From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Thu, 5 Jan 2017 02:31:32 +0000 (+0000)
Subject: Fix assertion failure on deduction failure due to too short template argument list.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=cf2ed0b529c8fb34b2e098c30adce12a577d05f3;p=clang

Fix assertion failure on deduction failure due to too short template argument list.

We were previously incorrectly using TDK_TooFewArguments to report a template
argument list that's too short, but it actually means that the number of
arguments in a top-level function call was insufficient. When diagnosing the
problem, SemaOverload would (rightly) assert that the failure kind didn't make
any sense.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@291064 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index c16b28bcf1..893c813485 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -1899,8 +1899,9 @@ DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
 
       // Check whether we have enough arguments.
       if (!hasTemplateArgumentForDeduction(Args, ArgIdx))
-        return NumberOfArgumentsMustMatch ? Sema::TDK_TooFewArguments
-                                          : Sema::TDK_Success;
+        return NumberOfArgumentsMustMatch
+                   ? Sema::TDK_MiscellaneousDeductionFailure
+                   : Sema::TDK_Success;
 
       // C++1z [temp.deduct.type]p9:
       //   During partial ordering, if Ai was originally a pack expansion [and]
diff --git a/test/SemaTemplate/deduction.cpp b/test/SemaTemplate/deduction.cpp
index 5695cab9a2..f98fd9bea0 100644
--- a/test/SemaTemplate/deduction.cpp
+++ b/test/SemaTemplate/deduction.cpp
@@ -407,3 +407,10 @@ namespace overload_vs_pack {
     void test() { j(x, f, x); }
   }
 }
+
+namespace b29946541 {
+  template<typename> class A {};
+  template<typename T, typename U, template<typename, typename> class C>
+  void f(C<T, U>); // expected-note {{failed template argument deduction}}
+  void g(A<int> a) { f(a); } // expected-error {{no match}}
+}