public void AssertEmptyStack()
{
#if STATIC
if (ig.__StackHeight != 0)
{
throw new InternalErrorException("Await yields with non-empty stack in `{0}",
member_context.GetSignatureForError());
}
#endif
}
public void ErrorInvalidVariance (IMemberContext mc, Variance expected)
{
Report.SymbolRelatedToPreviousError (mc.CurrentMemberDefinition);
string input_variance = Variance == Variance.Contravariant ? "contravariant" : "covariant";
string gtype_variance;
switch (expected) {
case Variance.Contravariant: gtype_variance = "contravariantly"; break;
case Variance.Covariant: gtype_variance = "covariantly"; break;
default: gtype_variance = "invariantly"; break;
}
Delegate d = mc as Delegate;
string parameters = d != null ? d.Parameters.GetSignatureForError () : "";
Report.Error (1961, Location,
"The {2} type parameter `{0}' must be {3} valid on `{1}{4}'",
GetSignatureForError (), mc.GetSignatureForError (), input_variance, gtype_variance, parameters);
}
public string GetSignatureForError()
{
return(MemberContext.GetSignatureForError());
}
//
// Resolve the constraints types with only possible early checks, return
// value `false' is reserved for recursive failure
//
public bool Resolve (IMemberContext context, TypeParameter tp)
{
if (resolved)
return true;
if (resolving)
return false;
resolving = true;
var spec = tp.Type;
List<TypeParameterSpec> tparam_types = null;
bool iface_found = false;
spec.BaseType = TypeManager.object_type;
for (int i = 0; i < constraints.Count; ++i) {
var constraint = constraints[i];
if (constraint is SpecialContraintExpr) {
spec.SpecialConstraint |= ((SpecialContraintExpr) constraint).Constraint;
if (spec.HasSpecialStruct)
spec.BaseType = TypeManager.value_type;
// Set to null as it does not have a type
constraints[i] = null;
continue;
}
var type_expr = constraints[i] = constraint.ResolveAsTypeTerminal (context, false);
if (type_expr == null)
continue;
var gexpr = type_expr as GenericTypeExpr;
if (gexpr != null && gexpr.HasDynamicArguments ()) {
context.Compiler.Report.Error (1968, constraint.Location,
"A constraint cannot be the dynamic type `{0}'", gexpr.GetSignatureForError ());
continue;
}
var type = type_expr.Type;
if (!context.CurrentMemberDefinition.IsAccessibleAs (type)) {
context.Compiler.Report.SymbolRelatedToPreviousError (type);
context.Compiler.Report.Error (703, loc,
"Inconsistent accessibility: constraint type `{0}' is less accessible than `{1}'",
type.GetSignatureForError (), context.GetSignatureForError ());
}
if (type.IsInterface) {
if (!spec.AddInterface (type)) {
context.Compiler.Report.Error (405, constraint.Location,
"Duplicate constraint `{0}' for type parameter `{1}'", type.GetSignatureForError (), tparam.Value);
}
iface_found = true;
continue;
}
var constraint_tp = type as TypeParameterSpec;
if (constraint_tp != null) {
if (tparam_types == null) {
tparam_types = new List<TypeParameterSpec> (2);
} else if (tparam_types.Contains (constraint_tp)) {
context.Compiler.Report.Error (405, constraint.Location,
"Duplicate constraint `{0}' for type parameter `{1}'", type.GetSignatureForError (), tparam.Value);
continue;
}
//
// Checks whether each generic method parameter constraint type
// is valid with respect to T
//
if (tp.IsMethodTypeParameter) {
TypeManager.CheckTypeVariance (type, Variance.Contravariant, context);
}
var tp_def = constraint_tp.MemberDefinition as TypeParameter;
if (tp_def != null && !tp_def.ResolveConstraints (context)) {
context.Compiler.Report.Error (454, constraint.Location,
"Circular constraint dependency involving `{0}' and `{1}'",
constraint_tp.GetSignatureForError (), tp.GetSignatureForError ());
continue;
}
//
// Checks whether there are no conflicts between type parameter constraints
//
// class Foo<T, U>
// where T : A
// where U : B, T
//
// A and B are not convertible and only 1 class constraint is allowed
//
if (constraint_tp.HasTypeConstraint) {
if (spec.HasTypeConstraint || spec.HasSpecialStruct) {
if (!CheckConflictingInheritedConstraint (spec.BaseType, constraint_tp.BaseType, context, constraint.Location))
continue;
} else {
for (int ii = 0; ii < tparam_types.Count; ++ii) {
if (!tparam_types[ii].HasTypeConstraint)
continue;
if (!CheckConflictingInheritedConstraint (tparam_types[ii].BaseType, constraint_tp.BaseType, context, constraint.Location))
break;
}
}
}
if (constraint_tp.HasSpecialStruct) {
context.Compiler.Report.Error (456, constraint.Location,
"Type parameter `{0}' has the `struct' constraint, so it cannot be used as a constraint for `{1}'",
constraint_tp.GetSignatureForError (), tp.GetSignatureForError ());
continue;
}
tparam_types.Add (constraint_tp);
continue;
}
if (iface_found || spec.HasTypeConstraint) {
context.Compiler.Report.Error (406, constraint.Location,
"The class type constraint `{0}' must be listed before any other constraints. Consider moving type constraint to the beginning of the constraint list",
type.GetSignatureForError ());
}
if (spec.HasSpecialStruct || spec.HasSpecialClass) {
context.Compiler.Report.Error (450, type_expr.Location,
"`{0}': cannot specify both a constraint class and the `class' or `struct' constraint",
type.GetSignatureForError ());
}
if (type == InternalType.Dynamic) {
context.Compiler.Report.Error (1967, constraint.Location, "A constraint cannot be the dynamic type");
continue;
}
if (type.IsSealed || !type.IsClass) {
context.Compiler.Report.Error (701, loc,
"`{0}' is not a valid constraint. A constraint must be an interface, a non-sealed class or a type parameter",
TypeManager.CSharpName (type));
continue;
}
if (type.IsStatic) {
context.Compiler.Report.Error (717, constraint.Location,
"`{0}' is not a valid constraint. Static classes cannot be used as constraints",
type.GetSignatureForError ());
} else if (type == TypeManager.array_type || type == TypeManager.delegate_type ||
type == TypeManager.enum_type || type == TypeManager.value_type ||
type == TypeManager.object_type || type == TypeManager.multicast_delegate_type) {
context.Compiler.Report.Error (702, constraint.Location,
"A constraint cannot be special class `{0}'", type.GetSignatureForError ());
continue;
}
spec.BaseType = type;
}
if (tparam_types != null)
spec.TypeArguments = tparam_types.ToArray ();
resolving = false;
resolved = true;
return true;
}
