class SyntaxTree::Parser

def on_aref(collection, index)

on_aref: (untyped collection, (nil | Args) index) -> ARef
:call-seq: 
def on_aref(collection, index)
  consume_token(LBracket)
  rbracket = consume_token(RBracket)
  ARef.new(
    collection: collection,
    index: index,
    location: collection.location.to(rbracket.location)
  )
end