Representation of template type parameters and non-type template
parameters, with some semantic analysis:
  - Template parameters are introduced into template parameter scope
  - Complain about template parameter shadowing (except in Microsoft mode)

Note that we leak template parameter declarations like crazy, a
problem we'll remedy once we actually create proper declarations for
templates. 

Next up: dependent types and value-dependent/type-dependent
expressions.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@60597 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index e4386ec..a3264b0 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -341,6 +341,12 @@
 /// DeclCanBeLvalue - Determine whether the given declaration can be
 /// an lvalue. This is a helper routine for isLvalue.
 static bool DeclCanBeLvalue(const NamedDecl *Decl, ASTContext &Ctx) {
+  // C++ [temp.param]p6:
+  //   A non-type non-reference template-parameter is not an lvalue.
+  if (const NonTypeTemplateParmDecl *NTTParm 
+        = dyn_cast<NonTypeTemplateParmDecl>(Decl))
+    return NTTParm->getType()->isReferenceType();
+
   return isa<VarDecl>(Decl) || isa<CXXFieldDecl>(Decl) ||
     // C++ 3.10p2: An lvalue refers to an object or function.
     (Ctx.getLangOptions().CPlusPlus &&