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erg/crates/erg_compiler/context/compare.rs
Shunsuke Shibayama c9dda183ab feat: implement Structural types
2023-02-23 01:37:54 +09:00

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//! provides type-comparison
use std::option::Option; // conflicting to Type::Option
use erg_common::error::MultiErrorDisplay;
use erg_common::style::colors::DEBUG_ERROR;
use erg_common::traits::StructuralEq;
use crate::ty::constructors::{and, not, or, poly};
use crate::ty::free::{Constraint, FreeKind};
use crate::ty::typaram::{OpKind, TyParam, TyParamOrdering};
use crate::ty::value::ValueObj;
use crate::ty::value::ValueObj::Inf;
use crate::ty::{Predicate, RefinementType, SubrKind, SubrType, Type};
use Predicate as Pred;
use erg_common::dict::Dict;
use erg_common::vis::Field;
use erg_common::{assume_unreachable, log};
use TyParamOrdering::*;
use Type::*;
use crate::context::cache::{SubtypePair, GLOBAL_TYPE_CACHE};
use crate::context::{Context, Variance};
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum Credibility {
Maybe,
Absolutely,
}
use Credibility::*;
use super::ContextKind;
impl Context {
fn register_cache(&self, sup: &Type, sub: &Type, result: bool) {
GLOBAL_TYPE_CACHE.register(SubtypePair::new(sub.clone(), sup.clone()), result);
}
// TODO: is it impossible to avoid .clone()?
fn inquire_cache(&self, sup: &Type, sub: &Type) -> Option<bool> {
let res = GLOBAL_TYPE_CACHE.get(&SubtypePair::new(sub.clone(), sup.clone()));
if res.is_some() {
log!(info "cache hit");
}
res
}
pub(crate) fn eq_tp(&self, lhs: &TyParam, rhs: &TyParam, allow_cast: bool) -> bool {
match (lhs, rhs) {
(TyParam::Type(lhs), TyParam::Type(rhs)) => {
return self.same_type_of(lhs, rhs, allow_cast)
}
(TyParam::Mono(l), TyParam::Mono(r)) => {
if let (Some(l), Some(r)) = (self.rec_get_const_obj(l), self.rec_get_const_obj(r)) {
return l == r;
}
}
(TyParam::UnaryOp { op: lop, val: lval }, TyParam::UnaryOp { op: rop, val: rval }) => {
return lop == rop && self.eq_tp(lval, rval, allow_cast);
}
(
TyParam::BinOp {
op: lop,
lhs: ll,
rhs: lr,
},
TyParam::BinOp {
op: rop,
lhs: rl,
rhs: rr,
},
) => {
return lop == rop
&& self.eq_tp(ll, rl, allow_cast)
&& self.eq_tp(lr, rr, allow_cast);
}
(
TyParam::App {
name: ln,
args: largs,
},
TyParam::App {
name: rn,
args: rargs,
},
) => {
return ln == rn
&& largs.len() == rargs.len()
&& largs
.iter()
.zip(rargs.iter())
.all(|(l, r)| self.eq_tp(l, r, allow_cast))
}
(TyParam::FreeVar(fv), other) | (other, TyParam::FreeVar(fv)) => match &*fv.borrow() {
FreeKind::Linked(linked) | FreeKind::UndoableLinked { t: linked, .. } => {
return self.eq_tp(linked, other, allow_cast);
}
FreeKind::Unbound { constraint, .. }
| FreeKind::NamedUnbound { constraint, .. } => {
let t = constraint.get_type().unwrap();
if cfg!(feature = "debug") && t == &Uninited {
panic!("Uninited type variable: {fv}");
}
let other_t = self.type_of(other);
return self.same_type_of(t, &other_t, allow_cast);
}
},
(TyParam::Value(ValueObj::Type(l)), TyParam::Type(r)) => {
return self.same_type_of(l.typ(), r.as_ref(), allow_cast);
}
(TyParam::Type(l), TyParam::Value(ValueObj::Type(r))) => {
return self.same_type_of(l.as_ref(), r.typ(), allow_cast);
}
(l, r) if l == r => {
return true;
}
(l, r) if l.has_unbound_var() || r.has_unbound_var() => {
let lt = self.get_tp_t(l).unwrap();
let rt = self.get_tp_t(r).unwrap();
return self.same_type_of(&lt, &rt, allow_cast);
}
_ => {}
}
self.shallow_eq_tp(lhs, rhs)
}
pub(crate) fn related(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
self.supertype_of(lhs, rhs, allow_cast) || self.subtype_of(lhs, rhs, allow_cast)
}
pub(crate) fn supertype_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
let res = match Self::cheap_supertype_of(lhs, rhs, allow_cast) {
(Absolutely, judge) => judge,
(Maybe, judge) => {
judge
|| self.structural_supertype_of(lhs, rhs, allow_cast)
|| self.nominal_supertype_of(lhs, rhs, allow_cast)
}
};
log!("answer: {lhs} {DEBUG_ERROR}:>{RESET} {rhs} == {res}");
res
}
/// e.g.
/// Named :> Module
/// => Module.super_types == [Named]
///
/// Seq(T) :> Range(T)
/// => Range(T).super_types == [Eq, Mutate, Seq('T), Output('T)]
pub(crate) fn subtype_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
match Self::cheap_subtype_of(lhs, rhs, allow_cast) {
(Absolutely, judge) => judge,
(Maybe, judge) => {
judge
|| self.structural_subtype_of(lhs, rhs, allow_cast)
|| self.nominal_subtype_of(lhs, rhs, allow_cast)
}
}
}
pub(crate) fn same_type_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
self.supertype_of(lhs, rhs, allow_cast) && self.subtype_of(lhs, rhs, allow_cast)
}
pub(crate) fn cheap_supertype_of(
lhs: &Type,
rhs: &Type,
allow_cast: bool,
) -> (Credibility, bool) {
if lhs == rhs {
return (Absolutely, true);
}
match (lhs, rhs) {
(Obj, _) | (_, Never | Failure) if allow_cast => (Absolutely, true),
(_, Obj) if lhs.is_simple_class() && allow_cast => (Absolutely, false),
(Never | Failure, _) if rhs.is_simple_class() && allow_cast => (Absolutely, false),
(Float | Ratio | Int | Nat | Bool, Bool)
| (Float | Ratio | Int | Nat, Nat)
| (Float | Ratio | Int, Int)
| (Float | Ratio, Ratio)
if allow_cast =>
{
(Absolutely, true)
}
(Type, ClassType | TraitType) if allow_cast => (Absolutely, true),
(Uninited, _) | (_, Uninited) => panic!("used an uninited type variable"),
(
Mono(n),
Subr(SubrType {
kind: SubrKind::Func,
..
}),
) if &n[..] == "GenericFunc" && allow_cast => (Absolutely, true),
(
Mono(n),
Subr(SubrType {
kind: SubrKind::Proc,
..
}),
) if &n[..] == "GenericProc" && allow_cast => (Absolutely, true),
(Mono(l), Poly { name: r, .. })
if &l[..] == "GenericArray" && &r[..] == "Array" && allow_cast =>
{
(Absolutely, true)
}
(Mono(l), Poly { name: r, .. })
if &l[..] == "GenericDict" && &r[..] == "Dict" && allow_cast =>
{
(Absolutely, true)
}
(Mono(l), Mono(r))
if &l[..] == "GenericCallable"
&& (&r[..] == "GenericFunc"
|| &r[..] == "GenericProc"
|| &r[..] == "GenericFuncMethod"
|| &r[..] == "GenericProcMethod")
&& allow_cast =>
{
(Absolutely, true)
}
(FreeVar(l), FreeVar(r)) => {
if l.structural_eq(r) {
(Absolutely, true)
} else {
(Maybe, false)
}
}
(_, FreeVar(fv)) | (FreeVar(fv), _) => match fv.get_subsup() {
Some((Type::Never, Type::Obj)) if allow_cast => (Absolutely, true),
_ => (Maybe, false),
},
(Mono(n), Subr(_) | Quantified(_)) if &n[..] == "GenericCallable" && allow_cast => {
(Absolutely, true)
}
(lhs, rhs) if lhs.is_simple_class() && rhs.is_simple_class() => (Absolutely, false),
_ => (Maybe, false),
}
}
fn cheap_subtype_of(lhs: &Type, rhs: &Type, allow_cast: bool) -> (Credibility, bool) {
Self::cheap_supertype_of(rhs, lhs, allow_cast)
}
/// make judgments that include supertypes in the same namespace & take into account glue patches
/// 同一名前空間にある上位型を含めた判定&接着パッチを考慮した判定を行う
fn nominal_supertype_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
if !allow_cast && lhs != rhs {
return false;
}
if let Some(res) = self.inquire_cache(lhs, rhs) {
return res;
}
if let (Absolutely, judge) = self.classes_supertype_of(lhs, rhs, allow_cast) {
self.register_cache(lhs, rhs, judge);
return judge;
}
if let (Absolutely, judge) = self.traits_supertype_of(lhs, rhs, allow_cast) {
self.register_cache(lhs, rhs, judge);
return judge;
}
self.register_cache(lhs, rhs, false);
false
}
fn nominal_subtype_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
self.nominal_supertype_of(rhs, lhs, allow_cast)
}
pub(crate) fn find_patches_of<'a>(
&'a self,
typ: &'a Type,
allow_cast: bool,
) -> impl Iterator<Item = &'a Context> {
self.all_patches().into_iter().filter(move |ctx| {
if let ContextKind::Patch(base) = &ctx.kind {
return self.supertype_of(base, typ, allow_cast);
}
false
})
}
fn _find_compatible_glue_patch(
&self,
sup: &Type,
sub: &Type,
allow_cast: bool,
) -> Option<&Context> {
for patch in self.all_patches().into_iter() {
if let ContextKind::GluePatch(tr_inst) = &patch.kind {
if self.subtype_of(sub, &tr_inst.sub_type, allow_cast)
&& self.subtype_of(&tr_inst.sup_trait, sup, allow_cast)
{
return Some(patch);
}
}
}
None
}
fn classes_supertype_of(
&self,
lhs: &Type,
rhs: &Type,
allow_cast: bool,
) -> (Credibility, bool) {
if !self.is_class(lhs) || !self.is_class(rhs) {
return (Maybe, false);
}
if let Some((_, ty_ctx)) = self.get_nominal_type_ctx(rhs) {
for rhs_sup in ty_ctx.super_classes.iter() {
let rhs_sup = if rhs_sup.has_qvar() {
let rhs = match rhs {
Type::Ref(t) => t,
Type::RefMut { before, .. } => before,
other => other,
};
// let subst_ctx = SubstContext::new(rhs, self, Location::Unknown);
// subst_ctx.substitute(rhs_sup.clone()).unwrap()
rhs.clone()
} else {
rhs_sup.clone()
};
// Not `supertype_of` (only structures are compared)
match Self::cheap_supertype_of(lhs, &rhs_sup, allow_cast) {
(Absolutely, true) => {
return (Absolutely, true);
}
(Maybe, _) => {
if self.structural_supertype_of(lhs, &rhs_sup, allow_cast) {
return (Absolutely, true);
}
}
_ => {}
}
}
}
(Maybe, false)
}
// e.g. Eq(Nat) :> Nat
// Nat.super_traits = [Add(Nat), Eq(Nat), Sub(Float), ...]
// e.g. Eq :> ?L or ?R (if ?L <: Eq and ?R <: Eq)
fn traits_supertype_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> (Credibility, bool) {
if !self.is_trait(lhs) {
return (Maybe, false);
}
if let Some((_, rhs_ctx)) = self.get_nominal_type_ctx(rhs) {
for rhs_sup in rhs_ctx.super_traits.iter() {
// Not `supertype_of` (only structures are compared)
match Self::cheap_supertype_of(lhs, rhs_sup, allow_cast) {
(Absolutely, true) => {
return (Absolutely, true);
}
(Maybe, _) => {
if self.structural_supertype_of(lhs, rhs_sup, allow_cast) {
return (Absolutely, true);
}
}
_ => {}
}
}
}
(Maybe, false)
}
/// lhs :> rhs?
/// ```python
/// assert supertype_of(Int, Nat) # i: Int = 1 as Nat
/// assert supertype_of(Bool, Bool)
/// ```
/// This function does not consider the nominal subtype relation.
/// Use `supertype_of` for complete judgement.
/// 単一化、評価等はここでは行わない、スーパータイプになる可能性があるかだけ判定する
/// ので、lhsが(未連携)型変数の場合は単一化せずにtrueを返す
pub(crate) fn structural_supertype_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
match (lhs, rhs) {
// Proc :> Func if params are compatible
(Subr(ls), Subr(rs)) if ls.kind == rs.kind || ls.kind.is_proc() => {
if !allow_cast && ls.kind != rs.kind {
return false;
}
let kw_check = || {
for lpt in ls.default_params.iter() {
if let Some(rpt) = rs
.default_params
.iter()
.find(|rpt| rpt.name() == lpt.name())
{
if !self.subtype_of(lpt.typ(), rpt.typ(), allow_cast) {
return false;
}
} else {
return false;
}
}
true
};
// () -> Never <: () -> Int <: () -> Object
// (Object) -> Int <: (Int) -> Int <: (Never) -> Int
let same_params_len = ls.non_default_params.len() == rs.non_default_params.len()
// REVIEW:
&& ls.default_params.len() == rs.default_params.len();
let return_t_judge = self.supertype_of(&ls.return_t, &rs.return_t, allow_cast); // covariant
let non_defaults_judge = ls
.non_default_params
.iter()
.zip(rs.non_default_params.iter())
.all(|(l, r)| self.subtype_of(l.typ(), r.typ(), allow_cast));
let var_params_judge = ls
.var_params
.as_ref()
.zip(rs.var_params.as_ref())
.map(|(l, r)| self.subtype_of(l.typ(), r.typ(), allow_cast))
.unwrap_or(true);
same_params_len
&& return_t_judge
&& non_defaults_judge
&& var_params_judge
&& kw_check() // contravariant
}
// ?T(<: Nat) !:> ?U(:> Int)
// ?T(<: Nat) :> ?U(<: Int) (?U can be smaller than ?T)
(FreeVar(lfv), FreeVar(rfv)) => match (lfv.get_subsup(), rfv.get_subsup()) {
(Some((_, l_sup)), Some((r_sub, _))) => {
self.supertype_of(&l_sup, &r_sub, allow_cast)
}
_ => {
if lfv.is_linked() {
self.supertype_of(&lfv.crack(), rhs, allow_cast)
} else if rfv.is_linked() {
self.supertype_of(lhs, &rfv.crack(), allow_cast)
} else {
false
}
}
},
// true if it can be a supertype, false if it cannot (due to type constraints)
// No type constraints are imposed here, as subsequent type decisions are made according to the possibilities
// ?P(<: Mul ?P) :> Int
// => ?P.undoable_link(Int)
// => Mul Int :> Int
(FreeVar(lfv), rhs) => {
match &*lfv.borrow() {
FreeKind::Linked(t) | FreeKind::UndoableLinked { t, .. } => {
self.supertype_of(t, rhs, allow_cast)
}
FreeKind::Unbound { constraint: _, .. }
| FreeKind::NamedUnbound { constraint: _, .. } => {
if let Some((_sub, sup)) = lfv.get_subsup() {
lfv.forced_undoable_link(rhs);
let res = self.supertype_of(&sup, rhs, allow_cast);
lfv.undo();
res
} else if let Some(lfvt) = lfv.get_type() {
// e.g. lfv: ?L(: Int) is unreachable
// but
// ?L(: Array(Type, 3)) :> Array(Int, 3)
// => Array(Type, 3) :> Array(Typeof(Int), 3)
// => true
let rhs_meta = self.meta_type(rhs);
self.supertype_of(&lfvt, &rhs_meta, allow_cast)
} else {
// constraint is uninitalized
log!(err "constraint is uninitialized: {lfv}/{rhs}");
true
}
}
}
}
(lhs, FreeVar(rfv)) => match &*rfv.borrow() {
FreeKind::Linked(t) | FreeKind::UndoableLinked { t, .. } => {
self.supertype_of(lhs, t, allow_cast)
}
FreeKind::Unbound { constraint: _, .. }
| FreeKind::NamedUnbound { constraint: _, .. } => {
if let Some((sub, _sup)) = rfv.get_subsup() {
rfv.forced_undoable_link(lhs);
let res = self.supertype_of(lhs, &sub, allow_cast);
rfv.undo();
res
} else if let Some(rfvt) = rfv.get_type() {
let lhs_meta = self.meta_type(lhs);
self.supertype_of(&lhs_meta, &rfvt, allow_cast)
} else {
// constraint is uninitalized
log!(err "constraint is uninitialized: {lhs}/{rfv}");
true
}
}
},
(Type::Record(lhs), Type::Record(rhs)) => {
for (k, l) in lhs.iter() {
if let Some(r) = rhs.get(k) {
if !self.supertype_of(l, r, allow_cast) {
return false;
}
} else {
return false;
}
}
true
}
(Type, Record(rec)) if allow_cast => {
for (_, t) in rec.iter() {
if !self.supertype_of(&Type, t, allow_cast) {
return false;
}
}
true
}
(Type, Subr(subr)) => self.supertype_of(&Type, &subr.return_t, allow_cast),
(Type, Poly { name, params }) | (Poly { name, params }, Type)
if &name[..] == "Array" || &name[..] == "Set" =>
{
let elem_t = self.convert_tp_into_ty(params[0].clone()).unwrap();
self.supertype_of(&Type, &elem_t, allow_cast)
}
(Type, Poly { name, params }) | (Poly { name, params }, Type)
if &name[..] == "Tuple" =>
{
if let Ok(tps) = Vec::try_from(params[0].clone()) {
for tp in tps {
let Ok(t) = self.convert_tp_into_ty(tp) else {
return false;
};
if !self.supertype_of(&Type, &t, allow_cast) {
return false;
}
}
}
false
}
(Type, Poly { name, params }) | (Poly { name, params }, Type)
if &name[..] == "Dict" =>
{
// HACK: e.g. ?D: GenericDict
let Ok(dict) = Dict::try_from(params[0].clone()) else {
return false;
};
for (k, v) in dict.into_iter() {
let Ok(k) = self.convert_tp_into_ty(k) else {
return false;
};
let Ok(v) = self.convert_tp_into_ty(v) else {
return false;
};
if !self.supertype_of(&Type, &k, allow_cast)
|| !self.supertype_of(&Type, &v, allow_cast)
{
return false;
}
}
true
}
// REVIEW: maybe this is incomplete
// ({I: Int | I >= 0} :> {N: Int | N >= 0}) == true,
// ({I: Int | I >= 0} :> {I: Int | I >= 1}) == true,
// ({I: Int | I >= 0} :> {N: Nat | N >= 1}) == true,
// ({I: Int | I > 1 or I < -1} :> {I: Int | I >= 0}) == false,
// ({I: Int | I >= 0} :> {F: Float | F >= 0}) == false,
// {1, 2, 3} :> {1, } == true
(Refinement(l), Refinement(r)) => {
// no relation or l.t <: r.t (not equal)
if !self.supertype_of(&l.t, &r.t, allow_cast) {
return false;
}
let mut r_preds_clone = r.preds.clone();
for l_pred in l.preds.iter() {
for r_pred in r.preds.iter() {
if l_pred.subject().unwrap_or("") == &l.var[..]
&& r_pred.subject().unwrap_or("") == &r.var[..]
&& self.is_super_pred_of(l_pred, r_pred, allow_cast)
{
r_preds_clone.remove(r_pred);
}
}
}
r_preds_clone.is_empty()
}
(Nat, re @ Refinement(_)) if allow_cast => {
let nat = Type::Refinement(Nat.into_refinement());
self.structural_supertype_of(&nat, re, allow_cast)
}
(re @ Refinement(_), Nat) if allow_cast => {
let nat = Type::Refinement(Nat.into_refinement());
self.structural_supertype_of(re, &nat, allow_cast)
}
// Int :> {I: Int | ...} == true
// Int :> {I: Str| ...} == false
// Eq({1, 2}) :> {1, 2} (= {I: Int | I == 1 or I == 2})
// => Eq(Int) :> Eq({1, 2}) :> {1, 2}
// => true
// Bool :> {1} == true
(l, Refinement(r)) if allow_cast => {
if self.supertype_of(l, &r.t, allow_cast) {
return true;
}
let l = l.derefine();
if self.supertype_of(&l, &r.t, allow_cast) {
return true;
}
let l = Type::Refinement(l.into_refinement());
self.structural_supertype_of(&l, rhs, allow_cast)
}
// ({I: Int | True} :> Int) == true, ({N: Nat | ...} :> Int) == false, ({I: Int | I >= 0} :> Int) == false
(Refinement(l), r) if allow_cast => {
if l.preds
.iter()
.any(|p| p.mentions(&l.var) && p.can_be_false())
{
return false;
}
self.supertype_of(&l.t, r, allow_cast)
}
(Quantified(_), Quantified(_)) => {
let l = self.instantiate_dummy(lhs.clone());
let r = self.instantiate_dummy(rhs.clone());
self.sub_unify(&r, &l, &(), None).is_ok()
}
// (|T: Type| T -> T) !<: Obj -> Never
(Quantified(_), r) if allow_cast => {
let inst = self.instantiate_dummy(lhs.clone());
self.sub_unify(r, &inst, &(), None).is_ok()
}
(l, Quantified(_)) if allow_cast => {
let inst = self.instantiate_dummy(rhs.clone());
self.sub_unify(&inst, l, &(), None).is_ok()
}
// Int or Str :> Str or Int == (Int :> Str && Str :> Int) || (Int :> Int && Str :> Str) == true
(Or(l_1, l_2), Or(r_1, r_2)) => {
(self.supertype_of(l_1, r_1, allow_cast) && self.supertype_of(l_2, r_2, allow_cast))
|| (self.supertype_of(l_1, r_2, allow_cast)
&& self.supertype_of(l_2, r_1, allow_cast))
}
// not Nat :> not Int == true
(Not(l), Not(r)) => self.subtype_of(l, r, allow_cast),
// (Int or Str) :> Nat == Int :> Nat || Str :> Nat == true
// (Num or Show) :> Show == Num :> Show || Show :> Num == true
(Or(l_or, r_or), rhs) if allow_cast => {
self.supertype_of(l_or, rhs, allow_cast) || self.supertype_of(r_or, rhs, allow_cast)
}
// Int :> (Nat or Str) == Int :> Nat && Int :> Str == false
(lhs, Or(l_or, r_or)) if allow_cast => {
self.supertype_of(lhs, l_or, allow_cast) && self.supertype_of(lhs, r_or, allow_cast)
}
(And(l_1, l_2), And(r_1, r_2)) => {
(self.supertype_of(l_1, r_1, allow_cast) && self.supertype_of(l_2, r_2, allow_cast))
|| (self.supertype_of(l_1, r_2, allow_cast)
&& self.supertype_of(l_2, r_1, allow_cast))
}
// (Num and Show) :> Show == false
(And(l_and, r_and), rhs) if allow_cast => {
self.supertype_of(l_and, rhs, allow_cast)
&& self.supertype_of(r_and, rhs, allow_cast)
}
// Show :> (Num and Show) == true
(lhs, And(l_and, r_and)) if allow_cast => {
self.supertype_of(lhs, l_and, allow_cast)
|| self.supertype_of(lhs, r_and, allow_cast)
}
// RefMut are invariant
(Ref(l), Ref(r)) => self.supertype_of(l, r, allow_cast),
// TはすべてのRef(T)のメソッドを持つので、Ref(T)のサブタイプ
// REVIEW: RefMut is invariant, maybe
(Ref(l), r) if allow_cast => self.supertype_of(l, r, allow_cast),
(RefMut { before: l, .. }, r) if allow_cast => self.supertype_of(l, r, allow_cast),
// `Eq(Set(T, N)) :> Set(T, N)` will be false, such cases are judged by nominal_supertype_of
(
Poly {
name: ln,
params: lparams,
},
Poly {
name: rn,
params: rparams,
},
) => {
if ln != rn || lparams.len() != rparams.len() {
return false;
}
// [Int; 2] :> [Int; 3]
if &ln[..] == "Array" || &ln[..] == "Set" {
let lt = self.convert_tp_into_ty(lparams[0].clone()).unwrap();
let rt = self.convert_tp_into_ty(rparams[0].clone()).unwrap();
let llen = lparams[1].clone();
let rlen = rparams[1].clone();
self.supertype_of(&lt, &rt, allow_cast)
&& self
.eval_bin_tp(OpKind::Le, llen, rlen)
.map(|tp| matches!(tp, TyParam::Value(ValueObj::Bool(true))))
.unwrap_or_else(|e| {
e.fmt_all_stderr();
todo!();
})
} else {
self.poly_supertype_of(lhs, lparams, rparams, allow_cast)
}
}
(Proj { .. }, _) => {
if let Some(cands) = self.get_candidates(lhs) {
for cand in cands.into_iter() {
if self.supertype_of(&cand, rhs, allow_cast) {
return true;
}
}
}
false
}
(_, Proj { .. }) => {
if let Some(cands) = self.get_candidates(rhs) {
for cand in cands.into_iter() {
if self.supertype_of(lhs, &cand, allow_cast) {
return true;
}
}
}
false
}
(Structural(l), Structural(r)) => self.structural_supertype_of(l, r, allow_cast),
(Structural(l), r) => {
log!(err "{l}/{r}");
let r_fields = self.fields(r);
log!(err "{r_fields}");
for (l_field, l_ty) in self.fields(l) {
log!(err "{l_field} = {l_ty}");
if let Some((r_field, r_ty)) = r_fields.get_key_value(&l_field) {
if r_field.vis != l_field.vis || !self.supertype_of(&l_ty, r_ty, allow_cast)
{
return false;
}
} else {
return false;
}
}
true
}
(_l, _r) => false,
}
}
pub fn fields(&self, t: &Type) -> Dict<Field, Type> {
match t {
Type::FreeVar(fv) if fv.is_linked() => self.fields(&fv.crack()),
Type::Record(fields) => fields.clone(),
other => {
let (_, ctx) = self
.get_nominal_type_ctx(other)
.unwrap_or_else(|| panic!("{other} is not found"));
ctx.locals
.iter()
.chain(ctx.decls.iter())
.map(|(name, vi)| (Field::new(vi.vis, name.inspect().clone()), vi.t.clone()))
.collect()
}
}
}
pub(crate) fn poly_supertype_of(
&self,
typ: &Type,
lparams: &[TyParam],
rparams: &[TyParam],
allow_cast: bool,
) -> bool {
log!(
"poly_supertype_of: {typ}, {}, {}",
erg_common::fmt_vec(lparams),
erg_common::fmt_vec(rparams)
);
let (_, ctx) = self
.get_nominal_type_ctx(typ)
.unwrap_or_else(|| panic!("{typ} is not found"));
let variances = ctx.type_params_variance();
debug_assert_eq!(lparams.len(), variances.len());
lparams
.iter()
.zip(rparams.iter())
.zip(variances.iter())
.all(|((lp, rp), variance)| self.supertype_of_tp(lp, rp, *variance, allow_cast))
}
fn supertype_of_tp(
&self,
lp: &TyParam,
rp: &TyParam,
variance: Variance,
allow_cast: bool,
) -> bool {
if lp == rp {
return true;
}
match (lp, rp, variance) {
(TyParam::FreeVar(fv), _, _) if fv.is_linked() => {
self.supertype_of_tp(&fv.crack(), rp, variance, allow_cast)
}
(_, TyParam::FreeVar(fv), _) if fv.is_linked() => {
self.supertype_of_tp(lp, &fv.crack(), variance, allow_cast)
}
// _: Type :> T == true
(TyParam::Erased(t), TyParam::Type(_), _)
| (TyParam::Type(_), TyParam::Erased(t), _)
if t.as_ref() == &Type =>
{
true
}
(TyParam::Array(lp), TyParam::Array(rp), _)
| (TyParam::Tuple(lp), TyParam::Tuple(rp), _) => {
for (l, r) in lp.iter().zip(rp.iter()) {
if !self.supertype_of_tp(l, r, variance, allow_cast) {
return false;
}
}
true
}
// {Int: Str} :> {Int: Str, Bool: Int}
(TyParam::Dict(ld), TyParam::Dict(rd), _) => {
if ld.len() > rd.len() {
return false;
}
for (k, lv) in ld.iter() {
if let Some(rv) = rd.get(k) {
if !self.supertype_of_tp(lv, rv, variance, allow_cast) {
return false;
}
} else {
return false;
}
}
true
}
(TyParam::Type(l), TyParam::Type(r), Variance::Contravariant) => {
self.subtype_of(l, r, allow_cast)
}
(TyParam::Type(l), TyParam::Type(r), Variance::Covariant) => {
self.supertype_of(l, r, allow_cast)
}
(TyParam::Type(l), TyParam::Type(r), Variance::Invariant) => {
self.same_type_of(l, r, allow_cast)
}
(TyParam::FreeVar(fv), _, _) if fv.is_unbound() => {
let fv_t = fv.get_type().unwrap();
let rp_t = self.get_tp_t(rp).unwrap();
if variance == Variance::Contravariant {
self.subtype_of(&fv_t, &rp_t, allow_cast)
} else if variance == Variance::Covariant {
self.supertype_of(&fv_t, &rp_t, allow_cast)
} else {
self.same_type_of(&fv_t, &rp_t, allow_cast)
}
}
_ => self.eq_tp(lp, rp, allow_cast),
}
}
/// lhs <: rhs?
pub(crate) fn structural_subtype_of(&self, lhs: &Type, rhs: &Type, allow_cast: bool) -> bool {
self.structural_supertype_of(rhs, lhs, allow_cast)
}
pub(crate) fn _structural_same_type_of(
&self,
lhs: &Type,
rhs: &Type,
allow_cast: bool,
) -> bool {
self.structural_supertype_of(lhs, rhs, allow_cast)
&& self.structural_subtype_of(lhs, rhs, allow_cast)
}
pub(crate) fn try_cmp(
&self,
l: &TyParam,
r: &TyParam,
allow_cast: bool,
) -> Option<TyParamOrdering> {
match (l, r) {
(TyParam::Value(l), TyParam::Value(r)) =>
l.try_cmp(r).map(Into::into),
// TODO: 型を見て判断する
(TyParam::BinOp{ op, lhs, rhs }, r) => {
if let Ok(l) = self.eval_bin_tp(*op, lhs.as_ref().clone(), rhs.as_ref().clone()) {
self.try_cmp(&l, r, allow_cast)
} else { Some(Any) }
},
(TyParam::FreeVar(fv), p) if fv.is_linked() => {
self.try_cmp(&fv.crack(), p, allow_cast)
}
(p, TyParam::FreeVar(fv)) if fv.is_linked() => {
self.try_cmp(p, &fv.crack(), allow_cast)
}
(
l @ (TyParam::FreeVar(_) | TyParam::Erased(_)),
r @ (TyParam::FreeVar(_) | TyParam::Erased(_)),
) /* if v.is_unbound() */ => {
let l_t = self.get_tp_t(l).unwrap();
let r_t = self.get_tp_t(r).unwrap();
if self.supertype_of(&l_t, &r_t, allow_cast) || self.subtype_of(&l_t, &r_t, allow_cast) {
Some(Any)
} else { Some(NotEqual) }
},
// Intervalとしてのl..rはl<=rであることが前提となっている
// try_cmp((n: 1..10), 1) -> Some(GreaterEqual)
// try_cmp((n: 0..2), 1) -> Some(Any)
// try_cmp((n: 2.._), 1) -> Some(Greater)
// try_cmp((n: -1.._), 1) -> Some(Any)
// try_cmp((n: ?K), "a") -> Some(Any)
// try_cmp((n: Int), "a") -> Some(NotEqual)
(l @ (TyParam::Erased(_) | TyParam::FreeVar(_)), p) => {
let lt = self.get_tp_t(l).unwrap();
let pt = self.get_tp_t(p).unwrap();
let l_inf = self.inf(&lt);
let l_sup = self.sup(&lt);
if let (Some(inf), Some(sup)) = (l_inf, l_sup) {
// (n: Int, 1) -> (-inf..inf, 1) -> (cmp(-inf, 1), cmp(inf, 1)) -> (Less, Greater) -> Any
// (n: 5..10, 2) -> (cmp(5..10, 2), cmp(5..10, 2)) -> (Greater, Greater) -> Greater
match (
self.try_cmp(&inf, p, allow_cast).unwrap(),
self.try_cmp(&sup, p, allow_cast).unwrap()
) {
(Less, Less) => Some(Less),
(Less, Equal) => Some(LessEqual),
(Less, LessEqual) => Some(LessEqual),
(Less, NotEqual) => Some(NotEqual),
(Less, Greater | GreaterEqual | Any) => Some(Any),
(Equal, Less) => assume_unreachable!(),
(Equal, Equal) => Some(Equal),
(Equal, Greater) => Some(GreaterEqual),
(Equal, LessEqual) => Some(Equal),
(Equal, NotEqual) => Some(GreaterEqual),
(Equal, GreaterEqual | Any) => Some(GreaterEqual),
(Greater, Less) => assume_unreachable!(),
(Greater, Equal) => assume_unreachable!(),
(Greater, Greater | NotEqual | GreaterEqual | Any) => Some(Greater),
(Greater, LessEqual) => assume_unreachable!(),
(LessEqual, Less) => assume_unreachable!(),
(LessEqual, Equal | LessEqual) => Some(LessEqual),
(LessEqual, Greater | NotEqual | GreaterEqual | Any) => Some(Any),
(NotEqual, Less) => Some(Less),
(NotEqual, Equal | LessEqual) => Some(LessEqual),
(NotEqual, Greater | GreaterEqual | Any) => Some(Any),
(NotEqual, NotEqual) => Some(NotEqual),
(GreaterEqual, Less) => assume_unreachable!(),
(GreaterEqual, Equal | LessEqual) => Some(Equal),
(GreaterEqual, Greater | NotEqual | GreaterEqual | Any) => Some(GreaterEqual),
(Any, Less) => Some(Less),
(Any, Equal | LessEqual) => Some(LessEqual),
(Any, Greater | NotEqual | GreaterEqual | Any) => Some(Any),
(l, r) =>
todo!("cmp({inf}, {sup}) = {l:?}, cmp({inf}, {sup}) = {r:?}"),
}
} else {
match (self.supertype_of(&lt, &pt, allow_cast), self.subtype_of(&lt, &pt, allow_cast)) {
(true, true) => Some(Any),
(true, false) => Some(Any),
(false, true) => Some(NotEqual),
(false, false) => Some(NoRelation),
}
}
}
(l, r @ (TyParam::Erased(_) | TyParam::FreeVar(_))) =>
self.try_cmp(r, l, allow_cast).map(|ord| ord.reverse()),
(_l, _r) => {
erg_common::fmt_dbg!(_l, _r,);
None
},
}
}
/// returns union of two types (A or B)
pub(crate) fn union(&self, lhs: &Type, rhs: &Type) -> Type {
let allow_cast = true;
if lhs == rhs {
return lhs.clone();
}
// `?T or ?U` will not be unified
// `Set!(?T, 3) or Set(?T, 3)` wii be unified to Set(?T, 3)
if !lhs.is_unbound_var() && !rhs.is_unbound_var() {
match (
self.supertype_of(lhs, rhs, allow_cast),
self.subtype_of(lhs, rhs, allow_cast),
) {
(true, true) => return lhs.clone(), // lhs = rhs
(true, false) => return lhs.clone(), // lhs :> rhs
(false, true) => return rhs.clone(),
(false, false) => {}
}
}
match (lhs, rhs) {
(FreeVar(fv), other) | (other, FreeVar(fv)) if fv.is_linked() => {
self.union(&fv.crack(), other)
}
(Refinement(l), Refinement(r)) => Type::Refinement(self.union_refinement(l, r)),
(t, Type::Never) | (Type::Never, t) => t.clone(),
// Array({1, 2}, 2), Array({3, 4}, 2) ==> Array({1, 2, 3, 4}, 2)
(
Type::Poly {
name: ln,
params: lps,
},
Type::Poly {
name: rn,
params: rps,
},
) if ln == rn => {
debug_assert_eq!(lps.len(), rps.len());
let mut unified_params = vec![];
for (lp, rp) in lps.iter().zip(rps.iter()) {
match (lp, rp) {
(TyParam::Type(l), TyParam::Type(r)) => {
unified_params.push(TyParam::t(self.union(l, r)))
}
(_, _) => {
if self.eq_tp(lp, rp, allow_cast) {
unified_params.push(lp.clone());
} else {
return or(lhs.clone(), rhs.clone());
}
}
}
}
poly(ln, unified_params)
}
(l, r) => or(l.clone(), r.clone()),
}
}
fn union_refinement(&self, lhs: &RefinementType, rhs: &RefinementType) -> RefinementType {
// TODO: warn if lhs.t !:> rhs.t && rhs.t !:> lhs.t
let union = self.union(&lhs.t, &rhs.t);
let name = lhs.var.clone();
let rhs_preds = rhs
.preds
.iter()
.map(|p| p.clone().change_subject_name(name.clone()))
.collect();
// FIXME: predの包含関係も考慮する
RefinementType::new(lhs.var.clone(), union, lhs.preds.clone().concat(rhs_preds))
}
/// returns intersection of two types (A and B)
pub(crate) fn intersection(&self, lhs: &Type, rhs: &Type) -> Type {
let allow_cast = true;
if lhs == rhs {
return lhs.clone();
}
// ?T and ?U will not be unified
if !lhs.is_unbound_var() && !rhs.is_unbound_var() {
match (
self.supertype_of(lhs, rhs, allow_cast),
self.subtype_of(lhs, rhs, allow_cast),
) {
(true, true) => return lhs.clone(), // lhs = rhs
(true, false) => return rhs.clone(), // lhs :> rhs
(false, true) => return lhs.clone(),
(false, false) => {}
}
}
match (lhs, rhs) {
(FreeVar(fv), other) | (other, FreeVar(fv)) if fv.is_linked() => {
self.intersection(&fv.crack(), other)
}
(Refinement(l), Refinement(r)) => Type::Refinement(self.intersection_refinement(l, r)),
// {.i = Int} and {.s = Str} == {.i = Int; .s = Str}
(Record(l), Record(r)) => Type::Record(l.clone().concat(r.clone())),
// {i = Int; j = Int} and not {i = Int} == {j = Int}
// not {i = Int} and {i = Int; j = Int} == {j = Int}
(other @ Record(rec), Not(t)) | (Not(t), other @ Record(rec)) => match t.as_ref() {
Type::FreeVar(fv) => self.intersection(&fv.crack(), other),
Type::Record(rec2) => Type::Record(rec.clone().diff(rec2.clone())),
_ => Type::Never,
},
(l, r) if self.is_trait(l) && self.is_trait(r) => and(l.clone(), r.clone()),
(_l, _r) => Type::Never,
}
}
fn intersection_refinement(
&self,
lhs: &RefinementType,
rhs: &RefinementType,
) -> RefinementType {
let intersec = self.intersection(&lhs.t, &rhs.t);
let name = lhs.var.clone();
let rhs_preds = rhs
.preds
.iter()
.map(|p| p.clone().change_subject_name(name.clone()))
.collect();
RefinementType::new(
lhs.var.clone(),
intersec,
lhs.preds.clone().concat(rhs_preds),
)
}
/// returns complement (not A)
#[allow(clippy::only_used_in_recursion)]
pub(crate) fn complement(&self, ty: &Type) -> Type {
match ty {
FreeVar(fv) if fv.is_linked() => self.complement(&fv.crack()),
Not(t) => *t.clone(),
Refinement(r) => Type::Refinement(r.clone().invert()),
other => not(other.clone()),
}
}
/// see doc/LANG/compiler/refinement_subtyping.md
/// ```python
/// assert is_super_pred({I >= 0}, {I == 0})
/// assert is_super_pred({T >= 0}, {I == 0})
/// assert !is_super_pred({I < 0}, {I == 0})
/// ```
fn is_super_pred_of(&self, lhs: &Predicate, rhs: &Predicate, allow_cast: bool) -> bool {
match (lhs, rhs) {
(Pred::LessEqual { rhs, .. }, _) if !rhs.has_upper_bound() => true,
(Pred::GreaterEqual { rhs, .. }, _) if !rhs.has_lower_bound() => true,
(
Pred::Equal { .. },
Pred::GreaterEqual { .. } | Pred::LessEqual { .. } | Pred::NotEqual { .. },
)
| (Pred::LessEqual { .. }, Pred::GreaterEqual { .. })
| (Pred::GreaterEqual { .. }, Pred::LessEqual { .. })
| (Pred::NotEqual { .. }, Pred::Equal { .. }) => false,
(Pred::Equal { rhs, .. }, Pred::Equal { rhs: rhs2, .. })
| (Pred::NotEqual { rhs, .. }, Pred::NotEqual { rhs: rhs2, .. }) => self
.try_cmp(rhs, rhs2, allow_cast)
.map(|ord| ord.canbe_eq())
.unwrap_or(false),
// {T >= 0} :> {T >= 1}, {T >= 0} :> {T == 1}
(
Pred::GreaterEqual { rhs, .. },
Pred::GreaterEqual { rhs: rhs2, .. } | Pred::Equal { rhs: rhs2, .. },
) => self
.try_cmp(rhs, rhs2, allow_cast)
.map(|ord| ord.canbe_le())
.unwrap_or(false),
(
Pred::LessEqual { rhs, .. },
Pred::LessEqual { rhs: rhs2, .. } | Pred::Equal { rhs: rhs2, .. },
) => self
.try_cmp(rhs, rhs2, allow_cast)
.map(|ord| ord.canbe_ge())
.unwrap_or(false),
(lhs @ (Pred::GreaterEqual { .. } | Pred::LessEqual { .. }), Pred::And(l, r)) => {
self.is_super_pred_of(lhs, l, allow_cast)
|| self.is_super_pred_of(lhs, r, allow_cast)
}
(lhs, Pred::Or(l, r)) => {
self.is_super_pred_of(lhs, l, allow_cast)
&& self.is_super_pred_of(lhs, r, allow_cast)
}
(Pred::Or(l, r), rhs @ (Pred::GreaterEqual { .. } | Pred::LessEqual { .. })) => {
self.is_super_pred_of(l, rhs, allow_cast)
|| self.is_super_pred_of(r, rhs, allow_cast)
}
(Pred::And(l, r), rhs) => {
self.is_super_pred_of(l, rhs, allow_cast)
&& self.is_super_pred_of(r, rhs, allow_cast)
}
(lhs, rhs) => todo!("{lhs}/{rhs}"),
}
}
pub(crate) fn is_sub_constraint_of(
&self,
l: &Constraint,
r: &Constraint,
allow_cast: bool,
) -> bool {
match (l, r) {
// (?I: Nat) <: (?I: Int)
(Constraint::TypeOf(lhs), Constraint::TypeOf(rhs)) => {
self.subtype_of(lhs, rhs, allow_cast)
}
// (?T <: Int) <: (?T: Type)
(Constraint::Sandwiched { sub: Never, .. }, Constraint::TypeOf(Type)) => true,
// (Int <: ?T) <: (Nat <: ?U)
// (?T <: Nat) <: (?U <: Int)
// (Int <: ?T <: Ratio) <: (Nat <: ?U <: Complex)
// TODO: deny cyclic constraint
(
Constraint::Sandwiched {
sub: lsub,
sup: lsup,
..
},
Constraint::Sandwiched {
sub: rsub,
sup: rsup,
..
},
) => {
self.supertype_of(lsub, rsub, allow_cast) && self.subtype_of(lsup, rsup, allow_cast)
}
_ => false,
}
}
#[inline]
fn type_of(&self, p: &TyParam) -> Type {
self.get_tp_t(p).unwrap_or(Type::Obj)
}
// sup/inf({±∞}) = ±∞ではあるが、Inf/NegInfにはOrdを実装しない
fn sup(&self, t: &Type) -> Option<TyParam> {
match t {
Int | Nat | Float => Some(TyParam::value(Inf)),
Refinement(refine) => {
let mut maybe_max = None;
for pred in refine.preds.iter() {
match pred {
Pred::LessEqual { lhs, rhs } | Pred::Equal { lhs, rhs }
if lhs == &refine.var =>
{
if let Some(max) = &maybe_max {
if self.try_cmp(rhs, max, true) == Some(Greater) {
maybe_max = Some(rhs.clone());
}
} else {
maybe_max = Some(rhs.clone());
}
}
_ => {}
}
}
maybe_max
}
_other => None,
}
}
fn inf(&self, t: &Type) -> Option<TyParam> {
match t {
Int | Float => Some(TyParam::value(-Inf)),
Nat => Some(TyParam::value(0usize)),
Refinement(refine) => {
let mut maybe_min = None;
for pred in refine.preds.iter() {
match pred {
Predicate::GreaterEqual { lhs, rhs } | Predicate::Equal { lhs, rhs }
if lhs == &refine.var =>
{
if let Some(min) = &maybe_min {
if self.try_cmp(rhs, min, true) == Some(Less) {
maybe_min = Some(rhs.clone());
}
} else {
maybe_min = Some(rhs.clone());
}
}
_ => {}
}
}
maybe_min
}
_other => None,
}
}
/// If lhs and rhs are in a subtype relation, return the smaller one
/// Return None if they are not related
/// lhsとrhsが包含関係にあるとき小さいほうを返す
/// 関係なければNoneを返す
pub(crate) fn min<'t>(&self, lhs: &'t Type, rhs: &'t Type) -> Option<&'t Type> {
// If they are the same, either one can be returned.
match (
self.supertype_of(lhs, rhs, true),
self.subtype_of(lhs, rhs, true),
) {
(true, true) | (true, false) => Some(rhs),
(false, true) => Some(lhs),
(false, false) => None,
}
}
pub(crate) fn _max<'t>(&self, lhs: &'t Type, rhs: &'t Type) -> Option<&'t Type> {
// If they are the same, either one can be returned.
match (
self.supertype_of(lhs, rhs, true),
self.subtype_of(lhs, rhs, true),
) {
(true, true) | (true, false) => Some(lhs),
(false, true) => Some(rhs),
(false, false) => None,
}
}
pub(crate) fn cmp_t<'t>(&self, lhs: &'t Type, rhs: &'t Type) -> TyParamOrdering {
match self.min(lhs, rhs) {
Some(l) if l == lhs => TyParamOrdering::Less,
Some(_) => TyParamOrdering::Greater,
None => TyParamOrdering::NoRelation,
}
}
}
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