[modules] When determining whether a name from a module replaces a name we

already have, check whether the name from the module is actually newer than the
existing declaration. If it isn't, we might (say) replace a visible declaration
with an injected friend, and thus make it invisible (or lose a default argument
or an array bound).

llvm-svn: 228661

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 8edbc1871b4..9184a9fd828 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -414,6 +414,8 @@ void LookupResult::resolveKind() {
     if (!Unique.insert(D).second) {
       // If it's not unique, pull something off the back (and
       // continue at this index).
+      // FIXME: This is wrong. We need to take the more recent declaration in
+      // order to get the right type, default arguments, etc.
       Decls[I] = Decls[--N];
       continue;
     }
@@ -1254,6 +1256,9 @@ static NamedDecl *findAcceptableDecl(Sema &SemaRef, NamedDecl *D) {
 
   for (auto RD : D->redecls()) {
     if (auto ND = dyn_cast<NamedDecl>(RD)) {
+      // FIXME: This is wrong in the case where the previous declaration is not
+      // visible in the same scope as D. This needs to be done much more
+      // carefully.
       if (LookupResult::isVisible(SemaRef, ND))
         return ND;
     }