PR47682: Merge the DeclContext of a merged FunctionDecl before we inherit

default arguments.

When a function is declared with a qualified name, its eventual semantic
DeclContext may differ from the scope specified by the qualifier if it
redeclares a function in an inline namespace. In this case, we need to
update the DeclContext to be that of the previous declaration, and we
need to do so before we decide whether to inherit default arguments from
that previous declaration, because we only inherit default arguments
from declarations in the same scope.

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 832fd83..3ee0c43 100644 (file)
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -3238,6 +3238,10 @@ bool Sema::MergeFunctionDecl(FunctionDecl *New, NamedDecl *&OldD,
     }
   }
 
+  // If the old declaration was found in an inline namespace and the new
+  // declaration was qualified, update the DeclContext to match.
+  adjustDeclContextForDeclaratorDecl(New, Old);
+
   // If the old declaration is invalid, just give up here.
   if (Old->isInvalidDecl())
     return true;
@@ -4052,6 +4056,10 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) {
     return New->setInvalidDecl();
   }
 
+  // If the old declaration was found in an inline namespace and the new
+  // declaration was qualified, update the DeclContext to match.
+  adjustDeclContextForDeclaratorDecl(New, Old);
+
   // Ensure the template parameters are compatible.
   if (NewTemplate &&
       !TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
@@ -4236,7 +4244,6 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) {
   New->setPreviousDecl(Old);
   if (NewTemplate)
     NewTemplate->setPreviousDecl(OldTemplate);
-  adjustDeclContextForDeclaratorDecl(New, Old);
 
   // Inherit access appropriately.
   New->setAccess(Old->getAccess());
@@ -10788,7 +10795,6 @@ bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
       NewTemplateDecl->mergePrevDecl(OldTemplateDecl);
 
       NewFD->setPreviousDeclaration(OldFD);
-      adjustDeclContextForDeclaratorDecl(NewFD, OldFD);
       if (NewFD->isCXXClassMember()) {
         NewFD->setAccess(OldTemplateDecl->getAccess());
         NewTemplateDecl->setAccess(OldTemplateDecl->getAccess());
@@ -10815,7 +10821,6 @@ bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
         auto *OldFD = cast<FunctionDecl>(OldDecl);
         // This needs to happen first so that 'inline' propagates.
         NewFD->setPreviousDeclaration(OldFD);
-        adjustDeclContextForDeclaratorDecl(NewFD, OldFD);
         if (NewFD->isCXXClassMember())
           NewFD->setAccess(OldFD->getAccess());
       }

diff --git a/clang/test/SemaCXX/default1.cpp b/clang/test/SemaCXX/default1.cpp
index 457cada..8345b24 100644 (file)
--- a/clang/test/SemaCXX/default1.cpp
+++ b/clang/test/SemaCXX/default1.cpp
@@ -95,4 +95,12 @@ void g2(int c = f2<int>()) {}
 template<typename T> int f3() { return T::error; } // expected-error {{no members}}
 void g3(int c = f3<int>()) {} // expected-note {{in instantiation of}}
 void use_g3() { g3(); }
+
+namespace PR47682 {
+  inline namespace A {
+    void f(int = 0);
+  }
+}
+void PR47682::f(int) {}
+void PR47682_test() { PR47682::f(); }
 #endif