diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_hir_typeck/src/cast.rs | 22 |
1 files changed, 8 insertions, 14 deletions
diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs index 8fa6ab8503d..7341d3fa3c4 100644 --- a/compiler/rustc_hir_typeck/src/cast.rs +++ b/compiler/rustc_hir_typeck/src/cast.rs @@ -876,20 +876,14 @@ impl<'a, 'tcx> CastCheck<'tcx> { // A<dyn Src<...> + SrcAuto> -> B<dyn Dst<...> + DstAuto>. need to make sure // - `Src` and `Dst` traits are the same // - traits have the same generic arguments - // - `SrcAuto` is a superset of `DstAuto` - (Some(src_principal), Some(dst_principal)) => { + // - projections are the same + // - `SrcAuto` (+auto traits implied by `Src`) is a superset of `DstAuto` + // + // Note that trait upcasting goes through a different mechanism (`coerce_unsized`) + // and is unaffected by this check. + (Some(src_principal), Some(_)) => { let tcx = fcx.tcx; - // Check that the traits are actually the same. - // The `dyn Src = dyn Dst` check below would suffice, - // but this may produce a better diagnostic. - // - // Note that trait upcasting goes through a different mechanism (`coerce_unsized`) - // and is unaffected by this check. - if src_principal.def_id() != dst_principal.def_id() { - return Err(CastError::DifferingKinds { src_kind, dst_kind }); - } - // We need to reconstruct trait object types. // `m_src` and `m_dst` won't work for us here because they will potentially // contain wrappers, which we do not care about. @@ -912,8 +906,8 @@ impl<'a, 'tcx> CastCheck<'tcx> { ty::Dyn, )); - // `dyn Src = dyn Dst`, this checks for matching traits/generics - // This is `demand_eqtype`, but inlined to give a better error. + // `dyn Src = dyn Dst`, this checks for matching traits/generics/projections + // This is `fcx.demand_eqtype`, but inlined to give a better error. let cause = fcx.misc(self.span); if fcx .at(&cause, fcx.param_env) |