From e673d71a07a85face6c3b7b60c1357f7dfe45255 Mon Sep 17 00:00:00 2001
From: Richard Trieu <rtrieu@google.com>
Date: Thu, 31 Jan 2013 02:47:46 +0000
Subject: [PATCH] When comparing two template template arguments in the
 template differ, consider them the same if they are actually the same; having
 the same name isn't enough.

Similar to r174013, template template arguments were also mistakenly considered
the same when they had the same name but were in different namespaces.
In addition, when printing template template arguments, use the qualified name
if the regular name is the same.

llvm-svn: 174029
---
 clang/lib/AST/ASTDiagnostic.cpp           | 19 ++++++++++++++-----
 clang/test/Misc/diag-template-diffing.cpp |  8 ++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/clang/lib/AST/ASTDiagnostic.cpp b/clang/lib/AST/ASTDiagnostic.cpp
index fb3544f03aa6..4f165132a6f5 100644
--- a/clang/lib/AST/ASTDiagnostic.cpp
+++ b/clang/lib/AST/ASTDiagnostic.cpp
@@ -894,8 +894,9 @@ class TemplateDiff {
         GetTemplateDecl(FromIter, DefaultTTPD, FromDecl);
         GetTemplateDecl(ToIter, DefaultTTPD, ToDecl);
         Tree.SetNode(FromDecl, ToDecl);
-        Tree.SetSame(FromDecl && ToDecl &&
-                     FromDecl->getIdentifier() == ToDecl->getIdentifier());
+        Tree.SetSame(
+            FromDecl && ToDecl &&
+            FromDecl->getCanonicalDecl() == ToDecl->getCanonicalDecl());
       }
 
       if (!FromIter.isEnd()) ++FromIter;
@@ -1278,21 +1279,29 @@ class TemplateDiff {
   void PrintTemplateTemplate(TemplateDecl *FromTD, TemplateDecl *ToTD,
                              bool FromDefault, bool ToDefault, bool Same) {
     assert((FromTD || ToTD) && "Only one template argument may be missing.");
+
+    std::string FromName = FromTD ? FromTD->getName() : "(no argument)";
+    std::string ToName = ToTD ? ToTD->getName() : "(no argument)";
+    if (FromTD && ToTD && FromName == ToName) {
+      FromName = FromTD->getQualifiedNameAsString();
+      ToName = ToTD->getQualifiedNameAsString();
+    }
+
     if (Same) {
       OS << "template " << FromTD->getNameAsString();
     } else if (!PrintTree) {
       OS << (FromDefault ? "(default) template " : "template ");
       Bold();
-      OS << (FromTD ? FromTD->getNameAsString() : "(no argument)");
+      OS << FromName;
       Unbold();
     } else {
       OS << (FromDefault ? "[(default) template " : "[template ");
       Bold();
-      OS << (FromTD ? FromTD->getNameAsString() : "(no argument)");
+      OS << FromName;
       Unbold();
       OS << " != " << (ToDefault ? "(default) template " : "template ");
       Bold();
-      OS << (ToTD ? ToTD->getNameAsString() : "(no argument)");
+      OS << ToName;
       Unbold();
       OS << ']';
     }
diff --git a/clang/test/Misc/diag-template-diffing.cpp b/clang/test/Misc/diag-template-diffing.cpp
index 7e9998c82810..c6fc32d1b349 100644
--- a/clang/test/Misc/diag-template-diffing.cpp
+++ b/clang/test/Misc/diag-template-diffing.cpp
@@ -859,6 +859,14 @@ namespace rdar12931988 {
     // CHECK-ELIDE-NOTREE: no known conversion from 'B::X<int>' to 'const rdar12931988::A::X<int>'
     ax = bx;
   }
+
+  template<template<typename> class> class Y {};
+
+  void bar(Y<A::X> ya, Y<B::X> yb) {
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'Y<template rdar12931988::B::X>' to 'Y<template rdar12931988::A::X>'
+    ya = yb;
+  }
 }
 
 // CHECK-ELIDE-NOTREE: {{[0-9]*}} errors generated.
-- 
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