[ASTImporter] Lookup SearchName instead of Name

[szepet]

Summary

When the SearchName is already calculated we should use that for the lookup.
That is why the check for a found TypedefNameDecl can be relevant in the for loop and we (probably) have to iterate over fewer decls.
I havent added test cases because it does not produce a bug since in the isStrucuralMatch function calls to the StructuralEquivalenceContext::Finish() function and in case of unnamed decls it checks for TypeDefName and returns false (without any warning message).

[a.sidorin]

Looks good. Thank you!
Could you try to write a test using the fact that new code covers typedefs for anonymous structures?

[szepet]

Test case added.

[a.sidorin]

LGTM, thank you!

lib/AST/ASTImporter.cpp

if (!SearchName && D->getTypedefNameForAnonDecl()) {
     IDNS = Decl::IDNS_Ordinary;
   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
     IDNS |= Decl::IDNS_Ordinary;
   
   // We may already have an enum of the same name; try to find and match it.
   if (!DC->isFunctionOrMethod() && SearchName) {
     SmallVector<NamedDecl *, 4> ConflictingDecls;
     SmallVector<NamedDecl *, 2> FoundDecls;
-    DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
+    DC->getRedeclContext()->localUncachedLookup(SearchName, FoundDecls);
     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
         continue;
       
       Decl *Found = FoundDecls[I];
       if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Found)) {
         if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
           Found = Tag->getDecl();
Decl *ASTNodeImporter::VisitRecordDecl(RecordDecl *D) {
   } else if (Importer.getToContext().getLangOpts().CPlusPlus)
     IDNS |= Decl::IDNS_Ordinary;
 
   // We may already have a record of the same name; try to find and match it.
   RecordDecl *AdoptDecl = nullptr;
   if (!DC->isFunctionOrMethod()) {
     SmallVector<NamedDecl *, 4> ConflictingDecls;
     SmallVector<NamedDecl *, 2> FoundDecls;
-    DC->getRedeclContext()->localUncachedLookup(Name, FoundDecls);
+    DC->getRedeclContext()->localUncachedLookup(SearchName, FoundDecls);
     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
         continue;
       
       Decl *Found = FoundDecls[I];
       if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Found)) {
         if (const TagType *Tag = Typedef->getUnderlyingType()->getAs<TagType>())
           Found = Tag->getDecl();