haberman added inline comments.
================
Comment at: clang/lib/Sema/SemaStmt.cpp:605-609
+ while (!isa<CallExpr>(Ex)) {
+ auto *PE = cast<ParenExpr>(Ex);
+ Ex = IgnoreImplicitAsWritten(PE->getSubExpr());
+ PE->setSubExpr(Ex);
+ }
----------------
rsmith wrote:
> This loop is problematic: it's generally not safe to modify an expression
> that is used as a subexpression of another expression. (Modifying the
> `ReturnStmt` is, by contrast, much less problematic because the properties of
> a statement have less complex dependencies on the properties of its
> subexpressions.) In particular, if there were any implicit conversions here
> that changed the type or value category or similar, the enclosing parentheses
> would have the wrong type / value category / similar. Also there are
> possibilities here other than `CallExpr` and `ParenExpr`, such as anything
> else that we consider to be "parentheses" (such as a `GenericSelectionExpr`).
>
> But I think this loop should never be necessary, because all implicit
> conversions should always be on the outside of the parentheses. Do you have a
> testcase that needs it?
I removed it and my test cases still pass. I'm glad to know this isn't
necessary: I was coding defensively because I didn't know that I could count on
this invariant:
> all implicit conversions should always be on the outside of the parentheses.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D99517/new/
https://reviews.llvm.org/D99517
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