public bool ValidateTypeVariance(ComputationContext ctx, IOwnedNode placement, VarianceMode typeNamePosition)
{
// Programming in Scala, 2nd ed, p. 399 (all errors are mine)
TypeDefinition typedef = this.TargetType;
if (typedef.IsTemplateParameter)
{
TemplateParameter param = typedef.TemplateParameter;
TemplateDefinition template = param.EnclosingScope <TemplateDefinition>();
if (placement.EnclosingScopesToRoot().Contains(template))
{
bool covariant_in_immutable = param.Variance == VarianceMode.Out &&
(template.IsFunction() || template.CastType().InstanceOf.MutabilityOfType(ctx) == TypeMutability.ConstAsSource);
// don't report errors for covariant types which are used in immutable template types
if (!covariant_in_immutable &&
typeNamePosition.PositionCollides(param.Variance))
{
return(false);
}
}
}
else
{
for (int i = 0; i < typedef.Name.Parameters.Count; ++i)
{
if (!this.TemplateArguments[i].ValidateTypeVariance(ctx,
placement,
typeNamePosition.Flipped(typedef.Name.Parameters[i].Variance)))
{
return(false);
}
}
}
return(true);
}
public static bool IsFunctionContained(this IEntityVariable @this)
{
TemplateDefinition scope = @this.EnclosingScope <TemplateDefinition>();
return(scope.IsFunction());
}
