[clang] [clang-tools-extra] Add code completion for C++20 keywords. (PR #107982)

[via cfe-commits]

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@@ -2186,6 +2197,45 @@ AddOrdinaryNameResults(SemaCodeCompletion::ParserCompletionContext CCC,
       } else {
         Results.AddResult(Result("template", CodeCompletionResult::RK_Keyword));
       }
+
+      if (SemaRef.getLangOpts().CPlusPlus20 &&
+          SemaRef.getLangOpts().CPlusPlusModules) {
+        // export
+        Results.AddResult(Result("export", CodeCompletionResult::RK_Keyword));
+
+        if (SemaRef.CurContext->isTranslationUnit()) {
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cor3ntin wrote:

Well, exactly.
If we haven't see `module;`, we should propose `module;` and `export module`
If we have seen `module;` - we should not propose it again
If we have seem `export module`, we should not propose `import`


https://github.com/llvm/llvm-project/pull/107982