forge_credo_checks

defmodule ForgeCredoChecks do
  @moduledoc """
  Custom Credo checks targeting anti-patterns that LLMs commonly produce.

  Stock Credo ships checks for `filter |> filter`, `reject |> reject`,
  `map |> join`, `map |> into`, etc. but not the cases where one operation
  composes with the *complementary* one, nor the common map-building,
  sort-then-pick, and map-shape normalization anti-patterns. These checks fill
  those gaps.

  ## Two-pass Enum chains (suggests `Enum.reduce/3`)

    * `ForgeCredoChecks.FilterMap`: `Enum.filter |> Enum.map`
    * `ForgeCredoChecks.RejectMap`: `Enum.reject |> Enum.map`
    * `ForgeCredoChecks.MapReject`: `Enum.map |> Enum.reject`
    * `ForgeCredoChecks.MapRejectNil`: `Enum.map |> Enum.reject(&is_nil/1)`

  ## Hand-rolled map building (suggests `Map.new/2`)

    * `ForgeCredoChecks.MapNewFromInto`: `Enum.into(%{}, fn ...)`
    * `ForgeCredoChecks.MapNewFromReduce`: `Enum.reduce(_, %{}, &Map.put(acc, k, v))`

  ## Wasteful list-extremum patterns

    * `ForgeCredoChecks.ReverseListFirst`: `xs |> Enum.reverse() |> List.first()` becomes `List.last(xs)`
    * `ForgeCredoChecks.SortListFirst`: `Enum.sort \\| List.first` becomes `Enum.min`/`Enum.max`/`*_by`

  ## Map shape normalization

    * `ForgeCredoChecks.MapGetWithOr`: `Map.get(_, _) || fallback`
    * `ForgeCredoChecks.ChainedMapGet`: `Map.get(_, _) || Map.get(_, _)`

  ## LLM tells

    * `ForgeCredoChecks.NoInlineRegex`: inline `~r`/`~R` regex sigils inside function bodies
    * `ForgeCredoChecks.NoAnyOrTermTypes`: `any()` / `term()` in specs, callbacks, and type definitions
    * `ForgeCredoChecks.MultilineStringConcat`: multi-line string-literal `<>` concatenation (use a heredoc)

  ## Architecture and test discipline

    * `ForgeCredoChecks.OneModulePerFile`: every `defmodule` after the first in a source file (test files excluded by default)
    * `ForgeCredoChecks.TaintedSourceInspection`: source-grep constructs applied to text read from non-test `.ex` / `.exs` files
    * `ForgeCredoChecks.TimingAndPrivateStateGuard`: `Process.sleep/1` and `:sys.replace_state/2` call nodes
    * `ForgeCredoChecks.NoApplicationGetEnvInLib`: `Application.get_env/2,3` inside `lib/` (use `compile_env` or `fetch_env!` instead)
    * `ForgeCredoChecks.TelemetryControlFlow`: `:telemetry.attach`/`attach_many` with an inline handler that performs control flow (`send`, `GenServer.call`/`cast`) instead of observation-only recording
  """
end