Introduce the notion of instantiation dependence into Clang's AST. A
type/expression/template argument/etc. is instantiation-dependent if
it somehow involves a template parameter, even if it doesn't meet the
requirements for the more common kinds of dependence (dependent type,
type-dependent expression, value-dependent expression).
When we see an instantiation-dependent type, we know we always need to
perform substitution into that instantiation-dependent type. This
keeps us from short-circuiting evaluation in places where we
shouldn't, and lets us properly implement C++0x [temp.type]p2.
In theory, this would also allow us to properly mangle
instantiation-dependent-but-not-dependent decltype types per the
Itanium C++ ABI, but we aren't quite there because we still mangle
based on the canonical type in cases like, e.g.,
template<unsigned> struct A { };
template<typename T>
void f(A<sizeof(sizeof(decltype(T() + T())))>) { }
template void f<int>(A<sizeof(sizeof(int))>);
and therefore get the wrong answer.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134225 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/NestedNameSpecifier.cpp b/lib/AST/NestedNameSpecifier.cpp
index 2878dff..f6d4f25 100644
--- a/lib/AST/NestedNameSpecifier.cpp
+++ b/lib/AST/NestedNameSpecifier.cpp
@@ -174,6 +174,28 @@
return false;
}
+/// \brief Whether this nested name specifier refers to a dependent
+/// type or not.
+bool NestedNameSpecifier::isInstantiationDependent() const {
+ switch (getKind()) {
+ case Identifier:
+ // Identifier specifiers always represent dependent types
+ return true;
+
+ case Namespace:
+ case NamespaceAlias:
+ case Global:
+ return false;
+
+ case TypeSpec:
+ case TypeSpecWithTemplate:
+ return getAsType()->isInstantiationDependentType();
+ }
+
+ // Necessary to suppress a GCC warning.
+ return false;
+}
+
bool NestedNameSpecifier::containsUnexpandedParameterPack() const {
switch (getKind()) {
case Identifier: