypeManager.float_type){
534 if (target_type == TypeManager.double_type)
538 if (ImplicitReferenceConversionExists (expr, target_type))
541 if (expr is IntConstant){
542 int value = ((IntConstant) expr).Value;
544 if (target_type == TypeManager.sbyte_type){
545 if (value >= SByte.MinValue && value <= SByte.MaxValue)
547 } else if (target_type == TypeManager.byte_type){
548 if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
550 } else if (target_type == TypeManager.short_type){
551 if (value >= Int16.MinValue && value <= Int16.MaxValue)
553 } else if (target_type == TypeManager.ushort_type){
554 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
556 } else if (target_type == TypeManager.uint32_type){
559 } else if (target_type == TypeManager.uint64_type){
561 // we can optimize this case: a positive int32
562 // always fits on a uint64. But we need an opcode
569 if (value == 0 && expr is IntLiteral && TypeManager.IsEnumType (target_type))
573 if (expr is LongConstant && target_type == TypeManager.uint64_type){
575 // Try the implicit constant expression conversion
576 // from long to ulong, instead of a nice routine,
579 long v = ((LongConstant) expr).Value;
584 if ((target_type == TypeManager.enum_type ||
585 target_type.IsSubclassOf (TypeManager.enum_type)) &&
587 IntLiteral i = (IntLiteral) expr;
593 if (target_type == TypeManager.void_ptr_type && expr_type.IsPointer)
600 // Used internally by FindMostEncompassedType, this is used
601 // to avoid creating lots of objects in the tight loop inside
602 // FindMostEncompassedType
604 static EmptyExpression priv_fmet_param;
607 /// Finds "most encompassed type" according to the spec (13.4.2)
608 /// amongst the methods in the MethodGroupExpr
610 static Type FindMostEncompassedType (ArrayList types)
614 if (priv_fmet_param == null)
615 priv_fmet_param = new EmptyExpression ();
617 foreach (Type t in types){
618 priv_fmet_param.SetType (t);
625 if (ImplicitStandardConversionExists (priv_fmet_param, best))
633 // Used internally by FindMostEncompassingType, this is used
634 // to avoid creating lots of objects in the tight loop inside
635 // FindMostEncompassingType
637 static EmptyExpression priv_fmee_ret;
640 /// Finds "most encompassing type" according to the spec (13.4.2)
641 /// amongst the types in the given set
643 static Type FindMostEncompassingType (ArrayList types)
647 if (priv_fmee_ret == null)
648 priv_fmee_ret = new EmptyExpression ();
650 foreach (Type t in types){
651 priv_fmee_ret.SetType (best);
658 if (ImplicitStandardConversionExists (priv_fmee_ret, t))
666 // Used to avoid creating too many objects
668 static EmptyExpression priv_fms_expr;
671 /// Finds the most specific source Sx according to the rules of the spec (13.4.4)
672 /// by making use of FindMostEncomp* methods. Applies the correct rules separately
673 /// for explicit and implicit conversion operators.
675 static public Type FindMostSpecificSource (MethodGroupExpr me, Expression source,
676 bool apply_explicit_conv_rules,
679 ArrayList src_types_set = new ArrayList ();
681 if (priv_fms_expr == null)
682 priv_fms_expr = new EmptyExpression ();
685 // If any operator converts from S then Sx = S
687 Type source_type = source.Type;
688 foreach (MethodBase mb in me.Methods){
689 ParameterData pd = Invocation.GetParameterData (mb);
690 Type param_type = pd.ParameterType (0);
692 if (param_type == source_type)
695 if (apply_explicit_conv_rules) {
698 // Find the set of applicable user-defined conversion operators, U. This set
700 // user-defined implicit or explicit conversion operators declared by
701 // the classes or structs in D that convert from a type encompassing
702 // or encompassed by S to a type encompassing or encompassed by T
704 priv_fms_expr.SetType (param_type);
705 if (ImplicitStandardConversionExists (priv_fms_expr, source_type))
706 src_types_set.Add (param_type);
708 if (ImplicitStandardConversionExists (source, param_type))
709 src_types_set.Add (param_type);
713 // Only if S is encompassed by param_type
715 if (ImplicitStandardConversionExists (source, param_type))
716 src_types_set.Add (param_type);
721 // Explicit Conv rules
723 if (apply_explicit_conv_rules) {
724 ArrayList candidate_set = new ArrayList ();
726 foreach (Type param_type in src_types_set){
727 if (ImplicitStandardConversionExists (source, param_type))
728 candidate_set.Add (param_type);
731 if (candidate_set.Count != 0)
732 return FindMostEncompassedType (candidate_set);
738 if (apply_explicit_conv_rules)
739 return FindMostEncompassingType (src_types_set);
741 return FindMostEncompassedType (src_types_set);
745 // Useful in avoiding proliferation of objects
747 static EmptyExpression priv_fmt_expr;
750 /// Finds the most specific target Tx according to section 13.4.4
752 static public Type FindMostSpecificTarget (MethodGroupExpr me, Type target,
753 bool apply_explicit_conv_rules,
756 ArrayList tgt_types_set = new ArrayList ();
758 if (priv_fmt_expr == null)
759 priv_fmt_expr = new EmptyExpression ();
762 // If any operator converts to T then Tx = T
764 foreach (MethodInfo mi in me.Methods){
765 Type ret_type = mi.ReturnType;
767 if (ret_type == target)
770 if (apply_explicit_conv_rules) {
773 // Find the set of applicable user-defined conversion operators, U.
775 // This set consists of the
776 // user-defined implicit or explicit conversion operators declared by
777 // the classes or structs in D that convert from a type encompassing
778 // or encompassed by S to a type encompassing or encompassed by T
780 priv_fms_expr.SetType (ret_type);
781 if (ImplicitStandardConversionExists (priv_fms_expr, target))
782 tgt_types_set.Add (ret_type);
784 priv_fms_expr.SetType (target);
785 if (ImplicitStandardConversionExists (priv_fms_expr, ret_type))
786 tgt_types_set.Add (ret_type);
790 // Only if T is encompassed by param_type
792 priv_fms_expr.SetType (ret_type);
793 if (ImplicitStandardConversionExists (priv_fms_expr, target))
794 tgt_types_set.Add (ret_type);
799 // Explicit conv rules
801 if (apply_explicit_conv_rules) {
802 ArrayList candidate_set = new ArrayList ();
804 foreach (Type ret_type in tgt_types_set){
805 priv_fmt_expr.SetType (ret_type);
807 if (ImplicitStandardConversionExists (priv_fmt_expr, target))
808 candidate_set.Add (ret_type);
811 if (candidate_set.Count != 0)
812 return FindMostEncompassingType (candidate_set);
816 // Okay, final case !
818 if (apply_explicit_conv_rules)
819 return FindMostEncompassedType (tgt_types_set);
821 return FindMostEncompassingType (tgt_types_set);
825 /// User-defined Implicit conversions
827 static public Expression ImplicitUserConversion (EmitContext ec, Expression source,
828 Type target, Location loc)
830 return UserDefinedConversion (ec, source, target, loc, false);
834 /// User-defined Explicit conversions
836 static public Expression ExplicitUserConversion (EmitContext ec, Expression source,
837 Type target, Location loc)
839 return UserDefinedConversion (ec, source, target, loc, true);
843 /// Computes the MethodGroup for the user-defined conversion
844 /// operators from source_type to target_type. `look_for_explicit'
845 /// controls whether we should also include the list of explicit
848 static MethodGroupExpr GetConversionOperators (EmitContext ec,
849 Type source_type, Type target_type,
850 Location loc, bool look_for_explicit)
852 Expression mg1 = null, mg2 = null;
853 Expression mg5 = null, mg6 = null, mg7 = null, mg8 = null;
856 op_name = "op_Implicit";
858 MethodGroupExpr union3;
860 mg1 = Expression.MethodLookup (ec, source_type, op_name, loc);
861 if (source_type.BaseType != null)
862 mg2 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
865 union3 = (MethodGroupExpr) mg2;
866 else if (mg2 == null)
867 union3 = (MethodGroupExpr) mg1;
869 union3 = Invocation.MakeUnionSet (mg1, mg2, loc);
871 mg1 = Expression.MethodLookup (ec, target_type, op_name, loc);
874 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
876 union3 = (MethodGroupExpr) mg1;
879 if (target_type.BaseType != null)
880 mg1 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
884 union3 = Invocation.MakeUnionSet (union3, mg1, loc);
886 union3 = (MethodGroupExpr) mg1;
889 MethodGroupExpr union4 = null;
891 if (look_for_explicit) {
892 op_name = "op_Explicit";
894 mg5 = Expression.MemberLookup (ec, source_type, op_name, loc);
895 if (source_type.BaseType != null)
896 mg6 = Expression.MethodLookup (ec, source_type.BaseType, op_name, loc);
898 mg7 = Expression.MemberLookup (ec, target_type, op_name, loc);
899 if (target_type.BaseType != null)
900 mg8 = Expression.MethodLookup (ec, target_type.BaseType, op_name, loc);
902 MethodGroupExpr union5 = Invocation.MakeUnionSet (mg5, mg6, loc);
903 MethodGroupExpr union6 = Invocation.MakeUnionSet (mg7, mg8, loc);
905 union4 = Invocation.MakeUnionSet (union5, union6, loc);
908 return Invocation.MakeUnionSet (union3, union4, loc);
912 /// User-defined conversions
914 static public Expression UserDefinedConversion (EmitContext ec, Expression source,
915 Type target, Location loc,
916 bool look_for_explicit)
918 MethodGroupExpr union;
919 Type source_type = source.Type;
920 MethodBase method = null;
922 union = GetConversionOperators (ec, source_type, target, loc, look_for_explicit);
926 Type most_specific_source, most_specific_target;
928 most_specific_source = FindMostSpecificSource (union, source, look_for_explicit, loc);
929 if (most_specific_source == null)
932 most_specific_target = FindMostSpecificTarget (union, target, look_for_explicit, loc);
933 if (most_specific_target == null)
939 foreach (MethodBase mb in union.Methods){
940 ParameterData pd = Invocation.GetParameterData (mb);
941 MethodInfo mi = (MethodInfo) mb;
943 if (pd.ParameterType (0) == most_specific_source &&
944 mi.ReturnType == most_specific_target) {
950 if (method == null || count > 1)
955 // This will do the conversion to the best match that we
956 // found. Now we need to perform an implict standard conversion
957 // if the best match was not the type that we were requested
960 if (look_for_explicit)
961 source = ExplicitConversionStandard (ec, source, most_specific_source, loc);
963 source = ImplicitConversionStandard (ec, source, most_specific_source, loc);
969 e = new UserCast ((MethodInfo) method, source, loc);
970 if (e.Type != target){
971 if (!look_for_explicit)
972 e = ImplicitConversionStandard (ec, e, target, loc);
974 e = ExplicitConversionStandard (ec, e, target, loc);
981 /// Converts implicitly the resolved expression `expr' into the
982 /// `target_type'. It returns a new expression that can be used
983 /// in a context that expects a `target_type'.
985 static public Expression ImplicitConversion (EmitContext ec, Expression expr,
986 Type target_type, Location loc)
988 Type expr_type = expr.Type;
991 if (target_type == null)
992 throw new Exception ("Target type is null");
994 e = ImplicitConversionStandard (ec, expr, target_type, loc);
998 e = ImplicitUserConversion (ec, expr, target_type, loc);
1007 /// Attempts to apply the `Standard Implicit
1008 /// Conversion' rules to the expression `expr' into
1009 /// the `target_type'. It returns a new expression
1010 /// that can be used in a context that expects a
1013 /// This is different from `ImplicitConversion' in that the
1014 /// user defined implicit conversions are excluded.
1016 static public Expression ImplicitConversionStandard (EmitContext ec, Expression expr,
1017 Type target_type, Location loc)
1019 Type expr_type = expr.Type;
1022 if (expr_type == target_type && !(expr is NullLiteral))
1025 e = ImplicitNumericConversion (ec, expr, target_type, loc);
1029 e = ImplicitReferenceConversion (expr, target_type);
1033 if ((target_type == TypeManager.enum_type ||
1034 target_type.IsSubclassOf (TypeManager.enum_type)) &&
1035 expr is IntLiteral){
1036 IntLiteral i = (IntLiteral) expr;
1039 return new EnumConstant ((Constant) expr, target_type);
1043 if (expr_type.IsPointer){
1044 if (target_type == TypeManager.void_ptr_type)
1045 return new EmptyCast (expr, target_type);
1048 // yep, comparing pointer types cant be done with
1049 // t1 == t2, we have to compare their element types.
1051 if (target_type.IsPointer){
1052 if (TypeManager.GetElementType(target_type) == TypeManager.GetElementType(expr_type))
1057 if (target_type.IsPointer) {
1058 if (expr is NullLiteral)
1059 return new EmptyCast (expr, target_type);
1061 if (expr_type == TypeManager.void_ptr_type)
1062 return new EmptyCast (expr, target_type);
1070 /// Attemps to perform an implict constant conversion of the IntConstant
1071 /// into a different data type using casts (See Implicit Constant
1072 /// Expression Conversions)
1074 static public Expression TryImplicitIntConversion (Type target_type, IntConstant ic)
1076 int value = ic.Value;
1078 if (target_type == TypeManager.sbyte_type){
1079 if (value >= SByte.MinValue && value <= SByte.MaxValue)
1080 return new SByteConstant ((sbyte) value);
1081 } else if (target_type == TypeManager.byte_type){
1082 if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
1083 return new ByteConstant ((byte) value);
1084 } else if (target_type == TypeManager.short_type){
1085 if (value >= Int16.MinValue && value <= Int16.MaxValue)
1086 return new ShortConstant ((short) value);
1087 } else if (target_type == TypeManager.ushort_type){
1088 if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
1089 return new UShortConstant ((ushort) value);
1090 } else if (target_type == TypeManager.uint32_type){
1092 return new UIntConstant ((uint) value);
1093 } else if (target_type == TypeManager.uint64_type){
1095 // we can optimize this case: a positive int32
1096 // always fits on a uint64. But we need an opcode
1100 return new ULongConstant ((ulong) value);
1101 } else if (target_type == TypeManager.double_type)
1102 return new DoubleConstant ((double) value);
1103 else if (target_type == TypeManager.float_type)
1104 return new FloatConstant ((float) value);
1106 if (value == 0 && ic is IntLiteral && TypeManager.IsEnumType (target_type)){
1107 Type underlying = TypeManager.EnumToUnderlying (target_type);
1108 Constant e = (Constant) ic;
1111 // Possibly, we need to create a different 0 literal before passing
1114 if (underlying == TypeManager.int64_type)
1115 e = new LongLiteral (0);
1116 else if (underlying == TypeManager.uint64_type)
1117 e = new ULongLiteral (0);
1119 return new EnumConstant (e, target_type);
1124 static public void Error_CannotImplicitConversion (Location loc, Type source, Type target)
1126 string msg = "Cannot convert implicitly from `"+
1127 TypeManager.CSharpName (source) + "' to `" +
1128 TypeManager.CSharpName (target) + "'";
1130 Report.Error (29, loc, msg);
1134 /// Attemptes to implicityly convert `target' into `type', using
1135 /// ImplicitConversion. If there is no implicit conversion, then
1136 /// an error is signaled
1138 static public Expression ImplicitConversionRequired (EmitContext ec, Expression source,
1139 Type target_type, Location loc)
1143 e = ImplicitConversion (ec, source, target_type, loc);
1147 if (source is DoubleLiteral && target_type == TypeManager.float_type){
1148 Report.Error (664, loc,
1149 "Double literal cannot be implicitly converted to " +
1150 "float type, use F suffix to create a float literal");
1153 Error_CannotImplicitConversion (loc, source.Type, target_type);
1159 /// Performs the explicit numeric conversions
1161 static Expression ExplicitNumericConversion (EmitContext ec, Expression expr, Type target_type, Location loc)
1163 Type expr_type = expr.Type;
1166 // If we have an enumeration, extract the underlying type,
1167 // use this during the comparison, but wrap around the original
1170 Type real_target_type = target_type;
1172 if (TypeManager.IsEnumType (real_target_type))
1173 real_target_type = TypeManager.EnumToUnderlying (real_target_type);
1175 if (ImplicitStandardConversionExists (expr, real_target_type)){
1176 Expression ce = ImplicitConversionStandard (ec, expr, real_target_type, loc);
1178 if (real_target_type != target_type)
1179 return new EmptyCast (ce, target_type);
1183 if (expr_type == TypeManager.sbyte_type){
1185 // From sbyte to byte, ushort, uint, ulong, char
1187 if (real_target_type == TypeManager.byte_type)
1188 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U1);
1189 if (real_target_type == TypeManager.ushort_type)
1190 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U2);
1191 if (real_target_type == TypeManager.uint32_type)
1192 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U4);
1193 if (real_target_type == TypeManager.uint64_type)
1194 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_U8);
1195 if (real_target_type == TypeManager.char_type)
1196 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I1_CH);
1197 } else if (expr_type == TypeManager.byte_type){
1199 // From byte to sbyte and char
1201 if (real_target_type == TypeManager.sbyte_type)
1202 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_I1);
1203 if (real_target_type == TypeManager.char_type)
1204 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U1_CH);
1205 } else if (expr_type == TypeManager.short_type){
1207 // From short to sbyte, byte, ushort, uint, ulong, char
1209 if (real_target_type == TypeManager.sbyte_type)
1210 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_I1);
1211 if (real_target_type == TypeManager.byte_type)
1212 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U1);
1213 if (real_target_type == TypeManager.ushort_type)
1214 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U2);
1215 if (real_target_type == TypeManager.uint32_type)
1216 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U4);
1217 if (real_target_type == TypeManager.uint64_type)
1218 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_U8);
1219 if (real_target_type == TypeManager.char_type)
1220 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I2_CH);
1221 } else if (expr_type == TypeManager.ushort_type){
1223 // From ushort to sbyte, byte, short, char
1225 if (real_target_type == TypeManager.sbyte_type)
1226 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I1);
1227 if (real_target_type == TypeManager.byte_type)
1228 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_U1);
1229 if (real_target_type == TypeManager.short_type)
1230 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_I2);
1231 if (real_target_type == TypeManager.char_type)
1232 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U2_CH);
1233 } else if (expr_type == TypeManager.int32_type){
1235 // From int to sbyte, byte, short, ushort, uint, ulong, char
1237 if (real_target_type == TypeManager.sbyte_type)
1238 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I1);
1239 if (real_target_type == TypeManager.byte_type)
1240 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U1);
1241 if (real_target_type == TypeManager.short_type)
1242 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_I2);
1243 if (real_target_type == TypeManager.ushort_type)
1244 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U2);
1245 if (real_target_type == TypeManager.uint32_type)
1246 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U4);
1247 if (real_target_type == TypeManager.uint64_type)
1248 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_U8);
1249 if (real_target_type == TypeManager.char_type)
1250 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I4_CH);
1251 } else if (expr_type == TypeManager.uint32_type){
1253 // From uint to sbyte, byte, short, ushort, int, char
1255 if (real_target_type == TypeManager.sbyte_type)
1256 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I1);
1257 if (real_target_type == TypeManager.byte_type)
1258 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U1);
1259 if (real_target_type == TypeManager.short_type)
1260 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I2);
1261 if (real_target_type == TypeManager.ushort_type)
1262 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_U2);
1263 if (real_target_type == TypeManager.int32_type)
1264 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_I4);
1265 if (real_target_type == TypeManager.char_type)
1266 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U4_CH);
1267 } else if (expr_type == TypeManager.int64_type){
1269 // From long to sbyte, byte, short, ushort, int, uint, ulong, char
1271 if (real_target_type == TypeManager.sbyte_type)
1272 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I1);
1273 if (real_target_type == TypeManager.byte_type)
1274 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U1);
1275 if (real_target_type == TypeManager.short_type)
1276 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I2);
1277 if (real_target_type == TypeManager.ushort_type)
1278 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U2);
1279 if (real_target_type == TypeManager.int32_type)
1280 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_I4);
1281 if (real_target_type == TypeManager.uint32_type)
1282 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U4);
1283 if (real_target_type == TypeManager.uint64_type)
1284 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_U8);
1285 if (real_target_type == TypeManager.char_type)
1286 return new ConvCast (ec, expr, target_type, ConvCast.Mode.I8_CH);
1287 } else if (expr_type == TypeManager.uint64_type){
1289 // From ulong to sbyte, byte, short, ushort, int, uint, long, char
1291 if (real_target_type == TypeManager.sbyte_type)
1292 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I1);
1293 if (real_target_type == TypeManager.byte_type)
1294 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U1);
1295 if (real_target_type == TypeManager.short_type)
1296 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I2);
1297 if (real_target_type == TypeManager.ushort_type)
1298 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U2);
1299 if (real_target_type == TypeManager.int32_type)
1300 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I4);
1301 if (real_target_type == TypeManager.uint32_type)
1302 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_U4);
1303 if (real_target_type == TypeManager.int64_type)
1304 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_I8);
1305 if (real_target_type == TypeManager.char_type)
1306 return new ConvCast (ec, expr, target_type, ConvCast.Mode.U8_CH);
1307 } else if (expr_type == TypeManager.char_type){
1309 // From char to sbyte, byte, short
1311 if (real_target_type == TypeManager.sbyte_type)
1312 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I1);
1313 if (real_target_type == TypeManager.byte_type)
1314 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_U1);
1315 if (real_target_type == TypeManager.short_type)
1316 return new ConvCast (ec, expr, target_type, ConvCast.Mode.CH_I2);
1317 } else if (expr_type == TypeManager.float_type){
1319 // From float to sbyte, byte, short,
1320 // ushort, int, uint, long, ulong, char
1323 if (real_target_type == TypeManager.sbyte_type)
1324 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I1);
1325 if (real_target_type == TypeManager.byte_type)
1326 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U1);
1327 if (real_target_type == TypeManager.short_type)
1328 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I2);
1329 if (real_target_type == TypeManager.ushort_type)
1330 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U2);
1331 if (real_target_type == TypeManager.int32_type)
1332 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I4);
1333 if (real_target_type == TypeManager.uint32_type)
1334 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U4);
1335 if (real_target_type == TypeManager.int64_type)
1336 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_I8);
1337 if (real_target_type == TypeManager.uint64_type)
1338 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_U8);
1339 if (real_target_type == TypeManager.char_type)
1340 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R4_CH);
1341 } else if (expr_type == TypeManager.double_type){
1343 // From double to byte, byte, short,
1344 // ushort, int, uint, long, ulong,
1345 // char, float or decimal
1347 if (real_target_type == TypeManager.sbyte_type)
1348 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I1);
1349 if (real_target_type == TypeManager.byte_type)
1350 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U1);
1351 if (real_target_type == TypeManager.short_type)
1352 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I2);
1353 if (real_target_type == TypeManager.ushort_type)
1354 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U2);
1355 if (real_target_type == TypeManager.int32_type)
1356 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I4);
1357 if (real_target_type == TypeManager.uint32_type)
1358 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U4);
1359 if (real_target_type == TypeManager.int64_type)
1360 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_I8);
1361 if (real_target_type == TypeManager.uint64_type)
1362 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_U8);
1363 if (real_target_type == TypeManager.char_type)
1364 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_CH);
1365 if (real_target_type == TypeManager.float_type)
1366 return new ConvCast (ec, expr, target_type, ConvCast.Mode.R8_R4);
1369 // decimal is taken care of by the op_Explicit methods.
1375 /// Returns whether an explicit reference conversion can be performed
1376 /// from source_type to target_type
1378 public static bool ExplicitReferenceConversionExists (Type source_type, Type target_type)
1380 bool target_is_value_type = target_type.IsValueType;
1382 if (source_type == target_type)
1386 // From object to any reference type
1388 if (source_type == TypeManager.object_type && !target_is_value_type)
1392 // From any class S to any class-type T, provided S is a base class of T
1394 if (target_type.IsSubclassOf (source_type))
1398 // From any interface type S to any interface T provided S is not derived from T
1400 if (source_type.IsInterface && target_type.IsInterface){
1401 if (!target_type.IsSubclassOf (source_type))
1406 // From any class type S to any interface T, provided S is not sealed
1407 // and provided S does not implement T.
1409 if (target_type.IsInterface && !source_type.IsSealed &&
1410 !TypeManager.ImplementsInterface (source_type, target_type))
1414 // From any interface-type S to to any class type T, provided T is not
1415 // sealed, or provided T implements S.
1417 if (source_type.IsInterface &&
1418 (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)))
1422 // From an array type S with an element type Se to an array type T with an
1423 // element type Te provided all the following are true:
1424 // * S and T differe only in element type, in other words, S and T
1425 // have the same number of dimensions.
1426 // * Both Se and Te are reference types
1427 // * An explicit referenc conversions exist from Se to Te
1429 if (source_type.IsArray && target_type.IsArray) {
1430 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1432 Type source_element_type = TypeManager.GetElementType (source_type);
1433 Type target_element_type = TypeManager.GetElementType (target_type);
1435 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1436 if (ExplicitReferenceConversionExists (source_element_type,
1437 target_element_type))
1443 // From System.Array to any array-type
1444 if (source_type == TypeManager.array_type &&
1445 target_type.IsArray){
1450 // From System delegate to any delegate-type
1452 if (source_type == TypeManager.delegate_type &&
1453 target_type.IsSubclassOf (TypeManager.delegate_type))
1457 // From ICloneable to Array or Delegate types
1459 if (source_type == TypeManager.icloneable_type &&
1460 (target_type == TypeManager.array_type ||
1461 target_type == TypeManager.delegate_type))
1468 /// Implements Explicit Reference conversions
1470 static Expression ExplicitReferenceConversion (Expression source, Type target_type)
1472 Type source_type = source.Type;
1473 bool target_is_value_type = target_type.IsValueType;
1476 // From object to any reference type
1478 if (source_type == TypeManager.object_type && !target_is_value_type)
1479 return new ClassCast (source, target_type);
1483 // From any class S to any class-type T, provided S is a base class of T
1485 if (target_type.IsSubclassOf (source_type))
1486 return new ClassCast (source, target_type);
1489 // From any interface type S to any interface T provided S is not derived from T
1491 if (source_type.IsInterface && target_type.IsInterface){
1492 if (TypeManager.ImplementsInterface (source_type, target_type))
1495 return new ClassCast (source, target_type);
1499 // From any class type S to any interface T, provides S is not sealed
1500 // and provided S does not implement T.
1502 if (target_type.IsInterface && !source_type.IsSealed) {
1503 if (TypeManager.ImplementsInterface (source_type, target_type))
1506 return new ClassCast (source, target_type);
1511 // From any interface-type S to to any class type T, provided T is not
1512 // sealed, or provided T implements S.
1514 if (source_type.IsInterface) {
1515 if (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)) {
1516 if (target_type.IsClass)
1517 return new ClassCast (source, target_type);
1519 return new UnboxCast (source, target_type);
1525 // From an array type S with an element type Se to an array type T with an
1526 // element type Te provided all the following are true:
1527 // * S and T differe only in element type, in other words, S and T
1528 // have the same number of dimensions.
1529 // * Both Se and Te are reference types
1530 // * An explicit referenc conversions exist from Se to Te
1532 if (source_type.IsArray && target_type.IsArray) {
1533 if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
1535 Type source_element_type = TypeManager.GetElementType (source_type);
1536 Type target_element_type = TypeManager.GetElementType (target_type);
1538 if (!source_element_type.IsValueType && !target_element_type.IsValueType)
1539 if (ExplicitReferenceConversionExists (source_element_type,
1540 target_element_type))
1541 return new ClassCast (source, target_type);
1546 // From System.Array to any array-type
1547 if (source_type == TypeManager.array_type &&
1548 target_type.IsArray) {
1549 return new ClassCast (source, target_type);
1553 // From System delegate to any delegate-type
1555 if (source_type == TypeManager.delegate_type &&
1556 target_type.IsSubclassOf (TypeManager.delegate_type))
1557 return new ClassCast (source, target_type);
1560 // From ICloneable to Array or Delegate types
1562 if (source_type == TypeManager.icloneable_type &&
1563 (target_type == TypeManager.array_type ||
1564 target_type == TypeManager.delegate_type))
1565 return new ClassCast (source, target_type);
1571 /// Performs an explicit conversion of the expression `expr' whose
1572 /// type is expr.Type to `target_type'.
1574 static public Expression ExplicitConversion (EmitContext ec, Expression expr,
1575 Type target_type, Location loc)
1577 Type expr_type = expr.Type;
1578 Type original_expr_type = expr_type;
1580 if (expr_type.IsSubclassOf (TypeManager.enum_type)){
1581 if (target_type == TypeManager.enum_type ||
1582 target_type == TypeManager.object_type) {
1583 if (expr is EnumConstant)
1584 expr = ((EnumConstant) expr).Child;
1585 // We really need all these casts here .... :-(
1586 expr = new BoxedCast (new EmptyCast (expr, expr_type));
1587 return new EmptyCast (expr, target_type);
1588 } else if ((expr_type == TypeManager.enum_type) && target_type.IsValueType &&
1589 target_type.IsSubclassOf (TypeManager.enum_type))
1590 return new UnboxCast (expr, target_type);
1593 // Notice that we have kept the expr_type unmodified, which is only
1595 if (expr is EnumConstant)
1596 expr = ((EnumConstant) expr).Child;
1598 expr = new EmptyCast (expr, TypeManager.EnumToUnderlying (expr_type));
1599 expr_type = expr.Type;
1602 Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc);
1607 ne = ExplicitNumericConversion (ec, expr, target_type, loc);
1612 // Unboxing conversion.
1614 if (expr_type == TypeManager.object_type && target_type.IsValueType){
1615 if (expr is NullLiteral){
1616 Report.Error (37, loc, "Cannot convert null to value type `" +
1617 TypeManager.CSharpName (target_type) + "'");
1620 return new UnboxCast (expr, target_type);
1624 ne = ExplicitReferenceConversion (expr, target_type);
1629 if (target_type.IsPointer){
1630 if (expr_type.IsPointer)
1631 return new EmptyCast (expr, target_type);
1633 if (expr_type == TypeManager.sbyte_type ||
1634 expr_type == TypeManager.byte_type ||
1635 expr_type == TypeManager.short_type ||
1636 expr_type == TypeManager.ushort_type ||
1637 expr_type == TypeManager.int32_type ||
1638 expr_type == TypeManager.uint32_type ||
1639 expr_type == TypeManager.uint64_type ||
1640 expr_type == TypeManager.int64_type)
1641 return new OpcodeCast (expr, target_type, OpCodes.Conv_U);
1643 if (expr_type.IsPointer){
1644 Expression e = null;
1646 if (target_type == TypeManager.sbyte_type)
1647 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I1);
1648 else if (target_type == TypeManager.byte_type)
1649 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U1);
1650 else if (target_type == TypeManager.short_type)
1651 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I2);
1652 else if (target_type == TypeManager.ushort_type)
1653 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U2);
1654 else if (target_type == TypeManager.int32_type)
1655 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I4);
1656 else if (target_type == TypeManager.uint32_type)
1657 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U4);
1658 else if (target_type == TypeManager.uint64_type)
1659 e = new OpcodeCast (expr, target_type, OpCodes.Conv_U8);
1660 else if (target_type == TypeManager.int64_type){
1661 e = new OpcodeCast (expr, target_type, OpCodes.Conv_I8);
1667 ci = ImplicitConversionStandard (ec, e, target_type, loc);
1672 ce = ExplicitNumericConversion (ec, e, target_type, loc);
1676 // We should always be able to go from an uint32
1677 // implicitly or explicitly to the other integral
1680 throw new Exception ("Internal compiler error");
1685 ne = ExplicitUserConversion (ec, expr, target_type, loc);
1689 Error_CannotConvertType (loc, original_expr_type, target_type);
1694 /// Same as ExplicitConversion, only it doesn't include user defined conversions
1696 static public Expression ExplicitConversionStandard (EmitContext ec, Expression expr,
1697 Type target_type, Location l)
1699 Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
1704 ne = ExplicitNumericConversion (ec, expr, target_type, l);
1708 ne = ExplicitReferenceConversion (expr, target_type);
1712 Error_CannotConvertType (l, expr.Type, target_type);