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Fix a subtype unification bug

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This commit is contained in:
Shunsuke Shibayama 2022-12-22 17:56:42 +09:00
parent 27e5a1602d
commit af3ece6a1b
6 changed files with 74 additions and 20 deletions
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16
compiler/erg_compiler/context/tyvar.rs
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@ -9,6 +9,7 @@ use erg_common::{dict, set, Str};
#[allow(unused_imports)]
use erg_common::{fmt_vec, log};
use crate::context::instantiate::TyVarCache;
use crate::ty::constructors::*;
use crate::ty::free::{Constraint, FreeKind, HasLevel};
use crate::ty::typaram::TyParam;
@ -1374,10 +1375,6 @@ impl Context {
)));
}
match (maybe_sub, maybe_sup) {
/*
(Type::FreeVar(fv), _) if fv.is_generalized() => todo!("{maybe_sub}, {maybe_sup}"),
(_, Type::FreeVar(fv)) if fv.is_generalized() => todo!("{maybe_sub}, {maybe_sup}"),
*/
// lfv's sup can be shrunk (take min), rfv's sub can be expanded (take union)
// lfvのsupは縮小可能(minを取る)、rfvのsubは拡大可能(unionを取る)
// sub_unify(?T[0](:> Never, <: Int), ?U[1](:> Never, <: Nat)): (/* ?U[1] --> ?T[0](:> Never, <: Nat))
@ -1625,15 +1622,24 @@ impl Context {
// Zip(T, U) <: Iterable(Tuple([T, U]))
if ln != rn {
if let Some((sub_def_t, sub_ctx)) = self.get_nominal_type_ctx(maybe_sub) {
let mut tv_cache = TyVarCache::new(self.level, self);
let _sub_def_instance =
self.instantiate_t_inner(sub_def_t.clone(), &mut tv_cache, loc)?;
// e.g.
// maybe_sub: Zip(Int, Str)
// sub_def_t: Zip(T, U) ==> Zip(Int, Str)
// super_traits: [Iterable((T, U)), ...] ==> [Iterable((Int, Str)), ...]
self.substitute_typarams(sub_def_t, maybe_sub)
.map_err(|errs| {
Self::undo_substitute_typarams(sub_def_t);
errs
})?;
for sup_trait in sub_ctx.super_traits.iter() {
let sub_trait_instance =
self.instantiate_t_inner(sup_trait.clone(), &mut tv_cache, loc)?;
if self.supertype_of(maybe_sup, sup_trait) {
for (l_maybe_sub, r_maybe_sup) in
sup_trait.typarams().iter().zip(rps.iter())
sub_trait_instance.typarams().iter().zip(rps.iter())
{
self.sub_unify_tp(l_maybe_sub, r_maybe_sup, None, loc, false)
.map_err(|errs| {