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Diffstat (limited to 'tests/ui/lub-glb/empty-binders.rs')
-rw-r--r-- | tests/ui/lub-glb/empty-binders.rs | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/tests/ui/lub-glb/empty-binders.rs b/tests/ui/lub-glb/empty-binders.rs new file mode 100644 index 000000000..f9d07e79f --- /dev/null +++ b/tests/ui/lub-glb/empty-binders.rs @@ -0,0 +1,45 @@ +// check-pass +// +// Check that computing the lub works even for empty binders. +fn lt<'a: 'a>() -> &'a () { + &() +} + +fn lt_in_fn<'a: 'a>() -> fn(&'a ()) { + |_| () +} + +struct Contra<'a>(fn(&'a ())); +fn lt_in_contra<'a: 'a>() -> Contra<'a> { + Contra(|_| ()) +} + +fn ok<'a, 'b, 'upper, 'lower>(v: bool) +where + 'upper: 'a, + 'upper: 'b, + 'a: 'lower, + 'b: 'lower, + +{ + let _: &'lower () = match v { + true => lt::<'a>(), + false => lt::<'b>(), + }; + + // This errored in the past because LUB and GLB always + // bailed out when encountering binders, even if they were + // empty. + let _: fn(&'upper ()) = match v { + true => lt_in_fn::<'a>(), + false => lt_in_fn::<'b>(), + }; + + // This was already accepted, as relate didn't encounter any binders. + let _: Contra<'upper> = match v { + true => lt_in_contra::<'a>(), + false => lt_in_contra::<'b>(), + }; +} + +fn main() {} |