[clang] [clang] Add break/continue stmts with missing lable to the AST (PR #168332)

[Aaron Ballman via cfe-commits]

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@@ -2313,10 +2313,8 @@ StmtResult Parser::ParseBreakOrContinueStatement(bool IsContinue) {
       // TODO: Make this a compatibility/extension warning instead once the
       // syntax of this feature is finalised.
       Diag(LabelLoc, diag::err_c2y_labeled_break_continue) << IsContinue;
-    if (!Target) {
+    if (!Target)
       Diag(LabelLoc, diag::err_break_continue_label_not_found) << IsContinue;
-      return StmtError();
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AaronBallman wrote:

I'm not certain this is correct; we're emitting an error. I think that branch should return `StmtError()` rather than a valid `ContinueStmt` or `BreakStmt`. The prior branch not returning is a bit more reasonable when we have a valid target because the semantics the AST models will still be what the programmer intended. The same is not true for the case where we couldn't find the target; we could break to the nearest loop as a way to recover, but that may end up generating confusing false positives with CFG-based diagnostics, so I think a `RecoveryExpr` makes more sense. WDYT?

https://github.com/llvm/llvm-project/pull/168332