fix universes in the NLL type tests

In the NLL code, we were not accommodating universes in the
`type_test` logic. This led to issue 98095.
This commit is contained in:
Niko Matsakis 2022-06-15 17:28:05 -04:00
parent b7b3d2cee0
commit 12912b9cde
3 changed files with 61 additions and 1 deletions

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@ -1342,6 +1342,18 @@ fn eval_outlives(&self, sup_region: RegionVid, sub_region: RegionVid) -> bool {
let sub_region_scc = self.constraint_sccs.scc(sub_region);
let sup_region_scc = self.constraint_sccs.scc(sup_region);
// If we are checking that `'sup: 'sub`, and `'sub` contains
// some placeholder that `'sup` cannot name, then this is only
// true if `'sup` outlives static.
if !self.universe_compatible(sub_region_scc, sup_region_scc) {
debug!(
"eval_outlives: sub universe `{sub_region_scc:?}` is not nameable \
by super `{sup_region_scc:?}`, promoting to static",
);
return self.eval_outlives(sup_region, self.universal_regions.fr_static);
}
// Both the `sub_region` and `sup_region` consist of the union
// of some number of universal regions (along with the union
// of various points in the CFG; ignore those points for
@ -1356,6 +1368,9 @@ fn eval_outlives(&self, sup_region: RegionVid, sub_region: RegionVid) -> bool {
});
if !universal_outlives {
debug!(
"eval_outlives: returning false because sub region contains a universal region not present in super"
);
return false;
}
@ -1364,10 +1379,18 @@ fn eval_outlives(&self, sup_region: RegionVid, sub_region: RegionVid) -> bool {
if self.universal_regions.is_universal_region(sup_region) {
// Micro-opt: universal regions contain all points.
debug!(
"eval_outlives: returning true because super is universal and hence contains all points"
);
return true;
}
self.scc_values.contains_points(sup_region_scc, sub_region_scc)
let result = self.scc_values.contains_points(sup_region_scc, sub_region_scc);
debug!(
"eval_outlives: returning {} because of comparison between points in sup/sub",
result
);
result
}
/// Once regions have been propagated, this method is used to see

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@ -0,0 +1,21 @@
// Regression test for #98095: make sure that
// we detect that S needs to outlive 'static.
fn outlives_forall<T>()
where
for<'u> T: 'u,
{
}
fn test1<S>() {
outlives_forall::<S>();
//~^ ERROR `S` does not live long enough
}
struct Value<'a>(&'a ());
fn test2<'a>() {
outlives_forall::<Value<'a>>();
//~^ ERROR lifetime may not live long enough
}
fn main() {}

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@ -0,0 +1,16 @@
error: `S` does not live long enough
--> $DIR/type-test-universe.rs:11:5
|
LL | outlives_forall::<S>();
| ^^^^^^^^^^^^^^^^^^^^^^
error: lifetime may not live long enough
--> $DIR/type-test-universe.rs:17:5
|
LL | fn test2<'a>() {
| -- lifetime `'a` defined here
LL | outlives_forall::<Value<'a>>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
error: aborting due to 2 previous errors