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Invalid Erlang generated with shadowed variables in bit patterns #3315

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lpil opened this issue Jun 22, 2024 · 0 comments · May be fixed by #3331

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bug good first issue help wanted priority:high

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lpil commented Jun 22, 2024

pub fn go(code) {
  let pre = 1
  case code {
    <<pre:bytes-size(pre), _:bytes>> -> pre
    _ -> panic
  }
}

Generates this invalid Erlang:

go(Code) ->
    Pre = 1,
    case Code of
        <<Pre@1:Pre@1/binary, _/binary>> ->
            Pre@1;

        _ ->
            erlang:error(#{gleam_error => panic,
                    message => <<"panic expression evaluated"/utf8>>,

                    function => <<"go"/utf8>>,
                    line => 5})
    end.

Note how Pre@1 is being used for the size, not Pre.

The text was updated successfully, but these errors were encountered:

lpil added bug help wanted good first issue priority:high labels

Eingin linked a pull request

that will close this issue

Fix invalid erlang when shadowing the bit pattern's size variable #3331

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