[Index] Report specialization bases as references when IndexImplicitInstantiation is true

[MaskRay]

Summary

template <typename T> struct B {};
template <typename T> struct D : B<T> {}; // `B` was not reported as a reference

This patch fixes this.

[devnexen]

LGTM to me

lib/Index/IndexTypeSourceInfo.cpp

bool VisitObjCObjectTypeLoc(ObjCObjectTypeLoc TL) {
     }
     return true;
   }
 
   template<typename TypeLocType>
   bool HandleTemplateSpecializationTypeLoc(TypeLocType TL) {
     if (const auto *T = TL.getTypePtr()) {
       if (IndexCtx.shouldIndexImplicitInstantiation()) {
-        if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
+        if (CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
           IndexCtx.handleReference(RD, TL.getTemplateNameLoc(),
                                    Parent, ParentDC, SymbolRoleSet(), Relations);
-      } else {
-        if (const TemplateDecl *D = T->getTemplateName().getAsTemplateDecl())
-          IndexCtx.handleReference(D, TL.getTemplateNameLoc(),
-                                   Parent, ParentDC, SymbolRoleSet(), Relations);
+          return true;
+        }
       }
+      if (const TemplateDecl *D = T->getTemplateName().getAsTemplateDecl())
+        IndexCtx.handleReference(D, TL.getTemplateNameLoc(), Parent, ParentDC,
+                                 SymbolRoleSet(), Relations);
     }
     return true;
   }
 
   bool VisitTemplateSpecializationTypeLoc(TemplateSpecializationTypeLoc TL) {
     return HandleTemplateSpecializationTypeLoc(TL);
   }
 

test/Index/index-template-specialization.cpp

 template <typename T>
 class Foo {
 public:
   void f(T t) {}
 };
 
 void g() {
   Foo<int> foo;
   foo.f(0);
 }
 
+template <typename T>
+struct B {};
+
+template <typename T>
+struct D : B<T> {};
+
 // FIXME: if c-index-test uses OrigD for symbol info, refererences below should
 // refer to template specialization decls.
 // RUN: env CINDEXTEST_INDEXIMPLICITTEMPLATEINSTANTIATIONS=1 c-index-test -index-file %s | FileCheck %s
 // CHECK: [indexDeclaration]: kind: c++-class-template | name: Foo
 // CHECK-NEXT: [indexDeclaration]: kind: c++-instance-method | name: f
 // CHECK-NEXT: [indexDeclaration]: kind: function | name: g
 // CHECK-NEXT: [indexEntityReference]: kind: c++-class-template | name: Foo | USR: c:@ST>1#T@Foo
 // CHECK-NEXT: [indexEntityReference]: kind: c++-instance-method | name: f | USR: c:@ST>1#T@Foo@F@f#t0.0#
+
+// CHECK: [indexDeclaration]: kind: c++-class-template | name: D
+// CHECK-NEXT: <base>: kind: c++-class-template | name: B
+// CHECK-NEXT: [indexEntityReference]: kind: c++-class-template | name: B