diff --git a/compiler/rustc_middle/src/ty/codec.rs b/compiler/rustc_middle/src/ty/codec.rs
index 5ec665e913c..fb13614e4b3 100644
--- a/compiler/rustc_middle/src/ty/codec.rs
+++ b/compiler/rustc_middle/src/ty/codec.rs
@@ -385,7 +385,7 @@ impl<'tcx, D: TyDecoder<'tcx>> RefDecodable<'tcx, D> for [mir::abstract_const::N
 impl<'tcx, D: TyDecoder<'tcx>> RefDecodable<'tcx, D> for ty::List<ty::BoundVariableKind> {
     fn decode(decoder: &mut D) -> Result<&'tcx Self, D::Error> {
         let len = decoder.read_usize()?;
-        Ok(decoder.tcx().mk_bound_variable_kinds((0..len).map(|_| Decodable::decode(decoder)))?)
+        decoder.tcx().mk_bound_variable_kinds((0..len).map(|_| Decodable::decode(decoder)))
     }
 }