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chore: add sub_unify_with_coercion

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This commit is contained in:
Shunsuke Shibayama 2024-03-21 14:00:26 +09:00
parent bd39393746
commit 7d6ea6cf77
9 changed files with 157 additions and 21 deletions
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40
crates/erg_compiler/context/unify.rs
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@ -813,11 +813,11 @@ impl<'c, 'l, 'u, L: Locational> Unifier<'c, 'l, 'u, L> {
}
}
/// Assuming that `sub` is a subtype of `sup`, fill in the type variable to satisfy the assumption
/// Assuming that `sub` is a subtype of `sup`, fill in the type variable to satisfy the assumption.
///
/// When comparing arguments and parameter, the left side (`sub`) is the argument (found) and the right side (`sup`) is the parameter (expected)
/// When comparing arguments and parameter, the left side (`sub`) is the argument (found) and the right side (`sup`) is the parameter (expected).
///
/// The parameter type must be a supertype of the argument type
/// The parameter type must be a supertype of the argument type.
/// ```python
/// sub_unify({I: Int | I == 0}, ?T(<: Ord)): (/* OK */)
/// sub_unify(Int, ?T(:> Nat)): (?T :> Int)
@ -1626,8 +1626,16 @@ impl<'c, 'l, 'u, L: Locational> Unifier<'c, 'l, 'u, L> {
.sub_unify_tp(l_maybe_sub, r_maybe_sup, *variance, false)
.is_err()
{
log!(err "failed to unify {l_maybe_sub} <: {r_maybe_sup}");
continue 'l;
// retry with coercions
l_maybe_sub.coerce(Some(&list));
r_maybe_sup.coerce(Some(&list));
if unifier
.sub_unify_tp(l_maybe_sub, r_maybe_sup, *variance, false)
.is_err()
{
log!(err "failed to unify {l_maybe_sub} <: {r_maybe_sup}?");
continue 'l;
}
}
}
drop(list);
@ -1749,6 +1757,28 @@ impl Context {
unifier.sub_unify(maybe_sub, maybe_sup)
}
pub(crate) fn sub_unify_with_coercion(
&self,
maybe_sub: &Type,
maybe_sup: &Type,
loc: &impl Locational,
param_name: Option<&Str>,
) -> TyCheckResult<()> {
let unifier = Unifier::new(self, loc, None, false, param_name.cloned());
unifier.sub_unify(maybe_sub, maybe_sup).or_else(|err| {
log!(err "{err}");
maybe_sub.coerce(unifier.undoable);
maybe_sub.coerce(unifier.undoable);
let maybe_sub = self
.eval_t_params(maybe_sub.clone(), self.level, loc)
.map_err(|(_, errs)| errs)?;
let maybe_sup = self
.eval_t_params(maybe_sup.clone(), self.level, loc)
.map_err(|(_, errs)| errs)?;
unifier.sub_unify(&maybe_sub, &maybe_sup)
})
}
/// This will rewrite generalized type variables.
pub(crate) fn force_sub_unify(
&self,