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fix comment on check_type_tests

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This commit is contained in:
Niko Matsakis 2017-12-19 04:21:57 -05:00
parent 03bfb0f316
commit 3c56c3610e
1 changed files with 3 additions and 12 deletions
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15
src/librustc_mir/borrow_check/nll/region_infer/mod.rs
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@ -432,18 +432,9 @@ impl<'tcx> RegionInferenceContext<'tcx> {
}
/// Once regions have been propagated, this method is used to see
/// whether any of the constraints were too strong. In particular,
/// we want to check for a case where a universally quantified
/// region exceeded its bounds. Consider:
///
/// fn foo<'a, 'b>(x: &'a u32) -> &'b u32 { x }
///
/// In this case, returning `x` requires `&'a u32 <: &'b u32`
/// and hence we establish (transitively) a constraint that
/// `'a: 'b`. The `propagate_constraints` code above will
/// therefore add `end('a)` into the region for `'b` -- but we
/// have no evidence that `'b` outlives `'a`, so we want to report
/// an error.
/// whether the "type tests" produced by typeck were satisfied;
/// type tests encode type-outlives relationships like `T:
/// 'a`. See `TypeTest` for more details.
fn check_type_tests<'gcx>(
&self,
infcx: &InferCtxt<'_, 'gcx, 'tcx>,