sezaru

IO.warn doesn't stop compiler with --warning-as-errors

In my project, I have a compile-time code that can generate some warning depending on some circumstances.

To show the warning I do IO.warn(“…”).

The problem is that, with this, the compiler will happily continue even if I add –warning-as-errors option.

Shouldn’t that option make the compiler fail in this case or am I missing something here?

7 comments

#compiler

7 157 7

2025-11-06 15:14:03 UTC

Marked As Solved

Gazler

Phoenix Core Team

In this example, you have used --warning-as-errors and not --warnings-as-errors

Post #7

Also Liked

al2o3cr

FWIW, IO.warn/1 directly calls IO.warn/2:

github.com/elixir-lang/elixir

lib/elixir/lib/io.ex

4a8d4f29a


      
          def warn(message) do
            {:current_stacktrace, stacktrace} = Process.info(self(), :current_stacktrace)
            warn(message, Enum.drop(stacktrace, 2))
          end

@sezaru - long shot, but is it possible you’re running into something weird from the tail-call optimization mentioned in the docs for IO.warn/1?

Post #3

sezaru

Dear god, I can’t believe that was it…

Post #8

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IO.warn doesn't stop compiler with --warning-as-errors

sezaru

IO.warn doesn't stop compiler with --warning-as-errors

Marked As Solved

Gazler

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al2o3cr

sezaru

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