[PATCH] D53655: [ASTImporter] Fix redecl chain of classes and class templates

[Gabor Marton via Phabricator via cfe-commits]

martong marked 20 inline comments as done.
martong added inline comments.


================
Comment at: include/clang/ASTMatchers/ASTMatchers.h:1169
+///   matches 'a'.
+extern const internal::VariadicDynCastAllOfMatcher<Decl, IndirectFieldDecl>
+    indirectFieldDecl;
----------------
aaron.ballman wrote:
> Be sure to update Registry.cpp and regenerate the AST matcher documentation by running clang\docs\tools\dump_ast_matchers.py.
> 
> This change feels orthogonal to the rest of the patch; perhaps it should be split out into its own patch?
> This change feels orthogonal to the rest of the patch; perhaps it should be split out into its own patch?

I agree this part could go into a separate patch, but the first use of this new ASTMatcher is in the new unittests of this patch, so I think it fits better to add them here.


================
Comment at: lib/AST/ASTImporter.cpp:2644
 
-        PrevDecl = FoundRecord;
-
-        if (RecordDecl *FoundDef = FoundRecord->getDefinition()) {
-          if ((SearchName && !D->isCompleteDefinition() && !IsFriendTemplate)
-              || (D->isCompleteDefinition() &&
-                  D->isAnonymousStructOrUnion()
-                    == FoundDef->isAnonymousStructOrUnion())) {
-            // The record types structurally match, or the "from" translation
-            // unit only had a forward declaration anyway; call it the same
-            // function.
+        if (IsStructuralMatch(D, FoundRecord)) {
+          RecordDecl *FoundDef = FoundRecord->getDefinition();
----------------
a_sidorin wrote:
> IsStructuralMatch check will be repeated if (!SearchName && IsStructuralMatch). Is it expected behaviour?
Yes, this is intentional.
The first check does not emit any diagnostics. However, in the case you mention (`if (!SearchName && IsStructuralMatch)`) we have to emit diagnostics, because we found a real mismatch.



================
Comment at: lib/AST/ASTImporter.cpp:2667
       ConflictingDecls.push_back(FoundDecl);
-    }
+    } // for
 
----------------
a_sidorin wrote:
> Szelethus wrote:
> > Hah. We should do this more often.
> Unfortunately, it is a clear sign that we have to simplify the function. It's better to leave a FIXME instead.
I agree. Further, we should simplify all `Visit*Decl` functions where we iterate over the lookup results. The whole iteration could be part of a subroutine with a name like `FindEquivalentPreviousDecl`. But, I'd do that as a separate patch which focuses only on that refactor.


================
Comment at: lib/AST/ASTImporter.cpp:5064
+    if (!ToTemplated->getPreviousDecl()) {
+      auto *PrevTemplated =
+          FoundByLookup->getTemplatedDecl()->getMostRecentDecl();
----------------
aaron.ballman wrote:
> Do not use `auto` here as the type is not spelled out in the initialization.
Good catch.


================
Comment at: unittests/AST/ASTImporterTest.cpp:3794
+
+TEST_P(ImportFriendClasses, DeclsFromFriendsShouldBeInRedeclChains2) {
+  Decl *From, *To;
----------------
a_sidorin wrote:
> Will `DeclsFromFriendsShouldBeInRedeclChains` without number appear in another patch?
Sorry, `2` is an obsolete postfix. Removed it.


Repository:
  rC Clang

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D53655/new/

https://reviews.llvm.org/D53655