External functions are considered side-effect free when compiling for the other target

[yoshi-monster]

I have a package called wibble, exposing a function that calls some FFI for some side effect:

/// wibble.gleam
pub fn wibble() -> Nil {
  do_wibble()
  // more side-effecty things...
  Nil
}

@external(javascript, "wibble_ffi.mjs", "wibble")
fn do_wibble() -> Nil

Both my app and this package target javascript in their gleam.toml.

Another package I depend on (in this case lustre_dev_tools) targets erlang. When running gleam run -m lustre/dev start, my app and also that package are both compiled for the Erlang target.

While doing so, the compiler incorrectly emits a warning that the result value of do_wibble() is unused:

   ┌─ .../wibble.gleam:23:11
   │
23 │           do_wibble(component_name)
   │           ^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used

This expression computes a value without any side effects, but then the
value isn't used at all. You might want to assign it to a variable, or
delete the expression entirely if it's not needed.

I think the problem here is that do_wibble does not have an implementation for Erlang, and that case is assumed to not introduce side effects.

~ 💜

[lpil]

This function is side effect free, so I'm not immediately sure it makes sense to say that it is not.

You could introduce a side effect by giving it an FFI implementation, that would solve your problem here. It is less clear though, that is an annoyance.

[yoshi-monster]

Yeah I guess you could argue that a function that does not support a target at all cannot possibly have side-effects on that target.

I think it's very confusing to get warnings like this from another package and FFI code in my app when running a module from a package that uses the other target, though.

Another case where I noticed this is that running the tests in a javascript project that depends on lustre_dev_tools for example prints a bunch of unused value warnings in mist, wisp, and dev-tools itself.

[lpil]

I think that's an issue with the library today rather than a problem with this system. It's intended to warn about things not having side effects, which is it doing.

Perhaps there's some improvements we could make to the system in future...

[yoshi-monster]

I'm not quite sure I understand, sorry. Right now if I run the tests in my Lustre javascript project, I got tons of "unused value" warnings from Erlang-only dependencies that I got through lustre-dev-tools. Are you suggesting these should all ship with a Javascript FFI stub just to silence that warning?

Sorry if I wasn't clear originally, I wasn't quite sure which cases this includes when I made that issue.

I think if that's intended it would be better to accept that warning for now instead of adding these FFI stubs.

big compiler output dump of gleam test producing 49 warnings

› gleam test
  Compiling gleam_stdlib
  Compiling envoy
  Compiling filepath
  Compiling simplifile
  Compiling directories
  Compiling exception
  Compiling gleam_json
  Compiling gleam_community_colour
  Compiling gleam_regexp
  Compiling gleam_community_ansi
  Compiling gleam_crypto
  Compiling gleam_deque
  Compiling gleam_erlang
warning: Unused value
    ┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_erlang/src/gleam/erlang/process.gleam:576:3
    │
576 │   erlang_demonitor_process(monitor)
    │   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_erlang/src/gleam/erlang/process.gleam:623:3

│

623 │   demonitor_process(monitor)

│   ^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_erlang/src/gleam/erlang/process.gleam:727:3

│

727 │   erlang_unlink(pid)

│   ^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_erlang/src/gleam/erlang/process.gleam:793:3

│

793 │   erlang_kill(pid, Kill)

│   ^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_erlang/src/gleam/erlang/process.gleam:809:3

│

809 │   erlang_send_exit(pid, Normal)

│   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_erlang/src/gleam/erlang/process.gleam:821:3

│

821 │   erlang_send_exit(pid, reason)

│   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
Compiling gleam_http

Compiling gleam_httpc

Compiling gleam_otp

warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_otp/src/gleam/otp/system.gleam:78:3

│

78 │   erl_suspend(pid)

│   ^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_otp/src/gleam/otp/system.gleam:93:3

│

93 │   erl_resume(pid)

│   ^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_otp/src/gleam/otp/actor.gleam:403:3

│

403 │ ╭   case reason {

404 │ │     Abnormal(reason) -> process.send_abnormal_exit(process.self(), reason)

405 │ │     Killed -> process.kill(process.self())

406 │ │     _ -> Nil

407 │ │   }

│ ╰───^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_otp/src/gleam/otp/actor.gleam:490:7

│

490 │ ╭       log_warning(

491 │ │         charlist.from_string("Actor discarding unexpected message: ~s"),

492 │ │         [charlist.from_string(string.inspect(message))],

493 │ │       )

│ ╰───────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_otp/src/gleam/otp/actor.gleam:628:7

│

628 │       process.unlink(child)

│       ^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_otp/src/gleam/otp/actor.gleam:629:7

│

629 │       process.kill(child)

│       ^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gleam_otp/src/gleam/otp/actor.gleam:636:3

│

636 │   process.demonitor_process(monitor)

│   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
Compiling gleam_package_interface

Compiling gleam_yielder

Compiling snag

Compiling glint

Compiling glisten

warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/glisten/src/glisten/internal/handler.gleam:223:13

│

223 │ ╭             logging.log(

224 │ │               logging.Error,

225 │ │               "Caught error in user handler: " <> string.inspect(reason),

226 │ │             )

│ ╰─────────────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/glisten/src/glisten/internal/handler.gleam:245:13

│

245 │ ╭             logging.log(

246 │ │               logging.Error,

247 │ │               "Caught error in user handler: " <> string.inspect(reason),

248 │ │             )

│ ╰─────────────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/glisten/src/glisten/internal/acceptor.gleam:83:13

│

83 │ ╭             logging.log(

84 │ │               logging.Error,

85 │ │               "Failed to accept/start handler: " <> string.inspect(reason),

86 │ │             )

│ ╰─────────────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
Compiling gramps

warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gramps/src/gramps/websocket/compression.gleam:26:3

│

26 │   inflate_init(inflate_context, -15)

│   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/gramps/src/gramps/websocket/compression.gleam:28:3

│

28 │   deflate_init(deflate_context, Default, Deflated, -15, 8, Default)

│   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
Compiling houdini

Compiling lustre

Compiling mist

warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/clock.gleam:30:5

│

30 │     ets_new(MistClock, [Set, Protected, NamedTable, ReadConcurrency(True)])

│     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/clock.gleam:41:9

│

41 │         ets_insert(MistClock, #(DateHeader, date()))

│         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/clock.gleam:42:9

│

42 │         process.send_after(state, 1000, SetTime)

│         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/clock.gleam:64:7

│

64 │       logging.log(logging.Warning, "Failed to lookup date, re-calculating")

│       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/http/handler.gleam:77:3

│

77 │   logging.log(logging.Error, string.inspect(error))

│   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/http/handler.gleam:196:9

│

196 │ ╭         logging.log(

197 │ │           logging.Error,

198 │ │           "Failed to send file: " <> string.inspect(err),

199 │ │         )

│ ╰─────────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/http/handler.gleam:205:3

│

205 │ ╭   case file.close(file_descriptor) {

206 │ │     Ok(_nil) -> Nil

207 │ │     Error(reason) -> {

208 │ │       logging.log(

· │

212 │ │     }

213 │ │   }

│ ╰───^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/http2/frame.gleam:240:11

│

240 │           logging.log(logging.Debug, "oh noes!")

│           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/http2.gleam:108:5

│

108 │     logging.log(logging.Debug, "failed to send :(  " <> string.inspect(err))

│     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/http2/handler.gleam:297:7

│

297 │       logging.log(logging.Debug, "byteeee~~")

│       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/http2/handler.gleam:303:7

│

303 │       logging.log(logging.Debug, "Ignoring frame: " <> string.inspect(frame))

│       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/handler.gleam:74:11

│

74 │ ╭           logging.log(

75 │ │             logging.Debug,

76 │ │             "Error sending HTTP/2 data: " <> string.inspect(err),

77 │ │           )

│ ╰───────────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/handler.gleam:92:15

│

92 │               logging.log(logging.Error, string.inspect(err))

│               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:172:19

│

172 │                   compression.close(contexts.deflate)

│                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:180:19

│

180 │                   compression.close(contexts.deflate)

│                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:188:11

│

188 │           logging.log(logging.Error, "Received a malformed WebSocket frame")

│           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:192:15

│

192 │               compression.close(contexts.deflate)

│               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:219:19

│

219 │                   compression.close(contexts.deflate)

│                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:228:19

│

228 │                   compression.close(contexts.deflate)

│                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:245:15

│

245 │               compression.close(contexts.deflate)

│               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:255:13

│

255 │             compression.close(contexts.deflate)

│             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:263:9

│

263 │         logging.log(logging.Error, "Received a malformed WebSocket frame")

│         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:266:13

│

266 │             compression.close(contexts.deflate)

│             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist/internal/websocket.gleam:366:11

│

366 │ ╭           logging.log(

367 │ │             logging.Error,

368 │ │             "Caught error in websocket handler: " <> string.inspect(reason),

369 │ │           )

│ ╰───────────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist.gleam:648:7

│

648 │ ╭       logging.log(

649 │ │         logging.Error,

650 │ │         "Cannot send messages from a different process than the WebSocket: "

651 │ │           <> string.inspect(reason),

652 │ │       )

│ ╰───────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/mist/src/mist.gleam:672:7

│

672 │ ╭       logging.log(

673 │ │         logging.Error,

674 │ │         "Cannot send messages from a different process than the WebSocket: "

675 │ │           <> string.inspect(reason),

676 │ │       )

│ ╰───────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
Compiling tom

Compiling wisp

warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/wisp/src/wisp.gleam:1078:7

│

1078 │       log_error(string.inspect(error))

│       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/wisp/src/wisp.gleam:1252:11

│

1252 │           log_error_dict(dict.insert(details, c, error_kind_to_dynamic(kind)))

│           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/wisp/src/wisp.gleam:1307:3

│

1307 │ ╭   [

1308 │ │     int.to_string(response.status),

1309 │ │     " ",

1310 │ │     string.uppercase(http.method_to_string(req.method)),

· │

1314 │ │   |> string.concat

1315 │ │   |> log_info

│ ╰─────────────^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/wisp/src/wisp/wisp_mist.gleam:97:7

│

97 │       wisp.log_error(string.inspect(error))

│       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
Compiling lustre_dev_tools

warning: Unused value

┌─ /home/arkan/Projects/oss/lustre/examples/01-basics/01-hello-world/build/packages/lustre_dev_tools/src/lustre_dev_tools/server/live_reload.gleam:192:7

│

192 │       fs_subscribe(id)

│       ^^^^^^^^^^^^^^^^ This value is never used
This expression computes a value without any side effects, but then the

value isn't used at all. You might want to assign it to a variable, or

delete the expression entirely if it's not needed.
Compiling app

Compiled in 0.47s

Running app_test.main

hello