PR20625: Instantiate static constexpr member function of a local struct in a function...

This is necessary in order to allow the use of a constexpr member function, or
a member function with deduced return type, of a local class within a
surrounding instantiated function template specialization.

Patch by Michael Park!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@236063 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 8f2e95a6152ac994cf0a03fc009db96543fec4c5..57faa1cbad85ef8a5f23716320e2dd36370252f7 100644 (file)
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1302,11 +1302,19 @@ Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
   // DR1484 clarifies that the members of a local class are instantiated as part
   // of the instantiation of their enclosing entity.
   if (D->isCompleteDefinition() && D->isLocalClass()) {
+    Sema::SavePendingLocalImplicitInstantiationsRAII
+        SavedPendingLocalImplicitInstantiations(SemaRef);
+
     SemaRef.InstantiateClass(D->getLocation(), Record, D, TemplateArgs,
                              TSK_ImplicitInstantiation,
                              /*Complain=*/true);
+
     SemaRef.InstantiateClassMembers(D->getLocation(), Record, TemplateArgs,
                                     TSK_ImplicitInstantiation);
+
+    // This class may have local implicit instantiations that need to be
+    // performed within this scope.
+    SemaRef.PerformPendingInstantiations(/*LocalOnly=*/true);
   }
 
   SemaRef.DiagnoseUnusedNestedTypedefs(Record);

diff --git a/test/SemaTemplate/instantiate-local-class.cpp b/test/SemaTemplate/instantiate-local-class.cpp
index 367134a2a5311bc07040b0bf8a022a0f88faf2b1..668fb6fa65b8393ebbd5b157ff8e8a76fa41a22e 100644 (file)
--- a/test/SemaTemplate/instantiate-local-class.cpp
+++ b/test/SemaTemplate/instantiate-local-class.cpp
@@ -213,3 +213,16 @@ namespace PR23194 {
     return make_seed_pair();
   }
 }
+
+namespace PR20625 {
+template <typename T>
+void f() {
+  struct N {
+    static constexpr int get() { return 42; }
+  };
+  constexpr int n = N::get();
+  static_assert(n == 42, "n == 42");
+}
+
+void g() { f<void>(); }
+}