Error message: "Perhaps you need a let in a do block", when there is no do block.

This code:

main = return ()
 foo = return ()

Gives the error message:

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

But this isn't in a do block. It would be awesome if GHC checked whether there's a do block before giving a suggestion that depends on there being a do block.

Trac metadata

Trac field	Value
Version	8.4.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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