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dfireBirddfireBird
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implement basic inferring of lifetimes
1 parent 329adb5 commit b9e9e29

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14 files changed

+110
-86
lines changed

14 files changed

+110
-86
lines changed

‎crates/hir-ty/src/infer.rs

Lines changed: 10 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -57,7 +57,7 @@ use triomphe::Arc;
5757

5858
use crate::{
5959
db::HirDatabase,
60-
error_lifetime, fold_tys,
60+
fold_tys,
6161
generics::Generics,
6262
infer::{coerce::CoerceMany, unify::InferenceTable},
6363
lower::ImplTraitLoweringMode,
@@ -329,13 +329,13 @@ pub struct Adjustment {
329329
}
330330

331331
impl Adjustment {
332-
pub fn borrow(m: Mutability, ty: Ty) -> Self {
333-
let ty = TyKind::Ref(m, error_lifetime(), ty).intern(Interner);
334-
Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(m)), target: ty }
332+
pub fn borrow(m: Mutability, ty: Ty, lt: Lifetime) -> Self {
333+
let ty = TyKind::Ref(m, lt.clone(), ty).intern(Interner);
334+
Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(lt, m)), target: ty }
335335
}
336336
}
337337

338-
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
338+
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
339339
pub enum Adjust {
340340
/// Go from ! to any type.
341341
NeverToAny,
@@ -355,18 +355,18 @@ pub enum Adjust {
355355
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
356356
pub struct OverloadedDeref(pub Option<Mutability>);
357357

358-
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
358+
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
359359
pub enum AutoBorrow {
360360
/// Converts from T to &T.
361-
Ref(Mutability),
361+
Ref(Lifetime, Mutability),
362362
/// Converts from T to *T.
363363
RawPtr(Mutability),
364364
}
365365

366366
impl AutoBorrow {
367-
fn mutability(self) -> Mutability {
368-
let (AutoBorrow::Ref(m) | AutoBorrow::RawPtr(m)) = self;
369-
m
367+
fn mutability(&self) -> Mutability {
368+
let (AutoBorrow::Ref(_, m) | AutoBorrow::RawPtr(m)) = self;
369+
*m
370370
}
371371
}
372372

‎crates/hir-ty/src/infer/closure.rs

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -325,6 +325,7 @@ impl CapturedItemWithoutTy {
325325
BorrowKind::Mut { .. } => Mutability::Mut,
326326
_ => Mutability::Not,
327327
};
328+
// FIXME: use lifetime inference here
328329
TyKind::Ref(m, error_lifetime(), ty).intern(Interner)
329330
}
330331
};
@@ -474,7 +475,7 @@ impl InferenceContext<'_> {
474475

475476
fn walk_expr_with_adjust(&mut self, tgt_expr: ExprId, adjustment: &[Adjustment]) {
476477
if let Some((last, rest)) = adjustment.split_last() {
477-
match last.kind {
478+
match &last.kind {
478479
Adjust::NeverToAny | Adjust::Deref(None) | Adjust::Pointer(_) => {
479480
self.walk_expr_with_adjust(tgt_expr, rest)
480481
}

‎crates/hir-ty/src/infer/coerce.rs

Lines changed: 22 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -18,14 +18,13 @@ use triomphe::Arc;
1818
use crate::{
1919
autoderef::{Autoderef, AutoderefKind},
2020
db::HirDatabase,
21-
error_lifetime,
2221
infer::{
2322
Adjust, Adjustment, AutoBorrow, InferOk, InferenceContext, OverloadedDeref, PointerCast,
2423
TypeError, TypeMismatch,
2524
},
2625
utils::ClosureSubst,
27-
Canonical, DomainGoal, FnAbi, FnPointer, FnSig, Guidance, InEnvironment, Interner, Solution,
28-
Substitution, TraitEnvironment, Ty, TyBuilder, TyExt,
26+
Canonical, DomainGoal, FnAbi, FnPointer, FnSig, Guidance, InEnvironment, Interner, Lifetime,
27+
Solution, Substitution, TraitEnvironment, Ty, TyBuilder, TyExt,
2928
};
3029

3130
use super::unify::InferenceTable;
@@ -301,7 +300,7 @@ impl InferenceTable<'_> {
301300
// Examine the supertype and consider auto-borrowing.
302301
match to_ty.kind(Interner) {
303302
TyKind::Raw(mt, _) => return self.coerce_ptr(from_ty, to_ty, *mt),
304-
TyKind::Ref(mt, _, _) => return self.coerce_ref(from_ty, to_ty, *mt),
303+
TyKind::Ref(mt, lt, _) => return self.coerce_ref(from_ty, to_ty, *mt, lt),
305304
_ => {}
306305
}
307306

@@ -377,11 +376,17 @@ impl InferenceTable<'_> {
377376
/// Reborrows `&mut A` to `&mut B` and `&(mut) A` to `&B`.
378377
/// To match `A` with `B`, autoderef will be performed,
379378
/// calling `deref`/`deref_mut` where necessary.
380-
fn coerce_ref(&mut self, from_ty: Ty, to_ty: &Ty, to_mt: Mutability) -> CoerceResult {
381-
let from_mt = match from_ty.kind(Interner) {
382-
&TyKind::Ref(mt, _, _) => {
383-
coerce_mutabilities(mt, to_mt)?;
384-
mt
379+
fn coerce_ref(
380+
&mut self,
381+
from_ty: Ty,
382+
to_ty: &Ty,
383+
to_mt: Mutability,
384+
to_lt: &Lifetime,
385+
) -> CoerceResult {
386+
let (_from_lt, from_mt) = match from_ty.kind(Interner) {
387+
TyKind::Ref(mt, lt, _) => {
388+
coerce_mutabilities(*mt, to_mt)?;
389+
(lt.clone(), *mt) // clone is probably not good?
385390
}
386391
_ => return self.unify_and(&from_ty, to_ty, identity),
387392
};
@@ -427,8 +432,8 @@ impl InferenceTable<'_> {
427432
// compare those. Note that this means we use the target
428433
// mutability [1], since it may be that we are coercing
429434
// from `&mut T` to `&U`.
430-
let lt = error_lifetime(); // FIXME: handle lifetimes correctly, see rustc
431-
let derefd_from_ty = TyKind::Ref(to_mt, lt, referent_ty).intern(Interner);
435+
let lt = to_lt; // FIXME: Involve rustc LUB and SUB flag checks
436+
let derefd_from_ty = TyKind::Ref(to_mt, lt.clone(), referent_ty).intern(Interner);
432437
match autoderef.table.try_unify(&derefd_from_ty, to_ty) {
433438
Ok(result) => {
434439
found = Some(result.map(|()| derefd_from_ty));
@@ -472,8 +477,10 @@ impl InferenceTable<'_> {
472477
}
473478

474479
let mut adjustments = auto_deref_adjust_steps(&autoderef);
475-
adjustments
476-
.push(Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(to_mt)), target: ty.clone() });
480+
adjustments.push(Adjustment {
481+
kind: Adjust::Borrow(AutoBorrow::Ref(to_lt.clone(), to_mt)),
482+
target: ty.clone(),
483+
});
477484

478485
success(adjustments, ty, goals)
479486
}
@@ -621,11 +628,11 @@ impl InferenceTable<'_> {
621628
(TyKind::Ref(from_mt, _, from_inner), &TyKind::Ref(to_mt, _, _)) => {
622629
coerce_mutabilities(*from_mt, to_mt)?;
623630

624-
let lt = error_lifetime();
631+
let lt = self.new_lifetime_var();
625632
Some((
626633
Adjustment { kind: Adjust::Deref(None), target: from_inner.clone() },
627634
Adjustment {
628-
kind: Adjust::Borrow(AutoBorrow::Ref(to_mt)),
635+
kind: Adjust::Borrow(AutoBorrow::Ref(lt.clone(), to_mt)),
629636
target: TyKind::Ref(to_mt, lt, from_inner.clone()).intern(Interner),
630637
},
631638
))

‎crates/hir-ty/src/infer/expr.rs

Lines changed: 29 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -24,7 +24,6 @@ use crate::{
2424
autoderef::{builtin_deref, deref_by_trait, Autoderef},
2525
consteval,
2626
db::{InternedClosure, InternedCoroutine},
27-
error_lifetime,
2827
generics::{generics, Generics},
2928
infer::{
3029
coerce::{CoerceMany, CoercionCause},
@@ -635,7 +634,10 @@ impl InferenceContext<'_> {
635634
let inner_ty = self.infer_expr_inner(*expr, &expectation);
636635
match rawness {
637636
Rawness::RawPtr => TyKind::Raw(mutability, inner_ty),
638-
Rawness::Ref => TyKind::Ref(mutability, error_lifetime(), inner_ty),
637+
Rawness::Ref => {
638+
let lt = self.table.new_lifetime_var();
639+
TyKind::Ref(mutability, lt, inner_ty)
640+
}
639641
}
640642
.intern(Interner)
641643
}
@@ -786,7 +788,11 @@ impl InferenceContext<'_> {
786788
adj.apply(&mut self.table, base_ty)
787789
});
788790
// mutability will be fixed up in `InferenceContext::infer_mut`;
789-
adj.push(Adjustment::borrow(Mutability::Not, self_ty.clone()));
791+
adj.push(Adjustment::borrow(
792+
Mutability::Not,
793+
self_ty.clone(),
794+
self.table.new_lifetime_var(),
795+
));
790796
self.write_expr_adj(*base, adj);
791797
if let Some(func) = self
792798
.db
@@ -990,7 +996,7 @@ impl InferenceContext<'_> {
990996
match fn_x {
991997
FnTrait::FnOnce => (),
992998
FnTrait::FnMut => {
993-
if let TyKind::Ref(Mutability::Mut, _, inner) = derefed_callee.kind(Interner) {
999+
if let TyKind::Ref(Mutability::Mut, lt, inner) = derefed_callee.kind(Interner) {
9941000
if adjustments
9951001
.last()
9961002
.map(|it| matches!(it.kind, Adjust::Borrow(_)))
@@ -999,15 +1005,27 @@ impl InferenceContext<'_> {
9991005
// prefer reborrow to move
10001006
adjustments
10011007
.push(Adjustment { kind: Adjust::Deref(None), target: inner.clone() });
1002-
adjustments.push(Adjustment::borrow(Mutability::Mut, inner.clone()))
1008+
adjustments.push(Adjustment::borrow(
1009+
Mutability::Mut,
1010+
inner.clone(),
1011+
lt.clone(),
1012+
))
10031013
}
10041014
} else {
1005-
adjustments.push(Adjustment::borrow(Mutability::Mut, derefed_callee.clone()));
1015+
adjustments.push(Adjustment::borrow(
1016+
Mutability::Mut,
1017+
derefed_callee.clone(),
1018+
self.table.new_lifetime_var(),
1019+
));
10061020
}
10071021
}
10081022
FnTrait::Fn => {
10091023
if !matches!(derefed_callee.kind(Interner), TyKind::Ref(Mutability::Not, _, _)) {
1010-
adjustments.push(Adjustment::borrow(Mutability::Not, derefed_callee.clone()));
1024+
adjustments.push(Adjustment::borrow(
1025+
Mutability::Not,
1026+
derefed_callee.clone(),
1027+
self.table.new_lifetime_var(),
1028+
));
10111029
}
10121030
}
10131031
}
@@ -1310,23 +1328,23 @@ impl InferenceContext<'_> {
13101328
Some(sig) => {
13111329
let p_left = &sig.params()[0];
13121330
if matches!(op, BinaryOp::CmpOp(..) | BinaryOp::Assignment { .. }) {
1313-
if let &TyKind::Ref(mtbl, _, _) = p_left.kind(Interner) {
1331+
if let TyKind::Ref(mtbl, lt, _) = p_left.kind(Interner) {
13141332
self.write_expr_adj(
13151333
lhs,
13161334
vec![Adjustment {
1317-
kind: Adjust::Borrow(AutoBorrow::Ref(mtbl)),
1335+
kind: Adjust::Borrow(AutoBorrow::Ref(lt.clone(), *mtbl)),
13181336
target: p_left.clone(),
13191337
}],
13201338
);
13211339
}
13221340
}
13231341
let p_right = &sig.params()[1];
13241342
if matches!(op, BinaryOp::CmpOp(..)) {
1325-
if let &TyKind::Ref(mtbl, _, _) = p_right.kind(Interner) {
1343+
if let TyKind::Ref(mtbl, lt, _) = p_right.kind(Interner) {
13261344
self.write_expr_adj(
13271345
rhs,
13281346
vec![Adjustment {
1329-
kind: Adjust::Borrow(AutoBorrow::Ref(mtbl)),
1347+
kind: Adjust::Borrow(AutoBorrow::Ref(lt.clone(), *mtbl)),
13301348
target: p_right.clone(),
13311349
}],
13321350
);

‎crates/hir-ty/src/infer/mutability.rs

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -25,7 +25,7 @@ impl InferenceContext<'_> {
2525
Adjust::NeverToAny | Adjust::Deref(None) | Adjust::Pointer(_) => (),
2626
Adjust::Deref(Some(d)) => *d = OverloadedDeref(Some(mutability)),
2727
Adjust::Borrow(b) => match b {
28-
AutoBorrow::Ref(m) | AutoBorrow::RawPtr(m) => mutability = *m,
28+
AutoBorrow::Ref(_, m) | AutoBorrow::RawPtr(m) => mutability = *m,
2929
},
3030
}
3131
}
@@ -121,7 +121,7 @@ impl InferenceContext<'_> {
121121
.get_mut(&base)
122122
.and_then(|it| it.last_mut());
123123
if let Some(Adjustment {
124-
kind: Adjust::Borrow(AutoBorrow::Ref(mutability)),
124+
kind: Adjust::Borrow(AutoBorrow::Ref(_, mutability)),
125125
..
126126
}) = base_adjustments
127127
{

‎crates/hir-ty/src/infer/pat.rs

Lines changed: 9 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,6 @@ use stdx::TupleExt;
1212

1313
use crate::{
1414
consteval::{try_const_usize, usize_const},
15-
error_lifetime,
1615
infer::{BindingMode, Expectation, InferenceContext, TypeMismatch},
1716
lower::lower_to_chalk_mutability,
1817
primitive::UintTy,
@@ -394,19 +393,20 @@ impl InferenceContext<'_> {
394393
expected: &Ty,
395394
default_bm: BindingMode,
396395
) -> Ty {
397-
let expectation = match expected.as_reference() {
398-
Some((inner_ty, _lifetime, _exp_mut)) => inner_ty.clone(),
396+
let (expectation_type, expection_lt) = match expected.as_reference() {
397+
Some((inner_ty, lifetime, _exp_mut)) => (inner_ty.clone(), lifetime.clone()),
399398
None => {
400399
let inner_ty = self.table.new_type_var();
400+
let inner_lt = self.table.new_lifetime_var();
401401
let ref_ty =
402-
TyKind::Ref(mutability, error_lifetime(), inner_ty.clone()).intern(Interner);
402+
TyKind::Ref(mutability, inner_lt.clone(), inner_ty.clone()).intern(Interner);
403403
// Unification failure will be reported by the caller.
404404
self.unify(&ref_ty, expected);
405-
inner_ty
405+
(inner_ty, inner_lt)
406406
}
407407
};
408-
let subty = self.infer_pat(inner_pat, &expectation, default_bm);
409-
TyKind::Ref(mutability, error_lifetime(), subty).intern(Interner)
408+
let subty = self.infer_pat(inner_pat, &expectation_type, default_bm);
409+
TyKind::Ref(mutability, expection_lt, subty).intern(Interner)
410410
}
411411

412412
fn infer_bind_pat(
@@ -433,7 +433,8 @@ impl InferenceContext<'_> {
433433

434434
let bound_ty = match mode {
435435
BindingMode::Ref(mutability) => {
436-
TyKind::Ref(mutability, error_lifetime(), inner_ty.clone()).intern(Interner)
436+
let inner_lt = self.table.new_lifetime_var();
437+
TyKind::Ref(mutability, inner_lt, inner_ty.clone()).intern(Interner)
437438
}
438439
BindingMode::Move => inner_ty.clone(),
439440
};

‎crates/hir-ty/src/infer/unify.rs

Lines changed: 7 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -17,12 +17,12 @@ use triomphe::Arc;
1717

1818
use super::{InferOk, InferResult, InferenceContext, TypeError};
1919
use crate::{
20-
consteval::unknown_const, db::HirDatabase, error_lifetime, fold_generic_args,
21-
fold_tys_and_consts, to_chalk_trait_id, traits::FnTrait, AliasEq, AliasTy, BoundVar, Canonical,
22-
Const, ConstValue, DebruijnIndex, DomainGoal, GenericArg, GenericArgData, Goal, GoalData,
23-
Guidance, InEnvironment, InferenceVar, Interner, Lifetime, OpaqueTyId, ParamKind, ProjectionTy,
24-
ProjectionTyExt, Scalar, Solution, Substitution, TraitEnvironment, Ty, TyBuilder, TyExt,
25-
TyKind, VariableKind, WhereClause,
20+
consteval::unknown_const, db::HirDatabase, fold_generic_args, fold_tys_and_consts,
21+
to_chalk_trait_id, traits::FnTrait, AliasEq, AliasTy, BoundVar, Canonical, Const, ConstValue,
22+
DebruijnIndex, DomainGoal, GenericArg, GenericArgData, Goal, GoalData, Guidance, InEnvironment,
23+
InferenceVar, Interner, Lifetime, OpaqueTyId, ParamKind, ProjectionTy, ProjectionTyExt, Scalar,
24+
Solution, Substitution, TraitEnvironment, Ty, TyBuilder, TyExt, TyKind, VariableKind,
25+
WhereClause,
2626
};
2727

2828
impl InferenceContext<'_> {
@@ -105,7 +105,7 @@ impl<T: HasInterner<Interner = Interner>> Canonicalized<T> {
105105
VariableKind::Ty(TyVariableKind::Float) => ctx.new_float_var().cast(Interner),
106106
// Chalk can sometimes return new lifetime variables. We just replace them by errors
107107
// for now.
108-
VariableKind::Lifetime => error_lifetime().cast(Interner),
108+
VariableKind::Lifetime => ctx.new_lifetime_var().cast(Interner),
109109
VariableKind::Const(ty) => ctx.new_const_var(ty.clone()).cast(Interner),
110110
}),
111111
);

‎crates/hir-ty/src/method_resolution.rs

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -542,7 +542,8 @@ impl ReceiverAdjustments {
542542
}
543543
}
544544
if let Some(m) = self.autoref {
545-
let a = Adjustment::borrow(m, ty);
545+
let lt = table.new_lifetime_var();
546+
let a = Adjustment::borrow(m, ty, lt);
546547
ty = a.target.clone();
547548
adjust.push(a);
548549
}

‎crates/hir-ty/src/mir/lower.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -337,7 +337,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
337337
self.push_assignment(current, place, Operand::Copy(p).into(), expr_id.into());
338338
Ok(Some(current))
339339
}
340-
Adjust::Borrow(AutoBorrow::Ref(m) | AutoBorrow::RawPtr(m)) => {
340+
Adjust::Borrow(AutoBorrow::Ref(_, m) | AutoBorrow::RawPtr(m)) => {
341341
let Some((p, current)) =
342342
self.lower_expr_as_place_with_adjust(current, expr_id, true, rest)?
343343
else {

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