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resolve before canonicalization, ICE if unresolved

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This commit is contained in:
Michael Goulet 2023-08-02 01:31:31 +00:00
parent 5bea48ba18
commit eaf8af5de8
3 changed files with 115 additions and 68 deletions
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2
compiler/rustc_middle/src/traits/solve.rs
View File

@ -147,7 +147,7 @@ impl<'tcx> std::ops::Deref for ExternalConstraints<'tcx> {
}
/// Additional constraints returned on success.
#[derive(Debug, PartialEq, Eq, Clone, Hash, HashStable, Default)]
#[derive(Debug, PartialEq, Eq, Clone, Hash, HashStable, Default, TypeVisitable, TypeFoldable)]
pub struct ExternalConstraintsData<'tcx> {
// FIXME: implement this.
pub region_constraints: QueryRegionConstraints<'tcx>,

78
compiler/rustc_trait_selection/src/solve/canonicalize.rs
View File

@ -207,23 +207,18 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'_, 'tcx> {
t
}
fn fold_region(&mut self, mut r: ty::Region<'tcx>) -> ty::Region<'tcx> {
match self.canonicalize_mode {
CanonicalizeMode::Input => {
// Don't resolve infer vars in input, since it affects
// caching and may cause trait selection bugs which rely
// on regions to be equal.
}
CanonicalizeMode::Response { .. } => {
fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
if let ty::ReVar(vid) = *r {
r = self
let resolved_region = self
.infcx
.inner
.borrow_mut()
.unwrap_region_constraints()
.opportunistic_resolve_var(self.infcx.tcx, vid);
}
}
assert_eq!(
r, resolved_region,
"region var should have been resolved, {r} -> {resolved_region}"
);
}
let kind = match *r {
@ -278,39 +273,23 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'_, 'tcx> {
ty::Region::new_late_bound(self.interner(), self.binder_index, br)
}
fn fold_ty(&mut self, mut t: Ty<'tcx>) -> Ty<'tcx> {
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
let kind = match *t.kind() {
ty::Infer(ty::TyVar(mut vid)) => {
// We need to canonicalize the *root* of our ty var.
// This is so that our canonical response correctly reflects
// any equated inference vars correctly!
let root_vid = self.infcx.root_var(vid);
if root_vid != vid {
t = Ty::new_var(self.infcx.tcx, root_vid);
vid = root_vid;
}
match self.infcx.probe_ty_var(vid) {
Ok(t) => return self.fold_ty(t),
Err(ui) => CanonicalVarKind::Ty(CanonicalTyVarKind::General(ui)),
}
ty::Infer(ty::TyVar(vid)) => {
assert_eq!(self.infcx.root_var(vid), vid, "ty vid should have been resolved");
let Err(ui) = self.infcx.probe_ty_var(vid) else {
bug!("ty var should have been resolved: {t}");
};
CanonicalVarKind::Ty(CanonicalTyVarKind::General(ui))
}
ty::Infer(ty::IntVar(vid)) => {
let nt = self.infcx.opportunistic_resolve_int_var(vid);
if nt != t {
return self.fold_ty(nt);
} else {
assert_eq!(self.infcx.opportunistic_resolve_int_var(vid), t);
CanonicalVarKind::Ty(CanonicalTyVarKind::Int)
}
}
ty::Infer(ty::FloatVar(vid)) => {
let nt = self.infcx.opportunistic_resolve_float_var(vid);
if nt != t {
return self.fold_ty(nt);
} else {
assert_eq!(self.infcx.opportunistic_resolve_float_var(vid), t);
CanonicalVarKind::Ty(CanonicalTyVarKind::Float)
}
}
ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => {
bug!("fresh var during canonicalization: {t:?}")
}
@ -372,22 +351,19 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'_, 'tcx> {
Ty::new_bound(self.infcx.tcx, self.binder_index, bt)
}
fn fold_const(&mut self, mut c: ty::Const<'tcx>) -> ty::Const<'tcx> {
fn fold_const(&mut self, c: ty::Const<'tcx>) -> ty::Const<'tcx> {
let kind = match c.kind() {
ty::ConstKind::Infer(ty::InferConst::Var(mut vid)) => {
// We need to canonicalize the *root* of our const var.
// This is so that our canonical response correctly reflects
// any equated inference vars correctly!
let root_vid = self.infcx.root_const_var(vid);
if root_vid != vid {
c = ty::Const::new_var(self.infcx.tcx, root_vid, c.ty());
vid = root_vid;
}
match self.infcx.probe_const_var(vid) {
Ok(c) => return self.fold_const(c),
Err(universe) => CanonicalVarKind::Const(universe, c.ty()),
}
ty::ConstKind::Infer(ty::InferConst::Var(vid)) => {
assert_eq!(
self.infcx.root_const_var(vid),
vid,
"const var should have been resolved"
);
let Err(ui) = self.infcx.probe_const_var(vid) else {
bug!("const var should have been resolved");
};
// FIXME: we should fold this ty eventually
CanonicalVarKind::Const(ui, c.ty())
}
ty::ConstKind::Infer(ty::InferConst::Fresh(_)) => {
bug!("fresh var during canonicalization: {c:?}")

85
compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs
View File

@ -16,11 +16,15 @@ use rustc_index::IndexVec;
use rustc_infer::infer::canonical::query_response::make_query_region_constraints;
use rustc_infer::infer::canonical::CanonicalVarValues;
use rustc_infer::infer::canonical::{CanonicalExt, QueryRegionConstraints};
use rustc_infer::infer::InferCtxt;
use rustc_middle::traits::query::NoSolution;
use rustc_middle::traits::solve::{
ExternalConstraintsData, MaybeCause, PredefinedOpaquesData, QueryInput,
};
use rustc_middle::ty::{self, BoundVar, GenericArgKind, Ty, TyCtxt, TypeFoldable};
use rustc_middle::ty::{
self, BoundVar, GenericArgKind, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
TypeVisitableExt,
};
use rustc_span::DUMMY_SP;
use std::iter;
use std::ops::Deref;
@ -32,6 +36,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
&self,
goal: Goal<'tcx, T>,
) -> (Vec<ty::GenericArg<'tcx>>, CanonicalInput<'tcx, T>) {
let opaque_types = self.infcx.clone_opaque_types_for_query_response();
let (goal, opaque_types) =
(goal, opaque_types).fold_with(&mut EagerResolver { infcx: self.infcx });
let mut orig_values = Default::default();
let canonical_goal = Canonicalizer::canonicalize(
self.infcx,
@ -40,11 +48,9 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
QueryInput {
goal,
anchor: self.infcx.defining_use_anchor,
predefined_opaques_in_body: self.tcx().mk_predefined_opaques_in_body(
PredefinedOpaquesData {
opaque_types: self.infcx.clone_opaque_types_for_query_response(),
},
),
predefined_opaques_in_body: self
.tcx()
.mk_predefined_opaques_in_body(PredefinedOpaquesData { opaque_types }),
},
);
(orig_values, canonical_goal)
@ -69,6 +75,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
previous call to `try_evaluate_added_goals!`"
);
let certainty = certainty.unify_with(goals_certainty);
if let Certainty::OVERFLOW = certainty {
// If we have overflow, it's probable that we're substituting a type
// into itself infinitely and any partial substitutions in the query
@ -84,10 +91,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
return Ok(self.make_ambiguous_response_no_constraints(MaybeCause::Overflow));
}
let certainty = certainty.unify_with(goals_certainty);
let var_values = self.var_values;
let external_constraints = self.compute_external_query_constraints()?;
let (var_values, external_constraints) =
(var_values, external_constraints).fold_with(&mut EagerResolver { infcx: self.infcx });
let canonical = Canonicalizer::canonicalize(
self.infcx,
CanonicalizeMode::Response { max_input_universe: self.max_input_universe },
@ -334,3 +343,65 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
Ok(())
}
}
/// Resolves ty, region, and const vars to their inferred values or their root vars.
struct EagerResolver<'a, 'tcx> {
infcx: &'a InferCtxt<'tcx>,
}
impl<'tcx> TypeFolder<TyCtxt<'tcx>> for EagerResolver<'_, 'tcx> {
fn interner(&self) -> TyCtxt<'tcx> {
self.infcx.tcx
}
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
match *t.kind() {
ty::Infer(ty::TyVar(vid)) => match self.infcx.probe_ty_var(vid) {
Ok(t) => t.fold_with(self),
Err(_) => Ty::new_var(self.infcx.tcx, self.infcx.root_var(vid)),
},
ty::Infer(ty::IntVar(vid)) => self.infcx.opportunistic_resolve_int_var(vid),
ty::Infer(ty::FloatVar(vid)) => self.infcx.opportunistic_resolve_float_var(vid),
_ => {
if t.has_infer() {
t.super_fold_with(self)
} else {
t
}
}
}
}
fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
match *r {
ty::ReVar(vid) => self
.infcx
.inner
.borrow_mut()
.unwrap_region_constraints()
.opportunistic_resolve_var(self.infcx.tcx, vid),
_ => r,
}
}
fn fold_const(&mut self, c: ty::Const<'tcx>) -> ty::Const<'tcx> {
match c.kind() {
ty::ConstKind::Infer(ty::InferConst::Var(vid)) => {
// FIXME: we need to fold the ty too, I think.
match self.infcx.probe_const_var(vid) {
Ok(c) => c.fold_with(self),
Err(_) => {
ty::Const::new_var(self.infcx.tcx, self.infcx.root_const_var(vid), c.ty())
}
}
}
_ => {
if c.has_infer() {
c.super_fold_with(self)
} else {
c
}
}
}
}
}