Tracking issue for adding a `lifetime` specifier to `macro_rules!`

[nikomatsakis]

cc rust-lang/rfcs#1590 @sgrif

[sgrif]

I'll open a new PR soon, I want to do one more thing on top of #33135

[Phlosioneer]

Godspeed, @sgrif! This being in nightly would make my week.

[comex]

@sgrif Any update?

[brson]

This doesn't seem particularly hard. Help wanted.

[durka]

I wish we knew what the "one more thing" was besides just reopening the closed PR.

[mikeyhew]

I'd like to help implement this. Where do I start?

[petrochenkov]

@mikeyhew
This is a good issue to start working on the compiler frontend.
You may want to start with taking @sgrif's patch and rebasing it on the current master, and then making sure the tests pass.
Then you'll have to add a feature gate for lifetime matcher and some docs (unstable book section) (see e0cd766, and 1d46805, and #41012 as a whole for examples of the same things being done with vis matcher.)

@durka

I wish we knew what the "one more thing" was besides just reopening the closed PR.

This should be something truly marvelous, that this GitHub comment was too narrow to contain.