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

[Chuanqi Xu via Phabricator via cfe-commits]

ChuanqiXu accepted this revision.
ChuanqiXu added inline comments.
This revision is now accepted and ready to land.


================
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
----------------
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.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D142077/new/

https://reviews.llvm.org/D142077