[CodeCompletion] Ignore parsed completion decls in the first pass

If a code completion happens inside an attribute (or in the decl), we
should not insert parsed decls to the AST in the first pass.

rdar://problem/65898101

Author: rintaro

lib/Parse/ParseDecl.cpp

@@ -3754,7 +3754,8 @@ Parser::parseDecl(ParseDeclOptions Flags,
                               StaticSpelling, tryLoc, HasLetOrVarKeyword);
     StaticLoc = SourceLoc(); // we handled static if present.
     MayNeedOverrideCompletion = true;
-    if (DeclResult.hasCodeCompletion() && isCodeCompletionFirstPass())
+    if ((AttrStatus.hasCodeCompletion() || DeclResult.hasCodeCompletion())
+        && isCodeCompletionFirstPass())
       return;
     std::for_each(Entries.begin(), Entries.end(), Handler);
     if (auto *D = DeclResult.getPtrOrNull())
@@ -3801,7 +3802,8 @@ Parser::parseDecl(ParseDeclOptions Flags,
     llvm::SmallVector<Decl *, 4> Entries;
     DeclParsingContext.setCreateSyntax(SyntaxKind::EnumCaseDecl);
     DeclResult = parseDeclEnumCase(Flags, Attributes, Entries);
-    if (DeclResult.hasCodeCompletion() && isCodeCompletionFirstPass())
+    if ((AttrStatus.hasCodeCompletion() || DeclResult.hasCodeCompletion()) &&
+        isCodeCompletionFirstPass())
       break;
     std::for_each(Entries.begin(), Entries.end(), Handler);
     if (auto *D = DeclResult.getPtrOrNull())
@@ -3845,7 +3847,8 @@ Parser::parseDecl(ParseDeclOptions Flags,
     DeclResult = parseDeclSubscript(StaticLoc, StaticSpelling, Flags,
                                     Attributes, Entries);
     StaticLoc = SourceLoc(); // we handled static if present.
-    if (DeclResult.hasCodeCompletion() && isCodeCompletionFirstPass())
+    if ((AttrStatus.hasCodeCompletion() || DeclResult.hasCodeCompletion()) &&
+        isCodeCompletionFirstPass())
       break;
     std::for_each(Entries.begin(), Entries.end(), Handler);
     MayNeedOverrideCompletion = true;
@@ -4024,6 +4027,8 @@ Parser::parseDecl(ParseDeclOptions Flags,
       CodeCompletion->setAttrTargetDeclKind(DK);
     }
     DeclResult.setHasCodeCompletion();
+    if (isCodeCompletionFirstPass())
+      return DeclResult;
   }
 
   if (DeclResult.isNonNull()) {