No break spaces

I thought I was going mad when the following code wasn't compiling:

{-# LANGUAGE UnicodeSyntax #-}
{-# LANGUAGE RankNTypes #-}

type F f = forall x . f x

GHC was producing the following error message:

mad.hs:4:21
    Illegal symbol '.' in type
    Perhaps you intended -XRankNTypes or similar flag
    to enable explicit-forall syntax: forall <tvs>. <type>

It turns out that I had somehow inserted a unicode no break space, character code U+00a0, in the line importing RankNTypes, just after the first #. Baffling.

This begs the question: should GHC treat this unicode space as an ordinary space when the UnicodeSyntax extension is enabled? If not should there have been some warning that I had inserted this symbol in a language pragma?

Trac metadata

Trac field	Value
Version	7.6.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture