pretty-printer loses parens in "if (1 == fail) { }"

[jruderman]

fn f() { if (1 == fail) { } else { } }

and

fn f() { if 1 == (fail) { } else { } }

lose their parens, becoming something that fails to parse:

fn f() { if 1 == fail { } else { } }

This could be solved by parenthesizing the whole discriminant, parenthesizing just the "fail", or getting rid of the syntactic ambiguity. I see a way to do the first option, by making pprust::print_maybe_parens_discrim recurse right. I could write that patch, along with tests, if you think it's the right thing to do.

[brson]

Yes, I agree with your solution. print_maybe_parens_discrim should be looking at the rightmost expression.

[catamorphism]

Reproduced as of 7/26/2012.

[catamorphism]

Fixed now that we have paren nodes.