rsmith added inline comments.
================
Comment at: lib/Sema/SemaExprCXX.cpp:7713-7714
+ // Add the newly created typos to the TypoExprs list, even if they
+ // failed to apply. This allows them to be reaped although they won't
+ // emit any diagnostic.
+ SavedTypoExprs.set_union(TypoExprs);
----------------
What prevents diagnostics from being emitted for `TypoExpr`s we create for an
outer transform that we end up discarding? Eg, in:
```
struct Y {};
struct Z { int value; };
struct A {
Y get_me_a_Y();
};
struct B {
Z get_me_a_Z();
};
A make_an_A();
B make_a_B();
int f() {
return make_an_E().get_me_a_Z().value;
}
```
I'm concerned that we will:
* try correcting `make_me_an_E` (`TypoExpr` `T0`) to `make_me_an_A` (because
that correction has the minimum edit distance) and discover that there is no
`get_me_a_Z` member, creating a new `TypoExpr` `T1`, and recurse:
* try correcting `get_me_a_Z` (`TypoExpr` `T1`) to `get_me_a_Y` and discover
that there is no `value` member
* no correction works: bail out of recursive step
* try correcting `make_me_an_E` (`TypoExpr` `T0`) to `make_me_a_B` and succeed
But now we still have `T1` in our list of `TypoExpr`s, and will presumably
diagnose it (and take action below if it turned out to be ambiguous etc).
================
Comment at: lib/Sema/SemaExprCXX.cpp:7762-7787
// Ensure none of the TypoExprs have multiple typo correction candidates
// with the same edit length that pass all the checks and filters.
// TODO: Properly handle various permutations of possible corrections when
// there is more than one potentially ambiguous typo correction.
// Also, disable typo correction while attempting the transform when
// handling potentially ambiguous typo corrections as any new TypoExprs
will
// have been introduced by the application of one of the correction
----------------
What happens if an ambiguous `TypoExpr` is created as a result of one of the
outer level transformations?
In that case, I think that we will try alternatives for that `TypoExpr` here,
but that `TypoExpr` is not in the expression we're transforming (it was created
within `RecursiveTransformLoop` and isn't part of `E`), so we're just redoing
the same transformation we already did but with typo-correction disabled. This
means that the transform will fail (because we hit a typo and can't correct
it), so we'll accept the original set of corrections despite them being
ambiguous.
Repository:
rC Clang
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D62648/new/
https://reviews.llvm.org/D62648
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