No escape hatch for typing error

Questions / Help
, ,
1

I’m currently migrating my codebase to Elixir 1.18.2. I was able to solve all the typing issues, except for one. The following code:

defmodule Run do
  def test do
    try do
      Code.compile_string("a + ")
    rescue
      e ->
        case e do
          %{column: column, snippet: %{offset: offset}} ->
            {:error, column + offset}

          _ ->
            {:error, :unknown}
        end
    end
  end
end

Gives me the following compilation warning:

image
image1089×1623 55.6 KB

This could be solved by adding guards, that will allow for infering the types in a future release. But at the moment I’m not able to migrate this code and there is no scapehatch for it.

2

Ah, I was able to workaround this warning by creating a ‘sum/2’ function. Since the type checking doesn’t flow throught functions, it works fine.

3

Sorry, can you show the full code that raises no warning?

4

Sure

defmodule Run do
  def test do
    try do
      Code.compile_string("a + ")
    rescue
      e ->
        case e do
          %{column: column, snippet: %{offset: offset}} ->
            {:error, sum(column, offset)}

          _ ->
            {:error, :unknown}
        end
    end
  end

  def sum(a, b) do
    a + b
  end
end
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