From 130b7e713e879c4c989186d94643be8c834de355 Mon Sep 17 00:00:00 2001 From: Gavin Gray Date: Tue, 21 Nov 2023 20:37:36 +0100 Subject: [PATCH] Add trait obligation tracking to FulfillCtxt and expose FnCtxt in rustc_infer using callback. Pass each obligation to an fn callback with its respective inference context. This avoids needing to keep around copies of obligations or inference contexts. Specify usability of inspect_typeck in comment. --- compiler/rustc_hir_typeck/src/lib.rs | 24 +++- compiler/rustc_infer/src/infer/at.rs | 1 + compiler/rustc_infer/src/infer/mod.rs | 16 ++- compiler/rustc_infer/src/traits/mod.rs | 8 ++ .../src/solve/fulfill.rs | 136 ++++++++++-------- 5 files changed, 121 insertions(+), 64 deletions(-) diff --git a/compiler/rustc_hir_typeck/src/lib.rs b/compiler/rustc_hir_typeck/src/lib.rs index 67c35d717a1ec..80467ca9381e3 100644 --- a/compiler/rustc_hir_typeck/src/lib.rs +++ b/compiler/rustc_hir_typeck/src/lib.rs @@ -60,6 +60,7 @@ use rustc_hir::{HirIdMap, Node}; use rustc_hir_analysis::astconv::AstConv; use rustc_hir_analysis::check::check_abi; use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; +use rustc_infer::traits::ObligationInspector; use rustc_middle::query::Providers; use rustc_middle::traits; use rustc_middle::ty::{self, Ty, TyCtxt}; @@ -139,7 +140,7 @@ fn used_trait_imports(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &UnordSet(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &ty::TypeckResults<'tcx> { let fallback = move || tcx.type_of(def_id.to_def_id()).instantiate_identity(); - typeck_with_fallback(tcx, def_id, fallback) + typeck_with_fallback(tcx, def_id, fallback, None) } /// Used only to get `TypeckResults` for type inference during error recovery. @@ -149,14 +150,28 @@ fn diagnostic_only_typeck<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &ty::T let span = tcx.hir().span(tcx.local_def_id_to_hir_id(def_id)); Ty::new_error_with_message(tcx, span, "diagnostic only typeck table used") }; - typeck_with_fallback(tcx, def_id, fallback) + typeck_with_fallback(tcx, def_id, fallback, None) } -#[instrument(level = "debug", skip(tcx, fallback), ret)] +/// Same as `typeck` but `inspect` is invoked on evaluation of each root obligation. +/// Inspecting obligations only works with the new trait solver. +/// This function is *only to be used* by external tools, it should not be +/// called from within rustc. Note, this is not a query, and thus is not cached. +pub fn inspect_typeck<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: LocalDefId, + inspect: ObligationInspector<'tcx>, +) -> &'tcx ty::TypeckResults<'tcx> { + let fallback = move || tcx.type_of(def_id.to_def_id()).instantiate_identity(); + typeck_with_fallback(tcx, def_id, fallback, Some(inspect)) +} + +#[instrument(level = "debug", skip(tcx, fallback, inspector), ret)] fn typeck_with_fallback<'tcx>( tcx: TyCtxt<'tcx>, def_id: LocalDefId, fallback: impl Fn() -> Ty<'tcx> + 'tcx, + inspector: Option>, ) -> &'tcx ty::TypeckResults<'tcx> { // Closures' typeck results come from their outermost function, // as they are part of the same "inference environment". @@ -178,6 +193,9 @@ fn typeck_with_fallback<'tcx>( let param_env = tcx.param_env(def_id); let inh = Inherited::new(tcx, def_id); + if let Some(inspector) = inspector { + inh.infcx.attach_obligation_inspector(inspector); + } let mut fcx = FnCtxt::new(&inh, param_env, def_id); if let Some(hir::FnSig { header, decl, .. }) = fn_sig { diff --git a/compiler/rustc_infer/src/infer/at.rs b/compiler/rustc_infer/src/infer/at.rs index e60e3ffeaa72c..0f1af81d9f04c 100644 --- a/compiler/rustc_infer/src/infer/at.rs +++ b/compiler/rustc_infer/src/infer/at.rs @@ -90,6 +90,7 @@ impl<'tcx> InferCtxt<'tcx> { universe: self.universe.clone(), intercrate, next_trait_solver: self.next_trait_solver, + obligation_inspector: self.obligation_inspector.clone(), } } } diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index e164041c5991e..39c41a93c3bd1 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -13,7 +13,9 @@ use rustc_middle::infer::unify_key::{ConstVidKey, EffectVidKey}; use self::opaque_types::OpaqueTypeStorage; pub(crate) use self::undo_log::{InferCtxtUndoLogs, Snapshot, UndoLog}; -use crate::traits::{self, ObligationCause, PredicateObligations, TraitEngine, TraitEngineExt}; +use crate::traits::{ + self, ObligationCause, ObligationInspector, PredicateObligations, TraitEngine, TraitEngineExt, +}; use rustc_data_structures::fx::FxIndexMap; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; @@ -334,6 +336,8 @@ pub struct InferCtxt<'tcx> { pub intercrate: bool, next_trait_solver: bool, + + pub obligation_inspector: Cell>>, } impl<'tcx> ty::InferCtxtLike for InferCtxt<'tcx> { @@ -708,6 +712,7 @@ impl<'tcx> InferCtxtBuilder<'tcx> { universe: Cell::new(ty::UniverseIndex::ROOT), intercrate, next_trait_solver, + obligation_inspector: Cell::new(None), } } } @@ -1724,6 +1729,15 @@ impl<'tcx> InferCtxt<'tcx> { } } } + + /// Attach a callback to be invoked on each root obligation evaluated in the new trait solver. + pub fn attach_obligation_inspector(&self, inspector: ObligationInspector<'tcx>) { + debug_assert!( + self.obligation_inspector.get().is_none(), + "shouldn't override a set obligation inspector" + ); + self.obligation_inspector.set(Some(inspector)); + } } impl<'tcx> TypeErrCtxt<'_, 'tcx> { diff --git a/compiler/rustc_infer/src/traits/mod.rs b/compiler/rustc_infer/src/traits/mod.rs index fdae093aac8b4..72ec07375ac0e 100644 --- a/compiler/rustc_infer/src/traits/mod.rs +++ b/compiler/rustc_infer/src/traits/mod.rs @@ -13,12 +13,15 @@ use std::hash::{Hash, Hasher}; use hir::def_id::LocalDefId; use rustc_hir as hir; +use rustc_middle::traits::query::NoSolution; +use rustc_middle::traits::solve::Certainty; use rustc_middle::ty::error::{ExpectedFound, TypeError}; use rustc_middle::ty::{self, Const, ToPredicate, Ty, TyCtxt}; use rustc_span::Span; pub use self::ImplSource::*; pub use self::SelectionError::*; +use crate::infer::InferCtxt; pub use self::engine::{TraitEngine, TraitEngineExt}; pub use self::project::MismatchedProjectionTypes; @@ -116,6 +119,11 @@ pub type PredicateObligations<'tcx> = Vec>; pub type Selection<'tcx> = ImplSource<'tcx, PredicateObligation<'tcx>>; +/// A callback that can be provided to `inspect_typeck`. Invoked on evaluation +/// of root obligations. +pub type ObligationInspector<'tcx> = + fn(&InferCtxt<'tcx>, &PredicateObligation<'tcx>, Result); + pub struct FulfillmentError<'tcx> { pub obligation: PredicateObligation<'tcx>, pub code: FulfillmentErrorCode<'tcx>, diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs index c847425ebf46a..f08622816ec28 100644 --- a/compiler/rustc_trait_selection/src/solve/fulfill.rs +++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs @@ -11,7 +11,7 @@ use rustc_middle::ty; use rustc_middle::ty::error::{ExpectedFound, TypeError}; use super::eval_ctxt::GenerateProofTree; -use super::{Certainty, InferCtxtEvalExt}; +use super::{Certainty, Goal, InferCtxtEvalExt}; /// A trait engine using the new trait solver. /// @@ -43,6 +43,21 @@ impl<'tcx> FulfillmentCtxt<'tcx> { ); FulfillmentCtxt { obligations: Vec::new(), usable_in_snapshot: infcx.num_open_snapshots() } } + + fn inspect_evaluated_obligation( + &self, + infcx: &InferCtxt<'tcx>, + obligation: &PredicateObligation<'tcx>, + result: &Result<(bool, Certainty, Vec>>), NoSolution>, + ) { + if let Some(inspector) = infcx.obligation_inspector.get() { + let result = match result { + Ok((_, c, _)) => Ok(*c), + Err(NoSolution) => Err(NoSolution), + }; + (inspector)(infcx, &obligation, result); + } + } } impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { @@ -100,65 +115,66 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { let mut has_changed = false; for obligation in mem::take(&mut self.obligations) { let goal = obligation.clone().into(); - let (changed, certainty, nested_goals) = - match infcx.evaluate_root_goal(goal, GenerateProofTree::IfEnabled).0 { - Ok(result) => result, - Err(NoSolution) => { - errors.push(FulfillmentError { - obligation: obligation.clone(), - code: match goal.predicate.kind().skip_binder() { - ty::PredicateKind::Clause(ty::ClauseKind::Projection(_)) => { - FulfillmentErrorCode::ProjectionError( - // FIXME: This could be a `Sorts` if the term is a type - MismatchedProjectionTypes { err: TypeError::Mismatch }, - ) - } - ty::PredicateKind::NormalizesTo(..) => { - FulfillmentErrorCode::ProjectionError( - MismatchedProjectionTypes { err: TypeError::Mismatch }, - ) - } - ty::PredicateKind::AliasRelate(_, _, _) => { - FulfillmentErrorCode::ProjectionError( - MismatchedProjectionTypes { err: TypeError::Mismatch }, - ) - } - ty::PredicateKind::Subtype(pred) => { - let (a, b) = infcx.instantiate_binder_with_placeholders( - goal.predicate.kind().rebind((pred.a, pred.b)), - ); - let expected_found = ExpectedFound::new(true, a, b); - FulfillmentErrorCode::SubtypeError( - expected_found, - TypeError::Sorts(expected_found), - ) - } - ty::PredicateKind::Coerce(pred) => { - let (a, b) = infcx.instantiate_binder_with_placeholders( - goal.predicate.kind().rebind((pred.a, pred.b)), - ); - let expected_found = ExpectedFound::new(false, a, b); - FulfillmentErrorCode::SubtypeError( - expected_found, - TypeError::Sorts(expected_found), - ) - } - ty::PredicateKind::Clause(_) - | ty::PredicateKind::ObjectSafe(_) - | ty::PredicateKind::Ambiguous => { - FulfillmentErrorCode::SelectionError( - SelectionError::Unimplemented, - ) - } - ty::PredicateKind::ConstEquate(..) => { - bug!("unexpected goal: {goal:?}") - } - }, - root_obligation: obligation, - }); - continue; - } - }; + let result = infcx.evaluate_root_goal(goal, GenerateProofTree::IfEnabled).0; + self.inspect_evaluated_obligation(infcx, &obligation, &result); + let (changed, certainty, nested_goals) = match result { + Ok(result) => result, + Err(NoSolution) => { + errors.push(FulfillmentError { + obligation: obligation.clone(), + code: match goal.predicate.kind().skip_binder() { + ty::PredicateKind::Clause(ty::ClauseKind::Projection(_)) => { + FulfillmentErrorCode::ProjectionError( + // FIXME: This could be a `Sorts` if the term is a type + MismatchedProjectionTypes { err: TypeError::Mismatch }, + ) + } + ty::PredicateKind::NormalizesTo(..) => { + FulfillmentErrorCode::ProjectionError( + MismatchedProjectionTypes { err: TypeError::Mismatch }, + ) + } + ty::PredicateKind::AliasRelate(_, _, _) => { + FulfillmentErrorCode::ProjectionError( + MismatchedProjectionTypes { err: TypeError::Mismatch }, + ) + } + ty::PredicateKind::Subtype(pred) => { + let (a, b) = infcx.instantiate_binder_with_placeholders( + goal.predicate.kind().rebind((pred.a, pred.b)), + ); + let expected_found = ExpectedFound::new(true, a, b); + FulfillmentErrorCode::SubtypeError( + expected_found, + TypeError::Sorts(expected_found), + ) + } + ty::PredicateKind::Coerce(pred) => { + let (a, b) = infcx.instantiate_binder_with_placeholders( + goal.predicate.kind().rebind((pred.a, pred.b)), + ); + let expected_found = ExpectedFound::new(false, a, b); + FulfillmentErrorCode::SubtypeError( + expected_found, + TypeError::Sorts(expected_found), + ) + } + ty::PredicateKind::Clause(_) + | ty::PredicateKind::ObjectSafe(_) + | ty::PredicateKind::Ambiguous => { + FulfillmentErrorCode::SelectionError( + SelectionError::Unimplemented, + ) + } + ty::PredicateKind::ConstEquate(..) => { + bug!("unexpected goal: {goal:?}") + } + }, + root_obligation: obligation, + }); + continue; + } + }; // Push any nested goals that we get from unifying our canonical response // with our obligation onto the fulfillment context. self.obligations.extend(nested_goals.into_iter().map(|goal| {