Implement name lookup for conversion function template specializations

(C++ [temp.mem]p5-6), which involves template argument deduction based
on the type named, e.g., given

  struct X { template<typename T> operator T*(); } x;

when we call

  x.operator int*();

we perform template argument deduction to determine that T=int. This
template argument deduction is needed for template specialization and
explicit instantiation, e.g.,

  template<> X::operator float*() { /* ... */ }

and when calling or otherwise naming a conversion function (as in the
first example). 

This fixes PR5742 and PR5762, although there's some remaining ugliness
that's causing out-of-line definitions of conversion function
templates to fail. I'll look into that separately.

llvm-svn: 93162

1 files changed, 7 insertions, 1 deletions

diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index ec08658b5cf..f463cbb7c89 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -1178,8 +1178,14 @@ public:
     LookupObjCImplementationName
   };
 
+  /// \brief Specifies whether (or how) name lookup is being performed for a
+  /// redeclaration (vs. a reference).
   enum RedeclarationKind {
-    NotForRedeclaration,
+    /// \brief The lookup is a reference to this name that is not for the
+    /// purpose of redeclaring the name.
+    NotForRedeclaration = 0,
+    /// \brief The lookup results will be used for redeclaration of a name,
+    /// if an entity by that name already exists.
     ForRedeclaration
   };