Crash in Macro.to_string

[lukaszsamson]

Elixir and Erlang/OTP versions

1.15.5

Operating system

any

Current behavior

I noticed this stacktrace

an exception was raised:
    ** (FunctionClauseError) no function clause matching in anonymous fn_1 in Code.Normalizer.normalize_kw_blocks/4
        (elixir 1.15.5) <REDACTED: user-file-path>:453: anonymous fn({:catchall, [closing: [line: 323, column: 20], line: 323, column: 11], []}) in Code.Normalizer.normalize_kw_blocks_4
        (elixir 1.15.5) <REDACTED: user-file-path>:1693: Enum."-map_2-lists^map_1-1-"/2
        (elixir 1.15.5) <REDACTED: user-file-path>:1693: Enum."-map_2-lists^map_1-1-"/2
        (elixir 1.15.5) <REDACTED: user-file-path>:453: Code.Normalizer.normalize_kw_blocks/4
        (elixir 1.15.5) <REDACTED: user-file-path>:1359: Code.quoted_to_algebra/2
        (elixir 1.15.5) <REDACTED: user-file-path>:1186: Macro.to_string/1

I'm not sure what the argument to Macro.to_string/1 was but it was extracted from AST with this match that tries to get function heads

{defname, location, [{_, head_location, _} = fn_head | _]} when defname in [:def, :defp, :defmacro, :defmacrop, :defguard, :defguardp, :defdelegate] ->
  Macro.to_string(fn_head)

I'm not sure if this is related to #12922 (the fix for that landed in 1.15.6)

Expected behavior

No crash

[sabiwara]

You're too fast @josevalim 😄