The following code suggests incorrect type for todo
pub fn curry(f: fn(a, b) -> c) -> fn(a) -> fn(b) -> c {
fn(a: a) {
todo
}
}producing a warning which suggests
[snip]
Hint: I think its type is `fn(a) -> c`.
which is obviously incorrect as todo should be replaced with a function of type fn(b) -> c.
Investigation
I have been digging in /compiler-core/_type/pretty.rs and added tests:
assert_string!(
fn_(
vec![Arc::new(Type::Var {
type_: Arc::new(RefCell::new(TypeVar::Generic { id: 78 })),
})],
fn_(
vec![Arc::new(Type::Var {
type_: Arc::new(RefCell::new(TypeVar::Generic { id: 2 })),
})],
Arc::new(Type::Named {
args: vec![],
module: "whatever".into(),
package: "whatever".into(),
name: "Bool".into(),
publicity: Publicity::Public,
inferred_variant: None,
}),
),
),
"fn(a) -> fn(b) -> Bool",
);and
assert_eq!(
pretty_print(fn_(vec![], fn_(vec![], int()))),
"fn() -> fn() -> Int"
);which both pass, so I guess the issue is not related to the pretty printer but rather happens somewhere in the type system.
Testing
I added the following snap test which currently fails
---
source: compiler-core/src/type_/tests/warnings.rs
expression: "pub fn main() {\n todo()\n }"
---
----- SOURCE CODE
pub fn curry(f: fn(a, b) -> c) -> fn(a) -> fn(b) -> c {
fn(a: a) {
todo
}
}
----- WARNING
warning: Unused variable
┌─ /src/warning/wrn.gleam:1:14
│
1 │ pub fn curry(f: fn(a, b) -> c) -> fn(a) -> fn(b) -> c {
│ ^^^^^^^^^^^^^^^^ This variable is never used
Hint: You can ignore it with an underscore: `_f`.
warning: Unused variable
┌─ /src/warning/wrn.gleam:2:16
│
2 │ fn(a: a) {
│ ^^^^ This variable is never used
Hint: You can ignore it with an underscore: `_a`.
warning: Todo found
┌─ /src/warning/wrn.gleam:3:17
│
3 │ todo
│ ^^^^ This code is incomplete
This code will crash if it is run. Be sure to finish it before
running your program.
Hint: I think its type is `fn(b) -> c`.
-old snapshot
+new results
────────────┬──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
29 29 │
30 30 │ This code will crash if it is run. Be sure to finish it before
31 31 │ running your program.
32 32 │
33 │-Hint: I think its type is `fn(b) -> c`.
33 │+Hint: I think its type is `fn(a) -> b`.
Further questions
The issue might be present with panic as well as the code follows similar logic as todo's code.
The following code suggests incorrect type for
todoproducing a warning which suggests
which is obviously incorrect as
todoshould be replaced with a function of typefn(b) -> c.Investigation
I have been digging in
/compiler-core/_type/pretty.rsand added tests:and
which both pass, so I guess the issue is not related to the pretty printer but rather happens somewhere in the type system.
Testing
I added the following snap test which currently fails
Further questions
The issue might be present with
panicas well as the code follows similar logic astodo's code.