Crash in `Macro.to_string`

[lukaszsamson]

Elixir and Erlang/OTP versions

1.17.3, 1.15.7

Operating system

any

Current behavior

I noticed this crash report

    ** (MatchError) no match of right hand side value: {:__block__, [line: 19], ["foo"]}
        (elixir 1.17.3) <REDACTED: user-file-path>:1333: Code.Formatter.interpolation_to_algebra_5
        (elixir 1.17.3) <REDACTED: user-file-path>:504: Code.Formatter.quoted_to_algebra_3
        (elixir 1.17.3) <REDACTED: user-file-path>:589: anonymous fn_3 in Code.Formatter.block_args_to_algebra_4
        (elixir 1.17.3) <REDACTED: user-file-path>:2015: Code.Formatter.each_quoted_to_algebra_without_comments_4
        (elixir 1.17.3) <REDACTED: user-file-path>:2001: Code.Formatter.quoted_to_algebra_with_comments_6
        (elixir 1.17.3) <REDACTED: user-file-path>:594: Code.Formatter.block_args_to_algebra_4
        (elixir 1.17.3) <REDACTED: user-file-path>:159: Code.Formatter.to_algebra_2
        (elixir 1.17.3) <REDACTED: user-file-path>:1136: Macro.to_string_1

and something older

    ** (FunctionClauseError) no function clause matching in anonymous fn_1 in Code.Normalizer.normalize_kw_blocks_4
        (elixir 1.15.7) <REDACTED: user-file-path>:453: anonymous fn({:__cursor__, [closing: [line: 23, column: 160], line: 23, column: 149], []}) in Code.Normalizer.normalize_kw_blocks_4
        (elixir 1.15.7) <REDACTED: user-file-path>:1693: Enum."-map_2-lists^map_1-1-"_2
        (elixir 1.15.7) <REDACTED: user-file-path>:1693: Enum."-map_2-lists^map_1-1-"_2
        (elixir 1.15.7) <REDACTED: user-file-path>:453: Code.Normalizer.normalize_kw_blocks_4
        (elixir 1.15.7) <REDACTED: user-file-path>:1359: Code.quoted_to_algebra_2
        (elixir 1.15.7) <REDACTED: user-file-path>:1186: Macro.to_string_1

No idea what AST triggered it

Expected behavior

No crash

[sabiwara]

For the first issue, it seems like a broken interpolation syntax, a valid one would look like:

iex> quote do: "hello #{:foo}"
{:<<>>, [],
 [
   "hello ",
   {:"::", [],
    [
      {{:., [], [Kernel, :to_string]}, [from_interpolation: true], [:foo]},
      {:binary, [], Elixir}
    ]}
 ]}

But in this case there is an arg matching neither is_binary nor {:"::", _, [{{:., _, [Kernel, :to_string]}, _meta, [quoted]}, {:binary, _, _}]}:

{:__block__, [line: 19], ["foo"]}

This sounds like something the normalizer would do: https://github.com/elixir-lang/elixir/blob/v1.17.3/lib/elixir/lib/code/normalizer.ex#L272
So perhaps the formatter should unpack :__block__ wrapped binaries here in that case?

The second one seems related to code fragments, with the cursor somewhere in a keyword block... Maybe it has been fixed since though, I found this.

[josevalim]

I can reproduce the second one with this:

Macro.to_string Code.string_to_quoted!("def foo, do: :bar, __cursor__()", token_metadata: true, literal_encoder: &{:ok, {:__block__, &2, [&1]}})

We are probably missing a Keyword.keyword? check.

[josevalim]

And here is a reproducer for the first one:

Macro.to_string Code.string_to_quoted!(~s|sigil_r <<"foo", 123>>, []|)