Fuel.effect: def of bolt@1.27.0.0
Import: import bolt@1.27.0.0/src/rules/pedantic/fuel.bend as Fuel
Lines 80-89 of bolt@1.27.0.0/src/rules/pedantic/fuel.bend: https://jend.leeeet.dev/read.txt?path=bolt@1.27.0.0/src/rules/pedantic/fuel.bend&start_line=80&end_line=89

import Base
import bolt@1.27.0.0/src/syntax/tree.bend as Tree
import bolt@1.27.0.0/src/rules/calls.bend as Calls

# does a def's header return an effect: a top-level `->` with the
# capitalized name `IO` right after it, on the next line (below) when the
# arrow ends the header?
def effect(sig: Tree.Node, +below: Tree.Node) -> Bool:
  match sig:
    case Tree.NCons{h, +rest}:
      +more = effect(rest, below)
      Bool.or(Bool.and(Calls.kind.leaf(~Calls.kind.arrow, h), effect.next(rest, below)), more)
    case other:
      False{}

Uses (7):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.or
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/rules/calls.bend&name=kind.arrow
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/rules/calls.bend&name=kind.leaf
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/rules/pedantic/fuel.bend&name=effect.next
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/syntax/tree.bend&name=Node