diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 497d220..d6bd134 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -3978,6 +3978,45 @@
   std::string getDefinition() { return TypeParam::Definition; }
   BindableMatcher<Decl> getPattern() const { return TypeParam().getPattern(); }
 
+  void CheckPreviousDecl(Decl *Prev, Decl *Current) {
+    ASSERT_NE(Prev, Current);
+    ASSERT_EQ(&Prev->getASTContext(), &Current->getASTContext());
+    EXPECT_EQ(Prev->getCanonicalDecl(), Current->getCanonicalDecl());
+
+    // Templates.
+    if (auto *PrevT = dyn_cast<TemplateDecl>(Prev)) {
+      EXPECT_EQ(Current->getPreviousDecl(), Prev);
+      auto *CurrentT = cast<TemplateDecl>(Current);
+      ASSERT_TRUE(PrevT->getTemplatedDecl());
+      ASSERT_TRUE(CurrentT->getTemplatedDecl());
+      EXPECT_EQ(CurrentT->getTemplatedDecl()->getPreviousDecl(),
+                PrevT->getTemplatedDecl());
+      return;
+    }
+
+    // Specializations.
+    if (auto *PrevF = dyn_cast<FunctionDecl>(Prev)) {
+      if (PrevF->getTemplatedKind() ==
+          FunctionDecl::TK_FunctionTemplateSpecialization) {
+        // There may be a hidden fwd spec decl before a spec decl.
+        // In that case the previous visible decl can be reached through that
+        // invisible one.
+        EXPECT_THAT(Prev, testing::AnyOf(
+                              Current->getPreviousDecl(),
+                              Current->getPreviousDecl()->getPreviousDecl()));
+        auto *ToTU = Prev->getTranslationUnitDecl();
+        auto *TemplateD = FirstDeclMatcher<FunctionTemplateDecl>().match(
+            ToTU, functionTemplateDecl());
+        auto *FirstSpecD = *(TemplateD->spec_begin());
+        EXPECT_EQ(FirstSpecD->getCanonicalDecl(), PrevF->getCanonicalDecl());
+        return;
+      }
+    }
+
+    // The rest: Classes, Functions, etc.
+    EXPECT_EQ(Current->getPreviousDecl(), Prev);
+  }
+
   void
   TypedTest_PrototypeShouldBeImportedAsAPrototypeWhenThereIsNoDefinition() {
     Decl *FromTU = getTuDecl(getPrototype(), Lang_CXX);
@@ -4030,14 +4069,8 @@
     EXPECT_TRUE(Imported1 == To1);
     EXPECT_FALSE(To0->isThisDeclarationADefinition());
     EXPECT_FALSE(To1->isThisDeclarationADefinition());
-    EXPECT_EQ(To1->getPreviousDecl(), To0);
-    if (auto *ToT0 = dyn_cast<TemplateDecl>(To0)) {
-      auto *ToT1 = cast<TemplateDecl>(To1);
-      ASSERT_TRUE(ToT0->getTemplatedDecl());
-      ASSERT_TRUE(ToT1->getTemplatedDecl());
-      EXPECT_EQ(ToT1->getTemplatedDecl()->getPreviousDecl(),
-                ToT0->getTemplatedDecl());
-    }
+
+    CheckPreviousDecl(To0, To1);
   }
 
   void TypedTest_ImportDefinitionAfterImportedPrototype() {
@@ -4059,14 +4092,8 @@
     EXPECT_TRUE(ImportedDef == ToDef);
     EXPECT_FALSE(ToProto->isThisDeclarationADefinition());
     EXPECT_TRUE(ToDef->isThisDeclarationADefinition());
-    EXPECT_EQ(ToDef->getPreviousDecl(), ToProto);
-    if (auto *ToProtoT = dyn_cast<TemplateDecl>(ToProto)) {
-      auto *ToDefT = cast<TemplateDecl>(ToDef);
-      ASSERT_TRUE(ToProtoT->getTemplatedDecl());
-      ASSERT_TRUE(ToDefT->getTemplatedDecl());
-      EXPECT_EQ(ToDefT->getTemplatedDecl()->getPreviousDecl(),
-                ToProtoT->getTemplatedDecl());
-    }
+
+    CheckPreviousDecl(ToProto, ToDef);
   }
 
   void TypedTest_ImportPrototypeAfterImportedDefinition() {
@@ -4088,14 +4115,8 @@
     EXPECT_TRUE(ImportedProto == ToProto);
     EXPECT_TRUE(ToDef->isThisDeclarationADefinition());
     EXPECT_FALSE(ToProto->isThisDeclarationADefinition());
-    EXPECT_EQ(ToProto->getPreviousDecl(), ToDef);
-    if (auto *ToDefT = dyn_cast<TemplateDecl>(ToDef)) {
-      auto *ToProtoT = cast<TemplateDecl>(ToProto);
-      ASSERT_TRUE(ToDefT->getTemplatedDecl());
-      ASSERT_TRUE(ToProtoT->getTemplatedDecl());
-      EXPECT_EQ(ToProtoT->getTemplatedDecl()->getPreviousDecl(),
-                ToDefT->getTemplatedDecl());
-    }
+
+    CheckPreviousDecl(ToDef, ToProto);
   }
 
   void TypedTest_ImportPrototypes() {
@@ -4117,27 +4138,8 @@
     EXPECT_TRUE(Imported1 == To1);
     EXPECT_FALSE(To0->isThisDeclarationADefinition());
     EXPECT_FALSE(To1->isThisDeclarationADefinition());
-    EXPECT_EQ(To1->getPreviousDecl(), To0);
-    if (auto *ToT0 = dyn_cast<TemplateDecl>(To0)) {
-      auto *ToT1 = cast<TemplateDecl>(To1);
-      ASSERT_TRUE(ToT0->getTemplatedDecl());
-      ASSERT_TRUE(ToT1->getTemplatedDecl());
-      EXPECT_EQ(ToT1->getTemplatedDecl()->getPreviousDecl(),
-                ToT0->getTemplatedDecl());
-    }
-    // Extra check for specializations.
-    // FIXME Add this check to other tests too (possibly factor out into a
-    // function), when they start to pass.
-    if (auto *From0F = dyn_cast<FunctionDecl>(From0)) {
-      auto *To0F = cast<FunctionDecl>(To0);
-      if (From0F->getTemplatedKind() ==
-          FunctionDecl::TK_FunctionTemplateSpecialization) {
-        auto *TemplateD = FirstDeclMatcher<FunctionTemplateDecl>().match(
-            ToTU, functionTemplateDecl());
-        auto *FirstSpecD = *(TemplateD->spec_begin());
-        EXPECT_EQ(FirstSpecD->getCanonicalDecl(), To0F->getCanonicalDecl());
-      }
-    }
+
+    CheckPreviousDecl(To0, To1);
   }
 
   void TypedTest_ImportDefinitions() {
@@ -4182,14 +4184,8 @@
     EXPECT_TRUE(ImportedProto == ToProto);
     EXPECT_TRUE(ToDef->isThisDeclarationADefinition());
     EXPECT_FALSE(ToProto->isThisDeclarationADefinition());
-    EXPECT_EQ(ToProto->getPreviousDecl(), ToDef);
-    if (auto *ToDefT = dyn_cast<TemplateDecl>(ToDef)) {
-      auto *ToProtoT = cast<TemplateDecl>(ToProto);
-      ASSERT_TRUE(ToDefT->getTemplatedDecl());
-      ASSERT_TRUE(ToProtoT->getTemplatedDecl());
-      EXPECT_EQ(ToProtoT->getTemplatedDecl()->getPreviousDecl(),
-                ToDefT->getTemplatedDecl());
-    }
+
+    CheckPreviousDecl(ToDef, ToProto);
   }
 
   void TypedTest_ImportPrototypeThenDefinition() {
@@ -4213,14 +4209,8 @@
     EXPECT_TRUE(ImportedProto == ToProto);
     EXPECT_TRUE(ToDef->isThisDeclarationADefinition());
     EXPECT_FALSE(ToProto->isThisDeclarationADefinition());
-    EXPECT_EQ(ToDef->getPreviousDecl(), ToProto);
-    if (auto *ToDefT = dyn_cast<TemplateDecl>(ToDef)) {
-      auto *ToProtoT = cast<TemplateDecl>(ToProto);
-      ASSERT_TRUE(ToDefT->getTemplatedDecl());
-      ASSERT_TRUE(ToProtoT->getTemplatedDecl());
-      EXPECT_EQ(ToDefT->getTemplatedDecl()->getPreviousDecl(),
-                ToProtoT->getTemplatedDecl());
-    }
+
+    CheckPreviousDecl(ToProto, ToDef);
   }
 
   void TypedTest_WholeRedeclChainIsImportedAtOnce() {
@@ -4262,7 +4252,8 @@
     EXPECT_TRUE(DefinitionD->getPreviousDecl());
     EXPECT_FALSE(
         DefinitionD->getPreviousDecl()->isThisDeclarationADefinition());
-    EXPECT_EQ(DefinitionD->getPreviousDecl()->getPreviousDecl(), ProtoD);
+
+    CheckPreviousDecl(ProtoD, DefinitionD->getPreviousDecl());
   }
 };
 
@@ -4366,11 +4357,10 @@
                                         ImportPrototypes)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplate, ,
                                         ImportPrototypes)
-// FIXME This does not pass, possible error with Spec import.
-ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec,
-                                        DISABLED_, ImportPrototypes)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplateSpec, ,
                                         ImportPrototypes)
+ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec, ,
+                                        ImportPrototypes)
 
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, Function, ,
                                         ImportDefinitions)
@@ -4382,11 +4372,10 @@
                                         ImportDefinitions)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplate, ,
                                         ImportDefinitions)
-// FIXME This does not pass, possible error with Spec import.
-ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec,
-                                        DISABLED_, ImportDefinitions)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplateSpec, ,
                                         ImportDefinitions)
+ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec, ,
+                                        ImportDefinitions)
 
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, Function, ,
                                         ImportDefinitionThenPrototype)
@@ -4398,9 +4387,7 @@
                                         ImportDefinitionThenPrototype)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplate, ,
                                         ImportDefinitionThenPrototype)
-// FIXME This does not pass, possible error with Spec import.
-ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec,
-                                        DISABLED_,
+ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec, ,
                                         ImportDefinitionThenPrototype)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplateSpec, ,
                                         ImportDefinitionThenPrototype)
@@ -4415,9 +4402,7 @@
                                         ImportPrototypeThenDefinition)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplate, ,
                                         ImportPrototypeThenDefinition)
-// FIXME This does not pass, possible error with Spec import.
-ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec,
-                                        DISABLED_,
+ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec, ,
                                         ImportPrototypeThenDefinition)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, ClassTemplateSpec, ,
                                         ImportPrototypeThenDefinition)
@@ -4437,9 +4422,7 @@
                                         ImportPrototypeThenProtoAndDefinition)
 ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplate, ,
                                         ImportPrototypeThenProtoAndDefinition)
-// FIXME This does not pass, possible error with Spec import.
-ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec,
-                                        DISABLED_,
+ASTIMPORTER_INSTANTIATE_TYPED_TEST_CASE(RedeclChain, FunctionTemplateSpec, ,
                                         ImportPrototypeThenProtoAndDefinition)
 
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, RedeclChainFunction,