[clang] [clang-repl] Suppress [[nodiscard]] warnings for REPL printed express (PR #178661)

[Vassil Vassilev via cfe-commits]

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@@ -5721,6 +5721,10 @@ Parser::DeclGroupPtrTy Parser::ParseTopLevelStmtDecl() {
       Tok.getAnnotationValue() != nullptr) {
     ConsumeAnnotationToken();
     TLSD->setSemiMissing();
+  } else if (R.isUsable()) {
+    // Semicolon is present, so the value is being discarded.
+    // Re-diagnose [[nodiscard]] warnings that were suppressed during parsing.
+    Actions.DiagnoseUnusedExprResult(R.get(), diag::warn_unused_expr);
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vgvassilev wrote:

I don't think we need this branch here. Why the other change is not sufficient?

https://github.com/llvm/llvm-project/pull/178661