diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index 01075d7c55a..7385c74389e 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -467,6 +467,11 @@ impl<'a, 'b, 'tcx> TypeFolder> for AssocTypeNormalizer<'a, 'b, 'tcx return ty; } + let (kind, data) = match *ty.kind() { + ty::Alias(kind, alias_ty) => (kind, alias_ty), + _ => return ty.super_fold_with(self), + }; + // We try to be a little clever here as a performance optimization in // cases where there are nested projections under binders. // For example: @@ -490,13 +495,11 @@ impl<'a, 'b, 'tcx> TypeFolder> for AssocTypeNormalizer<'a, 'b, 'tcx // replace bound vars if the current type is a `Projection` and we need // to make sure we don't forget to fold the substs regardless. - match *ty.kind() { + match kind { // This is really important. While we *can* handle this, this has // severe performance implications for large opaque types with // late-bound regions. See `issue-88862` benchmark. - ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) - if !substs.has_escaping_bound_vars() => - { + ty::Opaque if !data.substs.has_escaping_bound_vars() => { // Only normalize `impl Trait` outside of type inference, usually in codegen. match self.param_env.reveal() { Reveal::UserFacing => ty.super_fold_with(self), @@ -512,8 +515,8 @@ impl<'a, 'b, 'tcx> TypeFolder> for AssocTypeNormalizer<'a, 'b, 'tcx ); } - let substs = substs.fold_with(self); - let generic_ty = self.interner().type_of(def_id); + let substs = data.substs.fold_with(self); + let generic_ty = self.interner().type_of(data.def_id); let concrete_ty = generic_ty.subst(self.interner(), substs); self.depth += 1; let folded_ty = self.fold_ty(concrete_ty); @@ -522,8 +525,9 @@ impl<'a, 'b, 'tcx> TypeFolder> for AssocTypeNormalizer<'a, 'b, 'tcx } } } + ty::Opaque => ty.super_fold_with(self), - ty::Alias(ty::Projection, data) if !data.has_escaping_bound_vars() => { + ty::Projection if !data.has_escaping_bound_vars() => { // This branch is *mostly* just an optimization: when we don't // have escaping bound vars, we don't need to replace them with // placeholders (see branch below). *Also*, we know that we can @@ -562,7 +566,7 @@ impl<'a, 'b, 'tcx> TypeFolder> for AssocTypeNormalizer<'a, 'b, 'tcx normalized_ty.ty().unwrap() } - ty::Alias(ty::Projection, data) => { + ty::Projection => { // If there are escaping bound vars, we temporarily replace the // bound vars with placeholders. Note though, that in the case // that we still can't project for whatever reason (e.g. self @@ -611,8 +615,6 @@ impl<'a, 'b, 'tcx> TypeFolder> for AssocTypeNormalizer<'a, 'b, 'tcx ); normalized_ty } - - _ => ty.super_fold_with(self), } } diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs index b0cec3ce7a3..45307a85a31 100644 --- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs +++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs @@ -197,23 +197,30 @@ impl<'cx, 'tcx> FallibleTypeFolder> for QueryNormalizer<'cx, 'tcx> return Ok(*ty); } + let (kind, data) = match *ty.kind() { + ty::Alias(kind, data) => (kind, data), + _ => { + let res = ty.try_super_fold_with(self)?; + self.cache.insert(ty, res); + return Ok(res); + } + }; + // See note in `rustc_trait_selection::traits::project` about why we // wait to fold the substs. // Wrap this in a closure so we don't accidentally return from the outer function - let res = match *ty.kind() { + let res = match kind { // This is really important. While we *can* handle this, this has // severe performance implications for large opaque types with // late-bound regions. See `issue-88862` benchmark. - ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) - if !substs.has_escaping_bound_vars() => - { + ty::Opaque if !data.substs.has_escaping_bound_vars() => { // Only normalize `impl Trait` outside of type inference, usually in codegen. match self.param_env.reveal() { Reveal::UserFacing => ty.try_super_fold_with(self)?, Reveal::All => { - let substs = substs.try_fold_with(self)?; + let substs = data.substs.try_fold_with(self)?; let recursion_limit = self.interner().recursion_limit(); if !recursion_limit.value_within_limit(self.anon_depth) { // A closure or generator may have itself as in its upvars. @@ -228,7 +235,7 @@ impl<'cx, 'tcx> FallibleTypeFolder> for QueryNormalizer<'cx, 'tcx> return ty.try_super_fold_with(self); } - let generic_ty = self.interner().type_of(def_id); + let generic_ty = self.interner().type_of(data.def_id); let concrete_ty = generic_ty.subst(self.interner(), substs); self.anon_depth += 1; if concrete_ty == ty { @@ -248,7 +255,9 @@ impl<'cx, 'tcx> FallibleTypeFolder> for QueryNormalizer<'cx, 'tcx> } } - ty::Alias(ty::Projection, data) if !data.has_escaping_bound_vars() => { + ty::Opaque => ty.try_super_fold_with(self)?, + + ty::Projection if !data.has_escaping_bound_vars() => { // This branch is just an optimization: when we don't have escaping bound vars, // we don't need to replace them with placeholders (see branch below). @@ -297,7 +306,7 @@ impl<'cx, 'tcx> FallibleTypeFolder> for QueryNormalizer<'cx, 'tcx> } } - ty::Alias(ty::Projection, data) => { + ty::Projection => { // See note in `rustc_trait_selection::traits::project` let tcx = self.infcx.tcx; @@ -353,8 +362,6 @@ impl<'cx, 'tcx> FallibleTypeFolder> for QueryNormalizer<'cx, 'tcx> res } } - - _ => ty.try_super_fold_with(self)?, }; self.cache.insert(ty, res);