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mild refactors of the control flow (no functional changes)

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In the future, `check_type_tests` will also potentially propagate
constriants to its caller.
This commit is contained in:
Niko Matsakis 2017-12-04 04:47:59 -05:00
parent 47c1921b9a
commit 02e65250e4
1 changed files with 44 additions and 28 deletions
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72
src/librustc_mir/borrow_check/nll/region_infer/mod.rs
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@ -349,9 +349,22 @@ impl<'tcx> RegionInferenceContext<'tcx> {
self.propagate_constraints(mir);
// If this is a closure, we can propagate unsatisfied
// `outlives_requirements` to our creator, so create a vector
// to store those. Otherwise, we'll pass in `None` to the
// functions below, which will trigger them to report errors
// eagerly.
let mut outlives_requirements = if infcx.tcx.is_closure(mir_def_id) {
Some(vec![])
} else {
None
};
self.check_type_tests(infcx, mir);
let outlives_requirements = self.check_universal_regions(infcx, mir_def_id);
self.check_universal_regions(infcx, outlives_requirements.as_mut());
let outlives_requirements = outlives_requirements.unwrap_or(vec![]);
if outlives_requirements.is_empty() {
None
@ -429,18 +442,20 @@ impl<'tcx> RegionInferenceContext<'tcx> {
for type_test in &self.type_tests {
debug!("check_type_test: {:?}", type_test);
if !self.eval_region_test(
if self.eval_region_test(
mir,
type_test.point,
type_test.lower_bound,
&type_test.test,
) {
// Oh the humanity. Obviously we will do better than this error eventually.
infcx.tcx.sess.span_err(
type_test.span,
&format!("failed type test: {:?}", type_test),
);
continue;
}
// Oh the humanity. Obviously we will do better than this error eventually.
infcx.tcx.sess.span_err(
type_test.span,
&format!("failed type test: {:?}", type_test),
);
}
}
@ -538,11 +553,15 @@ impl<'tcx> RegionInferenceContext<'tcx> {
/// 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.
///
/// If `propagated_outlives_requirements` is `Some`, then we will
/// push unsatisfied obligations into there. Otherwise, we'll
/// report them as errors.
fn check_universal_regions(
&self,
infcx: &InferCtxt<'_, '_, 'tcx>,
mir_def_id: DefId,
) -> Vec<ClosureOutlivesRequirement> {
mut propagated_outlives_requirements: Option<&mut Vec<ClosureOutlivesRequirement>>,
) {
// The universal regions are always found in a prefix of the
// full list.
let universal_definitions = self.definitions
@ -555,25 +574,22 @@ impl<'tcx> RegionInferenceContext<'tcx> {
let mut outlives_requirements = vec![];
for (fr, _) in universal_definitions {
self.check_universal_region(infcx, fr, &mut outlives_requirements);
}
// If this is a closure, we can propagate unsatisfied
// `outlives_requirements` to our creator. Otherwise, we have
// to report a hard error here.
if infcx.tcx.is_closure(mir_def_id) {
return outlives_requirements;
// Propagate unsatisfied requirements if possible, else
// report them.
if let Some(propagated_outlives_requirements) = &mut propagated_outlives_requirements {
propagated_outlives_requirements.extend(outlives_requirements.drain(..));
} else {
for outlives_requirement in outlives_requirements.drain(..) {
self.report_error(
infcx,
outlives_requirement.free_region,
outlives_requirement.outlived_free_region,
outlives_requirement.blame_span,
);
}
}
}
for outlives_requirement in outlives_requirements {
self.report_error(
infcx,
outlives_requirement.free_region,
outlives_requirement.outlived_free_region,
outlives_requirement.blame_span,
);
}
vec![]
}
/// Check the final value for the free region `fr` to see if it
@ -588,7 +604,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
&self,
infcx: &InferCtxt<'_, '_, 'tcx>,
longer_fr: RegionVid,
outlives_requirements: &mut Vec<ClosureOutlivesRequirement>,
propagated_outlives_requirements: &mut Vec<ClosureOutlivesRequirement>,
) {
let inferred_values = self.inferred_values.as_ref().unwrap();
@ -626,7 +642,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
);
// Push the constraint `fr-: shorter_fr+`
outlives_requirements.push(ClosureOutlivesRequirement {
propagated_outlives_requirements.push(ClosureOutlivesRequirement {
free_region: fr_minus,
outlived_free_region: shorter_fr_plus,
blame_span: blame_span,