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.

llvm-svn: 291064

2 files changed, 10 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index c16b28bcf13..893c813485b 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/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/clang/test/SemaTemplate/deduction.cpp b/clang/test/SemaTemplate/deduction.cpp
index 5695cab9a27..f98fd9bea0c 100644
--- a/clang/test/SemaTemplate/deduction.cpp
+++ b/clang/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}}
+}