From f49b0dcce2d36e907c3eb12e97f2fab0a4e02dc6 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Wed, 10 Jan 2024 16:11:47 +0000 Subject: [PATCH 1/3] Check reveal and can_define_opaque_ty in try_normalize_ty_recur --- .../rustc_trait_selection/src/solve/mod.rs | 28 +++++++++++-------- 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs index 2f3111a2414d5..dac8b3cce805f 100644 --- a/compiler/rustc_trait_selection/src/solve/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/mod.rs @@ -22,6 +22,7 @@ use rustc_middle::traits::solve::{ CanonicalResponse, Certainty, ExternalConstraintsData, Goal, GoalSource, IsNormalizesToHack, QueryResult, Response, }; +use rustc_middle::traits::Reveal; use rustc_middle::ty::{self, OpaqueTypeKey, Ty, TyCtxt, UniverseIndex}; use rustc_middle::ty::{ CoercePredicate, RegionOutlivesPredicate, SubtypePredicate, TypeOutlivesPredicate, @@ -317,18 +318,21 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { }; // We do no always define opaque types eagerly to allow non-defining uses in the defining scope. - if let (DefineOpaqueTypes::No, ty::AliasKind::Opaque) = (define_opaque_types, kind) { - if let Some(def_id) = alias.def_id.as_local() { - if self - .unify_existing_opaque_tys( - param_env, - OpaqueTypeKey { def_id, args: alias.args }, - self.next_ty_infer(), - ) - .is_empty() - { - return Some(ty); - } + if let DefineOpaqueTypes::No = define_opaque_types + && let Reveal::UserFacing = param_env.reveal() + && let ty::Opaque = kind + && let Some(def_id) = alias.def_id.as_local() + && self.can_define_opaque_ty(def_id) + { + if self + .unify_existing_opaque_tys( + param_env, + OpaqueTypeKey { def_id, args: alias.args }, + self.next_ty_infer(), + ) + .is_empty() + { + return Some(ty); } } From 3799568895ac5469be8bf7bb4f6e0dad57b94d3c Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Wed, 10 Jan 2024 16:22:26 +0000 Subject: [PATCH 2/3] More comments --- .../src/solve/alias_relate.rs | 35 ++++++++++++++----- .../rustc_trait_selection/src/solve/mod.rs | 5 ++- 2 files changed, 30 insertions(+), 10 deletions(-) diff --git a/compiler/rustc_trait_selection/src/solve/alias_relate.rs b/compiler/rustc_trait_selection/src/solve/alias_relate.rs index 626569fb40fc0..c05c996175042 100644 --- a/compiler/rustc_trait_selection/src/solve/alias_relate.rs +++ b/compiler/rustc_trait_selection/src/solve/alias_relate.rs @@ -2,15 +2,29 @@ //! Doing this via a separate goal is called "deferred alias relation" and part //! of our more general approach to "lazy normalization". //! -//! This goal, e.g. `A alias-relate B`, may be satisfied by one of three branches: -//! * normalizes-to: If `A` is a projection, we can prove the equivalent -//! projection predicate with B as the right-hand side of the projection. -//! This goal is computed in both directions, if both are aliases. -//! * subst-relate: Equate `A` and `B` by their substs, if they're both -//! aliases with the same def-id. -//! * bidirectional-normalizes-to: If `A` and `B` are both projections, and both -//! may apply, then we can compute the "intersection" of both normalizes-to by -//! performing them together. This is used specifically to resolve ambiguities. +//! This is done by first normalizing both sides of the goal, ending up in +//! either a concrete type, rigid projection, opaque, or an infer variable. +//! These are related further according to the rules below: +//! +//! (1.) If we end up with a rigid projection and a rigid projection, then we +//! relate those projections structurally. +//! +//! (2.) If we end up with a rigid projection and an alias, then the opaque will +//! have its hidden type defined to be that rigid projection. +//! +//! (3.) If we end up with an opaque and an opaque, then we assemble two +//! candidates, one defining the LHS to be the hidden type of the RHS, and vice +//! versa. +//! +//! (4.) If we end up with an infer var and an opaque or rigid projection, then +//! we assign the alias to the infer var. +//! +//! (5.) If we end up with an opaque and a rigid (non-projection) type, then we +//! define the hidden type of the opaque to be the rigid type. +//! +//! (6.) Otherwise, if we end with two rigid (non-projection) or infer types, +//! relate them structurally. + use super::{EvalCtxt, GoalSource}; use rustc_infer::infer::DefineOpaqueTypes; use rustc_infer::traits::query::NoSolution; @@ -50,6 +64,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { self.relate(param_env, lhs, variance, rhs)?; self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } else if alias.is_opaque(tcx) { + // FIXME: This doesn't account for variance. self.define_opaque(param_env, alias, rhs) } else { Err(NoSolution) @@ -60,6 +75,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { self.relate(param_env, lhs, variance, rhs)?; self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } else if alias.is_opaque(tcx) { + // FIXME: This doesn't account for variance. self.define_opaque(param_env, alias, lhs) } else { Err(NoSolution) @@ -72,6 +88,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { } } + // FIXME: This needs a name that reflects that it's okay to bottom-out with an inference var. /// Normalize the `term` to equate it later. This does not define opaque types. #[instrument(level = "debug", skip(self, param_env), ret)] fn try_normalize_term( diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs index dac8b3cce805f..7c8f885a1f24c 100644 --- a/compiler/rustc_trait_selection/src/solve/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/mod.rs @@ -317,7 +317,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { return Some(ty); }; - // We do no always define opaque types eagerly to allow non-defining uses in the defining scope. + // We do no always define opaque types eagerly to allow non-defining uses + // in the defining scope. However, if we can unify this opaque to an existing + // opaque, then we should attempt to eagerly reveal the opaque, and we fall + // through. if let DefineOpaqueTypes::No = define_opaque_types && let Reveal::UserFacing = param_env.reveal() && let ty::Opaque = kind From 427c55c65c16225227ef289358a3c44e755e503b Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Wed, 13 Dec 2023 15:01:33 +0000 Subject: [PATCH 3/3] Simplify some redundant names --- .../src/diagnostics/explain_borrow.rs | 4 ++-- .../rustc_infer/src/infer/error_reporting/mod.rs | 6 +++--- compiler/rustc_infer/src/infer/relate/combine.rs | 9 ++++----- compiler/rustc_lint/src/types.rs | 3 +-- compiler/rustc_middle/src/ty/sty.rs | 6 +++--- compiler/rustc_smir/src/rustc_smir/convert/ty.rs | 14 ++++++-------- 6 files changed, 19 insertions(+), 23 deletions(-) diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs index f1e712d814a10..6606be2f9f42f 100644 --- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs +++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs @@ -315,7 +315,7 @@ impl<'tcx> BorrowExplanation<'tcx> { let mut failed = false; let elaborated_args = std::iter::zip(*args, &generics.params).map(|(arg, param)| { - if let Some(ty::Dynamic(obj, _, ty::DynKind::Dyn)) = arg.as_type().map(Ty::kind) { + if let Some(ty::Dynamic(obj, _, ty::Dyn)) = arg.as_type().map(Ty::kind) { let default = tcx.object_lifetime_default(param.def_id); let re_static = tcx.lifetimes.re_static; @@ -339,7 +339,7 @@ impl<'tcx> BorrowExplanation<'tcx> { has_dyn = true; - Ty::new_dynamic(tcx, obj, implied_region, ty::DynKind::Dyn).into() + Ty::new_dynamic(tcx, obj, implied_region, ty::Dyn).into() } else { arg } diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs index b1c360b61cb69..8b9825ee6dee8 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs @@ -2348,11 +2348,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> { GenericKind::Param(ref p) => format!("the parameter type `{p}`"), GenericKind::Placeholder(ref p) => format!("the placeholder type `{p:?}`"), GenericKind::Alias(ref p) => match p.kind(self.tcx) { - ty::AliasKind::Projection | ty::AliasKind::Inherent => { + ty::Projection | ty::Inherent => { format!("the associated type `{p}`") } - ty::AliasKind::Weak => format!("the type alias `{p}`"), - ty::AliasKind::Opaque => format!("the opaque type `{p}`"), + ty::Weak => format!("the type alias `{p}`"), + ty::Opaque => format!("the opaque type `{p}`"), }, }; diff --git a/compiler/rustc_infer/src/infer/relate/combine.rs b/compiler/rustc_infer/src/infer/relate/combine.rs index 8b31a1118cb75..0844b49379020 100644 --- a/compiler/rustc_infer/src/infer/relate/combine.rs +++ b/compiler/rustc_infer/src/infer/relate/combine.rs @@ -511,7 +511,7 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> { )); } else { match a_ty.kind() { - &ty::Alias(ty::AliasKind::Projection, data) => { + &ty::Alias(ty::Projection, data) => { // FIXME: This does not handle subtyping correctly, we could // instead create a new inference variable for `a_ty`, emitting // `Projection(a_ty, a_infer)` and `a_infer <: b_ty`. @@ -523,10 +523,9 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> { )) } // The old solver only accepts projection predicates for associated types. - ty::Alias( - ty::AliasKind::Inherent | ty::AliasKind::Weak | ty::AliasKind::Opaque, - _, - ) => return Err(TypeError::CyclicTy(a_ty)), + ty::Alias(ty::Inherent | ty::Weak | ty::Opaque, _) => { + return Err(TypeError::CyclicTy(a_ty)); + } _ => bug!("generalizated `{a_ty:?} to infer, not an alias"), } } diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs index 6dade43a18357..a86fe2db2b2d5 100644 --- a/compiler/rustc_lint/src/types.rs +++ b/compiler/rustc_lint/src/types.rs @@ -29,7 +29,6 @@ use rustc_span::{Span, Symbol}; use rustc_target::abi::{Abi, Size, WrappingRange}; use rustc_target::abi::{Integer, TagEncoding, Variants}; use rustc_target::spec::abi::Abi as SpecAbi; -use rustc_type_ir::DynKind; use std::iter; use std::ops::ControlFlow; @@ -675,7 +674,7 @@ fn lint_wide_pointer<'tcx>( } match ty.kind() { ty::RawPtr(TypeAndMut { mutbl: _, ty }) => (!ty.is_sized(cx.tcx, cx.param_env)) - .then(|| (refs, matches!(ty.kind(), ty::Dynamic(_, _, DynKind::Dyn)))), + .then(|| (refs, matches!(ty.kind(), ty::Dynamic(_, _, ty::Dyn)))), _ => None, } }; diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs index 38bf39bff908d..8cf5fc8013f1d 100644 --- a/compiler/rustc_middle/src/ty/sty.rs +++ b/compiler/rustc_middle/src/ty/sty.rs @@ -1225,7 +1225,7 @@ impl<'tcx> AliasTy<'tcx> { /// Whether this alias type is an opaque. pub fn is_opaque(self, tcx: TyCtxt<'tcx>) -> bool { - matches!(self.opt_kind(tcx), Some(ty::AliasKind::Opaque)) + matches!(self.opt_kind(tcx), Some(ty::Opaque)) } /// FIXME: rename `AliasTy` to `AliasTerm` and always handle @@ -2745,7 +2745,7 @@ impl<'tcx> Ty<'tcx> { // Extern types have metadata = (). | ty::Foreign(..) // `dyn*` has no metadata - | ty::Dynamic(_, _, DynKind::DynStar) + | ty::Dynamic(_, _, ty::DynStar) // If returned by `struct_tail_without_normalization` this is a unit struct // without any fields, or not a struct, and therefore is Sized. | ty::Adt(..) @@ -2754,7 +2754,7 @@ impl<'tcx> Ty<'tcx> { | ty::Tuple(..) => (tcx.types.unit, false), ty::Str | ty::Slice(_) => (tcx.types.usize, false), - ty::Dynamic(_, _, DynKind::Dyn) => { + ty::Dynamic(_, _, ty::Dyn) => { let dyn_metadata = tcx.require_lang_item(LangItem::DynMetadata, None); (tcx.type_of(dyn_metadata).instantiate(tcx, &[tail.into()]), false) }, diff --git a/compiler/rustc_smir/src/rustc_smir/convert/ty.rs b/compiler/rustc_smir/src/rustc_smir/convert/ty.rs index f0f1d798d44b4..c0ecbfb991413 100644 --- a/compiler/rustc_smir/src/rustc_smir/convert/ty.rs +++ b/compiler/rustc_smir/src/rustc_smir/convert/ty.rs @@ -12,12 +12,11 @@ use crate::rustc_smir::{alloc, Stable, Tables}; impl<'tcx> Stable<'tcx> for ty::AliasKind { type T = stable_mir::ty::AliasKind; fn stable(&self, _: &mut Tables<'tcx>) -> Self::T { - use rustc_middle::ty::AliasKind::*; match self { - Projection => stable_mir::ty::AliasKind::Projection, - Inherent => stable_mir::ty::AliasKind::Inherent, - Opaque => stable_mir::ty::AliasKind::Opaque, - Weak => stable_mir::ty::AliasKind::Weak, + ty::Projection => stable_mir::ty::AliasKind::Projection, + ty::Inherent => stable_mir::ty::AliasKind::Inherent, + ty::Opaque => stable_mir::ty::AliasKind::Opaque, + ty::Weak => stable_mir::ty::AliasKind::Weak, } } } @@ -34,10 +33,9 @@ impl<'tcx> Stable<'tcx> for ty::DynKind { type T = stable_mir::ty::DynKind; fn stable(&self, _: &mut Tables<'tcx>) -> Self::T { - use rustc_middle::ty::DynKind; match self { - DynKind::Dyn => stable_mir::ty::DynKind::Dyn, - DynKind::DynStar => stable_mir::ty::DynKind::DynStar, + ty::Dyn => stable_mir::ty::DynKind::Dyn, + ty::DynStar => stable_mir::ty::DynKind::DynStar, } } }