[PATCH] D53693: [ASTImporter] Typedef import brings in the complete type

[Gabor Marton via Phabricator via cfe-commits]

martong created this revision.
martong added a reviewer: a_sidorin.
Herald added subscribers: cfe-commits, Szelethus, dkrupp, rnkovacs.
Herald added a reviewer: a.sidorin.

When we already have an incomplete underlying type of a typedef in the
"To" context, and the "From" context has the same typedef, but the
underlying type is complete, then the imported type should be complete.

Fixes an assertion in Xerces:
Assertion `DD && "queried property of class with no definition"' failed.
This assert is happening in the analyzer engine, because that attempts
to query an underlying type of a typedef, which happens to be
incomplete.


Repository:
  rC Clang

https://reviews.llvm.org/D53693

Files:
  lib/AST/ASTImporter.cpp
  unittests/AST/ASTImporterTest.cpp


Index: unittests/AST/ASTImporterTest.cpp
===================================================================
--- unittests/AST/ASTImporterTest.cpp
+++ unittests/AST/ASTImporterTest.cpp
@@ -3726,6 +3726,38 @@
   EXPECT_EQ(To1->getPreviousDecl(), To0);
 }
 
+TEST_P(ASTImporterTestBase, ImportingTypedefShouldImportTheCompleteType) {
+  // We already have an incomplete underlying type in the "To" context.
+  auto Code =
+      R"(
+      template <typename T>
+      struct S {
+        void foo();
+      };
+      using U = S<int>;
+      )";
+  Decl *ToTU = getToTuDecl(Code, Lang_CXX11);
+  auto *ToD = FirstDeclMatcher<TypedefNameDecl>().match(ToTU,
+      typedefNameDecl(hasName("U")));
+  ASSERT_TRUE(ToD->getUnderlyingType()->isIncompleteType());
+
+  // The "From" context has the same typedef, but the underlying type is
+  // complete this time.
+  Decl *FromTU = getTuDecl(std::string(Code) +
+      R"(
+      void foo(U* u) {
+        u->foo();
+      }
+      )", Lang_CXX11);
+  auto *FromD = FirstDeclMatcher<TypedefNameDecl>().match(FromTU,
+      typedefNameDecl(hasName("U")));
+  ASSERT_FALSE(FromD->getUnderlyingType()->isIncompleteType());
+
+  // The imported type should be complete.
+  auto *ImportedD = cast<TypedefNameDecl>(Import(FromD, Lang_CXX11));
+  EXPECT_FALSE(ImportedD->getUnderlyingType()->isIncompleteType());
+}
+
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, DeclContextTest,
                         ::testing::Values(ArgVector()), );
 
Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -2306,8 +2306,14 @@
         continue;
       if (auto *FoundTypedef = dyn_cast<TypedefNameDecl>(FoundDecl)) {
         if (Importer.IsStructurallyEquivalent(
-                D->getUnderlyingType(), FoundTypedef->getUnderlyingType()))
+                D->getUnderlyingType(), FoundTypedef->getUnderlyingType())) {
+          QualType FromUT = D->getUnderlyingType();
+          QualType FoundUT = FoundTypedef->getUnderlyingType();
+          // If the "From" context has a complete underlying type but we
+          // already have a complete underlying type then return with that.
+          if (!FromUT->isIncompleteType() && !FoundUT->isIncompleteType())
             return Importer.MapImported(D, FoundTypedef);
+        }
       }
 
       ConflictingDecls.push_back(FoundDecl);


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