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Auto merge of #27096 - apasel422:issue-26217, r=nikomatsakis

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closes #26217

r? @nikomatsakis
This commit is contained in:
bors 2015-07-18 11:02:58 +00:00
commit a27fed7cbd
3 changed files with 40 additions and 12 deletions
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32
src/librustc/middle/traits/fulfill.rs
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@ -413,17 +413,33 @@ fn process_predicate<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
}
ty::Predicate::TypeOutlives(ref binder) => {
// For now, we just check that there are no higher-ranked
// regions. If there are, we will call this obligation an
// error. Eventually we should be able to support some
// cases here, I imagine (e.g., `for<'a> int : 'a`).
// Check if there are higher-ranked regions.
match selcx.tcx().no_late_bound_regions(binder) {
// If there are, inspect the underlying type further.
None => {
errors.push(
FulfillmentError::new(
obligation.clone(),
CodeSelectionError(Unimplemented)))
// Convert from `Binder<OutlivesPredicate<Ty, Region>>` to `Binder<Ty>`.
let binder = binder.map_bound_ref(|pred| pred.0);
// Check if the type has any bound regions.
match selcx.tcx().no_late_bound_regions(&binder) {
// If so, this obligation is an error (for now). Eventually we should be
// able to support additional cases here, like `for<'a> &'a str: 'a`.
None => {
errors.push(
FulfillmentError::new(
obligation.clone(),
CodeSelectionError(Unimplemented)))
}
// Otherwise, we have something of the form
// `for<'a> T: 'a where 'a not in T`, which we can treat as `T: 'static`.
Some(t_a) => {
register_region_obligation(t_a, ty::ReStatic,
obligation.cause.clone(),
region_obligations);
}
}
}
// If there aren't, register the obligation.
Some(ty::OutlivesPredicate(t_a, r_b)) => {
register_region_obligation(t_a, r_b,
obligation.cause.clone(),