[ASTImporter] Fix IsStructuralMatch specialization for EnumDecl to prevent re-importi...

Summary:
We may try and re-import an EnumDecl while trying to complete it in IsStructuralMatch(...) specialization for EnumDecl. This change mirrors a similar fix for the specialization for RecordDecl.

Differential Revision: https://reviews.llvm.org/D59845

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@357100 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index dbad548b5ce172b25155754950ba88917b1b2639..6048296fb2d37ea415e97ff6b985acb2c2d4d4d1 100644 (file)
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -1946,6 +1946,12 @@ bool ASTNodeImporter::IsStructuralMatch(VarDecl *FromVar, VarDecl *ToVar,
 }
 
 bool ASTNodeImporter::IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToEnum) {
+  // Eliminate a potential failure point where we attempt to re-import
+  // something we're trying to import while completin ToEnum
+  if (Decl *ToOrigin = Importer.GetOriginalDecl(ToEnum))
+    if (auto *ToOriginEnum = dyn_cast<EnumDecl>(ToOrigin))
+        ToEnum = ToOriginEnum;
+
   StructuralEquivalenceContext Ctx(
       Importer.getFromContext(), Importer.getToContext(),
       Importer.getNonEquivalentDecls(), getStructuralEquivalenceKind(Importer));