return false;
}
- static bool ExplicitTypeParameterConversionExists (Type source_type, Type target_type)
+ static Expression ExplicitTypeParameterConversion (Expression source, Type source_type, Type target_type)
{
#if GMCS_SOURCE
- if (TypeManager.IsGenericParameter (target_type)) {
- GenericConstraints gc = TypeManager.GetTypeParameterConstraints (target_type);
- if (gc == null)
- return false;
-
- foreach (Type iface in gc.InterfaceConstraints) {
- if (!TypeManager.IsGenericParameter (iface))
- continue;
-
- if (TypeManager.IsSubclassOf (source_type, iface))
- return true;
- }
- }
-#endif
- return target_type.IsInterface;
- }
-
- static Expression ExplicitTypeParameterConversion (Expression source, Type target_type)
- {
-#if GMCS_SOURCE
- Type source_type = source.Type;
-
if (TypeManager.IsGenericParameter (target_type)) {
GenericConstraints gc = TypeManager.GetTypeParameterConstraints (target_type);
if (gc == null)
continue;
if (TypeManager.IsSubclassOf (source_type, iface))
- return new ClassCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
}
}
if (target_type.IsInterface)
- return new ClassCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
#endif
return null;
}
// from an array-type S to an array-type of type T
if (target_type.IsArray && expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
+ //
+ // Both SE and TE are reference-types
+ //
Type expr_element_type = TypeManager.GetElementType (expr_type);
+ if (!TypeManager.IsReferenceType (expr_element_type))
+ return false;
+
+ Type target_element_type = TypeManager.GetElementType (target_type);
+ if (!TypeManager.IsReferenceType (target_element_type))
+ return false;
if (MyEmptyExpr == null)
MyEmptyExpr = new EmptyExpression ();
MyEmptyExpr.SetType (expr_element_type);
- Type target_element_type = TypeManager.GetElementType (target_type);
- if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
- return ImplicitStandardConversionExists (
- MyEmptyExpr, target_element_type);
+ return ImplicitStandardConversionExists (MyEmptyExpr, target_element_type);
}
// from an array-type to System.Array
if (expr_type == TypeManager.void_type)
return false;
+ if (expr.eclass == ExprClass.MethodGroup) {
+ if (TypeManager.IsDelegateType (target_type) && RootContext.Version != LanguageVersion.ISO_1) {
+ MethodGroupExpr mg = expr as MethodGroupExpr;
+ if (mg != null) {
+ return DelegateCreation.ImplicitStandardConversionExists (mg, target_type) != null;
+ }
+ }
+
+ return false;
+ }
+
//Console.WriteLine ("Expr is {0}", expr);
//Console.WriteLine ("{0} -> {1} ?", expr_type, target_type);
if (TypeManager.IsEqual (expr_type, target_type))
return true;
}
- if (expr.eclass == ExprClass.MethodGroup){
- if (TypeManager.IsDelegateType (target_type) && RootContext.Version != LanguageVersion.ISO_1){
- MethodGroupExpr mg = expr as MethodGroupExpr;
- if (mg != null){
- return DelegateCreation.ImplicitStandardConversionExists (mg, target_type) != null;
- }
- }
-
- return false;
- }
-
if (ImplicitReferenceConversionExists (expr, target_type))
return true;
if (source == null)
return null;
- return new UserCast (method, source, loc);
+ return new UserCast (method, source, loc).DoResolve (ec);
}
/// <summary>
}
if (expr_type == TypeManager.null_type && target_type.IsPointer)
- return EmptyCast.Create (NullPointer.Null, target_type);
+ return EmptyCast.Create (new NullPointer (loc), target_type);
}
if (expr_type == TypeManager.anonymous_method_type){
/// </summary>
public static bool ExplicitReferenceConversionExists (Type source_type, Type target_type)
{
- bool target_is_type_param = TypeManager.IsGenericParameter (target_type);
- bool target_is_value_type = target_type.IsValueType;
-
- if (source_type == target_type)
- return true;
-
- //
- // From generic parameter to any type
- //
- if (TypeManager.IsGenericParameter (source_type))
- return ExplicitTypeParameterConversionExists (source_type, target_type);
-
- //
- // From object to a generic parameter
- //
- if (source_type == TypeManager.object_type && target_is_type_param)
- return true;
-
- //
- // From object to any reference type
- //
- if (source_type == TypeManager.object_type && !target_is_value_type)
- return true;
-
- //
- // From any class S to any class-type T, provided S is a base class of T
- //
- if (TypeManager.IsSubclassOf (target_type, source_type))
- return true;
-
- //
- // From any interface type S to any interface T provided S is not derived from T
- //
- if (source_type.IsInterface && target_type.IsInterface){
- if (!TypeManager.IsSubclassOf (target_type, source_type))
- return true;
- }
-
- //
- // From any class type S to any interface T, provided S is not sealed
- // and provided S does not implement T.
- //
- if (target_type.IsInterface && !source_type.IsSealed &&
- !TypeManager.ImplementsInterface (source_type, target_type))
- return true;
-
- //
- // From any interface-type S to to any class type T, provided T is not
- // sealed, or provided T implements S.
- //
- if (source_type.IsInterface &&
- (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)))
- return true;
-
-
- if (source_type.IsInterface && IList_To_Array (source_type, target_type))
- return true;
-
- // From an array type S with an element type Se to an array type T with an
- // element type Te provided all the following are true:
- // * S and T differe only in element type, in other words, S and T
- // have the same number of dimensions.
- // * Both Se and Te are reference types
- // * An explicit referenc conversions exist from Se to Te
- //
- if (source_type.IsArray && target_type.IsArray) {
- if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
-
- Type source_element_type = TypeManager.GetElementType (source_type);
- Type target_element_type = TypeManager.GetElementType (target_type);
-
- if (TypeManager.IsGenericParameter (source_element_type) ||
- (!source_element_type.IsValueType && !target_element_type.IsValueType))
- if (ExplicitReferenceConversionExists (source_element_type,
- target_element_type))
- return true;
- }
-
- // From System.Array to any array-type
- if (source_type == TypeManager.array_type && target_type.IsArray) {
- return true;
- }
-
- //
- // From a single-dimensional array type S[] to System.Collections.Generic.IList<T> and its base interfaces,
- // provided that there is an explicit reference conversion from S to T
- //
- if (Array_To_IList (source_type, target_type, true))
- return true;
-
+ Expression e = ExplicitReferenceConversion (null, source_type, target_type);
+ if (e == null)
return false;
- }
- //
- // From System delegate to any delegate-type
- //
- if (source_type == TypeManager.delegate_type &&
- TypeManager.IsDelegateType (target_type))
+ if (e == EmptyExpression.Null)
return true;
- return false;
+ throw new InternalErrorException ("Invalid probing conversion result");
}
/// <summary>
/// Implements Explicit Reference conversions
/// </summary>
- static Expression ExplicitReferenceConversion (Expression source, Type target_type)
+ static Expression ExplicitReferenceConversion (Expression source, Type source_type, Type target_type)
{
- Type source_type = source.Type;
- bool target_is_type_param = TypeManager.IsGenericParameter (target_type);
bool target_is_value_type = target_type.IsValueType;
//
// From object to a generic parameter
//
- if (source_type == TypeManager.object_type && target_is_type_param)
- return new UnboxCast (source, target_type);
+ if (source_type == TypeManager.object_type && TypeManager.IsGenericParameter (target_type))
+ return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
//
// Explicit type parameter conversion.
//
-
if (TypeManager.IsGenericParameter (source_type))
- return ExplicitTypeParameterConversion (source, target_type);
+ return ExplicitTypeParameterConversion (source, source_type, target_type);
//
// From object to any reference type
//
if (source_type == TypeManager.object_type && !target_is_value_type)
- return new ClassCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
//
// Unboxing conversion.
if (((source_type == TypeManager.enum_type &&
!(source is TypeCast)) ||
source_type == TypeManager.value_type) && target_is_value_type)
- return new UnboxCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
//
// From any class S to any class-type T, provided S is a base class of T
//
if (TypeManager.IsSubclassOf (target_type, source_type))
- return new ClassCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
//
// From any class type S to any interface T, provides S is not sealed
//
if (target_type.IsInterface && !source_type.IsSealed &&
!TypeManager.ImplementsInterface (source_type, target_type)) {
- return new ClassCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
}
//
if (source_type.IsInterface) {
if (!target_type.IsSealed || TypeManager.ImplementsInterface (target_type, source_type)) {
if (target_type.IsClass)
- return new ClassCast (source, target_type);
- else
- return new UnboxCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
+
+ return source == null ? EmptyExpression.Null : new UnboxCast (source, target_type);
}
//
// array type S[], provided there is an implicit or explicit reference conversion from S to T.
//
if (IList_To_Array (source_type, target_type))
- return new ClassCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
return null;
}
if (source_type.IsArray) {
- //
- // From an array type S with an element type Se to an array type T with an
- // element type Te provided all the following are true:
- // * S and T differe only in element type, in other words, S and T
- // have the same number of dimensions.
- // * Both Se and Te are reference types
- // * An explicit referenc conversions exist from Se to Te
- //
- if (target_type.IsArray && source_type.GetArrayRank () == target_type.GetArrayRank ()) {
+ if (target_type.IsArray) {
+ //
+ // From System.Array to any array-type
+ //
+ if (source_type == TypeManager.array_type)
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
- Type source_element_type = TypeManager.GetElementType (source_type);
- Type target_element_type = TypeManager.GetElementType (target_type);
+ //
+ // From an array type S with an element type Se to an array type T with an
+ // element type Te provided all the following are true:
+ // * S and T differe only in element type, in other words, S and T
+ // have the same number of dimensions.
+ // * Both Se and Te are reference types
+ // * An explicit reference conversions exist from Se to Te
+ //
+ if (source_type.GetArrayRank () == target_type.GetArrayRank ()) {
- if (!source_element_type.IsValueType && !target_element_type.IsValueType)
- if (ExplicitReferenceConversionExists (source_element_type,
- target_element_type))
- return new ClassCast (source, target_type);
- }
+ source_type = TypeManager.GetElementType (source_type);
+ if (!TypeManager.IsReferenceType (source_type))
+ return null;
+
+ Type target_type_element = TypeManager.GetElementType (target_type);
+ if (!TypeManager.IsReferenceType (target_type_element))
+ return null;
- // From System.Array to any array-type
- if (source_type == TypeManager.array_type && target_type.IsArray) {
- return new ClassCast (source, target_type);
+ if (ExplicitReferenceConversionExists (source_type, target_type_element))
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
+
+ return null;
+ }
}
//
// provided that there is an explicit reference conversion from S to T
//
if (Array_To_IList (source_type, target_type, true))
- return new ClassCast (source, target_type);
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
return null;
}
//
// From System delegate to any delegate-type
//
- if (source_type == TypeManager.delegate_type &&
- TypeManager.IsDelegateType (target_type))
- return new ClassCast (source, target_type);
+ if (source_type == TypeManager.delegate_type && TypeManager.IsDelegateType (target_type))
+ return source == null ? EmptyExpression.Null : new ClassCast (source, target_type);
return null;
}
// null literal explicitly
//
if (expr_type != TypeManager.null_type){
- ne = ExplicitReferenceConversion (expr, target_type);
+ ne = ExplicitReferenceConversion (expr, expr_type, target_type);
if (ne != null)
return ne;
}
if (ne != null)
return ne;
- ne = ExplicitReferenceConversion (expr, target_type);
+ ne = ExplicitReferenceConversion (expr, expr.Type, target_type);
if (ne != null)
return ne;