[CodeComplete] Tweak code completion for `typename`.

[lh123]

Summary

Currently, clangd always completes typename as typename qualifier::name, I think the current behavior is not useful when the code completion is triggered in template <>. So I tweak it to typename identifier.

[kadircet]

LGTM, as previous version only saves a single character, i.e. pressing a single tab after qualifier vs hitting : twice, while it is annoying for the non-qualified case, now you need to delete the rest.

let me know if I should land this for you.

clang/lib/Sema/SemaCodeComplete.cpp

1693

nit: let's use name instead of identifier

[lh123]

address comment.
Also tweak code completion behavior for using.

[lh123]

If this patch looks good, please land it for me.

[kadircet]

clang/lib/Sema/SemaCodeComplete.cpp

2058

unfortunately the reasoning above doesn't apply here, as a using declaration *must* have a nested-name-specifier. e.g. using X; is not allowed. so please revert this (and following on using typename it requires a nested-name-specifier too)

[lh123]

clang/lib/Sema/SemaCodeComplete.cpp

2058

Yes, you are right. but I think complete using as using qualifier::name is not useful when user want input something like using A = B.

[lh123]

clang/lib/Sema/SemaCodeComplete.cpp

2058

I think we just need revert change for using typename qualifier::name. WDYT.

[kadircet]

clang/lib/Sema/SemaCodeComplete.cpp

2058

right but using declarations vs aliases are two different use cases, I would suggest adding a separate completion item for that in form:

using $alias$ = $type$;

[lh123]

Address comment.
I will add using $alias$ = $type$; in a separate patch.

clang/lib/Sema/SemaCodeComplete.cpp

CodeCompletionBuilder Builder(Results.getAllocator(),
                                 Results.getCodeCompletionTUInfo());
   if (LangOpts.CPlusPlus) {
     // C++-specific
     Results.AddResult(
         Result("bool", CCP_Type + (LangOpts.ObjC ? CCD_bool_in_ObjC : 0)));
     Results.AddResult(Result("class", CCP_Type));
     Results.AddResult(Result("wchar_t", CCP_Type));
 
-    // typename qualified-id
+    // typename identifier
     Builder.AddTypedTextChunk("typename");
     Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
-    Builder.AddPlaceholderChunk("qualifier");
-    Builder.AddTextChunk("::");
-    Builder.AddPlaceholderChunk("name");
+    Builder.AddPlaceholderChunk("identifier");
     Results.AddResult(Result(Builder.TakeString()));
 
     if (LangOpts.CPlusPlus11) {
       Results.AddResult(Result("auto", CCP_Type));
       Results.AddResult(Result("char16_t", CCP_Type));
       Results.AddResult(Result("char32_t", CCP_Type));
 
       Builder.AddTypedTextChunk("decltype");
case Sema::PCC_Namespace:
     AddTypedefResult(Results);
     LLVM_FALLTHROUGH;
 
   case Sema::PCC_Class:
     if (SemaRef.getLangOpts().CPlusPlus) {
       // Using declaration
       Builder.AddTypedTextChunk("using");
       Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
       Builder.AddPlaceholderChunk("qualifier");
       Builder.AddTextChunk("::");
       Builder.AddPlaceholderChunk("name");
       Builder.AddChunk(CodeCompletionString::CK_SemiColon);
       Results.AddResult(Result(Builder.TakeString()));
 
       // using typename qualifier::name (only in a dependent context)
       if (SemaRef.CurContext->isDependentContext()) {
         Builder.AddTypedTextChunk("using typename");

clang/test/CodeCompletion/ordinary-name-cxx11.cpp

void foo() {
   // CHECK-CC1-NEXT: COMPLETION: Pattern : [#void#]throw <#expression#>
   // CHECK-CC1-NEXT: COMPLETION: Pattern : [#bool#]true
   // CHECK-CC1-NEXT: COMPLETION: Pattern : try {
   // CHECK-CC1-NEXT: <#statements#>
   // CHECK-CC1-NEXT: }
   // CHECK-CC1: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-CC1-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
   // CHECK-CC1-NEXT: COMPLETION: Pattern : [#std::type_info#]typeid(<#expression-or-type#>)
-  // CHECK-CC1-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC1-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC1-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC1-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC1-NEXT: COMPLETION: union
   // CHECK-CC1-NEXT: COMPLETION: unsigned
   // CHECK-CC1-NEXT: COMPLETION: Pattern : using namespace <#identifier#>;
   // CHECK-CC1-NEXT: COMPLETION: void
   // CHECK-CC1-NEXT: COMPLETION: volatile
   // CHECK-CC1-NEXT: COMPLETION: wchar_t
void foo() {
   // CHECK-CC2-NEXT: COMPLETION: Pattern : static_assert(<#expression#>, <#message#>);
   // CHECK-CC2-NEXT: COMPLETION: struct
   // CHECK-CC2-NEXT: COMPLETION: t : t
   // CHECK-CC2-NEXT: COMPLETION: Pattern : template <#declaration#>
   // CHECK-CC2-NEXT: COMPLETION: Pattern : template<<#parameters#>>
   // CHECK-CC2-NEXT: COMPLETION: thread_local
   // CHECK-CC2-NEXT: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-CC2-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
-  // CHECK-CC2-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC2-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC2-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC2-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC2-NEXT: COMPLETION: union
   // CHECK-CC2-NEXT: COMPLETION: unsigned
   // CHECK-CC2-NEXT: COMPLETION: Pattern : using <#qualifier#>::<#name#>;
   // CHECK-CC2-NEXT: COMPLETION: Pattern : using namespace <#identifier#>;
   // CHECK-CC2-NEXT: COMPLETION: void
   // CHECK-CC2-NEXT: COMPLETION: volatile
void foo() {
   // CHECK-CC3-NEXT: COMPLETION: extern
   // CHECK-CC3-NEXT: COMPLETION: float
   // CHECK-CC3-NEXT: COMPLETION: friend
   // CHECK-CC3-NEXT: COMPLETION: inline
   // CHECK-CC3-NEXT: COMPLETION: int
   // CHECK-CC3-NEXT: COMPLETION: long
   // CHECK-CC3-NEXT: COMPLETION: mutable
   // CHECK-CC3-NEXT: COMPLETION: operator
   // CHECK-CC3-NEXT: COMPLETION: Pattern : private: 
   // CHECK-CC3-NEXT: COMPLETION: Pattern : protected: 
   // CHECK-CC3-NEXT: COMPLETION: Pattern : public: 
   // CHECK-CC3-NEXT: COMPLETION: short
   // CHECK-CC3-NEXT: COMPLETION: signed
   // CHECK-CC3-NEXT: COMPLETION: static
   // CHECK-CC3-NEXT: COMPLETION: Pattern : static_assert(<#expression#>, <#message#>);
   // CHECK-CC3-NEXT: COMPLETION: struct
   // CHECK-CC3-NEXT: COMPLETION: Pattern : template<<#parameters#>>
   // CHECK-CC3-NEXT: COMPLETION: thread_local
   // CHECK-CC3-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
-  // CHECK-CC3-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC3-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC3-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC3-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC3-NEXT: COMPLETION: union
   // CHECK-CC3-NEXT: COMPLETION: unsigned
   // CHECK-CC3-NEXT: COMPLETION: Pattern : using <#qualifier#>::<#name#>
   // CHECK-CC3-NEXT: COMPLETION: virtual
   // CHECK-CC3-NEXT: COMPLETION: void
   // CHECK-CC3-NEXT: COMPLETION: volatile
void foo() {
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#size_t#]sizeof...(<#parameter-pack#>)
   // CHECK-CC4-NEXT: COMPLETION: Pattern : static_cast<<#type#>>(<#expression#>)
   // CHECK-CC4-NEXT: COMPLETION: struct
   // CHECK-CC4-NEXT: COMPLETION: t : t
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#void#]throw <#expression#>
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#bool#]true
   // CHECK-CC4-NEXT: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#std::type_info#]typeid(<#expression-or-type#>)
-  // CHECK-CC4-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC4-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC4-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC4-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC4-NEXT: COMPLETION: union
   // CHECK-CC4-NEXT: COMPLETION: unsigned
   // CHECK-CC4-NEXT: COMPLETION: void
   // CHECK-CC4-NEXT: COMPLETION: volatile
   // CHECK-CC4-NEXT: COMPLETION: wchar_t
   // CHECK-CC4-NEXT: COMPLETION: X : X
void foo() {
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : switch (<#condition#>) {
   // CHECK-NO-RTTI: COMPLETION: t : t
   // CHECK-NO-RTTI-NOT: throw
   // CHECK-NO-RTTI: COMPLETION: Pattern : [#bool#]true
   // CHECK-NO-RTTI-NOT: try
   // CHECK-NO-RTTI: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
   // CHECK-NO-RTTI-NOT: typeid
-  // CHECK-NO-RTTI: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-NO-RTTI: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-NO-RTTI-NEXT: COMPLETION: union
   // CHECK-NO-RTTI-NEXT: COMPLETION: unsigned
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : using namespace <#identifier#>;
   // CHECK-NO-RTTI-NEXT: COMPLETION: void
   // CHECK-NO-RTTI-NEXT: COMPLETION: volatile
   // CHECK-NO-RTTI-NEXT: COMPLETION: wchar_t
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : while (<#condition#>) {
   // CHECK-NO-RTTI: COMPLETION: X : X
   // CHECK-NO-RTTI-NEXT: COMPLETION: y : [#int#]y
   // CHECK-NO-RTTI-NEXT: COMPLETION: z : [#void#]z(<#int#>)

clang/test/CodeCompletion/ordinary-name.cpp

void foo() {
   // CHECK-CC1-NEXT: COMPLETION: Pattern : try {
   // CHECK-CC1-NEXT: <#statements#>
   // CHECK-CC1-NEXT: } catch (<#declaration#>) {
   // CHECK-CC1-NEXT: <#statements#>
   // CHECK-CC1-NEXT: }
   // CHECK-CC1: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-CC1-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
   // CHECK-CC1-NEXT: COMPLETION: Pattern : [#std::type_info#]typeid(<#expression-or-type#>)
-  // CHECK-CC1-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC1-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC1-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC1-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC1-NEXT: COMPLETION: union
   // CHECK-CC1-NEXT: COMPLETION: unsigned
   // CHECK-CC1-NEXT: COMPLETION: Pattern : using namespace <#identifier#>;
   // CHECK-CC1-NEXT: COMPLETION: void
   // CHECK-CC1-NEXT: COMPLETION: volatile
   // CHECK-CC1-NEXT: COMPLETION: wchar_t
void foo() {
   // CHECK-CC2-NEXT: COMPLETION: signed
   // CHECK-CC2-NEXT: COMPLETION: static
   // CHECK-CC2-NEXT: COMPLETION: struct
   // CHECK-CC2-NEXT: COMPLETION: t : t
   // CHECK-CC2-NEXT: COMPLETION: Pattern : template <#declaration#>
   // CHECK-CC2-NEXT: COMPLETION: Pattern : template<<#parameters#>>
   // CHECK-CC2-NEXT: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-CC2-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
-  // CHECK-CC2-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC2-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC2-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC2-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC2-NEXT: COMPLETION: union
   // CHECK-CC2-NEXT: COMPLETION: unsigned
   // CHECK-CC2-NEXT: COMPLETION: Pattern : using <#qualifier#>::<#name#>;
   // CHECK-CC2-NEXT: COMPLETION: Pattern : using namespace <#identifier#>;
   // CHECK-CC2-NEXT: COMPLETION: void
   // CHECK-CC2-NEXT: COMPLETION: volatile
void foo() {
   // CHECK-CC3-NEXT: COMPLETION: extern
   // CHECK-CC3-NEXT: COMPLETION: float
   // CHECK-CC3-NEXT: COMPLETION: friend
   // CHECK-CC3-NEXT: COMPLETION: inline
   // CHECK-CC3-NEXT: COMPLETION: int
   // CHECK-CC3-NEXT: COMPLETION: long
   // CHECK-CC3-NEXT: COMPLETION: mutable
   // CHECK-CC3-NEXT: COMPLETION: operator
   // CHECK-CC3-NEXT: COMPLETION: Pattern : private: 
   // CHECK-CC3-NEXT: COMPLETION: Pattern : protected: 
   // CHECK-CC3-NEXT: COMPLETION: Pattern : public: 
   // CHECK-CC3-NEXT: COMPLETION: short
   // CHECK-CC3-NEXT: COMPLETION: signed
   // CHECK-CC3-NEXT: COMPLETION: static
   // CHECK-CC3-NEXT: COMPLETION: struct
   // CHECK-CC3-NEXT: COMPLETION: Pattern : template<<#parameters#>>
   // CHECK-CC3-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
-  // CHECK-CC3-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC3-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC3-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC3-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC3-NEXT: COMPLETION: union
   // CHECK-CC3-NEXT: COMPLETION: unsigned
   // CHECK-CC3-NEXT: COMPLETION: Pattern : using <#qualifier#>::<#name#>;
   // CHECK-CC3-NEXT: COMPLETION: virtual
   // CHECK-CC3-NEXT: COMPLETION: void
   // CHECK-CC3-NEXT: COMPLETION: volatile
void foo() {
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#size_t#]sizeof(<#expression-or-type#>)
   // CHECK-CC4-NEXT: COMPLETION: Pattern : static_cast<<#type#>>(<#expression#>)
   // CHECK-CC4-NEXT: COMPLETION: struct
   // CHECK-CC4-NEXT: COMPLETION: t : t
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#void#]throw <#expression#>
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#bool#]true
   // CHECK-CC4-NEXT: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-CC4-NEXT: COMPLETION: Pattern : [#std::type_info#]typeid(<#expression-or-type#>)
-  // CHECK-CC4-NEXT: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-CC4-NEXT: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-CC4-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-CC4-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-CC4-NEXT: COMPLETION: union
   // CHECK-CC4-NEXT: COMPLETION: unsigned
   // CHECK-CC4-NEXT: COMPLETION: void
   // CHECK-CC4-NEXT: COMPLETION: volatile
   // CHECK-CC4-NEXT: COMPLETION: wchar_t
   // CHECK-CC4-NEXT: COMPLETION: X : X
void foo() {
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : switch (<#condition#>) {
   // CHECK-NO-RTTI: COMPLETION: t : t
   // CHECK-NO-RTTI-NOT: throw
   // CHECK-NO-RTTI: COMPLETION: Pattern : [#bool#]true
   // CHECK-NO-RTTI-NOT: try
   // CHECK-NO-RTTI: COMPLETION: TYPEDEF : TYPEDEF
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : typedef <#type#> <#name#>;
   // CHECK-NO-RTTI-NOT: typeid
-  // CHECK-NO-RTTI: COMPLETION: Pattern : typename <#qualifier#>::<#name#>
+  // CHECK-NO-RTTI: COMPLETION: Pattern : typename <#identifier#>
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : typeof <#expression#>
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : typeof(<#type#>)
   // CHECK-NO-RTTI-NEXT: COMPLETION: union
   // CHECK-NO-RTTI-NEXT: COMPLETION: unsigned
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : using namespace <#identifier#>;
   // CHECK-NO-RTTI-NEXT: COMPLETION: void
   // CHECK-NO-RTTI-NEXT: COMPLETION: volatile
   // CHECK-NO-RTTI-NEXT: COMPLETION: wchar_t
   // CHECK-NO-RTTI-NEXT: COMPLETION: Pattern : while (<#condition#>) {
   // CHECK-NO-RTTI: COMPLETION: X : X
   // CHECK-NO-RTTI-NEXT: COMPLETION: y : [#int#]y
   // CHECK-NO-RTTI-NEXT: COMPLETION: z : [#void#]z(<#int#>)