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Merge #8360

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8360: Fix shifting of binders in FnPointer r=flodiebold a=flodiebold

 - don't shift in/out for Chalk mapping (we want to have the same binders now)
 - do shift in when creating the signature for a closure (though it shouldn't matter much)
 - do shift in when lowering a `fn()` type
 - correctly deal with the implied binder in TypeWalk

Tested with the binders validator on various repos, so I'm pretty sure this doesn't mess things up 😬 

Co-authored-by: Florian Diebold <flodiebold@gmail.com>
This commit is contained in:
bors[bot] 2021-04-05 21:03:01 +00:00 committed by GitHub
commit 4bc8a01830
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4 changed files with 23 additions and 10 deletions
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6
crates/hir_ty/src/infer/expr.rs
View file

@ -23,7 +23,7 @@ use crate::{
traits::{chalk::from_chalk, FnTrait},
utils::{generics, variant_data, Generics},
AdtId, Binders, CallableDefId, FnPointer, FnSig, FnSubst, InEnvironment, Interner,
ProjectionTyExt, Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyKind,
ProjectionTyExt, Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyKind, TypeWalk,
};
use super::{
@ -262,7 +262,9 @@ impl<'a> InferenceContext<'a> {
let sig_ty = TyKind::Function(FnPointer {
num_binders: 0,
sig: FnSig { abi: (), safety: chalk_ir::Safety::Safe, variadic: false },
substitution: FnSubst(Substitution::from_iter(&Interner, sig_tys.clone())),
substitution: FnSubst(
Substitution::from_iter(&Interner, sig_tys.clone()).shifted_in(&Interner),
),
})
.intern(&Interner);
let closure_id = self.db.intern_closure((self.owner, tgt_expr)).into();

5
crates/hir_ty/src/lower.rs
View file

@ -178,8 +178,9 @@ impl<'a> TyLoweringContext<'a> {
}
TypeRef::Placeholder => TyKind::Error.intern(&Interner),
TypeRef::Fn(params, is_varargs) => {
let substs =
Substitution::from_iter(&Interner, params.iter().map(|tr| self.lower_ty(tr)));
let substs = self.with_shifted_in(DebruijnIndex::ONE, |ctx| {
Substitution::from_iter(&Interner, params.iter().map(|tr| ctx.lower_ty(tr)))
});
TyKind::Function(FnPointer {
num_binders: 0, // FIXME lower `for<'a> fn()` correctly
sig: FnSig { abi: (), safety: Safety::Safe, variadic: *is_varargs },

9
crates/hir_ty/src/traits/chalk/mapping.rs
View file

@ -3,7 +3,7 @@
//! Chalk (in both directions); plus some helper functions for more specialized
//! conversions.
use chalk_ir::{cast::Cast, fold::shift::Shift, interner::HasInterner, LifetimeData};
use chalk_ir::{cast::Cast, interner::HasInterner, LifetimeData};
use chalk_solve::rust_ir;
use base_db::salsa::InternKey;
@ -25,7 +25,7 @@ impl ToChalk for Ty {
TyKind::Ref(m, ty) => ref_to_chalk(db, m, ty),
TyKind::Array(ty) => array_to_chalk(db, ty),
TyKind::Function(FnPointer { sig, substitution: substs, .. }) => {
let substitution = chalk_ir::FnSubst(substs.0.to_chalk(db).shifted_in(&Interner));
let substitution = chalk_ir::FnSubst(substs.0.to_chalk(db));
chalk_ir::TyKind::Function(chalk_ir::FnPointer {
num_binders: 0,
sig,
@ -132,10 +132,7 @@ impl ToChalk for Ty {
..
}) => {
assert_eq!(num_binders, 0);
let substs = crate::FnSubst(from_chalk(
db,
substitution.0.shifted_out(&Interner).expect("fn ptr should have no binders"),
));
let substs = crate::FnSubst(from_chalk(db, substitution.0));
TyKind::Function(FnPointer { num_binders, sig, substitution: substs })
}
chalk_ir::TyKind::BoundVar(idx) => TyKind::BoundVar(idx),

13
crates/hir_ty/src/walk.rs
View file

@ -92,6 +92,13 @@ pub trait TypeWalk {
self
}
fn shifted_in(self, _interner: &Interner) -> Self
where
Self: Sized,
{
self.shifted_in_from(DebruijnIndex::ONE)
}
/// Shifts up debruijn indices of `TyKind::Bound` vars by `n`.
fn shifted_in_from(self, n: DebruijnIndex) -> Self
where
@ -149,6 +156,9 @@ impl TypeWalk for Ty {
TyKind::Slice(ty) | TyKind::Array(ty) | TyKind::Ref(_, ty) | TyKind::Raw(_, ty) => {
ty.walk(f);
}
TyKind::Function(fn_pointer) => {
fn_pointer.substitution.0.walk(f);
}
_ => {
if let Some(substs) = self.substs() {
for t in substs.iter(&Interner) {
@ -180,6 +190,9 @@ impl TypeWalk for Ty {
TyKind::Slice(ty) | TyKind::Array(ty) | TyKind::Ref(_, ty) | TyKind::Raw(_, ty) => {
ty.walk_mut_binders(f, binders);
}
TyKind::Function(fn_pointer) => {
fn_pointer.substitution.0.walk_mut_binders(f, binders.shifted_in());
}
_ => {
if let Some(substs) = self.substs_mut() {
substs.walk_mut_binders(f, binders);