[modules] PR28752: Do not instantiate variable declarations which are not visible.

https://reviews.llvm.org/D24508

Patch developed in collaboration with Richard Smith!

llvm-svn: 283882

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 7baa85a6464..c9a45b2ecc5 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -9708,6 +9708,21 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init,
          VDecl->getDeclContext()->isDependentContext())) {
       // The previous definition is hidden, and multiple definitions are
       // permitted (in separate TUs). Form another definition of it.
+
+      // Demote the newly parsed definition to a fake declaration.
+      if (!VDecl->isThisDeclarationADemotedDefinition())
+        VDecl->demoteThisDefinitionToDeclaration();
+
+      // Make the definition visible from the point of the demotion on.
+      assert (!Hidden || Def == Hidden &&
+              "We were suggested another hidden definition!");
+      makeMergedDefinitionVisible(Def, VDecl->getLocation());
+
+      // If this is a variable template definition, make its enclosing template
+      // visible.
+      if (VarDecl *VarPattern = Def->getTemplateInstantiationPattern())
+        if (VarPattern->isThisDeclarationADefinition())
+          makeMergedDefinitionVisible(VarPattern, VDecl->getLocation());
     } else {
       Diag(VDecl->getLocation(), diag::err_redefinition)
         << VDecl->getDeclName();