Fix templated type alias completion when using global completion cache

[yvvan]

Summary

When we have enabled cache for global completions we did not have diagnostics for Bar and could not complete Ba as in provided code example.

template <typename T>
struct Foo { T member; };

template<typename T> using Bar = Foo<T>;

int main() {

Ba

}

[yvvan]

Ping

[yvvan]

one more Ping. this is quite a useful fix that does not cost much

[klimek]

Sorry for missing this - can you add a test?

[yvvan]

In D35355#831845, @klimek wrote:

Sorry for missing this - can you add a test?

I think I can :)
Will add it next week.

[yvvan]

Add unit-test for the case fixed in this review

[yvvan]

Ping...

[klimek]

LG

[yvvan]

Can someone help me to commit it to the proper branch?
(I don't have permissions)

[erikjv]

I'll commit it, probably next Tuesday.

cfe/trunk/lib/Frontend/ASTUnit.cpp

static unsigned getDeclShowContexts(const NamedDecl *ND,
   
   if (isa<UsingShadowDecl>(ND))
     ND = dyn_cast<NamedDecl>(ND->getUnderlyingDecl());
   if (!ND)
     return 0;
   
   uint64_t Contexts = 0;
   if (isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND) || 
-      isa<ClassTemplateDecl>(ND) || isa<TemplateTemplateParmDecl>(ND)) {
+      isa<ClassTemplateDecl>(ND) || isa<TemplateTemplateParmDecl>(ND) ||
+      isa<TypeAliasTemplateDecl>(ND)) {
     // Types can appear in these contexts.
     if (LangOpts.CPlusPlus || !isa<TagDecl>(ND))
       Contexts |= (1LL << CodeCompletionContext::CCC_TopLevel)
                |  (1LL << CodeCompletionContext::CCC_ObjCIvarList)
                |  (1LL << CodeCompletionContext::CCC_ClassStructUnion)
                |  (1LL << CodeCompletionContext::CCC_Statement)
                |  (1LL << CodeCompletionContext::CCC_Type)
                |  (1LL << CodeCompletionContext::CCC_ParenthesizedExpression);

cfe/trunk/lib/Parse/ParseTemplate.cpp

if (Context == Declarator::MemberContext) {
     return nullptr;
   }
 
   ParsedAttributesWithRange prefixAttrs(AttrFactory);
   MaybeParseCXX11Attributes(prefixAttrs);
 
   if (Tok.is(tok::kw_using)) {
     // FIXME: We should return the DeclGroup to the caller.
-    ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
+    auto usingDeclPtr = ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
                                                          prefixAttrs);
+    if (!usingDeclPtr)
       return nullptr;
+    return usingDeclPtr.get().getSingleDecl();
   }
 
   // Parse the declaration specifiers, stealing any diagnostics from
   // the template parameters.
   ParsingDeclSpec DS(*this, &DiagsFromTParams);
 
   ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
                              getDeclSpecContextFromDeclaratorContext(Context));
IdentifierInfo *TemplateII =
             ? TemplateName.Identifier
             : nullptr;
 
     OverloadedOperatorKind OpKind =
         TemplateName.getKind() == UnqualifiedId::IK_Identifier
             ? OO_None
             : TemplateName.OperatorFunctionId.Operator;
 
-    TemplateIdAnnotation *TemplateId = TemplateIdAnnotation::Create(
-      SS, TemplateKWLoc, TemplateNameLoc, TemplateII, OpKind, Template, TNK,
+    TemplateIdAnnotation *TemplateId = TemplateIdAnnotation::Create(
+      SS, TemplateKWLoc, TemplateNameLoc, TemplateII, OpKind, Template, TNK,
       LAngleLoc, RAngleLoc, TemplateArgs, TemplateIds);
     
     Tok.setAnnotationValue(TemplateId);
     if (TemplateKWLoc.isValid())
       Tok.setLocation(TemplateKWLoc);
     else
       Tok.setLocation(TemplateNameLoc);
   }

cfe/trunk/test/Index/code-completion.cpp

void test_overloaded() {
   // RUN: c-index-test -code-completion-at=%s:33:18 %s | FileCheck -check-prefix=CHECK-OVERLOAD %s
   overloaded(Z(), 0);
 }
 
 Z::operator int() const {
   return 0;
 }
 
+template <typename T>
+struct Foo { T member; };
+
+template<typename T> using Bar = Foo<T>;
+
+void test_template_alias() {
+  // RUN: env CINDEXTEST_COMPLETION_CACHING=1 c-index-test -code-completion-at=%s:47:1 %s | FileCheck -check-prefix=CHECK-TEMPLATE-ALIAS %s
+
+}
+
 // CHECK-MEMBER: FieldDecl:{ResultType double}{TypedText member}
 // CHECK-MEMBER: FieldDecl:{ResultType int}{Text X::}{TypedText member}
 // CHECK-MEMBER: FieldDecl:{ResultType float}{Text Y::}{TypedText member}
 // CHECK-MEMBER: CXXMethod:{ResultType void}{Informative Y::}{TypedText memfunc}{LeftParen (}{Optional {Placeholder int i = 17}}{RightParen )}
 // CHECK-MEMBER: CXXConversion:{TypedText operator int}{LeftParen (}{RightParen )}{Informative  const}
 // CHECK-MEMBER: CXXMethod:{ResultType Z &}{TypedText operator=}{LeftParen (}{Placeholder const Z &}{RightParen )}
 // CHECK-MEMBER: CXXMethod:{ResultType X &}{Text X::}{TypedText operator=}{LeftParen (}{Placeholder const X &}{RightParen )}
 // CHECK-MEMBER: CXXMethod:{ResultType Y &}{Text Y::}{TypedText operator=}{LeftParen (}{Placeholder const Y &}{RightParen )}

 // CHECK-EXPR-NEXT: Any type
 // CHECK-EXPR-NEXT: Any value
 // CHECK-EXPR-NEXT: Enum tag
 // CHECK-EXPR-NEXT: Union tag
 // CHECK-EXPR-NEXT: Struct tag
 // CHECK-EXPR-NEXT: Class name
 // CHECK-EXPR-NEXT: Nested name specifier
 // CHECK-EXPR-NEXT: Objective-C interface
+
+// CHECK-TEMPLATE-ALIAS: AliasTemplateDecl:{TypedText Bar}{LeftAngle <}{Placeholder typename T}{RightAngle >} (50)