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Recursive functions must be shared

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This commit is contained in:
Folkert 2020-01-16 23:53:03 +01:00
parent dbe615b4c5
commit 50f8bf1856
3 changed files with 58 additions and 13 deletions
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17
src/uniqueness/mod.rs
View file

@ -459,7 +459,9 @@ pub fn constrain_expr(
expected,
)
}
Closure(fn_var, _symbol, _recursion, args, boxed) => {
Closure(fn_var, _symbol, recursion, args, boxed) => {
use crate::can::expr::Recursive;
let (loc_body_expr, ret_var) = &**boxed;
let mut state = PatternState {
headers: SendMap::default(),
@ -485,11 +487,18 @@ pub fn constrain_expr(
vars.push(*pattern_var);
}
let fn_uniq_var = var_store.fresh();
vars.push(fn_uniq_var);
let fn_uniq_type;
if let Recursive::NotRecursive = recursion {
let fn_uniq_var = var_store.fresh();
vars.push(fn_uniq_var);
fn_uniq_type = Bool::Variable(fn_uniq_var);
} else {
// recursive definitions MUST be Shared
fn_uniq_type = Bool::Zero
}
let fn_type = constrain::attr_type(
Bool::Variable(fn_uniq_var),
fn_uniq_type,
Type::Function(pattern_types, Box::new(ret_type.clone())),
);
let body_type = Expected::NoExpectation(ret_type);

17
tests/test_infer.rs
View file

@ -1246,23 +1246,22 @@ mod test_infer {
);
}
// TODO add more realistic function when able
#[test]
fn integer_sum() {
with_larger_debug_stack(|| {
infer_eq_without_problem(
indoc!(
r#"
f = \n ->
infer_eq_without_problem(
indoc!(
r#"
f = \n ->
when n is
0 -> 0
_ -> f n
f
"#
),
"Int -> Int",
);
});
),
"Int -> Int",
);
}
// currently fails, the rank of Cons's ext_var is 3, where 2 is the highest pool

37
tests/test_uniqueness_infer.rs
View file

@ -1231,4 +1231,41 @@ mod test_infer_uniq {
"Attr.Attr * Int",
);
}
// TODO add more realistic recursive example when able
#[test]
fn factorial_is_shared() {
infer_eq_without_problem(
indoc!(
r#"
factorial = \n ->
when n is
0 -> 1
1 -> 1
m -> factorial m
factorial
"#
),
"Attr.Attr Attr.Shared (Attr.Attr * Int -> Attr.Attr * Int)",
);
}
// TODO add more realistic recursive example when able
#[test]
fn factorial_without_recursive_case_can_be_unique() {
infer_eq_without_problem(
indoc!(
r#"
factorial = \n ->
when n is
0 -> 1
_ -> 1
factorial
"#
),
"Attr.Attr * (Attr.Attr * Int -> Attr.Attr * Int)",
);
}
}