use std::mem;
use std::option::Option;
use erg_common::error::Location;
use erg_common::set::Set;
use erg_common::traits::{Locational, Stream};
use erg_common::Str;
use erg_common::{assume_unreachable, fn_name, log, set};
use crate::ty::constructors::*;
use crate::ty::free::{Constraint, Cyclicity, FreeKind};
use crate::ty::typaram::TyParam;
use crate::ty::value::ValueObj;
use crate::ty::{HasType, Predicate, TyBound, Type};
use crate::context::eval::SubstContext;
use crate::context::{Context, TyVarInstContext, Variance};
use crate::error::{SingleTyCheckResult, TyCheckError, TyCheckErrors, TyCheckResult};
use crate::hir;
use Predicate as Pred;
use Type::*;
use ValueObj::{Inf, NegInf};
use Variance::*;
impl Context {
pub const TOP_LEVEL: usize = 1;
pub const GENERIC_LEVEL: usize = usize::MAX;
fn _independentise(_t: Type, _ts: &[Type]) -> Type {
todo!()
}
fn generalize_tp(
&self,
free: TyParam,
variance: Variance,
bounds: &mut Set<TyBound>,
lazy_inits: &mut Set<Str>,
) -> TyParam {
match free {
TyParam::Type(t) => {
TyParam::t(self.generalize_t_inner(*t, variance, bounds, lazy_inits))
}
TyParam::FreeVar(v) if v.is_linked() => {
if let FreeKind::Linked(tp) = &mut *v.borrow_mut() {
*tp = self.generalize_tp(tp.clone(), variance, bounds, lazy_inits);
} else {
assume_unreachable!()
}
TyParam::FreeVar(v)
}
TyParam::FreeVar(fv) if fv.level() > Some(self.level) => match &*fv.borrow() {
FreeKind::Unbound { id, constraint, .. } => {
let name = format!("%{id}");
self.generalize_constraint(&name, constraint, variance, bounds, lazy_inits);
TyParam::mono_q(name)
}
FreeKind::NamedUnbound {
name, constraint, ..
} => {
self.generalize_constraint(name, constraint, variance, bounds, lazy_inits);
TyParam::mono_q(name)
}
_ => assume_unreachable!(),
},
other if other.has_no_unbound_var() => other,
other => todo!("{other}"),
}
}
pub(crate) fn generalize_t(&self, free_type: Type) -> Type {
if cfg!(feature = "debug") && free_type.has_qvar() {
panic!("{free_type} has qvars")
}
let mut bounds = set! {};
let mut lazy_inits = set! {};
let maybe_unbound_t =
self.generalize_t_inner(free_type, Covariant, &mut bounds, &mut lazy_inits);
if bounds.is_empty() {
maybe_unbound_t
} else {
quant(maybe_unbound_t, bounds)
}
}
pub(crate) fn generalize_t_given_bounds(
&self,
free_type: Type,
mut bounds: Set<TyBound>,
) -> Type {
let mut lazy_inits = set! {};
let maybe_unbound_t =
self.generalize_t_inner(free_type, Covariant, &mut bounds, &mut lazy_inits);
if bounds.is_empty() {
maybe_unbound_t
} else {
quant(maybe_unbound_t, bounds)
}
}
fn generalize_t_inner(
&self,
free_type: Type,
variance: Variance,
bounds: &mut Set<TyBound>,
lazy_inits: &mut Set<Str>,
) -> Type {
match free_type {
FreeVar(v) if v.is_linked() => {
if let FreeKind::Linked(t) = &mut *v.borrow_mut() {
*t = self.generalize_t_inner(t.clone(), variance, bounds, lazy_inits);
} else {
assume_unreachable!()
}
Type::FreeVar(v)
}
FreeVar(fv) if fv.level().unwrap() > self.level => {
let (name, constraint) = match &*fv.borrow() {
FreeKind::Unbound { id, constraint, .. } => {
(Str::from(format!("%{id}")), constraint.clone())
}
FreeKind::NamedUnbound {
name, constraint, ..
} => (name.clone(), constraint.clone()),
_ => assume_unreachable!(),
};
let (l, r) = constraint.get_sub_sup().unwrap();
let l = if l.has_qvar() {
let tv_ctx = TyVarInstContext::new(self.level, bounds.clone(), self);
self.instantiate_t(l.clone(), &tv_ctx, Location::Unknown)
.unwrap()
} else {
l.clone()
};
let r = if r.has_qvar() {
let tv_ctx = TyVarInstContext::new(self.level, bounds.clone(), self);
self.instantiate_t(r.clone(), &tv_ctx, Location::Unknown)
.unwrap()
} else {
r.clone()
};
if l == r {
fv.forced_link(&l);
FreeVar(fv)
} else if r != Obj && self.is_class(&r) && variance == Contravariant {
r
} else if l != Never && self.is_class(&l) && variance == Covariant {
l
} else {
self.generalize_constraint(&name, &constraint, variance, bounds, lazy_inits);
mono_q(name)
}
}
Subr(mut subr) => {
subr.non_default_params.iter_mut().for_each(|nd_param| {
*nd_param.typ_mut() = self.generalize_t_inner(
mem::take(nd_param.typ_mut()),
Contravariant,
bounds,
lazy_inits,
);
});
if let Some(var_args) = &mut subr.var_params {
*var_args.typ_mut() = self.generalize_t_inner(
mem::take(var_args.typ_mut()),
Contravariant,
bounds,
lazy_inits,
);
}
subr.default_params.iter_mut().for_each(|d_param| {
*d_param.typ_mut() = self.generalize_t_inner(
mem::take(d_param.typ_mut()),
Contravariant,
bounds,
lazy_inits,
);
});
let return_t =
self.generalize_t_inner(*subr.return_t, Covariant, bounds, lazy_inits);
subr_t(
subr.kind,
subr.non_default_params,
subr.var_params.map(|x| *x),
subr.default_params,
return_t,
)
}
Callable { .. } => todo!(),
Ref(t) => ref_(self.generalize_t_inner(*t, variance, bounds, lazy_inits)),
RefMut { before, after } => {
let after =
after.map(|aft| self.generalize_t_inner(*aft, variance, bounds, lazy_inits));
ref_mut(
self.generalize_t_inner(*before, variance, bounds, lazy_inits),
after,
)
}
Poly { name, mut params } => {
let params = params
.iter_mut()
.map(|p| self.generalize_tp(mem::take(p), variance, bounds, lazy_inits))
.collect::<Vec<_>>();
poly(name, params)
}
Proj { lhs, rhs } => {
let lhs = self.generalize_t_inner(*lhs, variance, bounds, lazy_inits);
proj(lhs, rhs)
}
ProjCall {
lhs,
attr_name,
mut args,
} => {
let lhs = self.generalize_tp(*lhs, variance, bounds, lazy_inits);
for arg in args.iter_mut() {
*arg = self.generalize_tp(mem::take(arg), variance, bounds, lazy_inits);
}
proj_call(lhs, attr_name, args)
}
And(l, r) => {
let l = self.generalize_t_inner(*l, variance, bounds, lazy_inits);
let r = self.generalize_t_inner(*r, variance, bounds, lazy_inits);
and(l, r)
}
Or(l, r) => {
let l = self.generalize_t_inner(*l, variance, bounds, lazy_inits);
let r = self.generalize_t_inner(*r, variance, bounds, lazy_inits);
or(l, r)
}
Not(l, r) => {
let l = self.generalize_t_inner(*l, variance, bounds, lazy_inits);
let r = self.generalize_t_inner(*r, variance, bounds, lazy_inits);
not(l, r)
}
other => other,
}
}
fn generalize_constraint<S: Into<Str>>(
&self,
name: S,
constraint: &Constraint,
variance: Variance,
bounds: &mut Set<TyBound>,
lazy_inits: &mut Set<Str>,
) {
let name = name.into();
if !lazy_inits.contains(&name[..]) {
lazy_inits.insert(name.clone());
match constraint {
Constraint::Sandwiched { sub, sup, .. } => {
let sub = self.generalize_t_inner(sub.clone(), variance, bounds, lazy_inits);
let sup = self.generalize_t_inner(sup.clone(), variance, bounds, lazy_inits);
bounds.insert(TyBound::sandwiched(sub, mono_q(name), sup));
}
Constraint::TypeOf(t) => {
let t = self.generalize_t_inner(t.clone(), variance, bounds, lazy_inits);
bounds.insert(TyBound::instance(Str::rc(&name[..]), t));
}
Constraint::Uninited => unreachable!(),
}
}
}
pub(crate) fn deref_tp(
&self,
tp: TyParam,
variance: Variance,
loc: Location,
) -> SingleTyCheckResult<TyParam> {
match tp {
TyParam::FreeVar(fv) if fv.is_linked() => {
let inner = fv.unwrap_linked();
self.deref_tp(inner, variance, loc)
}
TyParam::FreeVar(_fv) if self.level == 0 => Err(TyCheckError::dummy_infer_error(
self.cfg.input.clone(),
fn_name!(),
line!(),
)),
TyParam::Type(t) => Ok(TyParam::t(self.deref_tyvar(*t, variance, loc)?)),
TyParam::App { name, mut args } => {
for param in args.iter_mut() {
*param = self.deref_tp(mem::take(param), variance, loc)?;
}
Ok(TyParam::App { name, args })
}
TyParam::BinOp { .. } => todo!(),
TyParam::UnaryOp { .. } => todo!(),
TyParam::Array(tps) => {
let mut new_tps = vec![];
for tp in tps {
new_tps.push(self.deref_tp(tp, variance, loc)?);
}
Ok(TyParam::Array(new_tps))
}
TyParam::Tuple(tps) => {
let mut new_tps = vec![];
for tp in tps {
new_tps.push(self.deref_tp(tp, variance, loc)?);
}
Ok(TyParam::Tuple(new_tps))
}
TyParam::Proj { .. }
| TyParam::MonoQVar(_)
| TyParam::PolyQVar { .. }
| TyParam::Failure
if self.level == 0 =>
{
Err(TyCheckError::dummy_infer_error(
self.cfg.input.clone(),
fn_name!(),
line!(),
))
}
t => Ok(t),
}
}
fn deref_constraint(
&self,
constraint: Constraint,
variance: Variance,
loc: Location,
) -> SingleTyCheckResult<Constraint> {
match constraint {
Constraint::Sandwiched {
sub,
sup,
cyclicity: cyclic,
} => {
if cyclic.is_cyclic() {
return Err(TyCheckError::dummy_infer_error(
self.cfg.input.clone(),
fn_name!(),
line!(),
));
}
Ok(Constraint::new_sandwiched(
self.deref_tyvar(sub, variance, loc)?,
self.deref_tyvar(sup, variance, loc)?,
cyclic,
))
}
Constraint::TypeOf(t) => {
Ok(Constraint::new_type_of(self.deref_tyvar(t, variance, loc)?))
}
_ => unreachable!(),
}
}
pub(crate) fn deref_tyvar(
&self,
t: Type,
variance: Variance,
loc: Location,
) -> SingleTyCheckResult<Type> {
match t {
Type::FreeVar(fv) if fv.constraint_is_sandwiched() => {
let (sub_t, super_t) = fv.get_bound_types().unwrap();
if self.level <= fv.level().unwrap() {
if fv.cyclicity().is_super_cyclic() {
fv.forced_link(&sub_t);
}
if self.is_trait(&super_t) {
self.check_trait_impl(&sub_t, &super_t, loc)?;
}
if self.subtype_of(&sub_t, &super_t) {
match variance {
Variance::Covariant => Ok(sub_t),
Variance::Contravariant => Ok(super_t),
Variance::Invariant => {
if self.supertype_of(&sub_t, &super_t) {
Ok(sub_t)
} else {
Err(TyCheckError::subtyping_error(
self.cfg.input.clone(),
line!() as usize,
&self.deref_tyvar(sub_t, variance, loc)?,
&self.deref_tyvar(super_t, variance, loc)?,
loc,
self.caused_by(),
))
}
}
}
} else {
let sub_t = if cfg!(feature = "debug") {
sub_t
} else {
self.deref_tyvar(sub_t, variance, loc)?
};
let super_t = if cfg!(feature = "debug") {
super_t
} else {
self.deref_tyvar(super_t, variance, loc)?
};
Err(TyCheckError::subtyping_error(
self.cfg.input.clone(),
line!() as usize,
&sub_t,
&super_t,
loc,
self.caused_by(),
))
}
} else {
Ok(Type::FreeVar(fv))
}
}
Type::FreeVar(fv) if fv.is_unbound() => {
if self.level == 0 {
match &*fv.crack_constraint() {
Constraint::TypeOf(_) => Err(TyCheckError::dummy_infer_error(
self.cfg.input.clone(),
fn_name!(),
line!(),
)),
_ => unreachable!(),
}
} else {
let new_constraint = fv.crack_constraint().clone();
let new_constraint = self.deref_constraint(new_constraint, variance, loc)?;
fv.update_constraint(new_constraint);
Ok(Type::FreeVar(fv))
}
}
Type::FreeVar(fv) if fv.is_linked() => {
let t = fv.unwrap_linked();
self.deref_tyvar(t, variance, loc)
}
Type::Poly { name, mut params } => {
let typ = poly(&name, params.clone());
let ctx = self.get_nominal_type_ctx(&typ).unwrap();
let variances = ctx.type_params_variance();
for (param, variance) in params.iter_mut().zip(variances.into_iter()) {
*param = self.deref_tp(mem::take(param), variance, loc)?;
}
Ok(Type::Poly { name, params })
}
Type::Subr(mut subr) => {
for param in subr.non_default_params.iter_mut() {
*param.typ_mut() =
self.deref_tyvar(mem::take(param.typ_mut()), Contravariant, loc)?;
}
if let Some(var_args) = &mut subr.var_params {
*var_args.typ_mut() =
self.deref_tyvar(mem::take(var_args.typ_mut()), Contravariant, loc)?;
}
for d_param in subr.default_params.iter_mut() {
*d_param.typ_mut() =
self.deref_tyvar(mem::take(d_param.typ_mut()), Contravariant, loc)?;
}
subr.return_t =
Box::new(self.deref_tyvar(mem::take(&mut subr.return_t), Covariant, loc)?);
Ok(Type::Subr(subr))
}
Type::Ref(t) => {
let t = self.deref_tyvar(*t, variance, loc)?;
Ok(ref_(t))
}
Type::RefMut { before, after } => {
let before = self.deref_tyvar(*before, variance, loc)?;
let after = if let Some(after) = after {
Some(self.deref_tyvar(*after, variance, loc)?)
} else {
None
};
Ok(ref_mut(before, after))
}
Type::Callable { .. } => todo!(),
Type::Record(mut rec) => {
for (_, field) in rec.iter_mut() {
*field = self.deref_tyvar(mem::take(field), variance, loc)?;
}
Ok(Type::Record(rec))
}
Type::Refinement(refine) => {
let t = self.deref_tyvar(*refine.t, variance, loc)?;
Ok(refinement(refine.var, t, refine.preds))
}
Type::And(l, r) => {
let l = self.deref_tyvar(*l, variance, loc)?;
let r = self.deref_tyvar(*r, variance, loc)?;
Ok(self.intersection(&l, &r))
}
Type::Or(l, r) => {
let l = self.deref_tyvar(*l, variance, loc)?;
let r = self.deref_tyvar(*r, variance, loc)?;
Ok(self.union(&l, &r))
}
Type::Not(l, r) => {
let l = self.deref_tyvar(*l, variance, loc)?;
let r = self.deref_tyvar(*r, variance, loc)?;
Ok(not(l, r))
}
t => Ok(t),
}
}
pub(crate) fn trait_impl_exists(&self, class: &Type, trait_: &Type) -> bool {
if class.is_monomorphic() {
self.mono_class_trait_impl_exist(class, trait_)
} else {
self.poly_class_trait_impl_exists(class, trait_)
}
}
fn mono_class_trait_impl_exist(&self, class: &Type, trait_: &Type) -> bool {
let mut super_exists = false;
for inst in self.get_trait_impls(trait_).into_iter() {
let sub_type = if inst.sub_type.has_qvar() {
let sub_ctx = self.get_nominal_type_ctx(&inst.sub_type).unwrap();
let tv_ctx = TyVarInstContext::new(self.level, sub_ctx.bounds(), self);
self.instantiate_t(inst.sub_type, &tv_ctx, Location::Unknown)
.unwrap()
} else {
inst.sub_type
};
let sup_trait = if inst.sup_trait.has_qvar() {
let sup_ctx = self.get_nominal_type_ctx(&inst.sup_trait).unwrap();
let tv_ctx = TyVarInstContext::new(self.level, sup_ctx.bounds(), self);
self.instantiate_t(inst.sup_trait, &tv_ctx, Location::Unknown)
.unwrap()
} else {
inst.sup_trait
};
if self.supertype_of(&sub_type, class) && self.supertype_of(&sup_trait, trait_) {
super_exists = true;
break;
}
}
super_exists
}
fn poly_class_trait_impl_exists(&self, class: &Type, trait_: &Type) -> bool {
let mut super_exists = false;
let subst_ctx = if self.get_nominal_type_ctx(class).is_some() {
SubstContext::new(class, self, Location::Unknown)
} else {
return false;
};
for inst in self.get_trait_impls(trait_).into_iter() {
let sub_type = if inst.sub_type.has_qvar() {
if let Ok(t) = subst_ctx.substitute(inst.sub_type.clone()) {
t
} else {
continue;
}
} else {
inst.sub_type
};
let sup_trait = if inst.sup_trait.has_qvar() {
if let Ok(t) = subst_ctx.substitute(inst.sup_trait.clone()) {
t
} else {
continue;
}
} else {
inst.sup_trait
};
if self.supertype_of(&sub_type, class) && self.supertype_of(&sup_trait, trait_) {
super_exists = true;
break;
}
}
super_exists
}
fn check_trait_impl(
&self,
class: &Type,
trait_: &Type,
loc: Location,
) -> SingleTyCheckResult<()> {
if !self.trait_impl_exists(class, trait_) {
Err(TyCheckError::no_trait_impl_error(
self.cfg.input.clone(),
line!() as usize,
class,
trait_,
loc,
self.caused_by(),
None,
))
} else {
Ok(())
}
}
pub(crate) fn coerce(&self, t: &Type) {
match t {
Type::FreeVar(fv) if fv.is_linked() => {
self.coerce(&fv.crack());
}
Type::FreeVar(fv) if fv.is_unbound() => {
let (sub, _sup) = fv.get_bound_types().unwrap();
fv.link(&sub);
}
Type::And(l, r) | Type::Or(l, r) | Type::Not(l, r) => {
self.coerce(l);
self.coerce(r);
}
_ => {}
}
}
pub(crate) fn coerce_tp(&self, tp: &TyParam) {
match tp {
TyParam::FreeVar(fv) if fv.is_linked() => {
self.coerce_tp(&fv.crack());
}
TyParam::Type(t) => self.coerce(t),
_ => {}
}
}
pub(crate) fn resolve(
&mut self,
mut hir: hir::HIR,
) -> Result<hir::HIR, (hir::HIR, TyCheckErrors)> {
self.level = 0;
let mut errs = TyCheckErrors::empty();
for chunk in hir.module.iter_mut() {
if let Err(err) = self.resolve_expr_t(chunk) {
errs.push(err);
}
}
if errs.is_empty() {
Ok(hir)
} else {
Err((hir, errs))
}
}
fn resolve_expr_t(&self, expr: &mut hir::Expr) -> SingleTyCheckResult<()> {
match expr {
hir::Expr::Lit(_) => Ok(()),
hir::Expr::Accessor(acc) => {
let loc = acc.loc();
let t = acc.ref_mut_t();
*t = self.deref_tyvar(mem::take(t), Covariant, loc)?;
if let hir::Accessor::Attr(attr) = acc {
self.resolve_expr_t(&mut attr.obj)?;
}
Ok(())
}
hir::Expr::Array(array) => match array {
hir::Array::Normal(arr) => {
let loc = arr.loc();
arr.t = self.deref_tyvar(mem::take(&mut arr.t), Covariant, loc)?;
for elem in arr.elems.pos_args.iter_mut() {
self.resolve_expr_t(&mut elem.expr)?;
}
Ok(())
}
hir::Array::WithLength(arr) => {
let loc = arr.loc();
arr.t = self.deref_tyvar(mem::take(&mut arr.t), Covariant, loc)?;
self.resolve_expr_t(&mut arr.elem)?;
self.resolve_expr_t(&mut arr.len)?;
Ok(())
}
_ => todo!(),
},
hir::Expr::Tuple(tuple) => match tuple {
hir::Tuple::Normal(tup) => {
for elem in tup.elems.pos_args.iter_mut() {
self.resolve_expr_t(&mut elem.expr)?;
}
Ok(())
}
},
hir::Expr::Set(set) => match set {
hir::Set::Normal(st) => {
let loc = st.loc();
st.t = self.deref_tyvar(mem::take(&mut st.t), Covariant, loc)?;
for elem in st.elems.pos_args.iter_mut() {
self.resolve_expr_t(&mut elem.expr)?;
}
Ok(())
}
hir::Set::WithLength(st) => {
let loc = st.loc();
st.t = self.deref_tyvar(mem::take(&mut st.t), Covariant, loc)?;
self.resolve_expr_t(&mut st.elem)?;
self.resolve_expr_t(&mut st.len)?;
Ok(())
}
},
hir::Expr::Dict(dict) => match dict {
hir::Dict::Normal(dic) => {
let loc = dic.loc();
dic.t = self.deref_tyvar(mem::take(&mut dic.t), Covariant, loc)?;
for kv in dic.kvs.iter_mut() {
self.resolve_expr_t(&mut kv.key)?;
self.resolve_expr_t(&mut kv.value)?;
}
Ok(())
}
other => todo!("{other}"),
},
hir::Expr::Record(record) => {
for attr in record.attrs.iter_mut() {
match &mut attr.sig {
hir::Signature::Var(var) => {
*var.ref_mut_t() =
self.deref_tyvar(mem::take(var.ref_mut_t()), Covariant, var.loc())?;
}
hir::Signature::Subr(subr) => {
subr.t =
self.deref_tyvar(mem::take(&mut subr.t), Covariant, subr.loc())?;
}
}
for chunk in attr.body.block.iter_mut() {
self.resolve_expr_t(chunk)?;
}
}
Ok(())
}
hir::Expr::BinOp(binop) => {
let loc = binop.loc();
let t = binop.signature_mut_t().unwrap();
*t = self.deref_tyvar(mem::take(t), Covariant, loc)?;
self.resolve_expr_t(&mut binop.lhs)?;
self.resolve_expr_t(&mut binop.rhs)?;
Ok(())
}
hir::Expr::UnaryOp(unaryop) => {
let loc = unaryop.loc();
let t = unaryop.signature_mut_t().unwrap();
*t = self.deref_tyvar(mem::take(t), Covariant, loc)?;
self.resolve_expr_t(&mut unaryop.expr)?;
Ok(())
}
hir::Expr::Call(call) => {
let loc = call.loc();
if let Some(t) = call.signature_mut_t() {
*t = self.deref_tyvar(mem::take(t), Covariant, loc)?;
}
self.resolve_expr_t(&mut call.obj)?;
for arg in call.args.pos_args.iter_mut() {
self.resolve_expr_t(&mut arg.expr)?;
}
if let Some(var_args) = &mut call.args.var_args {
self.resolve_expr_t(&mut var_args.expr)?;
}
for arg in call.args.kw_args.iter_mut() {
self.resolve_expr_t(&mut arg.expr)?;
}
Ok(())
}
hir::Expr::Def(def) => {
if !def.sig.ref_t().is_quantified() {
match &mut def.sig {
hir::Signature::Var(var) => {
*var.ref_mut_t() =
self.deref_tyvar(mem::take(var.ref_mut_t()), Covariant, var.loc())?;
}
hir::Signature::Subr(subr) => {
subr.t =
self.deref_tyvar(mem::take(&mut subr.t), Covariant, subr.loc())?;
}
}
for chunk in def.body.block.iter_mut() {
self.resolve_expr_t(chunk)?;
}
}
Ok(())
}
hir::Expr::Lambda(lambda) => {
lambda.t = self.deref_tyvar(mem::take(&mut lambda.t), Covariant, lambda.loc())?;
for chunk in lambda.body.iter_mut() {
self.resolve_expr_t(chunk)?;
}
Ok(())
}
hir::Expr::ClassDef(class_def) => {
for def in class_def.methods.iter_mut() {
self.resolve_expr_t(def)?;
}
Ok(())
}
hir::Expr::AttrDef(attr_def) => {
for chunk in attr_def.block.iter_mut() {
self.resolve_expr_t(chunk)?;
}
Ok(())
}
hir::Expr::TypeAsc(tasc) => self.resolve_expr_t(&mut tasc.expr),
hir::Expr::Code(chunks) | hir::Expr::Compound(chunks) => {
for chunk in chunks.iter_mut() {
self.resolve_expr_t(chunk)?;
}
Ok(())
}
hir::Expr::Import(_) => unreachable!(),
}
}
fn occur(&self, maybe_sub: &Type, maybe_sup: &Type, loc: Location) -> TyCheckResult<()> {
match (maybe_sub, maybe_sup) {
(Type::FreeVar(sub), Type::FreeVar(sup)) => {
if sub.is_unbound() && sup.is_unbound() && sub == sup {
Err(TyCheckErrors::from(TyCheckError::subtyping_error(
self.cfg.input.clone(),
line!() as usize,
maybe_sub,
maybe_sup,
loc,
self.caused_by(),
)))
} else {
Ok(())
}
}
(Type::Subr(subr), Type::FreeVar(fv)) if fv.is_unbound() => {
for default_t in subr.default_params.iter().map(|pt| pt.typ()) {
self.occur(default_t, maybe_sup, loc)?;
}
if let Some(var_params) = subr.var_params.as_ref() {
self.occur(var_params.typ(), maybe_sup, loc)?;
}
for non_default_t in subr.non_default_params.iter().map(|pt| pt.typ()) {
self.occur(non_default_t, maybe_sup, loc)?;
}
self.occur(&subr.return_t, maybe_sup, loc)?;
Ok(())
}
(Type::FreeVar(fv), Type::Subr(subr)) if fv.is_unbound() => {
for default_t in subr.default_params.iter().map(|pt| pt.typ()) {
self.occur(maybe_sub, default_t, loc)?;
}
if let Some(var_params) = subr.var_params.as_ref() {
self.occur(maybe_sub, var_params.typ(), loc)?;
}
for non_default_t in subr.non_default_params.iter().map(|pt| pt.typ()) {
self.occur(maybe_sub, non_default_t, loc)?;
}
self.occur(maybe_sub, &subr.return_t, loc)?;
Ok(())
}
(Type::Poly { params, .. } | Type::PolyQVar { params, .. }, Type::FreeVar(fv))
if fv.is_unbound() =>
{
for param in params.iter().filter_map(|tp| {
if let TyParam::Type(t) = tp {
Some(t)
} else {
None
}
}) {
self.occur(param, maybe_sup, loc)?;
}
Ok(())
}
(Type::FreeVar(fv), Type::Poly { params, .. } | Type::PolyQVar { params, .. })
if fv.is_unbound() =>
{
for param in params.iter().filter_map(|tp| {
if let TyParam::Type(t) = tp {
Some(t)
} else {
None
}
}) {
self.occur(maybe_sub, param, loc)?;
}
Ok(())
}
_ => Ok(()),
}
}
pub(crate) fn sub_unify_tp(
&self,
maybe_sub: &TyParam,
maybe_sup: &TyParam,
variance: Option<Variance>,
loc: Location,
allow_divergence: bool,
) -> TyCheckResult<()> {
if maybe_sub.has_no_unbound_var()
&& maybe_sup.has_no_unbound_var()
&& maybe_sub == maybe_sup
{
return Ok(());
}
match (maybe_sub, maybe_sup) {
(TyParam::Type(maybe_sub), TyParam::Type(maybe_sup)) => {
self.sub_unify(maybe_sub, maybe_sup, loc, None)
}
(TyParam::FreeVar(lfv), TyParam::FreeVar(rfv))
if lfv.is_unbound() && rfv.is_unbound() =>
{
if lfv.level().unwrap() > rfv.level().unwrap() {
lfv.link(maybe_sup);
} else {
rfv.link(maybe_sub);
}
Ok(())
}
(TyParam::FreeVar(fv), tp) => {
match &*fv.borrow() {
FreeKind::Linked(l) | FreeKind::UndoableLinked { t: l, .. } => {
return self.sub_unify_tp(l, tp, variance, loc, allow_divergence);
}
FreeKind::Unbound { .. } | FreeKind::NamedUnbound { .. } => {}
} let fv_t = fv
.borrow()
.constraint()
.unwrap()
.get_type()
.unwrap()
.clone(); let tp_t = self.get_tp_t(tp)?;
if self.supertype_of(&fv_t, &tp_t) {
if fv.level() < Some(self.level) {
let new_constraint = Constraint::new_subtype_of(tp_t, Cyclicity::Not);
if self.is_sub_constraint_of(
fv.borrow().constraint().unwrap(),
&new_constraint,
) || fv.borrow().constraint().unwrap().get_type() == Some(&Type)
{
fv.update_constraint(new_constraint);
}
} else {
fv.link(tp);
}
Ok(())
} else if allow_divergence
&& (self.eq_tp(tp, &TyParam::value(Inf))
|| self.eq_tp(tp, &TyParam::value(NegInf)))
&& self.subtype_of(&fv_t, &mono("Num"))
{
fv.link(tp);
Ok(())
} else {
Err(TyCheckErrors::from(TyCheckError::unreachable(
self.cfg.input.clone(),
fn_name!(),
line!(),
)))
}
}
(tp, TyParam::FreeVar(fv)) => {
match &*fv.borrow() {
FreeKind::Linked(l) | FreeKind::UndoableLinked { t: l, .. } => {
return self.sub_unify_tp(l, tp, variance, loc, allow_divergence);
}
FreeKind::Unbound { .. } | FreeKind::NamedUnbound { .. } => {}
} let fv_t = fv
.borrow()
.constraint()
.unwrap()
.get_type()
.unwrap()
.clone(); let tp_t = self.get_tp_t(tp)?;
if self.supertype_of(&fv_t, &tp_t) {
if fv.level() < Some(self.level) {
let new_constraint = Constraint::new_subtype_of(tp_t, Cyclicity::Not);
if self.is_sub_constraint_of(
fv.borrow().constraint().unwrap(),
&new_constraint,
) || fv.borrow().constraint().unwrap().get_type() == Some(&Type)
{
fv.update_constraint(new_constraint);
}
} else {
fv.link(tp);
}
Ok(())
} else if allow_divergence
&& (self.eq_tp(tp, &TyParam::value(Inf))
|| self.eq_tp(tp, &TyParam::value(NegInf)))
&& self.subtype_of(&fv_t, &mono("Num"))
{
fv.link(tp);
Ok(())
} else {
Err(TyCheckErrors::from(TyCheckError::unreachable(
self.cfg.input.clone(),
fn_name!(),
line!(),
)))
}
}
(TyParam::UnaryOp { op: lop, val: lval }, TyParam::UnaryOp { op: rop, val: rval })
if lop == rop =>
{
self.sub_unify_tp(lval, rval, variance, loc, allow_divergence)
}
(
TyParam::BinOp { op: lop, lhs, rhs },
TyParam::BinOp {
op: rop,
lhs: lhs2,
rhs: rhs2,
},
) if lop == rop => {
self.sub_unify_tp(lhs, lhs2, variance, loc, allow_divergence)?;
self.sub_unify_tp(rhs, rhs2, variance, loc, allow_divergence)
}
(l, r) => panic!("type-parameter unification failed:\nl:{l}\nr: {r}"),
}
}
fn reunify_tp(
&self,
before: &TyParam,
after: &TyParam,
loc: Location,
) -> SingleTyCheckResult<()> {
match (before, after) {
(TyParam::Value(ValueObj::Mut(l)), TyParam::Value(ValueObj::Mut(r))) => {
*l.borrow_mut() = r.borrow().clone();
Ok(())
}
(TyParam::Value(ValueObj::Mut(l)), TyParam::Value(r)) => {
*l.borrow_mut() = r.clone();
Ok(())
}
(TyParam::Type(l), TyParam::Type(r)) => self.reunify(l, r, loc),
(TyParam::UnaryOp { op: lop, val: lval }, TyParam::UnaryOp { op: rop, val: rval })
if lop == rop =>
{
self.reunify_tp(lval, rval, loc)
}
(
TyParam::BinOp { op: lop, lhs, rhs },
TyParam::BinOp {
op: rop,
lhs: lhs2,
rhs: rhs2,
},
) if lop == rop => {
self.reunify_tp(lhs, lhs2, loc)?;
self.reunify_tp(rhs, rhs2, loc)
}
(l, r) if self.eq_tp(l, r) => Ok(()),
(l, r) => panic!("type-parameter re-unification failed:\nl: {l}\nr: {r}"),
}
}
fn sub_unify_pred(
&self,
l_pred: &Predicate,
r_pred: &Predicate,
loc: Location,
) -> TyCheckResult<()> {
match (l_pred, r_pred) {
(Pred::Value(_), Pred::Value(_)) | (Pred::Const(_), Pred::Const(_)) => Ok(()),
(Pred::Equal { rhs, .. }, Pred::Equal { rhs: rhs2, .. })
| (Pred::GreaterEqual { rhs, .. }, Pred::GreaterEqual { rhs: rhs2, .. })
| (Pred::LessEqual { rhs, .. }, Pred::LessEqual { rhs: rhs2, .. })
| (Pred::NotEqual { rhs, .. }, Pred::NotEqual { rhs: rhs2, .. }) => {
self.sub_unify_tp(rhs, rhs2, None, loc, false)
}
(Pred::And(l1, r1), Pred::And(l2, r2))
| (Pred::Or(l1, r1), Pred::Or(l2, r2))
| (Pred::Not(l1, r1), Pred::Not(l2, r2)) => {
match (
self.sub_unify_pred(l1, l2, loc),
self.sub_unify_pred(r1, r2, loc),
) {
(Ok(()), Ok(())) => Ok(()),
(Ok(()), Err(e)) | (Err(e), Ok(())) | (Err(e), Err(_)) => Err(e),
}
}
(Pred::GreaterEqual { rhs, .. }, Pred::And(l, r))
| (Predicate::And(l, r), Pred::GreaterEqual { rhs, .. }) => {
match (l.as_ref(), r.as_ref()) {
(
Pred::GreaterEqual { rhs: ge_rhs, .. },
Pred::LessEqual { rhs: le_rhs, .. },
)
| (
Pred::LessEqual { rhs: le_rhs, .. },
Pred::GreaterEqual { rhs: ge_rhs, .. },
) => {
self.sub_unify_tp(rhs, ge_rhs, None, loc, false)?;
self.sub_unify_tp(le_rhs, &TyParam::value(Inf), None, loc, true)
}
_ => Err(TyCheckErrors::from(TyCheckError::pred_unification_error(
self.cfg.input.clone(),
line!() as usize,
l_pred,
r_pred,
self.caused_by(),
))),
}
}
(Pred::LessEqual { rhs, .. }, Pred::And(l, r))
| (Pred::And(l, r), Pred::LessEqual { rhs, .. }) => match (l.as_ref(), r.as_ref()) {
(Pred::GreaterEqual { rhs: ge_rhs, .. }, Pred::LessEqual { rhs: le_rhs, .. })
| (Pred::LessEqual { rhs: le_rhs, .. }, Pred::GreaterEqual { rhs: ge_rhs, .. }) => {
self.sub_unify_tp(rhs, le_rhs, None, loc, false)?;
self.sub_unify_tp(ge_rhs, &TyParam::value(NegInf), None, loc, true)
}
_ => Err(TyCheckErrors::from(TyCheckError::pred_unification_error(
self.cfg.input.clone(),
line!() as usize,
l_pred,
r_pred,
self.caused_by(),
))),
},
(Pred::Equal { rhs, .. }, Pred::And(l, r))
| (Pred::And(l, r), Pred::Equal { rhs, .. }) => match (l.as_ref(), r.as_ref()) {
(Pred::GreaterEqual { rhs: ge_rhs, .. }, Pred::LessEqual { rhs: le_rhs, .. })
| (Pred::LessEqual { rhs: le_rhs, .. }, Pred::GreaterEqual { rhs: ge_rhs, .. }) => {
self.sub_unify_tp(rhs, le_rhs, None, loc, false)?;
self.sub_unify_tp(rhs, ge_rhs, None, loc, false)
}
_ => Err(TyCheckErrors::from(TyCheckError::pred_unification_error(
self.cfg.input.clone(),
line!() as usize,
l_pred,
r_pred,
self.caused_by(),
))),
},
_ => Err(TyCheckErrors::from(TyCheckError::pred_unification_error(
self.cfg.input.clone(),
line!() as usize,
l_pred,
r_pred,
self.caused_by(),
))),
}
}
pub(crate) fn reunify(
&self,
before_t: &Type,
after_t: &Type,
loc: Location,
) -> SingleTyCheckResult<()> {
match (before_t, after_t) {
(Type::FreeVar(fv), r) if fv.is_linked() => self.reunify(&fv.crack(), r, loc),
(l, Type::FreeVar(fv)) if fv.is_linked() => self.reunify(l, &fv.crack(), loc),
(Type::Ref(l), Type::Ref(r)) => self.reunify(l, r, loc),
(
Type::RefMut {
before: lbefore,
after: lafter,
},
Type::RefMut {
before: rbefore,
after: rafter,
},
) => {
self.reunify(lbefore, rbefore, loc)?;
match (lafter, rafter) {
(Some(lafter), Some(rafter)) => {
self.reunify(lafter, rafter, loc)?;
}
(None, None) => {}
_ => todo!(),
}
Ok(())
}
(Type::Ref(l), r) => self.reunify(l, r, loc),
(Type::RefMut { before, .. }, r) => self.reunify(before, r, loc),
(l, Type::Ref(r)) => self.reunify(l, r, loc),
(l, Type::RefMut { before, .. }) => self.reunify(l, before, loc),
(
Type::Poly {
name: ln,
params: lps,
},
Type::Poly {
name: rn,
params: rps,
},
) => {
if ln != rn {
let before_t = poly(ln.clone(), lps.clone());
return Err(TyCheckError::re_unification_error(
self.cfg.input.clone(),
line!() as usize,
&before_t,
after_t,
loc,
self.caused_by(),
));
}
for (l, r) in lps.iter().zip(rps.iter()) {
self.reunify_tp(l, r, loc)?;
}
Ok(())
}
(l, r) if self.same_type_of(l, r) => Ok(()),
(l, r) => Err(TyCheckError::re_unification_error(
self.cfg.input.clone(),
line!() as usize,
l,
r,
loc,
self.caused_by(),
)),
}
}
pub(crate) fn sub_unify(
&self,
maybe_sub: &Type,
maybe_sup: &Type,
loc: Location,
param_name: Option<&Str>,
) -> TyCheckResult<()> {
log!(info "trying sub_unify:\nmaybe_sub: {maybe_sub}\nmaybe_sup: {maybe_sup}");
if maybe_sub == &Type::Never || maybe_sup == &Type::Obj || maybe_sup == maybe_sub {
return Ok(());
}
self.occur(maybe_sub, maybe_sup, loc)?;
let maybe_sub_is_sub = self.subtype_of(maybe_sub, maybe_sup);
if maybe_sub.has_no_unbound_var() && maybe_sup.has_no_unbound_var() && maybe_sub_is_sub {
return Ok(());
}
if !maybe_sub_is_sub {
log!(err "{maybe_sub} !<: {maybe_sup}");
return Err(TyCheckErrors::from(TyCheckError::type_mismatch_error(
self.cfg.input.clone(),
line!() as usize,
loc,
self.caused_by(),
param_name.unwrap_or(&Str::ever("_")),
maybe_sup,
maybe_sub,
self.get_candidates(maybe_sub),
self.get_type_mismatch_hint(maybe_sup, maybe_sub),
)));
}
match (maybe_sub, maybe_sup) {
(Type::FreeVar(lfv), _) if lfv.is_linked() =>
self.sub_unify(&lfv.crack(), maybe_sup, loc, param_name),
(_, Type::FreeVar(rfv)) if rfv.is_linked() =>
self.sub_unify(maybe_sub, &rfv.crack(), loc, param_name),
(Type::FreeVar(lfv), Type::FreeVar(rfv))
if lfv.constraint_is_sandwiched() && rfv.constraint_is_sandwiched() =>
{
let (lsub, lsup) = lfv.get_bound_types().unwrap();
let l_cyc = lfv.cyclicity();
let (rsub, rsup) = rfv.get_bound_types().unwrap();
let r_cyc = rfv.cyclicity();
let cyclicity = l_cyc.combine(r_cyc);
let intersec = self.intersection(&lsup, &rsup);
let new_constraint = if intersec != Type::Never {
Constraint::new_sandwiched(self.union(&lsub, &rsub), intersec, cyclicity)
} else {
return Err(TyCheckErrors::from(TyCheckError::subtyping_error(
self.cfg.input.clone(),
line!() as usize,
maybe_sub,
maybe_sup,
loc,
self.caused_by(),
)));
};
if lfv.level().unwrap() <= rfv.level().unwrap() {
lfv.update_constraint(new_constraint);
rfv.link(maybe_sub);
} else {
rfv.update_constraint(new_constraint);
lfv.link(maybe_sup);
}
Ok(())
}
(_, Type::FreeVar(rfv)) if rfv.is_unbound() => {
let rfv_ref = unsafe { rfv.as_ptr().as_mut().unwrap() };
match rfv_ref {
FreeKind::NamedUnbound { constraint, .. }
| FreeKind::Unbound { constraint, .. } => match constraint {
Constraint::Sandwiched { sub, sup, cyclicity } => {
let new_sub = self.union(maybe_sub, sub);
*constraint = Constraint::new_sandwiched(new_sub, mem::take(sup), *cyclicity);
}
Constraint::TypeOf(ty) => {
if self.supertype_of(&Type, ty) {
*constraint = Constraint::new_supertype_of(maybe_sub.clone(), Cyclicity::Not);
} else {
todo!()
}
}
_ => unreachable!(),
},
_ => {}
}
Ok(())
}
(Type::FreeVar(lfv), _) if lfv.is_unbound() => {
match &mut *lfv.borrow_mut() {
FreeKind::NamedUnbound { constraint, .. }
| FreeKind::Unbound { constraint, .. } => match constraint {
Constraint::Sandwiched { sub, sup, cyclicity } => {
if let Some(new_sup) = self.min(sup, maybe_sup) {
*constraint =
Constraint::new_sandwiched(mem::take(sub), new_sup.clone(), *cyclicity);
} else {
let new_sup = self.union(sup, maybe_sup);
*constraint = Constraint::new_sandwiched(mem::take(sub), new_sup, *cyclicity);
}
}
Constraint::TypeOf(ty) => {
if self.supertype_of(&Type, ty) {
*constraint = Constraint::new_subtype_of(maybe_sup.clone(), Cyclicity::Not);
} else {
todo!()
}
}
_ => unreachable!(),
},
_ => {}
}
Ok(())
}
(Type::FreeVar(_fv), _r) => todo!(),
(Type::Record(lrec), Type::Record(rrec)) => {
for (k, l) in lrec.iter() {
if let Some(r) = rrec.get(k) {
self.sub_unify(l, r, loc, param_name)?;
} else {
return Err(TyCheckErrors::from(TyCheckError::subtyping_error(
self.cfg.input.clone(),
line!() as usize,
maybe_sub,
maybe_sup,
loc,
self.caused_by(),
)));
}
}
Ok(())
}
(Type::Subr(lsub), Type::Subr(rsub)) => {
for lpt in lsub.default_params.iter() {
if let Some(rpt) = rsub.default_params.iter().find(|rpt| rpt.name() == lpt.name()) {
self.sub_unify(rpt.typ(), lpt.typ(), loc, param_name)?;
} else { todo!() }
}
lsub.non_default_params.iter().zip(rsub.non_default_params.iter()).try_for_each(
|(l, r)| self.sub_unify(r.typ(), l.typ(), loc, param_name),
)?;
self.sub_unify(&lsub.return_t, &rsub.return_t, loc, param_name)?;
Ok(())
}
(
Type::Poly {
name: ln,
params: lps,
},
Type::Poly {
name: rn,
params: rps,
},
) => {
if ln != rn {
if let Some(sub_ctx) = self.get_nominal_type_ctx(maybe_sub) {
let subst_ctx = SubstContext::new(maybe_sub, self, loc);
for sup_trait in sub_ctx.super_traits.iter() {
let sup_trait = if sup_trait.has_qvar() {
subst_ctx.substitute(sup_trait.clone())?
} else {
sup_trait.clone()
};
if self.supertype_of(maybe_sup, &sup_trait) {
for (l_maybe_sub, r_maybe_sup) in sup_trait.typarams().iter().zip(rps.iter()) {
self.sub_unify_tp(l_maybe_sub, r_maybe_sup, None, loc, false)?;
}
return Ok(());
}
}
}
return Err(TyCheckErrors::from(TyCheckError::unification_error(
self.cfg.input.clone(),
line!() as usize,
maybe_sub,
maybe_sup,
loc,
self.caused_by(),
)));
}
for (l_maybe_sub, r_maybe_sup) in lps.iter().zip(rps.iter()) {
self.sub_unify_tp(l_maybe_sub, r_maybe_sup, None, loc, false)?;
}
Ok(())
}
(Type::And(l, r), _)
| (Type::Or(l, r), _)
| (Type::Not(l, r), _) => {
self.sub_unify(l, maybe_sup, loc, param_name)?;
self.sub_unify(r, maybe_sup, loc, param_name)?;
Ok(())
}
(_, Type::And(l, r))
| (_, Type::Or(l, r))
| (_, Type::Not(l, r)) => {
self.sub_unify(maybe_sub, l, loc, param_name)?;
self.sub_unify(maybe_sub, r, loc, param_name)?;
Ok(())
}
(_, Type::Ref(t)) => {
self.sub_unify(maybe_sub, t, loc, param_name)?;
Ok(())
}
(_, Type::RefMut{ before, .. }) => {
self.sub_unify(maybe_sub, before, loc, param_name)?;
Ok(())
}
(Type::Proj { .. }, _) => todo!(),
(_, Type::Proj { .. }) => todo!(),
(Refinement(l), Refinement(r)) => {
if l.preds.len() == 1 && r.preds.len() == 1 {
let l_first = l.preds.iter().next().unwrap();
let r_first = r.preds.iter().next().unwrap();
self.sub_unify_pred(l_first, r_first, loc)?;
return Ok(());
}
todo!("{l}, {r}")
},
(Type::Subr(_) | Type::Record(_), Type) => Ok(()),
(Type::Poly{ name, .. }, Type) if &name[..] == "Array" || &name[..] == "Tuple" => Ok(()),
_ => todo!("{maybe_sub} can be a subtype of {maybe_sup}, but failed to semi-unify (or existential types are not supported)"),
}
}
}