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Add uniqueness types for List.first

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This commit is contained in:
Richard Feldman 2020-07-10 21:54:52 -04:00
parent e4915985f7
commit a356e8a0f7
1 changed files with 27 additions and 3 deletions
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30
compiler/builtins/src/unique.rs
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@ -500,9 +500,33 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
unique_function(vec![list_type(star1, a)], int_type(star2))
});
// get : Attr (* | u) (List (Attr u a))
// , Attr * Int
// -> Attr * (Result (Attr u a) (Attr * [ OutOfBounds ]*))
// List.first :
// Attr (* | u) (List (Attr u a)),
// -> Attr * (Result (Attr u a) (Attr * [ OutOfBounds ]*))
let list_was_empty = SolvedType::TagUnion(
vec![(TagName::Global("ListWasEmpty".into()), vec![])],
Box::new(SolvedType::Wildcard),
);
add_type(Symbol::LIST_FIRST, {
let_tvars! { a, u, star1, star2, star3 };
unique_function(
vec![SolvedType::Apply(
Symbol::ATTR_ATTR,
vec![
container(star1, vec![u]),
SolvedType::Apply(Symbol::LIST_LIST, vec![attr_type(u, a)]),
],
)],
result_type(star2, attr_type(u, a), lift(star3, list_was_empty)),
)
});
// List.get :
// Attr (* | u) (List (Attr u a)),
// Attr * Int
// -> Attr * (Result (Attr u a) (Attr * [ OutOfBounds ]*))
let index_out_of_bounds = SolvedType::TagUnion(
vec![(TagName::Global("OutOfBounds".into()), vec![])],
Box::new(SolvedType::Wildcard),