-Woperator-whitespace ignores (*), (.), and (-)
Observe:
ghci> :set -Woperator-whitespace
ghci> f = \x y -> x* y
ghci> f = \x y -> x. y
ghci> f = \x y -> x- y
ghci> f = \x y -> x+ y
<interactive>:5:14: warning: [-Woperator-whitespace]
The suffix use of a ‘+’ might be repurposed as special syntax
by a future language extension.
Suggested fix: add whitespace around it.
That’s because these operators are ITstar
, ITdot
, and ITminus
respectively, rather than ITvarsym
. So they are handled by a different codepath which does not generate the warning.