We only infer types from patterns defined in the same function. Therefore, the example above won’t work yet because:
The example you provided will work either by 1.18 or by 1.19. 
Not sure if this is an issue in Elixir 1.17 or not, but warnings related to Absinthe are failing the build of our project with the --warnings-as-errors flag.
As I’m sure everyone is aware, that flag usually only fails the build if the project itself contains warnings.
This is the issue opened with Absinthe:
https://github.com/absinthe-graphql/absinthe/issues/1319
You probably should not have --warnings-as-errors when compiling dependencies, as you have little control over dependencies’ code. Instead I prefer to first run mix deps.compile (without --warnings-as-errors) and then mix compile --warnings-as-errors to get warning-errors only from my application code.
This is correct, --warnings-as-errors should only be failing if the warnings is emitting when compiling the project, not its dependencies.
In this case, I suspect this is because of meta programming - the library is probably generating code which gets compiled when compiling the project.
Instead I prefer to first run
mix deps.compile(without--warnings-as-errors) and thenmix compile --warnings-as-errorsto get warning-errors only from my application code.
This should be the same as just running mix compile --warnings-as-errors, for the reason mentioned above.
Here is a very hacky way of suppressing the ubiquitous warning (bash shell) in the log output only (it will still fail warnings-as-errors compilation).
mix test 2>&1 | awk '/you must add parentheses instead/{p=0} /^$/{p=1} p'
quick hand-wavey explanation:
2> means "redirect the error output, usually called stderr&1 refers to stdoutawk does awk things. Run man awk in your shell for more info.NB: This redirects all warnings/errors to the stdout. Also you won’t get the nice green dots appearing 1-by-1. They will all appear at the same time (probably with no color).
I have just started testing apps against Elixir 1.17.0-rc.0 and it’s going well. Bravo to the Elixir core team!!!
