[clang] [clang] Check captured variables for noreturn attribute (PR #155213)

[Erich Keane via cfe-commits]

================
@@ -467,6 +467,41 @@ struct TransferFunctions : public StmtVisitor<TransferFunctions> {
               AllValuesAreNoReturn = false;
     }
   }
+
+  void VisitCXXOperatorCallExpr(CXXOperatorCallExpr *CE) {
+    if (CE->getOperator() == OO_Call && CE->getNumArgs() > 0) {
+      Expr *Obj = CE->getArg(0)->IgnoreParenCasts();
+      if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Obj))
+        Obj = MTE->getSubExpr();
+      if (auto *DRE = dyn_cast<DeclRefExpr>(Obj)) {
+        auto *D = dyn_cast<VarDecl>(DRE->getDecl());
+        if (D->hasInit())
+          Obj = D->getInit();
+      }
+      Visit(Obj);
+    }
+  }
+
+  void VisitLambdaExpr(LambdaExpr *LE) {
+    for (const LambdaCapture &Capture : LE->captures())
+      if (Capture.capturesVariable())
+        if (const VarDecl *VD = dyn_cast<VarDecl>(Capture.getCapturedVar()))
+          if (VD == Var)
+            if (Capture.getCaptureKind() == LCK_ByRef)
+              AllValuesAreNoReturn = false;
+  }
+
+  void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE) {
+    Visit(MTE->getSubExpr());
+  }
+
+  void VisitExprWithCleanups(FullExpr *FE) {
+    Visit(FE->getSubExpr());
+  }
+
+  void VisitCXXConstructExpr(CXXConstructExpr *CE) {
+    Visit(CE->getArg(0));
----------------
erichkeane wrote:

This doesn't seem right at all.  the 'this' argument in a `CXXConstructExpr ` does NOT get placed in the 0 arg (in fact, they are not present), so you can't assume 0 exists here.  AND it isn't really clear why the 0 arg is important here, but others arent?

https://github.com/llvm/llvm-project/pull/155213