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, 8 insertions, 10 deletions

diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index 40f3507d8b9..ea79d9fd78c 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -1312,20 +1312,18 @@ Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate,
 /// \param FunctionTemplate the function template for which we are performing
 /// template argument deduction.
 ///
-/// \param HasExplicitTemplateArgs whether any template arguments were
-/// explicitly specified.
-///
-/// \param ExplicitTemplateArguments when @p HasExplicitTemplateArgs is true,
-/// the explicitly-specified template arguments.
-///
-/// \param NumExplicitTemplateArguments when @p HasExplicitTemplateArgs is true,
-/// the number of explicitly-specified template arguments in
-/// @p ExplicitTemplateArguments. This value may be zero.
+/// \param ExplicitTemplateArguments the explicit template arguments provided
+/// for this call.
 ///
 /// \param Args the function call arguments
 ///
 /// \param NumArgs the number of arguments in Args
 ///
+/// \param Name the name of the function being called. This is only significant
+/// when the function template is a conversion function template, in which
+/// case this routine will also perform template argument deduction based on
+/// the function to which 
+///
 /// \param Specialization if template argument deduction was successful,
 /// this will be set to the function template specialization produced by
 /// template argument deduction.
@@ -1336,7 +1334,7 @@ Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate,
 /// \returns the result of template argument deduction.
 Sema::TemplateDeductionResult
 Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                              const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                          const TemplateArgumentListInfo *ExplicitTemplateArgs,
                               Expr **Args, unsigned NumArgs,
                               FunctionDecl *&Specialization,
                               TemplateDeductionInfo &Info) {