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Simply constraint matching in solve

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ayazhafiz 2021-12-23 20:22:42 -06:00
parent d5bd58c298
commit 409ced0ef2
1 changed files with 51 additions and 57 deletions
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108
compiler/solve/src/solve.rs
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@ -629,69 +629,63 @@ fn solve(
}
}
}
Present(typ, constr) => {
Present(typ, PresenceConstraint::IsOpen) => {
let actual = type_to_var(subs, rank, pools, cached_aliases, typ);
match constr {
PresenceConstraint::IsOpen => {
let mut new_desc = subs.get(actual);
match new_desc.content {
Content::Structure(FlatType::TagUnion(tags, _)) => {
let new_ext = subs.fresh_unnamed_flex_var();
let new_union = Content::Structure(FlatType::TagUnion(tags, new_ext));
new_desc.content = new_union;
subs.set(actual, new_desc);
state
}
_ => {
// Today, an "open" constraint doesn't affect any types
// other than tag unions. Recursive tag unions are constructed
// at a later time (during occurs checks after tag unions are
// resolved), so that's not handled here either.
// NB: Handle record types here if we add presence constraints
// to their type inference as well.
state
}
}
let mut new_desc = subs.get(actual);
match new_desc.content {
Content::Structure(FlatType::TagUnion(tags, _)) => {
let new_ext = subs.fresh_unnamed_flex_var();
let new_union = Content::Structure(FlatType::TagUnion(tags, new_ext));
new_desc.content = new_union;
subs.set(actual, new_desc);
state
}
PresenceConstraint::IncludesTag(tag_name, tys) => {
let tag_ty = Type::TagUnion(
vec![(tag_name.clone(), tys.clone())],
Box::new(Type::EmptyTagUnion),
_ => {
// Today, an "open" constraint doesn't affect any types
// other than tag unions. Recursive tag unions are constructed
// at a later time (during occurs checks after tag unions are
// resolved), so that's not handled here either.
// NB: Handle record types here if we add presence constraints
// to their type inference as well.
state
}
}
}
Present(typ, PresenceConstraint::IncludesTag(tag_name, tys)) => {
let actual = type_to_var(subs, rank, pools, cached_aliases, typ);
let tag_ty = Type::TagUnion(
vec![(tag_name.clone(), tys.clone())],
Box::new(Type::EmptyTagUnion),
);
let includes = type_to_var(subs, rank, pools, cached_aliases, &tag_ty);
match unify(subs, actual, includes, Mode::Present) {
Success(vars) => {
introduce(subs, rank, pools, &vars);
state
}
Failure(vars, actual_type, expected_type) => {
introduce(subs, rank, pools, &vars);
// TODO: do we need a better error type here?
let problem = TypeError::BadExpr(
Region::zero(),
Category::When,
actual_type,
Expected::NoExpectation(expected_type),
);
let includes = type_to_var(subs, rank, pools, cached_aliases, &tag_ty);
match unify(subs, actual, includes, Mode::Present) {
Success(vars) => {
introduce(subs, rank, pools, &vars);
problems.push(problem);
state
}
Failure(vars, actual_type, expected_type) => {
introduce(subs, rank, pools, &vars);
// TODO: do we need a better error type here?
let problem = TypeError::BadExpr(
Region::zero(),
Category::When,
actual_type,
Expected::NoExpectation(expected_type),
);
problems.push(problem);
state
}
BadType(vars, problem) => {
introduce(subs, rank, pools, &vars);
problems.push(TypeError::BadType(problem));
state
}
}
state
}
PresenceConstraint::Pattern(_, _, _) => {
unreachable!("Handled in a previous branch")
BadType(vars, problem) => {
introduce(subs, rank, pools, &vars);
problems.push(TypeError::BadType(problem));
state
}
}
}