[PATCH] D54414: [Sema] Make sure we substitute an instantiation-dependent default template parameter

[Erik Pilkington via Phabricator via cfe-commits]

erik.pilkington created this revision.
erik.pilkington added a reviewer: rsmith.
Herald added a subscriber: dexonsmith.

Previously, we'd accept the attached test because we didn't substitute into `void_t` when we really ought to of.

Fixes llvm.org/PR39623

Thanks!


Repository:
  rC Clang

https://reviews.llvm.org/D54414

Files:
  clang/lib/Sema/SemaTemplate.cpp
  clang/test/SemaCXX/alias-template.cpp


Index: clang/test/SemaCXX/alias-template.cpp
===================================================================
--- clang/test/SemaCXX/alias-template.cpp
+++ clang/test/SemaCXX/alias-template.cpp
@@ -179,3 +179,13 @@
 };
 static_assert(__is_same(S<3>::U, X[2]), ""); // expected-error {{static_assert failed}}
 }
+
+namespace PR39623 {
+template <class T>
+using void_t = void;
+
+template <class T, class = void_t<typename T::wait_what>>
+int sfinae_me() { return 0; } // expected-note{{candidate template ignored: substitution failure}}
+
+int g = sfinae_me<int>(); // expected-error{{no matching function for call to 'sfinae_me'}}
+}
Index: clang/lib/Sema/SemaTemplate.cpp
===================================================================
--- clang/lib/Sema/SemaTemplate.cpp
+++ clang/lib/Sema/SemaTemplate.cpp
@@ -4434,7 +4434,7 @@
 
   // If the argument type is dependent, instantiate it now based
   // on the previously-computed template arguments.
-  if (ArgType->getType()->isDependentType()) {
+  if (ArgType->getType()->isInstantiationDependentType()) {
     Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
                                      Param, Template, Converted,
                                      SourceRange(TemplateLoc, RAngleLoc));


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