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| author | Ariel Ben-Yehuda <ariel.byd@gmail.com> | 2017-10-06 17:12:24 +0300 |
|---|---|---|
| committer | Ariel Ben-Yehuda <ariel.byd@gmail.com> | 2017-10-06 17:12:24 +0300 |
| commit | 91fdadba6103b6926ff0c886a6a5da002a80994a (patch) | |
| tree | 74d521109519d6a0620db73d5bcc59b75e99bd8e | |
| parent | 9ae6ed78acf9dc865e2300a7db556389eed9692d (diff) | |
| download | rust-91fdadba6103b6926ff0c886a6a5da002a80994a.tar.gz | |
fix logic error in #44269's `prune_cache_value_obligations`
We want to retain obligations that *contain* inference variables, not
obligations that *don't contain* them, in order to fix #43132. Because
of surrounding changes to inference, the ICE doesn't occur in its
original case, but I believe it could still be made to occur on master.
Maybe I should try to write a new test case? Certainly not right now
(I'm mainly trying to get us a beta that we can ship) but maybe before
we land this PR on nightly?
This seems to cause a 10% performance regression in my imprecise
attempt to benchmark item-body checking for #43613, but it's better to
be slow and right than fast and wrong. If we want to recover that, I
think we can change the constrained-type-parameter code to actually
give a list of projections that are important for resolving inference
variables and filter everything else out.
| -rw-r--r-- | src/librustc/traits/project.rs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/librustc/traits/project.rs b/src/librustc/traits/project.rs index 54e31aed272..b5449f51769 100644 --- a/src/librustc/traits/project.rs +++ b/src/librustc/traits/project.rs @@ -639,7 +639,7 @@ fn prune_cache_value_obligations<'a, 'gcx, 'tcx>(infcx: &'a InferCtxt<'a, 'gcx, // but we have `T: Foo<X = ?1>` and `?1: Bar<X = // ?0>`). ty::Predicate::Projection(ref data) => - !infcx.any_unresolved_type_vars(&data.ty()), + infcx.any_unresolved_type_vars(&data.ty()), // We are only interested in `T: Foo<X = U>` predicates, whre // `U` references one of `unresolved_type_vars`. =) |