module_keyword: module Name do instead of mod Name do

The module keyword is mod. The caret is on module, and the fix replaces it with mod. It fires for a top-level module and for a nested one.

A program that triggers it

module Main do
  needs IO.Console
  fn main(_console : Cap(IO.Console)) do
    println("hello")
  end
end

The fix

Replace module with mod. forge fix and the editor’s quick fix apply it.

mod Main do
  needs IO.Console
  fn main(_console : Cap(IO.Console)) do
    println("hello")
  end
end

Why the rule exists

module is the OCaml and Elixir spelling (defmodule). It is not reserved in March: the standard library uses module as a parameter name, so the parser only treats it as this slip when an upper-case name follows it directly.

See also: the language reference.