diff options
| -rw-r--r-- | compiler/rustc_middle/src/ty/mod.rs | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs index 169e8e792ab..ce1b1d6973e 100644 --- a/compiler/rustc_middle/src/ty/mod.rs +++ b/compiler/rustc_middle/src/ty/mod.rs @@ -1332,6 +1332,10 @@ impl<'tcx> OpaqueHiddenType<'tcx> { let id_substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id()); debug!(?id_substs); + // This zip may have several times the same lifetime in `substs` paired with a different + // lifetime from `id_substs`. In that case, we actually want to pick the last one, as it + // is the one we introduced in the impl-trait desugaring to be meaningful. The other ones + // are redundant. let map = substs.iter().zip(id_substs); let map: FxHashMap<GenericArg<'tcx>, GenericArg<'tcx>> = match origin { |