UnaryExpression are always prefix

[amasad]

The prefix boolean field on UnaryExpressions is redundant because all operators are currently prefix.

[ariya]

While it's likely harmless, doesn't this fall into "Non-additive modifications"?

[forivall]

I'm speculating that it's so that UpdateExpression and UnaryExpressions can be handled by the same functions, or some other historical reason like a Mozilla js extension that added non-prefix unary expressions.

[RReverser]

Yeah, we discussed this with @dherman and, unfortunately, this is one of redundant design decisions that were here from the beginning and thus breaking to remove.

[amasad]

Ok, makes sense.