2848 lines
114 KiB
Rust
2848 lines
114 KiB
Rust
//! This pass type-checks the MIR to ensure it is not broken.
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use std::rc::Rc;
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use std::{fmt, iter, mem};
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use either::Either;
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use rustc_data_structures::frozen::Frozen;
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use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_errors::struct_span_err;
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use rustc_hir as hir;
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use rustc_hir::def_id::{DefId, LocalDefId};
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use rustc_hir::lang_items::LangItem;
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use rustc_index::vec::{Idx, IndexVec};
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use rustc_infer::infer::canonical::QueryRegionConstraints;
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use rustc_infer::infer::outlives::env::RegionBoundPairs;
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use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
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use rustc_infer::infer::{
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InferCtxt, InferOk, LateBoundRegionConversionTime, NllRegionVariableOrigin,
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};
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use rustc_middle::mir::tcx::PlaceTy;
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use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
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use rustc_middle::mir::AssertKind;
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use rustc_middle::mir::*;
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use rustc_middle::ty::adjustment::PointerCast;
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use rustc_middle::ty::cast::CastTy;
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use rustc_middle::ty::fold::TypeFoldable;
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use rustc_middle::ty::subst::{GenericArgKind, Subst, SubstsRef, UserSubsts};
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use rustc_middle::ty::{
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self, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, RegionVid, ToPredicate, Ty,
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TyCtxt, UserType, UserTypeAnnotationIndex, WithConstness,
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};
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use rustc_span::{Span, DUMMY_SP};
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use rustc_target::abi::VariantIdx;
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use rustc_trait_selection::infer::InferCtxtExt as _;
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use rustc_trait_selection::opaque_types::{GenerateMemberConstraints, InferCtxtExt};
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use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _;
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use rustc_trait_selection::traits::query::type_op;
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use rustc_trait_selection::traits::query::type_op::custom::CustomTypeOp;
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use rustc_trait_selection::traits::query::{Fallible, NoSolution};
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use rustc_trait_selection::traits::{self, ObligationCause, PredicateObligations};
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use crate::dataflow::impls::MaybeInitializedPlaces;
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use crate::dataflow::move_paths::MoveData;
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use crate::dataflow::ResultsCursor;
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use crate::transform::{
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check_consts::ConstCx, promote_consts::is_const_fn_in_array_repeat_expression,
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};
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use crate::borrow_check::{
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borrow_set::BorrowSet,
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constraints::{OutlivesConstraint, OutlivesConstraintSet},
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facts::AllFacts,
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location::LocationTable,
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member_constraints::MemberConstraintSet,
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nll::ToRegionVid,
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path_utils,
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region_infer::values::{
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LivenessValues, PlaceholderIndex, PlaceholderIndices, RegionValueElements,
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},
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region_infer::{ClosureRegionRequirementsExt, TypeTest},
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renumber,
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type_check::free_region_relations::{CreateResult, UniversalRegionRelations},
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universal_regions::{DefiningTy, UniversalRegions},
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Upvar,
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};
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macro_rules! span_mirbug {
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($context:expr, $elem:expr, $($message:tt)*) => ({
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$crate::borrow_check::type_check::mirbug(
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$context.tcx(),
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$context.last_span,
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&format!(
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"broken MIR in {:?} ({:?}): {}",
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$context.body.source.def_id(),
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$elem,
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format_args!($($message)*),
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),
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)
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})
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}
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macro_rules! span_mirbug_and_err {
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($context:expr, $elem:expr, $($message:tt)*) => ({
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{
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span_mirbug!($context, $elem, $($message)*);
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$context.error()
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}
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})
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}
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mod constraint_conversion;
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pub mod free_region_relations;
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mod input_output;
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crate mod liveness;
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mod relate_tys;
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/// Type checks the given `mir` in the context of the inference
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/// context `infcx`. Returns any region constraints that have yet to
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/// be proven. This result is includes liveness constraints that
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/// ensure that regions appearing in the types of all local variables
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/// are live at all points where that local variable may later be
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/// used.
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///
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/// This phase of type-check ought to be infallible -- this is because
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/// the original, HIR-based type-check succeeded. So if any errors
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/// occur here, we will get a `bug!` reported.
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///
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/// # Parameters
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///
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/// - `infcx` -- inference context to use
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/// - `param_env` -- parameter environment to use for trait solving
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/// - `body` -- MIR body to type-check
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/// - `promoted` -- map of promoted constants within `body`
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/// - `universal_regions` -- the universal regions from `body`s function signature
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/// - `location_table` -- MIR location map of `body`
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/// - `borrow_set` -- information about borrows occurring in `body`
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/// - `all_facts` -- when using Polonius, this is the generated set of Polonius facts
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/// - `flow_inits` -- results of a maybe-init dataflow analysis
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/// - `move_data` -- move-data constructed when performing the maybe-init dataflow analysis
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/// - `elements` -- MIR region map
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pub(crate) fn type_check<'mir, 'tcx>(
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infcx: &InferCtxt<'_, 'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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body: &Body<'tcx>,
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promoted: &IndexVec<Promoted, Body<'tcx>>,
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universal_regions: &Rc<UniversalRegions<'tcx>>,
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location_table: &LocationTable,
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borrow_set: &BorrowSet<'tcx>,
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all_facts: &mut Option<AllFacts>,
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flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
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move_data: &MoveData<'tcx>,
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elements: &Rc<RegionValueElements>,
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upvars: &[Upvar<'tcx>],
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) -> MirTypeckResults<'tcx> {
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let implicit_region_bound = infcx.tcx.mk_region(ty::ReVar(universal_regions.fr_fn_body));
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let mut constraints = MirTypeckRegionConstraints {
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placeholder_indices: PlaceholderIndices::default(),
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placeholder_index_to_region: IndexVec::default(),
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liveness_constraints: LivenessValues::new(elements.clone()),
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outlives_constraints: OutlivesConstraintSet::default(),
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member_constraints: MemberConstraintSet::default(),
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closure_bounds_mapping: Default::default(),
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type_tests: Vec::default(),
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};
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let CreateResult {
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universal_region_relations,
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region_bound_pairs,
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normalized_inputs_and_output,
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} = free_region_relations::create(
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infcx,
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param_env,
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Some(implicit_region_bound),
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universal_regions,
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&mut constraints,
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);
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let mut borrowck_context = BorrowCheckContext {
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universal_regions,
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location_table,
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borrow_set,
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all_facts,
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constraints: &mut constraints,
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upvars,
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};
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let opaque_type_values = type_check_internal(
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infcx,
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param_env,
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body,
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promoted,
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®ion_bound_pairs,
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implicit_region_bound,
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&mut borrowck_context,
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&universal_region_relations,
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|mut cx| {
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cx.equate_inputs_and_outputs(&body, universal_regions, &normalized_inputs_and_output);
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liveness::generate(&mut cx, body, elements, flow_inits, move_data, location_table);
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translate_outlives_facts(&mut cx);
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cx.opaque_type_values
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},
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);
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MirTypeckResults { constraints, universal_region_relations, opaque_type_values }
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}
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fn type_check_internal<'a, 'tcx, R>(
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infcx: &'a InferCtxt<'a, 'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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body: &'a Body<'tcx>,
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promoted: &'a IndexVec<Promoted, Body<'tcx>>,
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region_bound_pairs: &'a RegionBoundPairs<'tcx>,
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implicit_region_bound: ty::Region<'tcx>,
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borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
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universal_region_relations: &'a UniversalRegionRelations<'tcx>,
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extra: impl FnOnce(TypeChecker<'a, 'tcx>) -> R,
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) -> R {
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let mut checker = TypeChecker::new(
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infcx,
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body,
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param_env,
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region_bound_pairs,
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implicit_region_bound,
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borrowck_context,
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universal_region_relations,
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);
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let errors_reported = {
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let mut verifier = TypeVerifier::new(&mut checker, body, promoted);
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verifier.visit_body(&body);
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verifier.errors_reported
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};
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if !errors_reported {
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// if verifier failed, don't do further checks to avoid ICEs
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checker.typeck_mir(body);
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}
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extra(checker)
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}
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fn translate_outlives_facts(typeck: &mut TypeChecker<'_, '_>) {
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let cx = &mut typeck.borrowck_context;
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if let Some(facts) = cx.all_facts {
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let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
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let location_table = cx.location_table;
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facts.outlives.extend(cx.constraints.outlives_constraints.outlives().iter().flat_map(
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|constraint: &OutlivesConstraint| {
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if let Some(from_location) = constraint.locations.from_location() {
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Either::Left(iter::once((
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constraint.sup,
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constraint.sub,
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location_table.mid_index(from_location),
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)))
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} else {
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Either::Right(
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location_table
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.all_points()
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.map(move |location| (constraint.sup, constraint.sub, location)),
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)
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}
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},
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));
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}
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}
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fn mirbug(tcx: TyCtxt<'_>, span: Span, msg: &str) {
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// We sometimes see MIR failures (notably predicate failures) due to
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// the fact that we check rvalue sized predicates here. So use `delay_span_bug`
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// to avoid reporting bugs in those cases.
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tcx.sess.diagnostic().delay_span_bug(span, msg);
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}
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enum FieldAccessError {
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OutOfRange { field_count: usize },
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}
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/// Verifies that MIR types are sane to not crash further checks.
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///
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/// The sanitize_XYZ methods here take an MIR object and compute its
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/// type, calling `span_mirbug` and returning an error type if there
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/// is a problem.
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struct TypeVerifier<'a, 'b, 'tcx> {
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cx: &'a mut TypeChecker<'b, 'tcx>,
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body: &'b Body<'tcx>,
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promoted: &'b IndexVec<Promoted, Body<'tcx>>,
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last_span: Span,
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errors_reported: bool,
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}
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impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
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fn visit_span(&mut self, span: &Span) {
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if !span.is_dummy() {
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self.last_span = *span;
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}
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}
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fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
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self.sanitize_place(place, location, context);
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}
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fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
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self.super_constant(constant, location);
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let ty = self.sanitize_type(constant, constant.literal.ty());
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self.cx.infcx.tcx.for_each_free_region(&ty, |live_region| {
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let live_region_vid =
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self.cx.borrowck_context.universal_regions.to_region_vid(live_region);
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self.cx
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.borrowck_context
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.constraints
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.liveness_constraints
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.add_element(live_region_vid, location);
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});
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if let Some(annotation_index) = constant.user_ty {
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if let Err(terr) = self.cx.relate_type_and_user_type(
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constant.literal.ty(),
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ty::Variance::Invariant,
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&UserTypeProjection { base: annotation_index, projs: vec![] },
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location.to_locations(),
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ConstraintCategory::Boring,
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) {
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let annotation = &self.cx.user_type_annotations[annotation_index];
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span_mirbug!(
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self,
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constant,
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"bad constant user type {:?} vs {:?}: {:?}",
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annotation,
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constant.literal.ty(),
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terr,
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);
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}
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} else {
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let tcx = self.tcx();
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let maybe_uneval = match constant.literal {
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ConstantKind::Ty(ct) => match ct.val {
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ty::ConstKind::Unevaluated(def, substs, promoted) => {
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Some((def, substs, promoted))
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}
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_ => None,
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},
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_ => None,
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};
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if let Some((def, substs, promoted)) = maybe_uneval {
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if let Some(promoted) = promoted {
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let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
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promoted: &Body<'tcx>,
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ty,
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san_ty| {
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if let Err(terr) = verifier.cx.eq_types(
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san_ty,
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ty,
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location.to_locations(),
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ConstraintCategory::Boring,
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) {
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span_mirbug!(
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verifier,
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promoted,
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"bad promoted type ({:?}: {:?}): {:?}",
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ty,
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san_ty,
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terr
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);
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};
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};
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if !self.errors_reported {
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let promoted_body = &self.promoted[promoted];
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self.sanitize_promoted(promoted_body, location);
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let promoted_ty = promoted_body.return_ty();
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check_err(self, promoted_body, ty, promoted_ty);
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}
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} else {
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if let Err(terr) = self.cx.fully_perform_op(
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location.to_locations(),
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ConstraintCategory::Boring,
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self.cx.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
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constant.literal.ty(),
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def.did,
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UserSubsts { substs, user_self_ty: None },
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)),
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) {
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span_mirbug!(
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self,
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constant,
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"bad constant type {:?} ({:?})",
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constant,
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terr
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);
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}
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}
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} else if let Some(static_def_id) = constant.check_static_ptr(tcx) {
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let unnormalized_ty = tcx.type_of(static_def_id);
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let locations = location.to_locations();
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let normalized_ty = self.cx.normalize(unnormalized_ty, locations);
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let literal_ty = constant.literal.ty().builtin_deref(true).unwrap().ty;
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if let Err(terr) = self.cx.eq_types(
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normalized_ty,
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literal_ty,
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locations,
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ConstraintCategory::Boring,
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) {
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span_mirbug!(self, constant, "bad static type {:?} ({:?})", constant, terr);
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}
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}
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if let ty::FnDef(def_id, substs) = *constant.literal.ty().kind() {
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let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
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self.cx.normalize_and_prove_instantiated_predicates(
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instantiated_predicates,
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location.to_locations(),
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);
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}
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}
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}
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fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
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self.super_rvalue(rvalue, location);
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let rval_ty = rvalue.ty(self.body, self.tcx());
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self.sanitize_type(rvalue, rval_ty);
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}
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fn visit_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>) {
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self.super_local_decl(local, local_decl);
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self.sanitize_type(local_decl, local_decl.ty);
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if let Some(user_ty) = &local_decl.user_ty {
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for (user_ty, span) in user_ty.projections_and_spans() {
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let ty = if !local_decl.is_nonref_binding() {
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// If we have a binding of the form `let ref x: T = ..`
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// then remove the outermost reference so we can check the
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// type annotation for the remaining type.
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if let ty::Ref(_, rty, _) = local_decl.ty.kind() {
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rty
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} else {
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bug!("{:?} with ref binding has wrong type {}", local, local_decl.ty);
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}
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} else {
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local_decl.ty
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};
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|
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if let Err(terr) = self.cx.relate_type_and_user_type(
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ty,
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ty::Variance::Invariant,
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user_ty,
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Locations::All(*span),
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ConstraintCategory::TypeAnnotation,
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) {
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span_mirbug!(
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self,
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local,
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"bad user type on variable {:?}: {:?} != {:?} ({:?})",
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local,
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local_decl.ty,
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local_decl.user_ty,
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terr,
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);
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}
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}
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}
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}
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fn visit_body(&mut self, body: &Body<'tcx>) {
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self.sanitize_type(&"return type", body.return_ty());
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for local_decl in &body.local_decls {
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self.sanitize_type(local_decl, local_decl.ty);
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}
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if self.errors_reported {
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return;
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}
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self.super_body(body);
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}
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}
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|
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impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
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fn new(
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cx: &'a mut TypeChecker<'b, 'tcx>,
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body: &'b Body<'tcx>,
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promoted: &'b IndexVec<Promoted, Body<'tcx>>,
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) -> Self {
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TypeVerifier { body, promoted, cx, last_span: body.span, errors_reported: false }
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}
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fn tcx(&self) -> TyCtxt<'tcx> {
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self.cx.infcx.tcx
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}
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fn sanitize_type(&mut self, parent: &dyn fmt::Debug, ty: Ty<'tcx>) -> Ty<'tcx> {
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if ty.has_escaping_bound_vars() || ty.references_error() {
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span_mirbug_and_err!(self, parent, "bad type {:?}", ty)
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} else {
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ty
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}
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}
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|
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/// Checks that the types internal to the `place` match up with
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/// what would be expected.
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|
fn sanitize_place(
|
|
&mut self,
|
|
place: &Place<'tcx>,
|
|
location: Location,
|
|
context: PlaceContext,
|
|
) -> PlaceTy<'tcx> {
|
|
debug!("sanitize_place: {:?}", place);
|
|
|
|
let mut place_ty = PlaceTy::from_ty(self.body.local_decls[place.local].ty);
|
|
|
|
for elem in place.projection.iter() {
|
|
if place_ty.variant_index.is_none() {
|
|
if place_ty.ty.references_error() {
|
|
assert!(self.errors_reported);
|
|
return PlaceTy::from_ty(self.tcx().ty_error());
|
|
}
|
|
}
|
|
place_ty = self.sanitize_projection(place_ty, elem, place, location)
|
|
}
|
|
|
|
if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
|
|
let tcx = self.tcx();
|
|
let trait_ref = ty::TraitRef {
|
|
def_id: tcx.require_lang_item(LangItem::Copy, Some(self.last_span)),
|
|
substs: tcx.mk_substs_trait(place_ty.ty, &[]),
|
|
};
|
|
|
|
// To have a `Copy` operand, the type `T` of the
|
|
// value must be `Copy`. Note that we prove that `T: Copy`,
|
|
// rather than using the `is_copy_modulo_regions`
|
|
// test. This is important because
|
|
// `is_copy_modulo_regions` ignores the resulting region
|
|
// obligations and assumes they pass. This can result in
|
|
// bounds from `Copy` impls being unsoundly ignored (e.g.,
|
|
// #29149). Note that we decide to use `Copy` before knowing
|
|
// whether the bounds fully apply: in effect, the rule is
|
|
// that if a value of some type could implement `Copy`, then
|
|
// it must.
|
|
self.cx.prove_trait_ref(
|
|
trait_ref,
|
|
location.to_locations(),
|
|
ConstraintCategory::CopyBound,
|
|
);
|
|
}
|
|
|
|
place_ty
|
|
}
|
|
|
|
fn sanitize_promoted(&mut self, promoted_body: &'b Body<'tcx>, location: Location) {
|
|
// Determine the constraints from the promoted MIR by running the type
|
|
// checker on the promoted MIR, then transfer the constraints back to
|
|
// the main MIR, changing the locations to the provided location.
|
|
|
|
let parent_body = mem::replace(&mut self.body, promoted_body);
|
|
|
|
// Use new sets of constraints and closure bounds so that we can
|
|
// modify their locations.
|
|
let all_facts = &mut None;
|
|
let mut constraints = Default::default();
|
|
let mut closure_bounds = Default::default();
|
|
let mut liveness_constraints =
|
|
LivenessValues::new(Rc::new(RegionValueElements::new(&promoted_body)));
|
|
// Don't try to add borrow_region facts for the promoted MIR
|
|
|
|
let mut swap_constraints = |this: &mut Self| {
|
|
mem::swap(this.cx.borrowck_context.all_facts, all_facts);
|
|
mem::swap(
|
|
&mut this.cx.borrowck_context.constraints.outlives_constraints,
|
|
&mut constraints,
|
|
);
|
|
mem::swap(
|
|
&mut this.cx.borrowck_context.constraints.closure_bounds_mapping,
|
|
&mut closure_bounds,
|
|
);
|
|
mem::swap(
|
|
&mut this.cx.borrowck_context.constraints.liveness_constraints,
|
|
&mut liveness_constraints,
|
|
);
|
|
};
|
|
|
|
swap_constraints(self);
|
|
|
|
self.visit_body(&promoted_body);
|
|
|
|
if !self.errors_reported {
|
|
// if verifier failed, don't do further checks to avoid ICEs
|
|
self.cx.typeck_mir(promoted_body);
|
|
}
|
|
|
|
self.body = parent_body;
|
|
// Merge the outlives constraints back in, at the given location.
|
|
swap_constraints(self);
|
|
|
|
let locations = location.to_locations();
|
|
for constraint in constraints.outlives().iter() {
|
|
let mut constraint = *constraint;
|
|
constraint.locations = locations;
|
|
if let ConstraintCategory::Return(_)
|
|
| ConstraintCategory::UseAsConst
|
|
| ConstraintCategory::UseAsStatic = constraint.category
|
|
{
|
|
// "Returning" from a promoted is an assignment to a
|
|
// temporary from the user's point of view.
|
|
constraint.category = ConstraintCategory::Boring;
|
|
}
|
|
self.cx.borrowck_context.constraints.outlives_constraints.push(constraint)
|
|
}
|
|
for live_region in liveness_constraints.rows() {
|
|
self.cx
|
|
.borrowck_context
|
|
.constraints
|
|
.liveness_constraints
|
|
.add_element(live_region, location);
|
|
}
|
|
|
|
if !closure_bounds.is_empty() {
|
|
let combined_bounds_mapping =
|
|
closure_bounds.into_iter().flat_map(|(_, value)| value).collect();
|
|
let existing = self
|
|
.cx
|
|
.borrowck_context
|
|
.constraints
|
|
.closure_bounds_mapping
|
|
.insert(location, combined_bounds_mapping);
|
|
assert!(existing.is_none(), "Multiple promoteds/closures at the same location.");
|
|
}
|
|
}
|
|
|
|
fn sanitize_projection(
|
|
&mut self,
|
|
base: PlaceTy<'tcx>,
|
|
pi: PlaceElem<'tcx>,
|
|
place: &Place<'tcx>,
|
|
location: Location,
|
|
) -> PlaceTy<'tcx> {
|
|
debug!("sanitize_projection: {:?} {:?} {:?}", base, pi, place);
|
|
let tcx = self.tcx();
|
|
let base_ty = base.ty;
|
|
match pi {
|
|
ProjectionElem::Deref => {
|
|
let deref_ty = base_ty.builtin_deref(true);
|
|
PlaceTy::from_ty(deref_ty.map(|t| t.ty).unwrap_or_else(|| {
|
|
span_mirbug_and_err!(self, place, "deref of non-pointer {:?}", base_ty)
|
|
}))
|
|
}
|
|
ProjectionElem::Index(i) => {
|
|
let index_ty = Place::from(i).ty(self.body, tcx).ty;
|
|
if index_ty != tcx.types.usize {
|
|
PlaceTy::from_ty(span_mirbug_and_err!(self, i, "index by non-usize {:?}", i))
|
|
} else {
|
|
PlaceTy::from_ty(base_ty.builtin_index().unwrap_or_else(|| {
|
|
span_mirbug_and_err!(self, place, "index of non-array {:?}", base_ty)
|
|
}))
|
|
}
|
|
}
|
|
ProjectionElem::ConstantIndex { .. } => {
|
|
// consider verifying in-bounds
|
|
PlaceTy::from_ty(base_ty.builtin_index().unwrap_or_else(|| {
|
|
span_mirbug_and_err!(self, place, "index of non-array {:?}", base_ty)
|
|
}))
|
|
}
|
|
ProjectionElem::Subslice { from, to, from_end } => {
|
|
PlaceTy::from_ty(match base_ty.kind() {
|
|
ty::Array(inner, _) => {
|
|
assert!(!from_end, "array subslices should not use from_end");
|
|
tcx.mk_array(inner, to - from)
|
|
}
|
|
ty::Slice(..) => {
|
|
assert!(from_end, "slice subslices should use from_end");
|
|
base_ty
|
|
}
|
|
_ => span_mirbug_and_err!(self, place, "slice of non-array {:?}", base_ty),
|
|
})
|
|
}
|
|
ProjectionElem::Downcast(maybe_name, index) => match base_ty.kind() {
|
|
ty::Adt(adt_def, _substs) if adt_def.is_enum() => {
|
|
if index.as_usize() >= adt_def.variants.len() {
|
|
PlaceTy::from_ty(span_mirbug_and_err!(
|
|
self,
|
|
place,
|
|
"cast to variant #{:?} but enum only has {:?}",
|
|
index,
|
|
adt_def.variants.len()
|
|
))
|
|
} else {
|
|
PlaceTy { ty: base_ty, variant_index: Some(index) }
|
|
}
|
|
}
|
|
// We do not need to handle generators here, because this runs
|
|
// before the generator transform stage.
|
|
_ => {
|
|
let ty = if let Some(name) = maybe_name {
|
|
span_mirbug_and_err!(
|
|
self,
|
|
place,
|
|
"can't downcast {:?} as {:?}",
|
|
base_ty,
|
|
name
|
|
)
|
|
} else {
|
|
span_mirbug_and_err!(self, place, "can't downcast {:?}", base_ty)
|
|
};
|
|
PlaceTy::from_ty(ty)
|
|
}
|
|
},
|
|
ProjectionElem::Field(field, fty) => {
|
|
let fty = self.sanitize_type(place, fty);
|
|
match self.field_ty(place, base, field, location) {
|
|
Ok(ty) => {
|
|
let ty = self.cx.normalize(ty, location);
|
|
if let Err(terr) = self.cx.eq_types(
|
|
ty,
|
|
fty,
|
|
location.to_locations(),
|
|
ConstraintCategory::Boring,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
place,
|
|
"bad field access ({:?}: {:?}): {:?}",
|
|
ty,
|
|
fty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
Err(FieldAccessError::OutOfRange { field_count }) => span_mirbug!(
|
|
self,
|
|
place,
|
|
"accessed field #{} but variant only has {}",
|
|
field.index(),
|
|
field_count
|
|
),
|
|
}
|
|
PlaceTy::from_ty(fty)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn error(&mut self) -> Ty<'tcx> {
|
|
self.errors_reported = true;
|
|
self.tcx().ty_error()
|
|
}
|
|
|
|
fn field_ty(
|
|
&mut self,
|
|
parent: &dyn fmt::Debug,
|
|
base_ty: PlaceTy<'tcx>,
|
|
field: Field,
|
|
location: Location,
|
|
) -> Result<Ty<'tcx>, FieldAccessError> {
|
|
let tcx = self.tcx();
|
|
|
|
let (variant, substs) = match base_ty {
|
|
PlaceTy { ty, variant_index: Some(variant_index) } => match *ty.kind() {
|
|
ty::Adt(adt_def, substs) => (&adt_def.variants[variant_index], substs),
|
|
ty::Generator(def_id, substs, _) => {
|
|
let mut variants = substs.as_generator().state_tys(def_id, tcx);
|
|
let mut variant = match variants.nth(variant_index.into()) {
|
|
Some(v) => v,
|
|
None => bug!(
|
|
"variant_index of generator out of range: {:?}/{:?}",
|
|
variant_index,
|
|
substs.as_generator().state_tys(def_id, tcx).count()
|
|
),
|
|
};
|
|
return match variant.nth(field.index()) {
|
|
Some(ty) => Ok(ty),
|
|
None => Err(FieldAccessError::OutOfRange { field_count: variant.count() }),
|
|
};
|
|
}
|
|
_ => bug!("can't have downcast of non-adt non-generator type"),
|
|
},
|
|
PlaceTy { ty, variant_index: None } => match *ty.kind() {
|
|
ty::Adt(adt_def, substs) if !adt_def.is_enum() => {
|
|
(&adt_def.variants[VariantIdx::new(0)], substs)
|
|
}
|
|
ty::Closure(_, substs) => {
|
|
return match substs
|
|
.as_closure()
|
|
.tupled_upvars_ty()
|
|
.tuple_element_ty(field.index())
|
|
{
|
|
Some(ty) => Ok(ty),
|
|
None => Err(FieldAccessError::OutOfRange {
|
|
field_count: substs.as_closure().upvar_tys().count(),
|
|
}),
|
|
};
|
|
}
|
|
ty::Generator(_, substs, _) => {
|
|
// Only prefix fields (upvars and current state) are
|
|
// accessible without a variant index.
|
|
return match substs.as_generator().prefix_tys().nth(field.index()) {
|
|
Some(ty) => Ok(ty),
|
|
None => Err(FieldAccessError::OutOfRange {
|
|
field_count: substs.as_generator().prefix_tys().count(),
|
|
}),
|
|
};
|
|
}
|
|
ty::Tuple(tys) => {
|
|
return match tys.get(field.index()) {
|
|
Some(&ty) => Ok(ty.expect_ty()),
|
|
None => Err(FieldAccessError::OutOfRange { field_count: tys.len() }),
|
|
};
|
|
}
|
|
_ => {
|
|
return Ok(span_mirbug_and_err!(
|
|
self,
|
|
parent,
|
|
"can't project out of {:?}",
|
|
base_ty
|
|
));
|
|
}
|
|
},
|
|
};
|
|
|
|
if let Some(field) = variant.fields.get(field.index()) {
|
|
Ok(self.cx.normalize(field.ty(tcx, substs), location))
|
|
} else {
|
|
Err(FieldAccessError::OutOfRange { field_count: variant.fields.len() })
|
|
}
|
|
}
|
|
}
|
|
|
|
/// The MIR type checker. Visits the MIR and enforces all the
|
|
/// constraints needed for it to be valid and well-typed. Along the
|
|
/// way, it accrues region constraints -- these can later be used by
|
|
/// NLL region checking.
|
|
struct TypeChecker<'a, 'tcx> {
|
|
infcx: &'a InferCtxt<'a, 'tcx>,
|
|
param_env: ty::ParamEnv<'tcx>,
|
|
last_span: Span,
|
|
body: &'a Body<'tcx>,
|
|
/// User type annotations are shared between the main MIR and the MIR of
|
|
/// all of the promoted items.
|
|
user_type_annotations: &'a CanonicalUserTypeAnnotations<'tcx>,
|
|
region_bound_pairs: &'a RegionBoundPairs<'tcx>,
|
|
implicit_region_bound: ty::Region<'tcx>,
|
|
reported_errors: FxHashSet<(Ty<'tcx>, Span)>,
|
|
borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
|
|
universal_region_relations: &'a UniversalRegionRelations<'tcx>,
|
|
opaque_type_values: FxHashMap<DefId, ty::ResolvedOpaqueTy<'tcx>>,
|
|
}
|
|
|
|
struct BorrowCheckContext<'a, 'tcx> {
|
|
universal_regions: &'a UniversalRegions<'tcx>,
|
|
location_table: &'a LocationTable,
|
|
all_facts: &'a mut Option<AllFacts>,
|
|
borrow_set: &'a BorrowSet<'tcx>,
|
|
constraints: &'a mut MirTypeckRegionConstraints<'tcx>,
|
|
upvars: &'a [Upvar<'tcx>],
|
|
}
|
|
|
|
crate struct MirTypeckResults<'tcx> {
|
|
crate constraints: MirTypeckRegionConstraints<'tcx>,
|
|
pub(in crate::borrow_check) universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
|
|
crate opaque_type_values: FxHashMap<DefId, ty::ResolvedOpaqueTy<'tcx>>,
|
|
}
|
|
|
|
/// A collection of region constraints that must be satisfied for the
|
|
/// program to be considered well-typed.
|
|
crate struct MirTypeckRegionConstraints<'tcx> {
|
|
/// Maps from a `ty::Placeholder` to the corresponding
|
|
/// `PlaceholderIndex` bit that we will use for it.
|
|
///
|
|
/// To keep everything in sync, do not insert this set
|
|
/// directly. Instead, use the `placeholder_region` helper.
|
|
crate placeholder_indices: PlaceholderIndices,
|
|
|
|
/// Each time we add a placeholder to `placeholder_indices`, we
|
|
/// also create a corresponding "representative" region vid for
|
|
/// that wraps it. This vector tracks those. This way, when we
|
|
/// convert the same `ty::RePlaceholder(p)` twice, we can map to
|
|
/// the same underlying `RegionVid`.
|
|
crate placeholder_index_to_region: IndexVec<PlaceholderIndex, ty::Region<'tcx>>,
|
|
|
|
/// In general, the type-checker is not responsible for enforcing
|
|
/// liveness constraints; this job falls to the region inferencer,
|
|
/// which performs a liveness analysis. However, in some limited
|
|
/// cases, the MIR type-checker creates temporary regions that do
|
|
/// not otherwise appear in the MIR -- in particular, the
|
|
/// late-bound regions that it instantiates at call-sites -- and
|
|
/// hence it must report on their liveness constraints.
|
|
crate liveness_constraints: LivenessValues<RegionVid>,
|
|
|
|
crate outlives_constraints: OutlivesConstraintSet,
|
|
|
|
crate member_constraints: MemberConstraintSet<'tcx, RegionVid>,
|
|
|
|
crate closure_bounds_mapping:
|
|
FxHashMap<Location, FxHashMap<(RegionVid, RegionVid), (ConstraintCategory, Span)>>,
|
|
|
|
crate type_tests: Vec<TypeTest<'tcx>>,
|
|
}
|
|
|
|
impl MirTypeckRegionConstraints<'tcx> {
|
|
fn placeholder_region(
|
|
&mut self,
|
|
infcx: &InferCtxt<'_, 'tcx>,
|
|
placeholder: ty::PlaceholderRegion,
|
|
) -> ty::Region<'tcx> {
|
|
let placeholder_index = self.placeholder_indices.insert(placeholder);
|
|
match self.placeholder_index_to_region.get(placeholder_index) {
|
|
Some(&v) => v,
|
|
None => {
|
|
let origin = NllRegionVariableOrigin::Placeholder(placeholder);
|
|
let region = infcx.next_nll_region_var_in_universe(origin, placeholder.universe);
|
|
self.placeholder_index_to_region.push(region);
|
|
region
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// The `Locations` type summarizes *where* region constraints are
|
|
/// required to hold. Normally, this is at a particular point which
|
|
/// created the obligation, but for constraints that the user gave, we
|
|
/// want the constraint to hold at all points.
|
|
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
|
|
pub enum Locations {
|
|
/// Indicates that a type constraint should always be true. This
|
|
/// is particularly important in the new borrowck analysis for
|
|
/// things like the type of the return slot. Consider this
|
|
/// example:
|
|
///
|
|
/// ```
|
|
/// fn foo<'a>(x: &'a u32) -> &'a u32 {
|
|
/// let y = 22;
|
|
/// return &y; // error
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Here, we wind up with the signature from the return type being
|
|
/// something like `&'1 u32` where `'1` is a universal region. But
|
|
/// the type of the return slot `_0` is something like `&'2 u32`
|
|
/// where `'2` is an existential region variable. The type checker
|
|
/// requires that `&'2 u32 = &'1 u32` -- but at what point? In the
|
|
/// older NLL analysis, we required this only at the entry point
|
|
/// to the function. By the nature of the constraints, this wound
|
|
/// up propagating to all points reachable from start (because
|
|
/// `'1` -- as a universal region -- is live everywhere). In the
|
|
/// newer analysis, though, this doesn't work: `_0` is considered
|
|
/// dead at the start (it has no usable value) and hence this type
|
|
/// equality is basically a no-op. Then, later on, when we do `_0
|
|
/// = &'3 y`, that region `'3` never winds up related to the
|
|
/// universal region `'1` and hence no error occurs. Therefore, we
|
|
/// use Locations::All instead, which ensures that the `'1` and
|
|
/// `'2` are equal everything. We also use this for other
|
|
/// user-given type annotations; e.g., if the user wrote `let mut
|
|
/// x: &'static u32 = ...`, we would ensure that all values
|
|
/// assigned to `x` are of `'static` lifetime.
|
|
///
|
|
/// The span points to the place the constraint arose. For example,
|
|
/// it points to the type in a user-given type annotation. If
|
|
/// there's no sensible span then it's DUMMY_SP.
|
|
All(Span),
|
|
|
|
/// An outlives constraint that only has to hold at a single location,
|
|
/// usually it represents a point where references flow from one spot to
|
|
/// another (e.g., `x = y`)
|
|
Single(Location),
|
|
}
|
|
|
|
impl Locations {
|
|
pub fn from_location(&self) -> Option<Location> {
|
|
match self {
|
|
Locations::All(_) => None,
|
|
Locations::Single(from_location) => Some(*from_location),
|
|
}
|
|
}
|
|
|
|
/// Gets a span representing the location.
|
|
pub fn span(&self, body: &Body<'_>) -> Span {
|
|
match self {
|
|
Locations::All(span) => *span,
|
|
Locations::Single(l) => body.source_info(*l).span,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
|
|
fn new(
|
|
infcx: &'a InferCtxt<'a, 'tcx>,
|
|
body: &'a Body<'tcx>,
|
|
param_env: ty::ParamEnv<'tcx>,
|
|
region_bound_pairs: &'a RegionBoundPairs<'tcx>,
|
|
implicit_region_bound: ty::Region<'tcx>,
|
|
borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
|
|
universal_region_relations: &'a UniversalRegionRelations<'tcx>,
|
|
) -> Self {
|
|
let mut checker = Self {
|
|
infcx,
|
|
last_span: DUMMY_SP,
|
|
body,
|
|
user_type_annotations: &body.user_type_annotations,
|
|
param_env,
|
|
region_bound_pairs,
|
|
implicit_region_bound,
|
|
borrowck_context,
|
|
reported_errors: Default::default(),
|
|
universal_region_relations,
|
|
opaque_type_values: FxHashMap::default(),
|
|
};
|
|
checker.check_user_type_annotations();
|
|
checker
|
|
}
|
|
|
|
fn unsized_feature_enabled(&self) -> bool {
|
|
let features = self.tcx().features();
|
|
features.unsized_locals || features.unsized_fn_params
|
|
}
|
|
|
|
/// Equate the inferred type and the annotated type for user type annotations
|
|
fn check_user_type_annotations(&mut self) {
|
|
debug!(
|
|
"check_user_type_annotations: user_type_annotations={:?}",
|
|
self.user_type_annotations
|
|
);
|
|
for user_annotation in self.user_type_annotations {
|
|
let CanonicalUserTypeAnnotation { span, ref user_ty, inferred_ty } = *user_annotation;
|
|
let (annotation, _) =
|
|
self.infcx.instantiate_canonical_with_fresh_inference_vars(span, user_ty);
|
|
match annotation {
|
|
UserType::Ty(mut ty) => {
|
|
ty = self.normalize(ty, Locations::All(span));
|
|
|
|
if let Err(terr) = self.eq_types(
|
|
ty,
|
|
inferred_ty,
|
|
Locations::All(span),
|
|
ConstraintCategory::BoringNoLocation,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
user_annotation,
|
|
"bad user type ({:?} = {:?}): {:?}",
|
|
ty,
|
|
inferred_ty,
|
|
terr
|
|
);
|
|
}
|
|
|
|
self.prove_predicate(
|
|
ty::PredicateKind::WellFormed(inferred_ty.into()).to_predicate(self.tcx()),
|
|
Locations::All(span),
|
|
ConstraintCategory::TypeAnnotation,
|
|
);
|
|
}
|
|
UserType::TypeOf(def_id, user_substs) => {
|
|
if let Err(terr) = self.fully_perform_op(
|
|
Locations::All(span),
|
|
ConstraintCategory::BoringNoLocation,
|
|
self.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
|
|
inferred_ty,
|
|
def_id,
|
|
user_substs,
|
|
)),
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
user_annotation,
|
|
"bad user type AscribeUserType({:?}, {:?} {:?}): {:?}",
|
|
inferred_ty,
|
|
def_id,
|
|
user_substs,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Given some operation `op` that manipulates types, proves
|
|
/// predicates, or otherwise uses the inference context, executes
|
|
/// `op` and then executes all the further obligations that `op`
|
|
/// returns. This will yield a set of outlives constraints amongst
|
|
/// regions which are extracted and stored as having occurred at
|
|
/// `locations`.
|
|
///
|
|
/// **Any `rustc_infer::infer` operations that might generate region
|
|
/// constraints should occur within this method so that those
|
|
/// constraints can be properly localized!**
|
|
fn fully_perform_op<R>(
|
|
&mut self,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
op: impl type_op::TypeOp<'tcx, Output = R>,
|
|
) -> Fallible<R> {
|
|
let (r, opt_data) = op.fully_perform(self.infcx)?;
|
|
|
|
if let Some(data) = &opt_data {
|
|
self.push_region_constraints(locations, category, data);
|
|
}
|
|
|
|
Ok(r)
|
|
}
|
|
|
|
fn push_region_constraints(
|
|
&mut self,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
data: &QueryRegionConstraints<'tcx>,
|
|
) {
|
|
debug!("push_region_constraints: constraints generated at {:?} are {:#?}", locations, data);
|
|
|
|
constraint_conversion::ConstraintConversion::new(
|
|
self.infcx,
|
|
self.borrowck_context.universal_regions,
|
|
self.region_bound_pairs,
|
|
Some(self.implicit_region_bound),
|
|
self.param_env,
|
|
locations,
|
|
category,
|
|
&mut self.borrowck_context.constraints,
|
|
)
|
|
.convert_all(data);
|
|
}
|
|
|
|
/// Convenient wrapper around `relate_tys::relate_types` -- see
|
|
/// that fn for docs.
|
|
fn relate_types(
|
|
&mut self,
|
|
a: Ty<'tcx>,
|
|
v: ty::Variance,
|
|
b: Ty<'tcx>,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) -> Fallible<()> {
|
|
relate_tys::relate_types(
|
|
self.infcx,
|
|
self.param_env,
|
|
a,
|
|
v,
|
|
b,
|
|
locations,
|
|
category,
|
|
Some(self.borrowck_context),
|
|
)
|
|
}
|
|
|
|
fn sub_types(
|
|
&mut self,
|
|
sub: Ty<'tcx>,
|
|
sup: Ty<'tcx>,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) -> Fallible<()> {
|
|
self.relate_types(sub, ty::Variance::Covariant, sup, locations, category)
|
|
}
|
|
|
|
/// Try to relate `sub <: sup`; if this fails, instantiate opaque
|
|
/// variables in `sub` with their inferred definitions and try
|
|
/// again. This is used for opaque types in places (e.g., `let x:
|
|
/// impl Foo = ..`).
|
|
fn sub_types_or_anon(
|
|
&mut self,
|
|
sub: Ty<'tcx>,
|
|
sup: Ty<'tcx>,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) -> Fallible<()> {
|
|
if let Err(terr) = self.sub_types(sub, sup, locations, category) {
|
|
if let ty::Opaque(..) = sup.kind() {
|
|
// When you have `let x: impl Foo = ...` in a closure,
|
|
// the resulting inferend values are stored with the
|
|
// def-id of the base function.
|
|
let parent_def_id =
|
|
self.tcx().closure_base_def_id(self.body.source.def_id()).expect_local();
|
|
return self.eq_opaque_type_and_type(sub, sup, parent_def_id, locations, category);
|
|
} else {
|
|
return Err(terr);
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
fn eq_types(
|
|
&mut self,
|
|
a: Ty<'tcx>,
|
|
b: Ty<'tcx>,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) -> Fallible<()> {
|
|
self.relate_types(a, ty::Variance::Invariant, b, locations, category)
|
|
}
|
|
|
|
fn relate_type_and_user_type(
|
|
&mut self,
|
|
a: Ty<'tcx>,
|
|
v: ty::Variance,
|
|
user_ty: &UserTypeProjection,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) -> Fallible<()> {
|
|
debug!(
|
|
"relate_type_and_user_type(a={:?}, v={:?}, user_ty={:?}, locations={:?})",
|
|
a, v, user_ty, locations,
|
|
);
|
|
|
|
let annotated_type = self.user_type_annotations[user_ty.base].inferred_ty;
|
|
let mut curr_projected_ty = PlaceTy::from_ty(annotated_type);
|
|
|
|
let tcx = self.infcx.tcx;
|
|
|
|
for proj in &user_ty.projs {
|
|
let projected_ty = curr_projected_ty.projection_ty_core(
|
|
tcx,
|
|
self.param_env,
|
|
proj,
|
|
|this, field, &()| {
|
|
let ty = this.field_ty(tcx, field);
|
|
self.normalize(ty, locations)
|
|
},
|
|
);
|
|
curr_projected_ty = projected_ty;
|
|
}
|
|
debug!(
|
|
"user_ty base: {:?} freshened: {:?} projs: {:?} yields: {:?}",
|
|
user_ty.base, annotated_type, user_ty.projs, curr_projected_ty
|
|
);
|
|
|
|
let ty = curr_projected_ty.ty;
|
|
self.relate_types(a, v, ty, locations, category)?;
|
|
|
|
Ok(())
|
|
}
|
|
|
|
fn eq_opaque_type_and_type(
|
|
&mut self,
|
|
revealed_ty: Ty<'tcx>,
|
|
anon_ty: Ty<'tcx>,
|
|
anon_owner_def_id: LocalDefId,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) -> Fallible<()> {
|
|
debug!(
|
|
"eq_opaque_type_and_type( \
|
|
revealed_ty={:?}, \
|
|
anon_ty={:?})",
|
|
revealed_ty, anon_ty
|
|
);
|
|
|
|
// Fast path for the common case.
|
|
if !anon_ty.has_opaque_types() {
|
|
if let Err(terr) = self.eq_types(anon_ty, revealed_ty, locations, category) {
|
|
span_mirbug!(
|
|
self,
|
|
locations,
|
|
"eq_opaque_type_and_type: `{:?}=={:?}` failed with `{:?}`",
|
|
revealed_ty,
|
|
anon_ty,
|
|
terr
|
|
);
|
|
}
|
|
return Ok(());
|
|
}
|
|
|
|
let infcx = self.infcx;
|
|
let tcx = infcx.tcx;
|
|
let param_env = self.param_env;
|
|
let body = self.body;
|
|
let concrete_opaque_types = &tcx.typeck(anon_owner_def_id).concrete_opaque_types;
|
|
let mut opaque_type_values = Vec::new();
|
|
|
|
debug!("eq_opaque_type_and_type: mir_def_id={:?}", body.source.def_id());
|
|
let opaque_type_map = self.fully_perform_op(
|
|
locations,
|
|
category,
|
|
CustomTypeOp::new(
|
|
|infcx| {
|
|
let mut obligations = ObligationAccumulator::default();
|
|
|
|
let dummy_body_id = hir::CRATE_HIR_ID;
|
|
let (output_ty, opaque_type_map) =
|
|
obligations.add(infcx.instantiate_opaque_types(
|
|
anon_owner_def_id,
|
|
dummy_body_id,
|
|
param_env,
|
|
anon_ty,
|
|
locations.span(body),
|
|
));
|
|
debug!(
|
|
"eq_opaque_type_and_type: \
|
|
instantiated output_ty={:?} \
|
|
opaque_type_map={:#?} \
|
|
revealed_ty={:?}",
|
|
output_ty, opaque_type_map, revealed_ty
|
|
);
|
|
// Make sure that the inferred types are well-formed. I'm
|
|
// not entirely sure this is needed (the HIR type check
|
|
// didn't do this) but it seems sensible to prevent opaque
|
|
// types hiding ill-formed types.
|
|
obligations.obligations.push(traits::Obligation::new(
|
|
ObligationCause::dummy(),
|
|
param_env,
|
|
ty::PredicateKind::WellFormed(revealed_ty.into()).to_predicate(infcx.tcx),
|
|
));
|
|
obligations.add(
|
|
infcx
|
|
.at(&ObligationCause::dummy(), param_env)
|
|
.eq(output_ty, revealed_ty)?,
|
|
);
|
|
|
|
for (&opaque_def_id, opaque_decl) in &opaque_type_map {
|
|
let resolved_ty = infcx.resolve_vars_if_possible(opaque_decl.concrete_ty);
|
|
let concrete_is_opaque = if let ty::Opaque(def_id, _) = resolved_ty.kind() {
|
|
*def_id == opaque_def_id
|
|
} else {
|
|
false
|
|
};
|
|
let opaque_defn_ty = match concrete_opaque_types.get(&opaque_def_id) {
|
|
None => {
|
|
if !concrete_is_opaque {
|
|
tcx.sess.delay_span_bug(
|
|
body.span,
|
|
&format!(
|
|
"Non-defining use of {:?} with revealed type",
|
|
opaque_def_id,
|
|
),
|
|
);
|
|
}
|
|
continue;
|
|
}
|
|
Some(opaque_defn_ty) => opaque_defn_ty,
|
|
};
|
|
debug!("opaque_defn_ty = {:?}", opaque_defn_ty);
|
|
let subst_opaque_defn_ty =
|
|
opaque_defn_ty.concrete_type.subst(tcx, opaque_decl.substs);
|
|
let renumbered_opaque_defn_ty =
|
|
renumber::renumber_regions(infcx, subst_opaque_defn_ty);
|
|
|
|
debug!(
|
|
"eq_opaque_type_and_type: concrete_ty={:?}={:?} opaque_defn_ty={:?}",
|
|
opaque_decl.concrete_ty, resolved_ty, renumbered_opaque_defn_ty,
|
|
);
|
|
|
|
if !concrete_is_opaque {
|
|
// Equate concrete_ty (an inference variable) with
|
|
// the renumbered type from typeck.
|
|
obligations.add(
|
|
infcx
|
|
.at(&ObligationCause::dummy(), param_env)
|
|
.eq(opaque_decl.concrete_ty, renumbered_opaque_defn_ty)?,
|
|
);
|
|
opaque_type_values.push((
|
|
opaque_def_id,
|
|
ty::ResolvedOpaqueTy {
|
|
concrete_type: renumbered_opaque_defn_ty,
|
|
substs: opaque_decl.substs,
|
|
},
|
|
));
|
|
} else {
|
|
// We're using an opaque `impl Trait` type without
|
|
// 'revealing' it. For example, code like this:
|
|
//
|
|
// type Foo = impl Debug;
|
|
// fn foo1() -> Foo { ... }
|
|
// fn foo2() -> Foo { foo1() }
|
|
//
|
|
// In `foo2`, we're not revealing the type of `Foo` - we're
|
|
// just treating it as the opaque type.
|
|
//
|
|
// When this occurs, we do *not* want to try to equate
|
|
// the concrete type with the underlying defining type
|
|
// of the opaque type - this will always fail, since
|
|
// the defining type of an opaque type is always
|
|
// some other type (e.g. not itself)
|
|
// Essentially, none of the normal obligations apply here -
|
|
// we're just passing around some unknown opaque type,
|
|
// without actually looking at the underlying type it
|
|
// gets 'revealed' into
|
|
debug!(
|
|
"eq_opaque_type_and_type: non-defining use of {:?}",
|
|
opaque_def_id,
|
|
);
|
|
}
|
|
}
|
|
|
|
debug!("eq_opaque_type_and_type: equated");
|
|
|
|
Ok(InferOk {
|
|
value: Some(opaque_type_map),
|
|
obligations: obligations.into_vec(),
|
|
})
|
|
},
|
|
|| "input_output".to_string(),
|
|
),
|
|
)?;
|
|
|
|
self.opaque_type_values.extend(opaque_type_values);
|
|
|
|
let universal_region_relations = self.universal_region_relations;
|
|
|
|
// Finally, if we instantiated the anon types successfully, we
|
|
// have to solve any bounds (e.g., `-> impl Iterator` needs to
|
|
// prove that `T: Iterator` where `T` is the type we
|
|
// instantiated it with).
|
|
if let Some(opaque_type_map) = opaque_type_map {
|
|
for (opaque_def_id, opaque_decl) in opaque_type_map {
|
|
self.fully_perform_op(
|
|
locations,
|
|
ConstraintCategory::OpaqueType,
|
|
CustomTypeOp::new(
|
|
|_cx| {
|
|
infcx.constrain_opaque_type(
|
|
opaque_def_id,
|
|
&opaque_decl,
|
|
GenerateMemberConstraints::IfNoStaticBound,
|
|
universal_region_relations,
|
|
);
|
|
Ok(InferOk { value: (), obligations: vec![] })
|
|
},
|
|
|| "opaque_type_map".to_string(),
|
|
),
|
|
)?;
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
fn tcx(&self) -> TyCtxt<'tcx> {
|
|
self.infcx.tcx
|
|
}
|
|
|
|
fn check_stmt(&mut self, body: &Body<'tcx>, stmt: &Statement<'tcx>, location: Location) {
|
|
debug!("check_stmt: {:?}", stmt);
|
|
let tcx = self.tcx();
|
|
match stmt.kind {
|
|
StatementKind::Assign(box (ref place, ref rv)) => {
|
|
// Assignments to temporaries are not "interesting";
|
|
// they are not caused by the user, but rather artifacts
|
|
// of lowering. Assignments to other sorts of places *are* interesting
|
|
// though.
|
|
let category = match place.as_local() {
|
|
Some(RETURN_PLACE) => {
|
|
if let BorrowCheckContext {
|
|
universal_regions:
|
|
UniversalRegions { defining_ty: DefiningTy::Const(def_id, _), .. },
|
|
..
|
|
} = self.borrowck_context
|
|
{
|
|
if tcx.is_static(*def_id) {
|
|
ConstraintCategory::UseAsStatic
|
|
} else {
|
|
ConstraintCategory::UseAsConst
|
|
}
|
|
} else {
|
|
ConstraintCategory::Return(ReturnConstraint::Normal)
|
|
}
|
|
}
|
|
Some(l) if !body.local_decls[l].is_user_variable() => {
|
|
ConstraintCategory::Boring
|
|
}
|
|
_ => ConstraintCategory::Assignment,
|
|
};
|
|
|
|
let place_ty = place.ty(body, tcx).ty;
|
|
let place_ty = self.normalize(place_ty, location);
|
|
let rv_ty = rv.ty(body, tcx);
|
|
let rv_ty = self.normalize(rv_ty, location);
|
|
if let Err(terr) =
|
|
self.sub_types_or_anon(rv_ty, place_ty, location.to_locations(), category)
|
|
{
|
|
span_mirbug!(
|
|
self,
|
|
stmt,
|
|
"bad assignment ({:?} = {:?}): {:?}",
|
|
place_ty,
|
|
rv_ty,
|
|
terr
|
|
);
|
|
}
|
|
|
|
if let Some(annotation_index) = self.rvalue_user_ty(rv) {
|
|
if let Err(terr) = self.relate_type_and_user_type(
|
|
rv_ty,
|
|
ty::Variance::Invariant,
|
|
&UserTypeProjection { base: annotation_index, projs: vec![] },
|
|
location.to_locations(),
|
|
ConstraintCategory::Boring,
|
|
) {
|
|
let annotation = &self.user_type_annotations[annotation_index];
|
|
span_mirbug!(
|
|
self,
|
|
stmt,
|
|
"bad user type on rvalue ({:?} = {:?}): {:?}",
|
|
annotation,
|
|
rv_ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
|
|
self.check_rvalue(body, rv, location);
|
|
if !self.unsized_feature_enabled() {
|
|
let trait_ref = ty::TraitRef {
|
|
def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
|
|
substs: tcx.mk_substs_trait(place_ty, &[]),
|
|
};
|
|
self.prove_trait_ref(
|
|
trait_ref,
|
|
location.to_locations(),
|
|
ConstraintCategory::SizedBound,
|
|
);
|
|
}
|
|
}
|
|
StatementKind::SetDiscriminant { ref place, variant_index } => {
|
|
let place_type = place.ty(body, tcx).ty;
|
|
let adt = match place_type.kind() {
|
|
ty::Adt(adt, _) if adt.is_enum() => adt,
|
|
_ => {
|
|
span_bug!(
|
|
stmt.source_info.span,
|
|
"bad set discriminant ({:?} = {:?}): lhs is not an enum",
|
|
place,
|
|
variant_index
|
|
);
|
|
}
|
|
};
|
|
if variant_index.as_usize() >= adt.variants.len() {
|
|
span_bug!(
|
|
stmt.source_info.span,
|
|
"bad set discriminant ({:?} = {:?}): value of of range",
|
|
place,
|
|
variant_index
|
|
);
|
|
};
|
|
}
|
|
StatementKind::AscribeUserType(box (ref place, ref projection), variance) => {
|
|
let place_ty = place.ty(body, tcx).ty;
|
|
if let Err(terr) = self.relate_type_and_user_type(
|
|
place_ty,
|
|
variance,
|
|
projection,
|
|
Locations::All(stmt.source_info.span),
|
|
ConstraintCategory::TypeAnnotation,
|
|
) {
|
|
let annotation = &self.user_type_annotations[projection.base];
|
|
span_mirbug!(
|
|
self,
|
|
stmt,
|
|
"bad type assert ({:?} <: {:?} with projections {:?}): {:?}",
|
|
place_ty,
|
|
annotation,
|
|
projection.projs,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
|
|
..
|
|
}) => span_bug!(
|
|
stmt.source_info.span,
|
|
"Unexpected StatementKind::CopyNonOverlapping, should only appear after lowering_intrinsics",
|
|
),
|
|
StatementKind::FakeRead(..)
|
|
| StatementKind::StorageLive(..)
|
|
| StatementKind::StorageDead(..)
|
|
| StatementKind::LlvmInlineAsm { .. }
|
|
| StatementKind::Retag { .. }
|
|
| StatementKind::Coverage(..)
|
|
| StatementKind::Nop => {}
|
|
}
|
|
}
|
|
|
|
fn check_terminator(
|
|
&mut self,
|
|
body: &Body<'tcx>,
|
|
term: &Terminator<'tcx>,
|
|
term_location: Location,
|
|
) {
|
|
debug!("check_terminator: {:?}", term);
|
|
let tcx = self.tcx();
|
|
match term.kind {
|
|
TerminatorKind::Goto { .. }
|
|
| TerminatorKind::Resume
|
|
| TerminatorKind::Abort
|
|
| TerminatorKind::Return
|
|
| TerminatorKind::GeneratorDrop
|
|
| TerminatorKind::Unreachable
|
|
| TerminatorKind::Drop { .. }
|
|
| TerminatorKind::FalseEdge { .. }
|
|
| TerminatorKind::FalseUnwind { .. }
|
|
| TerminatorKind::InlineAsm { .. } => {
|
|
// no checks needed for these
|
|
}
|
|
|
|
TerminatorKind::DropAndReplace { ref place, ref value, target: _, unwind: _ } => {
|
|
let place_ty = place.ty(body, tcx).ty;
|
|
let rv_ty = value.ty(body, tcx);
|
|
|
|
let locations = term_location.to_locations();
|
|
if let Err(terr) =
|
|
self.sub_types(rv_ty, place_ty, locations, ConstraintCategory::Assignment)
|
|
{
|
|
span_mirbug!(
|
|
self,
|
|
term,
|
|
"bad DropAndReplace ({:?} = {:?}): {:?}",
|
|
place_ty,
|
|
rv_ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
TerminatorKind::SwitchInt { ref discr, switch_ty, .. } => {
|
|
let discr_ty = discr.ty(body, tcx);
|
|
if let Err(terr) = self.sub_types(
|
|
discr_ty,
|
|
switch_ty,
|
|
term_location.to_locations(),
|
|
ConstraintCategory::Assignment,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
term,
|
|
"bad SwitchInt ({:?} on {:?}): {:?}",
|
|
switch_ty,
|
|
discr_ty,
|
|
terr
|
|
);
|
|
}
|
|
if !switch_ty.is_integral() && !switch_ty.is_char() && !switch_ty.is_bool() {
|
|
span_mirbug!(self, term, "bad SwitchInt discr ty {:?}", switch_ty);
|
|
}
|
|
// FIXME: check the values
|
|
}
|
|
TerminatorKind::Call { ref func, ref args, ref destination, from_hir_call, .. } => {
|
|
let func_ty = func.ty(body, tcx);
|
|
debug!("check_terminator: call, func_ty={:?}", func_ty);
|
|
let sig = match func_ty.kind() {
|
|
ty::FnDef(..) | ty::FnPtr(_) => func_ty.fn_sig(tcx),
|
|
_ => {
|
|
span_mirbug!(self, term, "call to non-function {:?}", func_ty);
|
|
return;
|
|
}
|
|
};
|
|
let (sig, map) = self.infcx.replace_bound_vars_with_fresh_vars(
|
|
term.source_info.span,
|
|
LateBoundRegionConversionTime::FnCall,
|
|
sig,
|
|
);
|
|
let sig = self.normalize(sig, term_location);
|
|
self.check_call_dest(body, term, &sig, destination, term_location);
|
|
|
|
self.prove_predicates(
|
|
sig.inputs_and_output.iter().map(|ty| ty::PredicateKind::WellFormed(ty.into())),
|
|
term_location.to_locations(),
|
|
ConstraintCategory::Boring,
|
|
);
|
|
|
|
// The ordinary liveness rules will ensure that all
|
|
// regions in the type of the callee are live here. We
|
|
// then further constrain the late-bound regions that
|
|
// were instantiated at the call site to be live as
|
|
// well. The resulting is that all the input (and
|
|
// output) types in the signature must be live, since
|
|
// all the inputs that fed into it were live.
|
|
for &late_bound_region in map.values() {
|
|
let region_vid =
|
|
self.borrowck_context.universal_regions.to_region_vid(late_bound_region);
|
|
self.borrowck_context
|
|
.constraints
|
|
.liveness_constraints
|
|
.add_element(region_vid, term_location);
|
|
}
|
|
|
|
self.check_call_inputs(body, term, &sig, args, term_location, from_hir_call);
|
|
}
|
|
TerminatorKind::Assert { ref cond, ref msg, .. } => {
|
|
let cond_ty = cond.ty(body, tcx);
|
|
if cond_ty != tcx.types.bool {
|
|
span_mirbug!(self, term, "bad Assert ({:?}, not bool", cond_ty);
|
|
}
|
|
|
|
if let AssertKind::BoundsCheck { ref len, ref index } = *msg {
|
|
if len.ty(body, tcx) != tcx.types.usize {
|
|
span_mirbug!(self, len, "bounds-check length non-usize {:?}", len)
|
|
}
|
|
if index.ty(body, tcx) != tcx.types.usize {
|
|
span_mirbug!(self, index, "bounds-check index non-usize {:?}", index)
|
|
}
|
|
}
|
|
}
|
|
TerminatorKind::Yield { ref value, .. } => {
|
|
let value_ty = value.ty(body, tcx);
|
|
match body.yield_ty() {
|
|
None => span_mirbug!(self, term, "yield in non-generator"),
|
|
Some(ty) => {
|
|
if let Err(terr) = self.sub_types(
|
|
value_ty,
|
|
ty,
|
|
term_location.to_locations(),
|
|
ConstraintCategory::Yield,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
term,
|
|
"type of yield value is {:?}, but the yield type is {:?}: {:?}",
|
|
value_ty,
|
|
ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_call_dest(
|
|
&mut self,
|
|
body: &Body<'tcx>,
|
|
term: &Terminator<'tcx>,
|
|
sig: &ty::FnSig<'tcx>,
|
|
destination: &Option<(Place<'tcx>, BasicBlock)>,
|
|
term_location: Location,
|
|
) {
|
|
let tcx = self.tcx();
|
|
match *destination {
|
|
Some((ref dest, _target_block)) => {
|
|
let dest_ty = dest.ty(body, tcx).ty;
|
|
let dest_ty = self.normalize(dest_ty, term_location);
|
|
let category = match dest.as_local() {
|
|
Some(RETURN_PLACE) => {
|
|
if let BorrowCheckContext {
|
|
universal_regions:
|
|
UniversalRegions { defining_ty: DefiningTy::Const(def_id, _), .. },
|
|
..
|
|
} = self.borrowck_context
|
|
{
|
|
if tcx.is_static(*def_id) {
|
|
ConstraintCategory::UseAsStatic
|
|
} else {
|
|
ConstraintCategory::UseAsConst
|
|
}
|
|
} else {
|
|
ConstraintCategory::Return(ReturnConstraint::Normal)
|
|
}
|
|
}
|
|
Some(l) if !body.local_decls[l].is_user_variable() => {
|
|
ConstraintCategory::Boring
|
|
}
|
|
_ => ConstraintCategory::Assignment,
|
|
};
|
|
|
|
let locations = term_location.to_locations();
|
|
|
|
if let Err(terr) =
|
|
self.sub_types_or_anon(sig.output(), dest_ty, locations, category)
|
|
{
|
|
span_mirbug!(
|
|
self,
|
|
term,
|
|
"call dest mismatch ({:?} <- {:?}): {:?}",
|
|
dest_ty,
|
|
sig.output(),
|
|
terr
|
|
);
|
|
}
|
|
|
|
// When `unsized_fn_params` and `unsized_locals` are both not enabled,
|
|
// this check is done at `check_local`.
|
|
if self.unsized_feature_enabled() {
|
|
let span = term.source_info.span;
|
|
self.ensure_place_sized(dest_ty, span);
|
|
}
|
|
}
|
|
None => {
|
|
if !self
|
|
.tcx()
|
|
.conservative_is_privately_uninhabited(self.param_env.and(sig.output()))
|
|
{
|
|
span_mirbug!(self, term, "call to converging function {:?} w/o dest", sig);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_call_inputs(
|
|
&mut self,
|
|
body: &Body<'tcx>,
|
|
term: &Terminator<'tcx>,
|
|
sig: &ty::FnSig<'tcx>,
|
|
args: &[Operand<'tcx>],
|
|
term_location: Location,
|
|
from_hir_call: bool,
|
|
) {
|
|
debug!("check_call_inputs({:?}, {:?})", sig, args);
|
|
if args.len() < sig.inputs().len() || (args.len() > sig.inputs().len() && !sig.c_variadic) {
|
|
span_mirbug!(self, term, "call to {:?} with wrong # of args", sig);
|
|
}
|
|
for (n, (fn_arg, op_arg)) in sig.inputs().iter().zip(args).enumerate() {
|
|
let op_arg_ty = op_arg.ty(body, self.tcx());
|
|
let op_arg_ty = self.normalize(op_arg_ty, term_location);
|
|
let category = if from_hir_call {
|
|
ConstraintCategory::CallArgument
|
|
} else {
|
|
ConstraintCategory::Boring
|
|
};
|
|
if let Err(terr) =
|
|
self.sub_types(op_arg_ty, fn_arg, term_location.to_locations(), category)
|
|
{
|
|
span_mirbug!(
|
|
self,
|
|
term,
|
|
"bad arg #{:?} ({:?} <- {:?}): {:?}",
|
|
n,
|
|
fn_arg,
|
|
op_arg_ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_iscleanup(&mut self, body: &Body<'tcx>, block_data: &BasicBlockData<'tcx>) {
|
|
let is_cleanup = block_data.is_cleanup;
|
|
self.last_span = block_data.terminator().source_info.span;
|
|
match block_data.terminator().kind {
|
|
TerminatorKind::Goto { target } => {
|
|
self.assert_iscleanup(body, block_data, target, is_cleanup)
|
|
}
|
|
TerminatorKind::SwitchInt { ref targets, .. } => {
|
|
for target in targets.all_targets() {
|
|
self.assert_iscleanup(body, block_data, *target, is_cleanup);
|
|
}
|
|
}
|
|
TerminatorKind::Resume => {
|
|
if !is_cleanup {
|
|
span_mirbug!(self, block_data, "resume on non-cleanup block!")
|
|
}
|
|
}
|
|
TerminatorKind::Abort => {
|
|
if !is_cleanup {
|
|
span_mirbug!(self, block_data, "abort on non-cleanup block!")
|
|
}
|
|
}
|
|
TerminatorKind::Return => {
|
|
if is_cleanup {
|
|
span_mirbug!(self, block_data, "return on cleanup block")
|
|
}
|
|
}
|
|
TerminatorKind::GeneratorDrop { .. } => {
|
|
if is_cleanup {
|
|
span_mirbug!(self, block_data, "generator_drop in cleanup block")
|
|
}
|
|
}
|
|
TerminatorKind::Yield { resume, drop, .. } => {
|
|
if is_cleanup {
|
|
span_mirbug!(self, block_data, "yield in cleanup block")
|
|
}
|
|
self.assert_iscleanup(body, block_data, resume, is_cleanup);
|
|
if let Some(drop) = drop {
|
|
self.assert_iscleanup(body, block_data, drop, is_cleanup);
|
|
}
|
|
}
|
|
TerminatorKind::Unreachable => {}
|
|
TerminatorKind::Drop { target, unwind, .. }
|
|
| TerminatorKind::DropAndReplace { target, unwind, .. }
|
|
| TerminatorKind::Assert { target, cleanup: unwind, .. } => {
|
|
self.assert_iscleanup(body, block_data, target, is_cleanup);
|
|
if let Some(unwind) = unwind {
|
|
if is_cleanup {
|
|
span_mirbug!(self, block_data, "unwind on cleanup block")
|
|
}
|
|
self.assert_iscleanup(body, block_data, unwind, true);
|
|
}
|
|
}
|
|
TerminatorKind::Call { ref destination, cleanup, .. } => {
|
|
if let &Some((_, target)) = destination {
|
|
self.assert_iscleanup(body, block_data, target, is_cleanup);
|
|
}
|
|
if let Some(cleanup) = cleanup {
|
|
if is_cleanup {
|
|
span_mirbug!(self, block_data, "cleanup on cleanup block")
|
|
}
|
|
self.assert_iscleanup(body, block_data, cleanup, true);
|
|
}
|
|
}
|
|
TerminatorKind::FalseEdge { real_target, imaginary_target } => {
|
|
self.assert_iscleanup(body, block_data, real_target, is_cleanup);
|
|
self.assert_iscleanup(body, block_data, imaginary_target, is_cleanup);
|
|
}
|
|
TerminatorKind::FalseUnwind { real_target, unwind } => {
|
|
self.assert_iscleanup(body, block_data, real_target, is_cleanup);
|
|
if let Some(unwind) = unwind {
|
|
if is_cleanup {
|
|
span_mirbug!(self, block_data, "cleanup in cleanup block via false unwind");
|
|
}
|
|
self.assert_iscleanup(body, block_data, unwind, true);
|
|
}
|
|
}
|
|
TerminatorKind::InlineAsm { destination, .. } => {
|
|
if let Some(target) = destination {
|
|
self.assert_iscleanup(body, block_data, target, is_cleanup);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn assert_iscleanup(
|
|
&mut self,
|
|
body: &Body<'tcx>,
|
|
ctxt: &dyn fmt::Debug,
|
|
bb: BasicBlock,
|
|
iscleanuppad: bool,
|
|
) {
|
|
if body[bb].is_cleanup != iscleanuppad {
|
|
span_mirbug!(self, ctxt, "cleanuppad mismatch: {:?} should be {:?}", bb, iscleanuppad);
|
|
}
|
|
}
|
|
|
|
fn check_local(&mut self, body: &Body<'tcx>, local: Local, local_decl: &LocalDecl<'tcx>) {
|
|
match body.local_kind(local) {
|
|
LocalKind::ReturnPointer | LocalKind::Arg => {
|
|
// return values of normal functions are required to be
|
|
// sized by typeck, but return values of ADT constructors are
|
|
// not because we don't include a `Self: Sized` bounds on them.
|
|
//
|
|
// Unbound parts of arguments were never required to be Sized
|
|
// - maybe we should make that a warning.
|
|
return;
|
|
}
|
|
LocalKind::Var | LocalKind::Temp => {}
|
|
}
|
|
|
|
// When `unsized_fn_params` or `unsized_locals` is enabled, only function calls
|
|
// and nullary ops are checked in `check_call_dest`.
|
|
if !self.unsized_feature_enabled() {
|
|
let span = local_decl.source_info.span;
|
|
let ty = local_decl.ty;
|
|
self.ensure_place_sized(ty, span);
|
|
}
|
|
}
|
|
|
|
fn ensure_place_sized(&mut self, ty: Ty<'tcx>, span: Span) {
|
|
let tcx = self.tcx();
|
|
|
|
// Erase the regions from `ty` to get a global type. The
|
|
// `Sized` bound in no way depends on precise regions, so this
|
|
// shouldn't affect `is_sized`.
|
|
let erased_ty = tcx.erase_regions(ty);
|
|
if !erased_ty.is_sized(tcx.at(span), self.param_env) {
|
|
// in current MIR construction, all non-control-flow rvalue
|
|
// expressions evaluate through `as_temp` or `into` a return
|
|
// slot or local, so to find all unsized rvalues it is enough
|
|
// to check all temps, return slots and locals.
|
|
if self.reported_errors.replace((ty, span)).is_none() {
|
|
let mut diag = struct_span_err!(
|
|
self.tcx().sess,
|
|
span,
|
|
E0161,
|
|
"cannot move a value of type {0}: the size of {0} \
|
|
cannot be statically determined",
|
|
ty
|
|
);
|
|
|
|
// While this is located in `nll::typeck` this error is not
|
|
// an NLL error, it's a required check to prevent creation
|
|
// of unsized rvalues in certain cases:
|
|
// * operand of a box expression
|
|
// * callee in a call expression
|
|
diag.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
fn aggregate_field_ty(
|
|
&mut self,
|
|
ak: &AggregateKind<'tcx>,
|
|
field_index: usize,
|
|
location: Location,
|
|
) -> Result<Ty<'tcx>, FieldAccessError> {
|
|
let tcx = self.tcx();
|
|
|
|
match *ak {
|
|
AggregateKind::Adt(def, variant_index, substs, _, active_field_index) => {
|
|
let variant = &def.variants[variant_index];
|
|
let adj_field_index = active_field_index.unwrap_or(field_index);
|
|
if let Some(field) = variant.fields.get(adj_field_index) {
|
|
Ok(self.normalize(field.ty(tcx, substs), location))
|
|
} else {
|
|
Err(FieldAccessError::OutOfRange { field_count: variant.fields.len() })
|
|
}
|
|
}
|
|
AggregateKind::Closure(_, substs) => {
|
|
match substs.as_closure().upvar_tys().nth(field_index) {
|
|
Some(ty) => Ok(ty),
|
|
None => Err(FieldAccessError::OutOfRange {
|
|
field_count: substs.as_closure().upvar_tys().count(),
|
|
}),
|
|
}
|
|
}
|
|
AggregateKind::Generator(_, substs, _) => {
|
|
// It doesn't make sense to look at a field beyond the prefix;
|
|
// these require a variant index, and are not initialized in
|
|
// aggregate rvalues.
|
|
match substs.as_generator().prefix_tys().nth(field_index) {
|
|
Some(ty) => Ok(ty),
|
|
None => Err(FieldAccessError::OutOfRange {
|
|
field_count: substs.as_generator().prefix_tys().count(),
|
|
}),
|
|
}
|
|
}
|
|
AggregateKind::Array(ty) => Ok(ty),
|
|
AggregateKind::Tuple => {
|
|
unreachable!("This should have been covered in check_rvalues");
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_rvalue(&mut self, body: &Body<'tcx>, rvalue: &Rvalue<'tcx>, location: Location) {
|
|
let tcx = self.tcx();
|
|
|
|
match rvalue {
|
|
Rvalue::Aggregate(ak, ops) => {
|
|
self.check_aggregate_rvalue(&body, rvalue, ak, ops, location)
|
|
}
|
|
|
|
Rvalue::Repeat(operand, len) => {
|
|
// If the length cannot be evaluated we must assume that the length can be larger
|
|
// than 1.
|
|
// If the length is larger than 1, the repeat expression will need to copy the
|
|
// element, so we require the `Copy` trait.
|
|
if len.try_eval_usize(tcx, self.param_env).map_or(true, |len| len > 1) {
|
|
match operand {
|
|
Operand::Copy(..) | Operand::Constant(..) => {
|
|
// These are always okay: direct use of a const, or a value that can evidently be copied.
|
|
}
|
|
Operand::Move(place) => {
|
|
// Make sure that repeated elements implement `Copy`.
|
|
let span = body.source_info(location).span;
|
|
let ty = operand.ty(body, tcx);
|
|
if !self.infcx.type_is_copy_modulo_regions(self.param_env, ty, span) {
|
|
let ccx = ConstCx::new_with_param_env(tcx, body, self.param_env);
|
|
let is_const_fn =
|
|
is_const_fn_in_array_repeat_expression(&ccx, &place, &body);
|
|
|
|
debug!("check_rvalue: is_const_fn={:?}", is_const_fn);
|
|
|
|
let def_id = body.source.def_id().expect_local();
|
|
self.infcx.report_selection_error(
|
|
&traits::Obligation::new(
|
|
ObligationCause::new(
|
|
span,
|
|
self.tcx().hir().local_def_id_to_hir_id(def_id),
|
|
traits::ObligationCauseCode::RepeatVec(is_const_fn),
|
|
),
|
|
self.param_env,
|
|
ty::Binder::bind(ty::TraitRef::new(
|
|
self.tcx().require_lang_item(
|
|
LangItem::Copy,
|
|
Some(self.last_span),
|
|
),
|
|
tcx.mk_substs_trait(ty, &[]),
|
|
))
|
|
.without_const()
|
|
.to_predicate(self.tcx()),
|
|
),
|
|
&traits::SelectionError::Unimplemented,
|
|
false,
|
|
false,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
Rvalue::NullaryOp(_, ty) => {
|
|
// Even with unsized locals cannot box an unsized value.
|
|
if self.unsized_feature_enabled() {
|
|
let span = body.source_info(location).span;
|
|
self.ensure_place_sized(ty, span);
|
|
}
|
|
|
|
let trait_ref = ty::TraitRef {
|
|
def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
|
|
substs: tcx.mk_substs_trait(ty, &[]),
|
|
};
|
|
|
|
self.prove_trait_ref(
|
|
trait_ref,
|
|
location.to_locations(),
|
|
ConstraintCategory::SizedBound,
|
|
);
|
|
}
|
|
|
|
Rvalue::Cast(cast_kind, op, ty) => {
|
|
match cast_kind {
|
|
CastKind::Pointer(PointerCast::ReifyFnPointer) => {
|
|
let fn_sig = op.ty(body, tcx).fn_sig(tcx);
|
|
|
|
// The type that we see in the fcx is like
|
|
// `foo::<'a, 'b>`, where `foo` is the path to a
|
|
// function definition. When we extract the
|
|
// signature, it comes from the `fn_sig` query,
|
|
// and hence may contain unnormalized results.
|
|
let fn_sig = self.normalize(fn_sig, location);
|
|
|
|
let ty_fn_ptr_from = tcx.mk_fn_ptr(fn_sig);
|
|
|
|
if let Err(terr) = self.eq_types(
|
|
ty_fn_ptr_from,
|
|
ty,
|
|
location.to_locations(),
|
|
ConstraintCategory::Cast,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"equating {:?} with {:?} yields {:?}",
|
|
ty_fn_ptr_from,
|
|
ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
|
|
CastKind::Pointer(PointerCast::ClosureFnPointer(unsafety)) => {
|
|
let sig = match op.ty(body, tcx).kind() {
|
|
ty::Closure(_, substs) => substs.as_closure().sig(),
|
|
_ => bug!(),
|
|
};
|
|
let ty_fn_ptr_from = tcx.mk_fn_ptr(tcx.signature_unclosure(sig, *unsafety));
|
|
|
|
if let Err(terr) = self.eq_types(
|
|
ty_fn_ptr_from,
|
|
ty,
|
|
location.to_locations(),
|
|
ConstraintCategory::Cast,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"equating {:?} with {:?} yields {:?}",
|
|
ty_fn_ptr_from,
|
|
ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
|
|
CastKind::Pointer(PointerCast::UnsafeFnPointer) => {
|
|
let fn_sig = op.ty(body, tcx).fn_sig(tcx);
|
|
|
|
// The type that we see in the fcx is like
|
|
// `foo::<'a, 'b>`, where `foo` is the path to a
|
|
// function definition. When we extract the
|
|
// signature, it comes from the `fn_sig` query,
|
|
// and hence may contain unnormalized results.
|
|
let fn_sig = self.normalize(fn_sig, location);
|
|
|
|
let ty_fn_ptr_from = tcx.safe_to_unsafe_fn_ty(fn_sig);
|
|
|
|
if let Err(terr) = self.eq_types(
|
|
ty_fn_ptr_from,
|
|
ty,
|
|
location.to_locations(),
|
|
ConstraintCategory::Cast,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"equating {:?} with {:?} yields {:?}",
|
|
ty_fn_ptr_from,
|
|
ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
|
|
CastKind::Pointer(PointerCast::Unsize) => {
|
|
let &ty = ty;
|
|
let trait_ref = ty::TraitRef {
|
|
def_id: tcx
|
|
.require_lang_item(LangItem::CoerceUnsized, Some(self.last_span)),
|
|
substs: tcx.mk_substs_trait(op.ty(body, tcx), &[ty.into()]),
|
|
};
|
|
|
|
self.prove_trait_ref(
|
|
trait_ref,
|
|
location.to_locations(),
|
|
ConstraintCategory::Cast,
|
|
);
|
|
}
|
|
|
|
CastKind::Pointer(PointerCast::MutToConstPointer) => {
|
|
let ty_from = match op.ty(body, tcx).kind() {
|
|
ty::RawPtr(ty::TypeAndMut {
|
|
ty: ty_from,
|
|
mutbl: hir::Mutability::Mut,
|
|
}) => ty_from,
|
|
_ => {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"unexpected base type for cast {:?}",
|
|
ty,
|
|
);
|
|
return;
|
|
}
|
|
};
|
|
let ty_to = match ty.kind() {
|
|
ty::RawPtr(ty::TypeAndMut {
|
|
ty: ty_to,
|
|
mutbl: hir::Mutability::Not,
|
|
}) => ty_to,
|
|
_ => {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"unexpected target type for cast {:?}",
|
|
ty,
|
|
);
|
|
return;
|
|
}
|
|
};
|
|
if let Err(terr) = self.sub_types(
|
|
ty_from,
|
|
ty_to,
|
|
location.to_locations(),
|
|
ConstraintCategory::Cast,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"relating {:?} with {:?} yields {:?}",
|
|
ty_from,
|
|
ty_to,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
|
|
CastKind::Pointer(PointerCast::ArrayToPointer) => {
|
|
let ty_from = op.ty(body, tcx);
|
|
|
|
let opt_ty_elem_mut = match ty_from.kind() {
|
|
ty::RawPtr(ty::TypeAndMut { mutbl: array_mut, ty: array_ty }) => {
|
|
match array_ty.kind() {
|
|
ty::Array(ty_elem, _) => Some((ty_elem, *array_mut)),
|
|
_ => None,
|
|
}
|
|
}
|
|
_ => None,
|
|
};
|
|
|
|
let (ty_elem, ty_mut) = match opt_ty_elem_mut {
|
|
Some(ty_elem_mut) => ty_elem_mut,
|
|
None => {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"ArrayToPointer cast from unexpected type {:?}",
|
|
ty_from,
|
|
);
|
|
return;
|
|
}
|
|
};
|
|
|
|
let (ty_to, ty_to_mut) = match ty.kind() {
|
|
ty::RawPtr(ty::TypeAndMut { mutbl: ty_to_mut, ty: ty_to }) => {
|
|
(ty_to, *ty_to_mut)
|
|
}
|
|
_ => {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"ArrayToPointer cast to unexpected type {:?}",
|
|
ty,
|
|
);
|
|
return;
|
|
}
|
|
};
|
|
|
|
if ty_to_mut == Mutability::Mut && ty_mut == Mutability::Not {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"ArrayToPointer cast from const {:?} to mut {:?}",
|
|
ty,
|
|
ty_to
|
|
);
|
|
return;
|
|
}
|
|
|
|
if let Err(terr) = self.sub_types(
|
|
ty_elem,
|
|
ty_to,
|
|
location.to_locations(),
|
|
ConstraintCategory::Cast,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"relating {:?} with {:?} yields {:?}",
|
|
ty_elem,
|
|
ty_to,
|
|
terr
|
|
)
|
|
}
|
|
}
|
|
|
|
CastKind::Misc => {
|
|
let ty_from = op.ty(body, tcx);
|
|
let cast_ty_from = CastTy::from_ty(ty_from);
|
|
let cast_ty_to = CastTy::from_ty(ty);
|
|
match (cast_ty_from, cast_ty_to) {
|
|
(None, _)
|
|
| (_, None | Some(CastTy::FnPtr))
|
|
| (Some(CastTy::Float), Some(CastTy::Ptr(_)))
|
|
| (Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Float)) => {
|
|
span_mirbug!(self, rvalue, "Invalid cast {:?} -> {:?}", ty_from, ty,)
|
|
}
|
|
(
|
|
Some(CastTy::Int(_)),
|
|
Some(CastTy::Int(_) | CastTy::Float | CastTy::Ptr(_)),
|
|
)
|
|
| (Some(CastTy::Float), Some(CastTy::Int(_) | CastTy::Float))
|
|
| (Some(CastTy::Ptr(_)), Some(CastTy::Int(_) | CastTy::Ptr(_)))
|
|
| (Some(CastTy::FnPtr), Some(CastTy::Int(_) | CastTy::Ptr(_))) => (),
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
Rvalue::Ref(region, _borrow_kind, borrowed_place) => {
|
|
self.add_reborrow_constraint(&body, location, region, borrowed_place);
|
|
}
|
|
|
|
Rvalue::BinaryOp(
|
|
BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge,
|
|
box (left, right),
|
|
) => {
|
|
let ty_left = left.ty(body, tcx);
|
|
match ty_left.kind() {
|
|
// Types with regions are comparable if they have a common super-type.
|
|
ty::RawPtr(_) | ty::FnPtr(_) => {
|
|
let ty_right = right.ty(body, tcx);
|
|
let common_ty = self.infcx.next_ty_var(TypeVariableOrigin {
|
|
kind: TypeVariableOriginKind::MiscVariable,
|
|
span: body.source_info(location).span,
|
|
});
|
|
self.relate_types(
|
|
common_ty,
|
|
ty::Variance::Contravariant,
|
|
ty_left,
|
|
location.to_locations(),
|
|
ConstraintCategory::Boring,
|
|
)
|
|
.unwrap_or_else(|err| {
|
|
bug!("Could not equate type variable with {:?}: {:?}", ty_left, err)
|
|
});
|
|
if let Err(terr) = self.relate_types(
|
|
common_ty,
|
|
ty::Variance::Contravariant,
|
|
ty_right,
|
|
location.to_locations(),
|
|
ConstraintCategory::Boring,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"unexpected comparison types {:?} and {:?} yields {:?}",
|
|
ty_left,
|
|
ty_right,
|
|
terr
|
|
)
|
|
}
|
|
}
|
|
// For types with no regions we can just check that the
|
|
// both operands have the same type.
|
|
ty::Int(_) | ty::Uint(_) | ty::Bool | ty::Char | ty::Float(_)
|
|
if ty_left == right.ty(body, tcx) => {}
|
|
// Other types are compared by trait methods, not by
|
|
// `Rvalue::BinaryOp`.
|
|
_ => span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"unexpected comparison types {:?} and {:?}",
|
|
ty_left,
|
|
right.ty(body, tcx)
|
|
),
|
|
}
|
|
}
|
|
|
|
Rvalue::AddressOf(..)
|
|
| Rvalue::ThreadLocalRef(..)
|
|
| Rvalue::Use(..)
|
|
| Rvalue::Len(..)
|
|
| Rvalue::BinaryOp(..)
|
|
| Rvalue::CheckedBinaryOp(..)
|
|
| Rvalue::UnaryOp(..)
|
|
| Rvalue::Discriminant(..) => {}
|
|
}
|
|
}
|
|
|
|
/// If this rvalue supports a user-given type annotation, then
|
|
/// extract and return it. This represents the final type of the
|
|
/// rvalue and will be unified with the inferred type.
|
|
fn rvalue_user_ty(&self, rvalue: &Rvalue<'tcx>) -> Option<UserTypeAnnotationIndex> {
|
|
match rvalue {
|
|
Rvalue::Use(_)
|
|
| Rvalue::ThreadLocalRef(_)
|
|
| Rvalue::Repeat(..)
|
|
| Rvalue::Ref(..)
|
|
| Rvalue::AddressOf(..)
|
|
| Rvalue::Len(..)
|
|
| Rvalue::Cast(..)
|
|
| Rvalue::BinaryOp(..)
|
|
| Rvalue::CheckedBinaryOp(..)
|
|
| Rvalue::NullaryOp(..)
|
|
| Rvalue::UnaryOp(..)
|
|
| Rvalue::Discriminant(..) => None,
|
|
|
|
Rvalue::Aggregate(aggregate, _) => match **aggregate {
|
|
AggregateKind::Adt(_, _, _, user_ty, _) => user_ty,
|
|
AggregateKind::Array(_) => None,
|
|
AggregateKind::Tuple => None,
|
|
AggregateKind::Closure(_, _) => None,
|
|
AggregateKind::Generator(_, _, _) => None,
|
|
},
|
|
}
|
|
}
|
|
|
|
fn check_aggregate_rvalue(
|
|
&mut self,
|
|
body: &Body<'tcx>,
|
|
rvalue: &Rvalue<'tcx>,
|
|
aggregate_kind: &AggregateKind<'tcx>,
|
|
operands: &[Operand<'tcx>],
|
|
location: Location,
|
|
) {
|
|
let tcx = self.tcx();
|
|
|
|
self.prove_aggregate_predicates(aggregate_kind, location);
|
|
|
|
if *aggregate_kind == AggregateKind::Tuple {
|
|
// tuple rvalue field type is always the type of the op. Nothing to check here.
|
|
return;
|
|
}
|
|
|
|
for (i, operand) in operands.iter().enumerate() {
|
|
let field_ty = match self.aggregate_field_ty(aggregate_kind, i, location) {
|
|
Ok(field_ty) => field_ty,
|
|
Err(FieldAccessError::OutOfRange { field_count }) => {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"accessed field #{} but variant only has {}",
|
|
i,
|
|
field_count
|
|
);
|
|
continue;
|
|
}
|
|
};
|
|
let operand_ty = operand.ty(body, tcx);
|
|
let operand_ty = self.normalize(operand_ty, location);
|
|
|
|
if let Err(terr) = self.sub_types(
|
|
operand_ty,
|
|
field_ty,
|
|
location.to_locations(),
|
|
ConstraintCategory::Boring,
|
|
) {
|
|
span_mirbug!(
|
|
self,
|
|
rvalue,
|
|
"{:?} is not a subtype of {:?}: {:?}",
|
|
operand_ty,
|
|
field_ty,
|
|
terr
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Adds the constraints that arise from a borrow expression `&'a P` at the location `L`.
|
|
///
|
|
/// # Parameters
|
|
///
|
|
/// - `location`: the location `L` where the borrow expression occurs
|
|
/// - `borrow_region`: the region `'a` associated with the borrow
|
|
/// - `borrowed_place`: the place `P` being borrowed
|
|
fn add_reborrow_constraint(
|
|
&mut self,
|
|
body: &Body<'tcx>,
|
|
location: Location,
|
|
borrow_region: ty::Region<'tcx>,
|
|
borrowed_place: &Place<'tcx>,
|
|
) {
|
|
// These constraints are only meaningful during borrowck:
|
|
let BorrowCheckContext { borrow_set, location_table, all_facts, constraints, .. } =
|
|
self.borrowck_context;
|
|
|
|
// In Polonius mode, we also push a `borrow_region` fact
|
|
// linking the loan to the region (in some cases, though,
|
|
// there is no loan associated with this borrow expression --
|
|
// that occurs when we are borrowing an unsafe place, for
|
|
// example).
|
|
if let Some(all_facts) = all_facts {
|
|
let _prof_timer = self.infcx.tcx.prof.generic_activity("polonius_fact_generation");
|
|
if let Some(borrow_index) = borrow_set.get_index_of(&location) {
|
|
let region_vid = borrow_region.to_region_vid();
|
|
all_facts.borrow_region.push((
|
|
region_vid,
|
|
borrow_index,
|
|
location_table.mid_index(location),
|
|
));
|
|
}
|
|
}
|
|
|
|
// If we are reborrowing the referent of another reference, we
|
|
// need to add outlives relationships. In a case like `&mut
|
|
// *p`, where the `p` has type `&'b mut Foo`, for example, we
|
|
// need to ensure that `'b: 'a`.
|
|
|
|
debug!(
|
|
"add_reborrow_constraint({:?}, {:?}, {:?})",
|
|
location, borrow_region, borrowed_place
|
|
);
|
|
|
|
let mut cursor = borrowed_place.projection.as_ref();
|
|
let tcx = self.infcx.tcx;
|
|
let field = path_utils::is_upvar_field_projection(
|
|
tcx,
|
|
&self.borrowck_context.upvars,
|
|
borrowed_place.as_ref(),
|
|
body,
|
|
);
|
|
let category = if let Some(field) = field {
|
|
let var_hir_id = self.borrowck_context.upvars[field.index()].place.get_root_variable();
|
|
// FIXME(project-rfc-2229#8): Use Place for better diagnostics
|
|
ConstraintCategory::ClosureUpvar(var_hir_id)
|
|
} else {
|
|
ConstraintCategory::Boring
|
|
};
|
|
|
|
while let [proj_base @ .., elem] = cursor {
|
|
cursor = proj_base;
|
|
|
|
debug!("add_reborrow_constraint - iteration {:?}", elem);
|
|
|
|
match elem {
|
|
ProjectionElem::Deref => {
|
|
let base_ty = Place::ty_from(borrowed_place.local, proj_base, body, tcx).ty;
|
|
|
|
debug!("add_reborrow_constraint - base_ty = {:?}", base_ty);
|
|
match base_ty.kind() {
|
|
ty::Ref(ref_region, _, mutbl) => {
|
|
constraints.outlives_constraints.push(OutlivesConstraint {
|
|
sup: ref_region.to_region_vid(),
|
|
sub: borrow_region.to_region_vid(),
|
|
locations: location.to_locations(),
|
|
category,
|
|
});
|
|
|
|
match mutbl {
|
|
hir::Mutability::Not => {
|
|
// Immutable reference. We don't need the base
|
|
// to be valid for the entire lifetime of
|
|
// the borrow.
|
|
break;
|
|
}
|
|
hir::Mutability::Mut => {
|
|
// Mutable reference. We *do* need the base
|
|
// to be valid, because after the base becomes
|
|
// invalid, someone else can use our mutable deref.
|
|
|
|
// This is in order to make the following function
|
|
// illegal:
|
|
// ```
|
|
// fn unsafe_deref<'a, 'b>(x: &'a &'b mut T) -> &'b mut T {
|
|
// &mut *x
|
|
// }
|
|
// ```
|
|
//
|
|
// As otherwise you could clone `&mut T` using the
|
|
// following function:
|
|
// ```
|
|
// fn bad(x: &mut T) -> (&mut T, &mut T) {
|
|
// let my_clone = unsafe_deref(&'a x);
|
|
// ENDREGION 'a;
|
|
// (my_clone, x)
|
|
// }
|
|
// ```
|
|
}
|
|
}
|
|
}
|
|
ty::RawPtr(..) => {
|
|
// deref of raw pointer, guaranteed to be valid
|
|
break;
|
|
}
|
|
ty::Adt(def, _) if def.is_box() => {
|
|
// deref of `Box`, need the base to be valid - propagate
|
|
}
|
|
_ => bug!("unexpected deref ty {:?} in {:?}", base_ty, borrowed_place),
|
|
}
|
|
}
|
|
ProjectionElem::Field(..)
|
|
| ProjectionElem::Downcast(..)
|
|
| ProjectionElem::Index(..)
|
|
| ProjectionElem::ConstantIndex { .. }
|
|
| ProjectionElem::Subslice { .. } => {
|
|
// other field access
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn prove_aggregate_predicates(
|
|
&mut self,
|
|
aggregate_kind: &AggregateKind<'tcx>,
|
|
location: Location,
|
|
) {
|
|
let tcx = self.tcx();
|
|
|
|
debug!(
|
|
"prove_aggregate_predicates(aggregate_kind={:?}, location={:?})",
|
|
aggregate_kind, location
|
|
);
|
|
|
|
let instantiated_predicates = match aggregate_kind {
|
|
AggregateKind::Adt(def, _, substs, _, _) => {
|
|
tcx.predicates_of(def.did).instantiate(tcx, substs)
|
|
}
|
|
|
|
// For closures, we have some **extra requirements** we
|
|
//
|
|
// have to check. In particular, in their upvars and
|
|
// signatures, closures often reference various regions
|
|
// from the surrounding function -- we call those the
|
|
// closure's free regions. When we borrow-check (and hence
|
|
// region-check) closures, we may find that the closure
|
|
// requires certain relationships between those free
|
|
// regions. However, because those free regions refer to
|
|
// portions of the CFG of their caller, the closure is not
|
|
// in a position to verify those relationships. In that
|
|
// case, the requirements get "propagated" to us, and so
|
|
// we have to solve them here where we instantiate the
|
|
// closure.
|
|
//
|
|
// Despite the opacity of the previous parapgrah, this is
|
|
// actually relatively easy to understand in terms of the
|
|
// desugaring. A closure gets desugared to a struct, and
|
|
// these extra requirements are basically like where
|
|
// clauses on the struct.
|
|
AggregateKind::Closure(def_id, substs)
|
|
| AggregateKind::Generator(def_id, substs, _) => {
|
|
self.prove_closure_bounds(tcx, def_id.expect_local(), substs, location)
|
|
}
|
|
|
|
AggregateKind::Array(_) | AggregateKind::Tuple => ty::InstantiatedPredicates::empty(),
|
|
};
|
|
|
|
self.normalize_and_prove_instantiated_predicates(
|
|
instantiated_predicates,
|
|
location.to_locations(),
|
|
);
|
|
}
|
|
|
|
fn prove_closure_bounds(
|
|
&mut self,
|
|
tcx: TyCtxt<'tcx>,
|
|
def_id: LocalDefId,
|
|
substs: SubstsRef<'tcx>,
|
|
location: Location,
|
|
) -> ty::InstantiatedPredicates<'tcx> {
|
|
if let Some(ref closure_region_requirements) = tcx.mir_borrowck(def_id).closure_requirements
|
|
{
|
|
let closure_constraints = QueryRegionConstraints {
|
|
outlives: closure_region_requirements.apply_requirements(
|
|
tcx,
|
|
def_id.to_def_id(),
|
|
substs,
|
|
),
|
|
|
|
// Presently, closures never propagate member
|
|
// constraints to their parents -- they are enforced
|
|
// locally. This is largely a non-issue as member
|
|
// constraints only come from `-> impl Trait` and
|
|
// friends which don't appear (thus far...) in
|
|
// closures.
|
|
member_constraints: vec![],
|
|
};
|
|
|
|
let bounds_mapping = closure_constraints
|
|
.outlives
|
|
.iter()
|
|
.enumerate()
|
|
.filter_map(|(idx, constraint)| {
|
|
let ty::OutlivesPredicate(k1, r2) =
|
|
constraint.no_bound_vars().unwrap_or_else(|| {
|
|
bug!("query_constraint {:?} contained bound vars", constraint,);
|
|
});
|
|
|
|
match k1.unpack() {
|
|
GenericArgKind::Lifetime(r1) => {
|
|
// constraint is r1: r2
|
|
let r1_vid = self.borrowck_context.universal_regions.to_region_vid(r1);
|
|
let r2_vid = self.borrowck_context.universal_regions.to_region_vid(r2);
|
|
let outlives_requirements =
|
|
&closure_region_requirements.outlives_requirements[idx];
|
|
Some((
|
|
(r1_vid, r2_vid),
|
|
(outlives_requirements.category, outlives_requirements.blame_span),
|
|
))
|
|
}
|
|
GenericArgKind::Type(_) | GenericArgKind::Const(_) => None,
|
|
}
|
|
})
|
|
.collect();
|
|
|
|
let existing = self
|
|
.borrowck_context
|
|
.constraints
|
|
.closure_bounds_mapping
|
|
.insert(location, bounds_mapping);
|
|
assert!(existing.is_none(), "Multiple closures at the same location.");
|
|
|
|
self.push_region_constraints(
|
|
location.to_locations(),
|
|
ConstraintCategory::ClosureBounds,
|
|
&closure_constraints,
|
|
);
|
|
}
|
|
|
|
tcx.predicates_of(def_id).instantiate(tcx, substs)
|
|
}
|
|
|
|
fn prove_trait_ref(
|
|
&mut self,
|
|
trait_ref: ty::TraitRef<'tcx>,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) {
|
|
self.prove_predicates(
|
|
Some(ty::PredicateKind::Trait(
|
|
ty::TraitPredicate { trait_ref },
|
|
hir::Constness::NotConst,
|
|
)),
|
|
locations,
|
|
category,
|
|
);
|
|
}
|
|
|
|
fn normalize_and_prove_instantiated_predicates(
|
|
&mut self,
|
|
instantiated_predicates: ty::InstantiatedPredicates<'tcx>,
|
|
locations: Locations,
|
|
) {
|
|
for predicate in instantiated_predicates.predicates {
|
|
let predicate = self.normalize(predicate, locations);
|
|
self.prove_predicate(predicate, locations, ConstraintCategory::Boring);
|
|
}
|
|
}
|
|
|
|
fn prove_predicates(
|
|
&mut self,
|
|
predicates: impl IntoIterator<Item = impl ToPredicate<'tcx>>,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) {
|
|
for predicate in predicates {
|
|
let predicate = predicate.to_predicate(self.tcx());
|
|
debug!("prove_predicates(predicate={:?}, locations={:?})", predicate, locations,);
|
|
|
|
self.prove_predicate(predicate, locations, category);
|
|
}
|
|
}
|
|
|
|
fn prove_predicate(
|
|
&mut self,
|
|
predicate: ty::Predicate<'tcx>,
|
|
locations: Locations,
|
|
category: ConstraintCategory,
|
|
) {
|
|
debug!("prove_predicate(predicate={:?}, location={:?})", predicate, locations,);
|
|
|
|
let param_env = self.param_env;
|
|
self.fully_perform_op(
|
|
locations,
|
|
category,
|
|
param_env.and(type_op::prove_predicate::ProvePredicate::new(predicate)),
|
|
)
|
|
.unwrap_or_else(|NoSolution| {
|
|
span_mirbug!(self, NoSolution, "could not prove {:?}", predicate);
|
|
})
|
|
}
|
|
|
|
fn typeck_mir(&mut self, body: &Body<'tcx>) {
|
|
self.last_span = body.span;
|
|
debug!("run_on_mir: {:?}", body.span);
|
|
|
|
for (local, local_decl) in body.local_decls.iter_enumerated() {
|
|
self.check_local(&body, local, local_decl);
|
|
}
|
|
|
|
for (block, block_data) in body.basic_blocks().iter_enumerated() {
|
|
let mut location = Location { block, statement_index: 0 };
|
|
for stmt in &block_data.statements {
|
|
if !stmt.source_info.span.is_dummy() {
|
|
self.last_span = stmt.source_info.span;
|
|
}
|
|
self.check_stmt(body, stmt, location);
|
|
location.statement_index += 1;
|
|
}
|
|
|
|
self.check_terminator(&body, block_data.terminator(), location);
|
|
self.check_iscleanup(&body, block_data);
|
|
}
|
|
}
|
|
|
|
fn normalize<T>(&mut self, value: T, location: impl NormalizeLocation) -> T
|
|
where
|
|
T: type_op::normalize::Normalizable<'tcx> + Copy + 'tcx,
|
|
{
|
|
debug!("normalize(value={:?}, location={:?})", value, location);
|
|
let param_env = self.param_env;
|
|
self.fully_perform_op(
|
|
location.to_locations(),
|
|
ConstraintCategory::Boring,
|
|
param_env.and(type_op::normalize::Normalize::new(value)),
|
|
)
|
|
.unwrap_or_else(|NoSolution| {
|
|
span_mirbug!(self, NoSolution, "failed to normalize `{:?}`", value);
|
|
value
|
|
})
|
|
}
|
|
}
|
|
|
|
trait NormalizeLocation: fmt::Debug + Copy {
|
|
fn to_locations(self) -> Locations;
|
|
}
|
|
|
|
impl NormalizeLocation for Locations {
|
|
fn to_locations(self) -> Locations {
|
|
self
|
|
}
|
|
}
|
|
|
|
impl NormalizeLocation for Location {
|
|
fn to_locations(self) -> Locations {
|
|
Locations::Single(self)
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Default)]
|
|
struct ObligationAccumulator<'tcx> {
|
|
obligations: PredicateObligations<'tcx>,
|
|
}
|
|
|
|
impl<'tcx> ObligationAccumulator<'tcx> {
|
|
fn add<T>(&mut self, value: InferOk<'tcx, T>) -> T {
|
|
let InferOk { value, obligations } = value;
|
|
self.obligations.extend(obligations);
|
|
value
|
|
}
|
|
|
|
fn into_vec(self) -> PredicateObligations<'tcx> {
|
|
self.obligations
|
|
}
|
|
}
|