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fix: handle lifetime variables in CallableSig query

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This commit is contained in:
Ryo Yoshida 2022-12-25 05:07:44 +09:00
parent 1927c2e1d8
commit a639917b66
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GPG Key ID: E25698A930586171
1 changed files with 22 additions and 42 deletions
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64
crates/hir-ty/src/lib.rs
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@ -40,7 +40,7 @@ use std::sync::Arc;
use chalk_ir::{ use chalk_ir::{
fold::{Shift, TypeFoldable}, fold::{Shift, TypeFoldable},
interner::HasInterner, interner::HasInterner,
NoSolution, UniverseIndex, NoSolution,
}; };
use hir_def::{expr::ExprId, type_ref::Rawness, TypeOrConstParamId}; use hir_def::{expr::ExprId, type_ref::Rawness, TypeOrConstParamId};
use hir_expand::name; use hir_expand::name;
@ -48,7 +48,9 @@ use itertools::Either;
use traits::FnTrait; use traits::FnTrait;
use utils::Generics; use utils::Generics;
use crate::{consteval::unknown_const, db::HirDatabase, utils::generics}; use crate::{
consteval::unknown_const, db::HirDatabase, infer::unify::InferenceTable, utils::generics,
};
pub use autoderef::autoderef; pub use autoderef::autoderef;
pub use builder::{ParamKind, TyBuilder}; pub use builder::{ParamKind, TyBuilder};
@ -533,53 +535,31 @@ pub fn callable_sig_from_fnonce(
let fn_once_trait = FnTrait::FnOnce.get_id(db, krate)?; let fn_once_trait = FnTrait::FnOnce.get_id(db, krate)?;
let output_assoc_type = db.trait_data(fn_once_trait).associated_type_by_name(&name![Output])?; let output_assoc_type = db.trait_data(fn_once_trait).associated_type_by_name(&name![Output])?;
let mut table = InferenceTable::new(db, env.clone());
let b = TyBuilder::trait_ref(db, fn_once_trait); let b = TyBuilder::trait_ref(db, fn_once_trait);
if b.remaining() != 2 { if b.remaining() != 2 {
return None; return None;
} }
let fn_once = b.push(self_ty.clone()).fill_with_bound_vars(DebruijnIndex::INNERMOST, 0).build();
let kinds = fn_once
.substitution
.iter(Interner)
.skip(1)
.map(|x| {
let vk = match x.data(Interner) {
chalk_ir::GenericArgData::Ty(_) => {
chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)
}
chalk_ir::GenericArgData::Lifetime(_) => chalk_ir::VariableKind::Lifetime,
chalk_ir::GenericArgData::Const(c) => {
chalk_ir::VariableKind::Const(c.data(Interner).ty.clone())
}
};
chalk_ir::WithKind::new(vk, UniverseIndex::ROOT)
})
.collect::<Vec<_>>();
// FIXME: chalk refuses to solve `<Self as FnOnce<^0.0>>::Output == ^0.1`, so we first solve // Register two obligations:
// `<Self as FnOnce<^0.0>>` and then replace `^0.0` with the concrete argument tuple. // - Self: FnOnce<?args_ty>
let trait_env = env.env.clone(); // - <Self as FnOnce<?args_ty>>::Output == ?ret_ty
let obligation = InEnvironment { goal: fn_once.cast(Interner), environment: trait_env }; let args_ty = table.new_type_var();
let canonical = let trait_ref = b.push(self_ty.clone()).push(args_ty.clone()).build();
Canonical { binders: CanonicalVarKinds::from_iter(Interner, kinds), value: obligation }; let projection = TyBuilder::assoc_type_projection(
let subst = match db.trait_solve(krate, canonical) { db,
Some(Solution::Unique(vars)) => vars.value.subst, output_assoc_type,
_ => return None, Some(trait_ref.substitution.clone()),
}; )
let args = subst.at(Interner, 0).ty(Interner)?; .build();
let params = match args.kind(Interner) { table.register_obligation(trait_ref.cast(Interner));
chalk_ir::TyKind::Tuple(_, subst) => { let ret_ty = table.normalize_projection_ty(projection);
subst.iter(Interner).filter_map(|arg| arg.ty(Interner).cloned()).collect::<Vec<_>>()
}
_ => return None,
};
let fn_once = let ret_ty = table.resolve_completely(ret_ty);
TyBuilder::trait_ref(db, fn_once_trait).push(self_ty.clone()).push(args.clone()).build(); let args_ty = table.resolve_completely(args_ty);
let projection =
TyBuilder::assoc_type_projection(db, output_assoc_type, Some(fn_once.substitution)).build();
let ret_ty = db.normalize_projection(projection, env); let params =
args_ty.as_tuple()?.iter(Interner).map(|it| it.assert_ty_ref(Interner)).cloned().collect();
Some(CallableSig::from_params_and_return(params, ret_ty, false, Safety::Safe)) Some(CallableSig::from_params_and_return(params, ret_ty, false, Safety::Safe))
} }