r293358 - -Wunused-func-template: do not warn on non-template function declarations that

[Richard Smith via cfe-commits]

Author: rsmith
Date: Fri Jan 27 19:50:33 2017
New Revision: 293358

URL: http://llvm.org/viewvc/llvm-project?rev=293358&view=rev
Log:
-Wunused-func-template: do not warn on non-template function declarations that
were nonetheless instantiated (particularly, non-template friends declared
within class templates).

Modified:
    cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
    cfe/trunk/test/SemaTemplate/undefined-template.cpp

Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=293358&r1=293357&r2=293358&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Fri Jan 27 19:50:33 2017
@@ -3726,7 +3726,12 @@ void Sema::InstantiateFunctionDefinition
       PendingInstantiations.push_back(
         std::make_pair(Function, PointOfInstantiation));
     } else if (TSK == TSK_ImplicitInstantiation) {
-      if (AtEndOfTU && !getDiagnostics().hasErrorOccurred()) {
+      if (AtEndOfTU && !getDiagnostics().hasErrorOccurred() &&
+          // A non-template function that is only lexically in a dependent
+          // context, such as a friend function in a class template, should
+          // not produce a warning.
+          (PatternDecl->getDescribedFunctionTemplate() ||
+           PatternDecl->getDeclContext()->isDependentContext())) {
         Diag(PointOfInstantiation, diag::warn_func_template_missing)
           << Function;
         Diag(PatternDecl->getLocation(), diag::note_forward_template_decl);

Modified: cfe/trunk/test/SemaTemplate/undefined-template.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/undefined-template.cpp?rev=293358&r1=293357&r2=293358&view=diff
==============================================================================
--- cfe/trunk/test/SemaTemplate/undefined-template.cpp (original)
+++ cfe/trunk/test/SemaTemplate/undefined-template.cpp Fri Jan 27 19:50:33 2017
@@ -134,6 +134,14 @@ void func_23(C1<int>::C2<long> *x) {
                         // expected-note at -1{{add an explicit instantiation declaration to suppress this warning if 'C1<int>::C2<long>::tmeth_2<int>' is explicitly instantiated in another translation unit}}
 }
 
+namespace test_24 {
+  template <typename T> struct X {
+    friend void g(int);
+    operator int() { return 0; }
+  };
+  void h(X<int> x) { g(x); } // no warning for use of 'g' despite the declaration having been instantiated from a template
+}
+
 int main() {
   return 0;
 }