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

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 196e847728..b6d5abfcc8 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -132,7 +132,7 @@ Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
                                                            bool IsTypeAlias) {
   bool Invalid = false;
   TypeSourceInfo *DI = D->getTypeSourceInfo();
-  if (DI->getType()->isDependentType() ||
+  if (DI->getType()->isInstantiationDependentType() ||
       DI->getType()->isVariablyModifiedType()) {
     DI = SemaRef.SubstType(DI, TemplateArgs,
                            D->getLocation(), D->getDeclName());
@@ -435,7 +435,7 @@ Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {
 Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
   bool Invalid = false;
   TypeSourceInfo *DI = D->getTypeSourceInfo();
-  if (DI->getType()->isDependentType() ||
+  if (DI->getType()->isInstantiationDependentType() ||
       DI->getType()->isVariablyModifiedType())  {
     DI = SemaRef.SubstType(DI, TemplateArgs,
                            D->getLocation(), D->getDeclName());