[PATCH] D142077: [Clang][SemaCXX][Coroutines] Fix misleading diagnostics with -Wunsequenced

[Bruno Cardoso Lopes via Phabricator via cfe-commits]

bruno added a comment.

Thanks for the review, will push once all tests pass!



================
Comment at: clang/lib/Sema/SemaChecking.cpp:15186
+      if (ChildExpr == CSE->getOperand())
+        // Do not recurse over a CoroutineSuspendExpr's operand.
+        // The operand is also a subexpression of getCommonExpr(), and
----------------
ChuanqiXu wrote:
> nridge wrote:
> > Out of curiosity, since `getCommonExpr()` is itself a subexpression of `getReadyExpr()`, `getSuspendExpr()`, and `getResumeExpr()` (which are also children of the `CoroutineSuspendExpr`), shouldn't `getCommonExpr()` be skipped for the same reason?
> >  since getCommonExpr() is itself a subexpression of getReadyExpr(), getSuspendExpr(), and getResumeExpr()
> 
> This looks not true. For this example:
> 
> ```
> co_await foo();
> ```
> 
> `foo()` is the Operand. And the Common is `auto __tmp__ = operator co_await(foo())`. ReadyExpr should be `__tmp__.await_ready();`. SuspendExpr should be `__tmp__.await_suspend();` and ResumeExpr should be `__tmp__.await_resume();`.
> 
> So the method here looks good to me.

> `foo()` is the Operand. And the Common is `auto __tmp__ = operator co_await(foo())`. ReadyExpr should be `__tmp__.await_ready();`. SuspendExpr should be `__tmp__.await_suspend();` and ResumeExpr should be `__tmp__.await_resume();`.

Exactly!




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  https://reviews.llvm.org/D142077/new/

https://reviews.llvm.org/D142077