+1 is considered valid syntax

[jfmengels]

As shown (roughly) here, +1 is parsed and considered as valid syntax, even though Elm rejects it with a syntax error.

It seems to be parsed as OperationApplication "+" Right (Application []) (Int 1). The Application is obviously invalid, and I am not sure how this will turn out in v8, where it has become a non-empty list. Also, its range is the emptyRange (0,0,0,0).

++1 also seems to compile even though it shouldn't.

[stil4m]

Fixed this. Both +1 and 1+ (same for other operators) are not accepted as valid syntax anymore and will not be parsed.