nandi.uk
Fork of daniellemaywood.uk/gleam — Wasm codegen work
stop warning for modules that are used only by private functions
author
Giacomo Cavalieri
committer
Louis Pilfold
date
(Sep 7, 2025, 2:32 PM +0100)
commit
064d8948
064d89485d9400d19ba51b2f9b23509204e4624b
parent
f7dc3b67
f7dc3b673ce91dda3cbfd147962391801ccbc9d9
change-id
xuzpvokp
xuzpvokpuwzuvnqqosurxlspzvtywyot
+139
-36
+9
-4
CHANGELOG.md
+9
-4
CHANGELOG.md
···
304
304
305
305
([Surya Rose](https://github.com/GearsDatapacks))
306
306
307
-
- The "Add type annotations" and "Generate function" code actions now ignore type
308
-
variables defined in other functions, improving the generated code. For example:
307
+
- The "Add type annotations" and "Generate function" code actions now ignore
308
+
type variables defined in other functions, improving the generated code.
309
+
For example:
309
310
310
311
```gleam
311
312
fn something(a: a, b: b, c: c) -> d { todo }
···
369
370
370
371
### Bug fixes
371
372
372
-
- Fixed a bug where literals using `\u{XXXX}` syntax in bit array pattern segments were not
373
-
translated to Erlang's `\x{XXXX}` syntax correctly.
373
+
- Fixed a bug where literals using `\u{XXXX}` syntax in bit array pattern
374
+
segments were not translated to Erlang's `\x{XXXX}` syntax correctly.
374
375
([Benjamin Peinhardt](https://github.com/bcpeinhardt))
375
376
376
377
- Fixed a bug where `echo` could crash on JavaScript if the module contains
···
433
434
- Fixed a bug where the compiler would reference a redeclared variable in a let
434
435
assert message, instead of the original variable, on the Erlang target.
435
436
([Danielle Maywood](https://github.com/DanielleMaywood))
437
+
438
+
- Fixed a bug where the compiler would report an imported module as unused if it
439
+
were used by private functions only.
440
+
([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+60
-5
compiler-core/src/reference.rs
+60
-5
compiler-core/src/reference.rs
···
1
-
use std::collections::HashMap;
1
+
use std::collections::{HashMap, HashSet};
2
2
3
3
use crate::ast::{Publicity, SrcSpan};
4
4
use bimap::{BiMap, Overwritten};
···
84
84
graph: StableGraph<(), (), Directed>,
85
85
entities: BiMap<Entity, NodeIndex>,
86
86
current_node: NodeIndex,
87
-
public_entities: Vec<Entity>,
87
+
public_entities: HashSet<Entity>,
88
88
entity_information: HashMap<Entity, EntityInformation>,
89
89
90
90
/// The locations of the references to each value in this module, used for
···
193
193
self.create_node_and_maybe_shadow(entity.clone(), self.current_node);
194
194
match publicity {
195
195
Publicity::Public | Publicity::Internal { .. } => {
196
-
self.public_entities.push(entity.clone());
196
+
let _ = self.public_entities.insert(entity.clone());
197
197
}
198
198
Publicity::Private => {}
199
199
}
···
223
223
};
224
224
match publicity {
225
225
Publicity::Public | Publicity::Internal { .. } => {
226
-
self.public_entities.push(entity.clone());
226
+
let _ = self.public_entities.insert(entity.clone());
227
227
}
228
228
Publicity::Private => {}
229
229
}
···
257
257
};
258
258
match publicity {
259
259
Publicity::Public | Publicity::Internal { .. } => {
260
-
self.public_entities.push(entity.clone());
260
+
let _ = self.public_entities.insert(entity.clone());
261
261
}
262
262
Publicity::Private => {}
263
263
}
···
423
423
}
424
424
}
425
425
426
+
for (entity, _) in self.entities.iter() {
427
+
let Some(index) = self.entities.get_by_left(entity) else {
428
+
continue;
429
+
};
430
+
431
+
if self.public_entities.contains(entity) {
432
+
self.mark_entity_as_used(&mut unused_values, entity, *index);
433
+
} else {
434
+
// If the entity is not public, we still want to mark referenced
435
+
// imports as used.
436
+
self.mark_referenced_imports_as_used(&mut unused_values, entity, *index);
437
+
}
438
+
}
439
+
426
440
unused_values
427
441
}
428
442
···
437
451
if let Some(entity) = self.entities.get_by_right(&node) {
438
452
self.mark_entity_as_used(unused, entity, node);
439
453
}
454
+
}
455
+
}
456
+
}
457
+
458
+
fn mark_referenced_imports_as_used(
459
+
&self,
460
+
unused: &mut HashMap<Entity, EntityInformation>,
461
+
entity: &Entity,
462
+
index: NodeIndex,
463
+
) {
464
+
// If the entity is a module there's no way it can reference other
465
+
// modules so we just ignore it.
466
+
// This also means that module aliases do not count as using a module!
467
+
if entity.layer == EntityLayer::Module {
468
+
return;
469
+
}
470
+
471
+
for node in self.graph.neighbors_directed(index, Direction::Outgoing) {
472
+
// We only want to mark referenced modules as used, so if the node
473
+
// is not a module we just skip it.
474
+
let Some(
475
+
module @ Entity {
476
+
layer: EntityLayer::Module,
477
+
..
478
+
},
479
+
) = self.entities.get_by_right(&node)
480
+
else {
481
+
continue;
482
+
};
483
+
484
+
// If the value appears in the module import list, it doesn't count
485
+
// as using it!
486
+
let is_imported_type = self
487
+
.type_references
488
+
.contains_key(&(module.name.clone(), entity.name.clone()));
489
+
let is_imported_value = self
490
+
.value_references
491
+
.contains_key(&(module.name.clone(), entity.name.clone()));
492
+
let appears_in_module_import_list = is_imported_type || is_imported_value;
493
+
if !(appears_in_module_import_list) {
494
+
self.mark_entity_as_used(unused, module, node);
440
495
}
441
496
}
442
497
}
-8
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__dead_code_detection__imported_module_alias_only_referenced_by_unused_function.snap
-8
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__dead_code_detection__imported_module_alias_only_referenced_by_unused_function.snap
···
20
20
21
21
22
22
----- WARNING
23
-
warning: Unused imported module
24
-
┌─ /src/warning/wrn.gleam:2:1
25
-
│
26
-
2 │ import wibble as wobble
27
-
│ ^^^^^^^^^^^^^^^^^^^^^^^ This imported module is never used
28
-
29
-
Hint: You can safely remove it.
30
-
31
23
warning: Unused private function
32
24
┌─ /src/warning/wrn.gleam:4:1
33
25
│
-11
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__dead_code_detection__imported_module_alias_only_referenced_by_unused_function_with_unqualified.snap
-11
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__dead_code_detection__imported_module_alias_only_referenced_by_unused_function_with_unqualified.snap
···
24
24
25
25
26
26
----- WARNING
27
-
warning: Unused imported module alias
28
-
┌─ /src/warning/wrn.gleam:2:29
29
-
│
30
-
2 │ import wibble.{type Wibble} as wobble
31
-
│ ^^^^^^^^^ This alias is never used
32
-
33
-
Hint: You can safely remove it.
34
-
35
-
import wibble as _
36
-
37
-
38
27
warning: Unused private function
39
28
┌─ /src/warning/wrn.gleam:4:1
40
29
│
-8
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__dead_code_detection__imported_module_only_referenced_by_unused_function.snap
-8
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__dead_code_detection__imported_module_only_referenced_by_unused_function.snap
···
20
20
21
21
22
22
----- WARNING
23
-
warning: Unused imported module
24
-
┌─ /src/warning/wrn.gleam:2:1
25
-
│
26
-
2 │ import wibble
27
-
│ ^^^^^^^^^^^^^ This imported module is never used
28
-
29
-
Hint: You can safely remove it.
30
-
31
23
warning: Unused private function
32
24
┌─ /src/warning/wrn.gleam:4:1
33
25
│
+23
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__warnings__aliased_module_used_by_unused_function_is_not_marked_as_unused.snap
+23
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__warnings__aliased_module_used_by_unused_function_is_not_marked_as_unused.snap
···
1
+
---
2
+
source: compiler-core/src/type_/tests/warnings.rs
3
+
expression: "import wibble as woo\nfn wobble() {\n woo.a\n}\n"
4
+
---
5
+
----- SOURCE CODE
6
+
-- wibble.gleam
7
+
pub const a = 1
8
+
9
+
-- main.gleam
10
+
import wibble as woo
11
+
fn wobble() {
12
+
woo.a
13
+
}
14
+
15
+
16
+
----- WARNING
17
+
warning: Unused private function
18
+
┌─ /src/warning/wrn.gleam:2:1
19
+
│
20
+
2 │ fn wobble() {
21
+
│ ^^^^^^^^^^^ This private function is never used
22
+
23
+
Hint: You can safely remove it.
+23
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__warnings__module_used_by_unused_function_is_not_marked_as_unused.snap
+23
compiler-core/src/type_/tests/snapshots/gleam_core__type___tests__warnings__module_used_by_unused_function_is_not_marked_as_unused.snap
···
1
+
---
2
+
source: compiler-core/src/type_/tests/warnings.rs
3
+
expression: "import wibble\nfn wobble() {\n wibble.a\n}\n"
4
+
---
5
+
----- SOURCE CODE
6
+
-- wibble.gleam
7
+
pub const a = 1
8
+
9
+
-- main.gleam
10
+
import wibble
11
+
fn wobble() {
12
+
wibble.a
13
+
}
14
+
15
+
16
+
----- WARNING
17
+
warning: Unused private function
18
+
┌─ /src/warning/wrn.gleam:2:1
19
+
│
20
+
2 │ fn wobble() {
21
+
│ ^^^^^^^^^^^ This private function is never used
22
+
23
+
Hint: You can safely remove it.
+24
compiler-core/src/type_/tests/warnings.rs
+24
compiler-core/src/type_/tests/warnings.rs
···
1517
1517
}
1518
1518
1519
1519
#[test]
1520
+
fn module_used_by_unused_function_is_not_marked_as_unused() {
1521
+
assert_warning!(
1522
+
("wibble", "pub const a = 1"),
1523
+
"import wibble
1524
+
fn wobble() {
1525
+
wibble.a
1526
+
}
1527
+
"
1528
+
);
1529
+
}
1530
+
1531
+
#[test]
1532
+
fn aliased_module_used_by_unused_function_is_not_marked_as_unused() {
1533
+
assert_warning!(
1534
+
("wibble", "pub const a = 1"),
1535
+
"import wibble as woo
1536
+
fn wobble() {
1537
+
woo.a
1538
+
}
1539
+
"
1540
+
);
1541
+
}
1542
+
1543
+
#[test]
1520
1544
fn calling_function_from_other_module_is_not_marked_unused() {
1521
1545
assert_no_warnings!(
1522
1546
("wibble", "wibble", "pub fn println(a) { panic }"),