// A container class for all the conversion operations
//
public class Convert {
- static public void Error_CannotConvertType (Location loc, Type source, Type target)
+ static void Error_CannotConvertType (Location loc, Type source, Type target)
{
Report.Error (30, loc, "Cannot convert type '" +
TypeManager.CSharpName (source) + "' to '" +
TypeManager.CSharpName (target) + "'");
}
+ static Expression TypeParameter_to_Null (Expression expr, Type target_type,
+ Location loc)
+ {
+ if (!TypeParameter_to_Null (target_type)) {
+ Report.Error (403, loc, "Cannot convert null to the type " +
+ "parameter `{0}' becaues it could be a value " +
+ "type. Consider using `default ({0})' instead.",
+ target_type);
+ return null;
+ }
+
+ return new NullCast (expr, target_type);
+ }
+
+ static bool TypeParameter_to_Null (Type target_type)
+ {
+ if ((target_type.BaseType == null) ||
+ (target_type.BaseType == TypeManager.value_type) ||
+ target_type.BaseType.IsValueType)
+ return false;
+
+ return true;
+ }
+
+ static Type TypeParam_EffectiveBaseType (Type t)
+ {
+ GenericConstraints gc = TypeManager.GetTypeParameterConstraints (t);
+ if (gc == null)
+ return TypeManager.object_type;
+
+ return TypeParam_EffectiveBaseType (gc);
+ }
+
+ static Type TypeParam_EffectiveBaseType (GenericConstraints gc)
+ {
+ ArrayList list = new ArrayList ();
+ list.Add (gc.EffectiveBaseClass);
+ foreach (Type t in gc.InterfaceConstraints) {
+ if (!t.IsGenericParameter)
+ continue;
+
+ GenericConstraints new_gc = TypeManager.GetTypeParameterConstraints (t);
+ if (new_gc != null)
+ list.Add (TypeParam_EffectiveBaseType (new_gc));
+ }
+ return FindMostEncompassedType (list);
+ }
+
+ static Expression TypeParameterConversion (Expression expr, bool is_reference, Type target_type)
+ {
+ if (is_reference)
+ return new EmptyCast (expr, target_type);
+ else
+ return new BoxedCast (expr, target_type);
+ }
+
+ static Expression ImplicitTypeParameterConversion (Expression expr, Type target_type)
+ {
+ Type expr_type = expr.Type;
+
+ GenericConstraints gc = TypeManager.GetTypeParameterConstraints (expr_type);
+
+ if (gc == null) {
+ if (target_type == TypeManager.object_type)
+ return new BoxedCast (expr);
+
+ return null;
+ }
+
+ // We're converting from a type parameter which is known to be a reference type.
+ bool is_reference = gc.IsReferenceType;
+ Type base_type = TypeParam_EffectiveBaseType (gc);
+
+ if (TypeManager.IsSubclassOf (base_type, target_type))
+ return TypeParameterConversion (expr, is_reference, target_type);
+
+ if (target_type.IsInterface) {
+ if (TypeManager.ImplementsInterface (base_type, target_type))
+ return TypeParameterConversion (expr, is_reference, target_type);
+
+ foreach (Type t in gc.InterfaceConstraints) {
+ if (TypeManager.IsSubclassOf (t, target_type))
+ return TypeParameterConversion (expr, is_reference, target_type);
+ }
+ }
+
+ foreach (Type t in gc.InterfaceConstraints) {
+ if (!t.IsGenericParameter)
+ continue;
+ if (TypeManager.IsSubclassOf (t, target_type))
+ return TypeParameterConversion (expr, is_reference, target_type);
+ }
+
+ return null;
+ }
+
static EmptyExpression MyEmptyExpr;
static public Expression ImplicitReferenceConversion (Expression expr, Type target_type)
{
if (expr_type == TypeManager.void_type)
return null;
+ if (expr_type.IsGenericParameter)
+ return ImplicitTypeParameterConversion (expr, target_type);
+
//
// notice that it is possible to write "ValueType v = 1", the ValueType here
// is an abstract class, and not really a value type, so we apply the same rules.
return new BoxedCast (expr);
if (expr_type.IsClass || expr_type.IsInterface || expr_type == TypeManager.enum_type)
return new EmptyCast (expr, target_type);
+
+ return null;
} else if (target_type == TypeManager.value_type) {
if (TypeManager.IsValueType (expr_type))
return new BoxedCast (expr);
if (expr is NullLiteral)
- return new BoxedCast (expr);
- } else if (expr_type.IsSubclassOf (target_type)) {
+ return new NullCast (expr, target_type);
+
+ return null;
+ } else if (TypeManager.IsSubclassOf (expr_type, target_type)) {
//
// Special case: enumeration to System.Enum.
// System.Enum is not a value type, it is a class, so we need
// a boxing conversion
//
- if (expr_type.IsEnum)
+ if (expr_type.IsEnum || expr_type.IsGenericParameter)
return new BoxedCast (expr);
return new EmptyCast (expr, target_type);
- } else {
+ }
- // This code is kind of mirrored inside ImplicitStandardConversionExists
- // with the small distinction that we only probe there
- //
- // Always ensure that the code here and there is in sync
+ // This code is kind of mirrored inside ImplicitStandardConversionExists
+ // with the small distinction that we only probe there
+ //
+ // Always ensure that the code here and there is in sync
- // from the null type to any reference-type.
- if (expr is NullLiteral){
- if (target_type.IsPointer)
- return NullPointer.Null;
+ // from the null type to any reference-type.
+ if (expr is NullLiteral){
+ if (target_type.IsPointer)
+ return NullPointer.Null;
- if (!target_type.IsValueType)
- return new NullCast (expr, target_type);
- }
+ if (!target_type.IsValueType)
+ return new NullCast (expr, target_type);
+ }
- // from any class-type S to any interface-type T.
- if (target_type.IsInterface) {
- if (TypeManager.ImplementsInterface (expr_type, target_type)){
- if (expr_type.IsClass)
- return new EmptyCast (expr, target_type);
- else if (TypeManager.IsValueType (expr_type) ||
- TypeManager.IsEnumType (expr_type))
- return new BoxedCast (expr, target_type);
- else
- return new EmptyCast (expr, target_type);
- }
+ // from any class-type S to any interface-type T.
+ if (target_type.IsInterface) {
+ if (target_type != TypeManager.iconvertible_type &&
+ expr_type.IsValueType && (expr is Constant) &&
+ !(expr is IntLiteral || expr is BoolLiteral ||
+ expr is FloatLiteral || expr is DoubleLiteral ||
+ expr is LongLiteral || expr is CharLiteral ||
+ expr is StringLiteral || expr is DecimalLiteral ||
+ expr is UIntLiteral || expr is ULongLiteral)) {
+ return null;
}
- // from any interface type S to interface-type T.
- if (expr_type.IsInterface && target_type.IsInterface) {
- if (TypeManager.ImplementsInterface (expr_type, target_type))
- return new EmptyCast (expr, target_type);
+ if (TypeManager.ImplementsInterface (expr_type, target_type)){
+ if (expr_type.IsGenericParameter || TypeManager.IsValueType (expr_type))
+ return new BoxedCast (expr, target_type);
else
- return null;
+ return new EmptyCast (expr, target_type);
}
+ }
+
+ // from any interface type S to interface-type T.
+ if (expr_type.IsInterface && target_type.IsInterface) {
+ if (TypeManager.ImplementsInterface (expr_type, target_type))
+ return new EmptyCast (expr, target_type);
+ else
+ return null;
+ }
- // from an array-type S to an array-type of type T
- if (expr_type.IsArray && target_type.IsArray) {
- if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
+ // from an array-type S to an array-type of type T
+ if (expr_type.IsArray && target_type.IsArray) {
+ if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
- Type expr_element_type = TypeManager.GetElementType (expr_type);
+ Type expr_element_type = TypeManager.GetElementType (expr_type);
- if (MyEmptyExpr == null)
- MyEmptyExpr = new EmptyExpression ();
+ if (MyEmptyExpr == null)
+ MyEmptyExpr = new EmptyExpression ();
- MyEmptyExpr.SetType (expr_element_type);
- Type target_element_type = TypeManager.GetElementType (target_type);
+ MyEmptyExpr.SetType (expr_element_type);
+ Type target_element_type = TypeManager.GetElementType (target_type);
- if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
- if (ImplicitStandardConversionExists (MyEmptyExpr,
+ if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
+ if (ImplicitStandardConversionExists (MyEmptyExpr,
target_element_type))
- return new EmptyCast (expr, target_type);
- }
+ return new EmptyCast (expr, target_type);
}
+ }
+ // from an array-type to System.Array
+ if (expr_type.IsArray && target_type == TypeManager.array_type)
+ return new EmptyCast (expr, target_type);
- // from an array-type to System.Array
- if (expr_type.IsArray && target_type == TypeManager.array_type)
- return new EmptyCast (expr, target_type);
-
- // from any delegate type to System.Delegate
- if ((expr_type == TypeManager.delegate_type ||
- expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
- target_type == TypeManager.delegate_type)
- return new EmptyCast (expr, target_type);
+ // from any delegate type to System.Delegate
+ if ((expr_type == TypeManager.delegate_type || TypeManager.IsDelegateType (expr_type)) &&
+ target_type == TypeManager.delegate_type)
+ return new EmptyCast (expr, target_type);
- // from any array-type or delegate type into System.ICloneable.
- if (expr_type.IsArray ||
- expr_type == TypeManager.delegate_type ||
- expr_type.IsSubclassOf (TypeManager.delegate_type))
- if (target_type == TypeManager.icloneable_type)
- return new EmptyCast (expr, target_type);
-
- // from a generic type definition to a generic instance.
- if (TypeManager.IsEqualGenericType (expr_type, target_type))
+ // from any array-type or delegate type into System.ICloneable.
+ if (expr_type.IsArray ||
+ expr_type == TypeManager.delegate_type || TypeManager.IsDelegateType (expr_type))
+ if (target_type == TypeManager.icloneable_type)
return new EmptyCast (expr, target_type);
-
- return null;
- }
-
+ // from a generic type definition to a generic instance.
+ if (TypeManager.IsEqual (expr_type, target_type))
+ return new EmptyCast (expr, target_type);
+
return null;
}
{
Type expr_type = expr.Type;
+ if (expr_type.IsGenericParameter)
+ return ImplicitTypeParameterConversion (expr, target_type) != null;
+
//
// This is the boxed case.
//
if (expr_type.IsClass || TypeManager.IsValueType (expr_type) ||
expr_type.IsInterface || expr_type == TypeManager.enum_type)
return true;
- } else if (expr_type.IsSubclassOf (target_type))
+
+ return false;
+ } else if (TypeManager.IsSubclassOf (expr_type, target_type))
return true;
- else {
- // Please remember that all code below actually comes
- // from ImplicitReferenceConversion so make sure code remains in sync
+
+ // Please remember that all code below actually comes
+ // from ImplicitReferenceConversion so make sure code remains in sync
- // from any class-type S to any interface-type T.
- if (target_type.IsInterface) {
- if (TypeManager.ImplementsInterface (expr_type, target_type))
- return true;
- }
+ // from any class-type S to any interface-type T.
+ if (target_type.IsInterface) {
+ if (TypeManager.ImplementsInterface (expr_type, target_type))
+ return true;
+ }
- // from any interface type S to interface-type T.
- if (expr_type.IsInterface && target_type.IsInterface)
- if (TypeManager.ImplementsInterface (expr_type, target_type))
- return true;
+ // from any interface type S to interface-type T.
+ if (expr_type.IsInterface && target_type.IsInterface)
+ if (TypeManager.ImplementsInterface (expr_type, target_type))
+ return true;
- // from an array-type S to an array-type of type T
- if (expr_type.IsArray && target_type.IsArray) {
- if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
+ // from an array-type S to an array-type of type T
+ if (expr_type.IsArray && target_type.IsArray) {
+ if (expr_type.GetArrayRank () == target_type.GetArrayRank ()) {
- Type expr_element_type = expr_type.GetElementType ();
+ Type expr_element_type = expr_type.GetElementType ();
- if (MyEmptyExpr == null)
- MyEmptyExpr = new EmptyExpression ();
+ if (MyEmptyExpr == null)
+ MyEmptyExpr = new EmptyExpression ();
- MyEmptyExpr.SetType (expr_element_type);
- Type target_element_type = TypeManager.GetElementType (target_type);
+ MyEmptyExpr.SetType (expr_element_type);
+ Type target_element_type = TypeManager.GetElementType (target_type);
- if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
- if (ImplicitStandardConversionExists (MyEmptyExpr,
+ if (!expr_element_type.IsValueType && !target_element_type.IsValueType)
+ if (ImplicitStandardConversionExists (MyEmptyExpr,
target_element_type))
- return true;
- }
+ return true;
}
+ }
- // from an array-type to System.Array
- if (expr_type.IsArray && (target_type == TypeManager.array_type))
- return true;
+ // from an array-type to System.Array
+ if (expr_type.IsArray && (target_type == TypeManager.array_type))
+ return true;
- // from any delegate type to System.Delegate
- if ((expr_type == TypeManager.delegate_type ||
- expr_type.IsSubclassOf (TypeManager.delegate_type)) &&
- target_type == TypeManager.delegate_type)
- if (target_type.IsAssignableFrom (expr_type))
- return true;
+ // from any delegate type to System.Delegate
+ if ((expr_type == TypeManager.delegate_type || TypeManager.IsDelegateType (expr_type)) &&
+ target_type == TypeManager.delegate_type)
+ if (target_type.IsAssignableFrom (expr_type))
+ return true;
- // from any array-type or delegate type into System.ICloneable.
- if (expr_type.IsArray ||
- expr_type == TypeManager.delegate_type ||
- expr_type.IsSubclassOf (TypeManager.delegate_type))
- if (target_type == TypeManager.icloneable_type)
- return true;
-
- // from the null type to any reference-type.
- if (expr is NullLiteral && !target_type.IsValueType &&
- !TypeManager.IsEnumType (target_type))
+ // from any array-type or delegate type into System.ICloneable.
+ if (expr_type.IsArray ||
+ expr_type == TypeManager.delegate_type || TypeManager.IsDelegateType (expr_type))
+ if (target_type == TypeManager.icloneable_type)
return true;
+
+ // from the null type to any reference-type.
+ if (expr is NullLiteral && !target_type.IsValueType && !TypeManager.IsEnumType (target_type))
+ return true;
+
+ // from a generic type definition to a generic instance.
+ if (TypeManager.IsEqual (expr_type, target_type))
+ return true;
- // from a generic type definition to a generic instance.
- if (TypeManager.IsEqualGenericType (expr_type, target_type))
- return true;
- }
return false;
}
// Attempt to do the implicit constant expression conversions
if (expr is Constant){
-
if (expr is IntConstant){
Expression e;
// we just inline it
//
long v = ((LongConstant) expr).Value;
- if (v > 0)
+ if (v >= 0)
return new ULongConstant ((ulong) v);
}
}
/// </summary>
public static bool ImplicitConversionExists (EmitContext ec, Expression expr, Type target_type)
{
+ if ((expr is NullLiteral) && target_type.IsGenericParameter)
+ return TypeParameter_to_Null (target_type);
+
if (ImplicitStandardConversionExists (expr, target_type))
return true;
return UserDefinedConversion (ec, source, target, loc, true);
}
+ static DoubleHash explicit_conv = new DoubleHash (100);
+ static DoubleHash implicit_conv = new DoubleHash (100);
/// <summary>
/// Computes the MethodGroup for the user-defined conversion
/// operators from source_type to target_type. `look_for_explicit'
op_name = "op_Implicit";
MethodGroupExpr union3;
+ object r;
+ if ((look_for_explicit ? explicit_conv : implicit_conv).Lookup (source_type, target_type, out r))
+ return (MethodGroupExpr) r;
mg1 = Expression.MethodLookup (ec, source_type, op_name, loc);
if (source_type.BaseType != null)
union4 = Invocation.MakeUnionSet (union5, union6, loc);
}
- return Invocation.MakeUnionSet (union3, union4, loc);
+ MethodGroupExpr ret = Invocation.MakeUnionSet (union3, union4, loc);
+ (look_for_explicit ? explicit_conv : implicit_conv).Insert (source_type, target_type, ret);
+ return ret;
}
/// <summary>
Type expr_type = expr.Type;
Expression e;
+ if ((expr is NullLiteral) && target_type.IsGenericParameter)
+ return TypeParameter_to_Null (expr, target_type, loc);
+
+ if (expr.eclass == ExprClass.MethodGroup){
+ if (!TypeManager.IsDelegateType (target_type)){
+ Report.Error (428, loc,
+ String.Format (
+ "Cannot convert method group to `{0}', since it is not a delegate",
+ TypeManager.CSharpName (target_type)));
+ return null;
+ }
+
+ return ImplicitDelegateCreation.Create (ec, (MethodGroupExpr) expr, target_type, loc);
+ }
+
if (expr_type.Equals (target_type) && !(expr is NullLiteral))
return expr;
{
Expression e;
+ int errors = Report.Errors;
e = ImplicitConversion (ec, source, target_type, loc);
+ if (Report.Errors > errors)
+ return null;
if (e != null)
return e;
/// </summary>
public static bool ExplicitReferenceConversionExists (Type source_type, Type target_type)
{
+ bool target_is_type_param = target_type.IsGenericParameter;
bool target_is_value_type = target_type.IsValueType;
if (source_type == target_type)
return true;
-
+
+ //
+ // From object to a generic parameter
+ //
+ if (source_type == TypeManager.object_type && target_is_type_param)
+ return true;
+
//
// From object to any reference type
//
//
// From any class S to any class-type T, provided S is a base class of T
//
- if (target_type.IsSubclassOf (source_type))
+ 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 (!target_type.IsSubclassOf (source_type))
+ if (!TypeManager.IsSubclassOf (target_type, source_type))
return true;
}
// From System delegate to any delegate-type
//
if (source_type == TypeManager.delegate_type &&
- target_type.IsSubclassOf (TypeManager.delegate_type))
+ TypeManager.IsDelegateType (target_type))
return true;
//
static Expression ExplicitReferenceConversion (Expression source, Type target_type)
{
Type source_type = source.Type;
+ bool target_is_type_param = target_type.IsGenericParameter;
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);
+
//
// From object to any reference type
//
if (source_type == TypeManager.object_type && !target_is_value_type)
return new ClassCast (source, target_type);
+ //
+ // Unboxing conversion.
+ //
+ if (((source_type == TypeManager.enum_type &&
+ !(source is EmptyCast)) ||
+ source_type == TypeManager.value_type) && target_is_value_type)
+ return new UnboxCast (source, target_type);
//
// From any class S to any class-type T, provided S is a base class of T
//
- if (target_type.IsSubclassOf (source_type))
+ if (TypeManager.IsSubclassOf (target_type, source_type))
return new ClassCast (source, target_type);
//
else
return new ClassCast (source, target_type);
}
-
+
//
// From any class type S to any interface T, provides S is not sealed
// and provided S does not implement T.
// From System delegate to any delegate-type
//
if (source_type == TypeManager.delegate_type &&
- target_type.IsSubclassOf (TypeManager.delegate_type))
+ TypeManager.IsDelegateType (target_type))
return new ClassCast (source, target_type);
//
/// type is expr.Type to `target_type'.
/// </summary>
static public Expression ExplicitConversion (EmitContext ec, Expression expr,
- Type target_type, Location loc)
+ Type target_type, Location loc)
{
Type expr_type = expr.Type;
Type original_expr_type = expr_type;
expr_type = expr.Type;
}
+ int errors = Report.Errors;
Expression ne = ImplicitConversionStandard (ec, expr, target_type, loc);
+ if (Report.Errors > errors)
+ return null;
if (ne != null)
return ne;
//
if (expr_type == TypeManager.object_type && target_type.IsValueType){
if (expr is NullLiteral){
- Report.Error (37, loc, "Cannot convert null to value type `" +
- TypeManager.CSharpName (target_type) + "'");
- return null;
+ //
+ // Skip the ExplicitReferenceConversion because we can not convert
+ // from Null to a ValueType, and ExplicitReference wont check against
+ // null literal explicitly
+ //
+ goto skip_explicit;
}
return new UnboxCast (expr, target_type);
+
}
ne = ExplicitReferenceConversion (expr, target_type);
if (ne != null)
return ne;
+ skip_explicit:
if (ec.InUnsafe){
if (target_type.IsPointer){
if (expr_type.IsPointer)
if (ne != null)
return ne;
+ if (expr is NullLiteral){
+ Report.Error (37, loc, "Cannot convert null to value type `" +
+ TypeManager.CSharpName (target_type) + "'");
+ return null;
+ }
+
Error_CannotConvertType (loc, original_expr_type, target_type);
return null;
}
/// Same as ExplicitConversion, only it doesn't include user defined conversions
/// </summary>
static public Expression ExplicitConversionStandard (EmitContext ec, Expression expr,
- Type target_type, Location l)
+ Type target_type, Location l)
{
+ int errors = Report.Errors;
Expression ne = ImplicitConversionStandard (ec, expr, target_type, l);
+ if (Report.Errors > errors)
+ return null;
if (ne != null)
return ne;
projects / mono.git / blobdiff