[clang][Sema] Add CodeCompletionContext::CCC_ObjCClassForwardDecl

- Use this new context in Sema to limit completions to seen ObjC class
  names

- Use this new context in clangd to disable include insertions when
  completing ObjC forward decls

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D150978

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index a42df66..f6a74fc 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -322,6 +322,7 @@ static uint64_t getDeclShowContexts(const NamedDecl *ND,
       if (ID->getDefinition())
         Contexts |= (1LL << CodeCompletionContext::CCC_Expression);
       Contexts |= (1LL << CodeCompletionContext::CCC_ObjCInterfaceName);
+      Contexts |= (1LL << CodeCompletionContext::CCC_ObjCClassForwardDecl);
     }
 
     // Deal with tag names.
@@ -2028,6 +2029,7 @@ static void CalculateHiddenNames(const CodeCompletionContext &Context,
   case CodeCompletionContext::CCC_IncludedFile:
   case CodeCompletionContext::CCC_Attribute:
   case CodeCompletionContext::CCC_NewName:
+  case CodeCompletionContext::CCC_ObjCClassForwardDecl:
     // We're looking for nothing, or we're looking for names that cannot
     // be hidden.
     return;