From cff420120f944b012850ba279f0ec50b72571aca Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Fri, 28 Sep 2018 03:18:53 +0000
Subject: [PATCH] Handle dependent class template names in class template
 argument deduction for new-expressions.

llvm-svn: 343293
---
 clang/lib/Sema/SemaInit.cpp                                | 5 ++++-
 .../SemaCXX/cxx1z-class-template-argument-deduction.cpp    | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index a678a31a5ac4..958dd66612c7 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -9155,8 +9155,11 @@ QualType Sema::DeduceTemplateSpecializationFromInitializer(
       TSInfo->getType()->getContainedDeducedType());
   assert(DeducedTST && "not a deduced template specialization type");
 
-  // We can only perform deduction for class templates.
   auto TemplateName = DeducedTST->getTemplateName();
+  if (TemplateName.isDependent())
+    return Context.DependentTy;
+
+  // We can only perform deduction for class templates.
   auto *Template =
       dyn_cast_or_null<ClassTemplateDecl>(TemplateName.getAsTemplateDecl());
   if (!Template) {
diff --git a/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp b/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
index cbf7c2eee51c..c310c651408d 100644
--- a/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
+++ b/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
@@ -307,6 +307,13 @@ namespace dependent {
   template int Var(int);
   template int Cast(int);
   template int New(int);
+
+  template<template<typename> typename Y> void test() {
+    Y(0);
+    new Y(0);
+    Y y(0);
+  }
+  template void test<X>();
 }
 
 namespace injected_class_name {