// 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 EmptyExpression MyEmptyExpr;
static public Expression ImplicitReferenceConversion (Expression expr, Type target_type)
{
// 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);
// 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;
+ }
+
if (TypeManager.ImplementsInterface (expr_type, target_type)){
- if (expr_type.IsClass)
+ if (expr_type.IsGenericParameter)
+ return new BoxedCast (expr, target_type);
+ else if (expr_type.IsClass)
return new EmptyCast (expr, target_type);
- else if (TypeManager.IsValueType (expr_type) ||
- TypeManager.IsEnumType (expr_type))
+ else if (TypeManager.IsValueType (expr_type))
return new BoxedCast (expr, target_type);
else
return new EmptyCast (expr, target_type);
if (expr_type.IsClass || TypeManager.IsValueType (expr_type) ||
expr_type.IsInterface || expr_type == TypeManager.enum_type)
return true;
- } else if (TypeManager.IsSubclassOf (expr_type, target_type))
+ } else if (TypeManager.IsSubclassOf (expr_type, target_type))
return true;
else {
// Please remember that all code below actually comes
// 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,
{
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
//
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
//
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.
/// 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;
/// 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