diff options
| -rw-r--r-- | compiler/rustc_hir_typeck/src/cast.rs | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs index 74be8529ec8..5a0e307ef6f 100644 --- a/compiler/rustc_hir_typeck/src/cast.rs +++ b/compiler/rustc_hir_typeck/src/cast.rs @@ -840,8 +840,16 @@ impl<'a, 'tcx> CastCheck<'tcx> { // contain wrappers, which we do not care about. // // e.g. we want to allow `dyn T -> (dyn T,)`, etc. - let src_obj = tcx.mk_ty_from_kind(ty::Dynamic(src_tty, tcx.lifetimes.re_erased, ty::Dyn)); - let dst_obj = tcx.mk_ty_from_kind(ty::Dynamic(dst_tty, tcx.lifetimes.re_erased, ty::Dyn)); + let src_obj = tcx.mk_ty_from_kind(ty::Dynamic( + src_tty, + tcx.lifetimes.re_erased, + ty::Dyn, + )); + let dst_obj = tcx.mk_ty_from_kind(ty::Dynamic( + dst_tty, + tcx.lifetimes.re_erased, + ty::Dyn, + )); // `dyn Src: Unsize<dyn Dst>` let cause = fcx.misc(self.span); @@ -853,7 +861,7 @@ impl<'a, 'tcx> CastCheck<'tcx> { tcx, tcx.require_lang_item(LangItem::Unsize, Some(self.span)), [src_obj, dst_obj], - ) + ), ); fcx.register_predicate(obligation); @@ -866,9 +874,11 @@ impl<'a, 'tcx> CastCheck<'tcx> { } // dyn Auto -> dyn Auto'? ok. - (None, None) - // dyn Trait -> dyn Auto? ok. - | (Some(_), None)=> Ok(CastKind::PtrPtrCast), + (None, None) => Ok(CastKind::PtrPtrCast), + + // dyn Trait -> dyn Auto? should be ok, but we used to not allow it. + // FIXME: allow this + (Some(_), None) => Err(CastError::DifferingKinds), // dyn Auto -> dyn Trait? not ok. (None, Some(_)) => Err(CastError::DifferingKinds), |