User-reported unhelpful error message

[codeworld-feedback]

Program: https://code.world/haskell#Pt0THvpalZwTvvHxVGdrdIA

Message:

program.hs:14:15: error:
    parse error on input ‘=’
    Perhaps you need a 'let' in a 'do' block?
    e.g. 'let x = 5' instead of 'x = 5'