macro future proofing rules.
(We may want to think about what this test was actually testing and
figure out a way to test it without running afoul of macro future
proofing. I spent some time trying to do this, e.g. by inserting
parenthesis in the macro input pattern, but I could not quickly get it
working, so I took this tack instead.)
macro_rules! parallel {
(
- for $id:ident in $iter:expr {
+ // If future has `pred`/`moelarry` fragments (where "pred" is
+ // "like expr, but with `{` in its FOLLOW set"), then could
+ // use `pred` instead of future-proof erroring here. See also:
+ //
+ // https://github.com/rust-lang/rfcs/pull/1384#issuecomment-160165525
+ for $id:ident in $iter:expr { //~ WARN `$iter:expr` is followed by `{`
$( $inner:expr; )*
}
) => {};