summaryrefslogtreecommitdiffstats
path: root/compiler/rustc_infer/src/infer/lub.rs
diff options
context:
space:
mode:
Diffstat (limited to 'compiler/rustc_infer/src/infer/lub.rs')
-rw-r--r--compiler/rustc_infer/src/infer/lub.rs5
1 files changed, 5 insertions, 0 deletions
diff --git a/compiler/rustc_infer/src/infer/lub.rs b/compiler/rustc_infer/src/infer/lub.rs
index 97ed4729b..c07ac1d3a 100644
--- a/compiler/rustc_infer/src/infer/lub.rs
+++ b/compiler/rustc_infer/src/infer/lub.rs
@@ -103,6 +103,11 @@ impl<'tcx> TypeRelation<'tcx> for Lub<'_, '_, 'tcx> {
where
T: Relate<'tcx>,
{
+ // LUB of a binder and itself is just itself
+ if a == b {
+ return Ok(a);
+ }
+
debug!("binders(a={:?}, b={:?})", a, b);
if a.skip_binder().has_escaping_bound_vars() || b.skip_binder().has_escaping_bound_vars() {
// When higher-ranked types are involved, computing the LUB is