Type checker requires `assert`, but then throws a warning about the compiled code

[rain breach]

This is not a bug per se, I think, but maybe it's something that's worth taking a look at.

I have a type with two constructors, Global and Local. At one point, I do this:

let Global(table: new_table) as new_env = Global(map.insert(into: table, for: name, insert: value))

As it is, gleam complains that new_env could be a Local instead of a Global. I mean, the r-value is explicitly a Global, but okay - I change it to

let assert Global(table: new_table) as new_env = Global(map.insert(into: table, for: name, insert: value)).

Now, when it compiles, Erlang gives a warning:

    _assert_subject = {global, gleam@map:insert(Table, Name, Value)},
    {global, New_table} = New_env = case _assert_subject of
        {global, _} -> _assert_subject;
        _assert_fail -> erlang:error(#{gleam_error => let_assert etc etc etc})

The warning says the _assert_fail clause cannot match because the previous one always matches... there's a redundancy here that's slightly annoying. This particular case is not high-priority, but hopefully the type checker will improve in the future and make this assert unnecessary? 😄

[hallow pebble]

I have a type with two constructors, Global and Local. At one point, I do this:

let Global(table: new_table) as new_env = Global(map.insert(into: table, for: name, insert: value))

but why

i assume you're leaving out some context as to why you're doing this but that aside

its possible in the future the compiler could refine types like this but there's no immediate plans for it

[potent comet]

Could we see the rest of the code?

[uneven flint]

like, why not write

let new_table = map.insert(into: table, for: name, insert: value)
let new_env = Global(new_table)

[misty cedar]

code is in #1047101890707603547 btw

[rain breach]

In the end this code was not doing what I wanted it to, so I removed it. Sorry for the bother 😦 thank you all anyway

[misty cedar]

Well it's still good to note that this is possible and produces something a bit unexpected