[clang] [clang] Share RecursiveASTVisitor for AST listing (PR #202661)

[Erich Keane via cfe-commits]

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@@ -48,6 +55,11 @@ namespace {
     void HandleTranslationUnit(ASTContext &Context) override {
       TranslationUnitDecl *D = Context.getTranslationUnitDecl();
 
+      if (OutputKind == List) {
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erichkeane wrote:

I'm concerned a touch how this is the same implementation as `!FilterString.empty` here.

https://github.com/llvm/llvm-project/pull/202661