aaron.ballman added inline comments.
================
Comment at: clang/lib/Parse/ParseStmt.cpp:1520-1525
+ if (IsConsteval) {
+ if (!isa_and_nonnull<class CompoundStmt>(ThenStmt.get())) {
+ Diag(ConstevalLoc, diag::err_expected_after) << "consteval"
+ << "{";
+ return StmtError();
+ }
----------------
aaron.ballman wrote:
> cor3ntin wrote:
> > aaron.ballman wrote:
> > > Oh. I see where the diagnostic is happening. I think it's unclean to
> > > parse a statement and then diagnose it later as being the wrong kind of
> > > statement -- why not parse the correct kind of statement initially?
> > I think the code reads better that way - we need to parse any kind of
> > statement in other cases. In any case the work is about the same
> Hmmm, this makes me a bit uncomfortable, but I'm not convinced it's a problem
> either. Calling `ParseCompoundStmt()` would require checking the token first
> to avoid an assert, so I can understand better wanting to avoid the messier
> code that comes from that. However, calling the correct parsing method also
> means that we don't attempt to parse something we shouldn't parse only to
> reject it much later; I'm a bit concerned that we'll get some bad error
> recovery when parsing the more general thing. However, my attempts to come up
> with test cases where this matters are so far falling pretty flat. One test
> that would help (and should pass still) is:
> ```
> if consteval ({1;}); // Do we correctly reject the statement expression?
> ```
Please hold off on changes here for the moment, as I think I may have
identified a DR. Consider code like:
```
if consteval [[]] {
}
```
According to the C++ grammar, this construct should not be accepted. However,
that's inconsistent with every other form of if statement and seems like a
defect to me. I've asked on the Core reflectors to see.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D110482/new/
https://reviews.llvm.org/D110482
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