error: expected identifier when building time-macros-impl v0.1.1

[tmiasko]

Steps to reproduce:

# time commit bc2cdc375206a3ba118ffe16eb7262db300a1201
$ git clone https://github.com/time-rs/time
$ cd time
# rustc commit 94fccccd2cdba42aed93ad7715e969ab6aad6301
$ cargo +stage1 check 
...
   Compiling time-macros-impl v0.1.1 (/home/tm/test/time/time-macros-impl)
error: expected identifier
   --> time-macros-impl/src/lib.rs:98:20
    |
98  |               pub fn $name(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    |                      ^^^^^
...
105 | / impl_macros! {
106 | |     time: Time,
107 | |     offset: Offset,
108 | |     date: Date,
109 | | }
    | |_- in this macro invocation
    |
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

Meta

Very recent regression; versions <= nightly-2020-05-24 are not affected.

[jonas-schievink]

@rustbot ping cleanup

[rustbot]

Hey Cleanup Crew ICE-breakers! This bug has been identified as a good
"Cleanup ICE-breaking candidate". In case it's useful, here are some
instructions for tackling these sorts of bugs. Maybe take a look?
Thanks! <3

cc @AminArria @chrissimpkins @contrun @DutchGhost @elshize @ethanboxx @h-michael @HallerPatrick @hdhoang @hellow554 @imtsuki @jakevossen5 @kanru @KarlK90 @LeSeulArtichaut @MAdrianMattocks @matheus-consoli @mental32 @nmccarty @Noah-Kennedy @pard68 @PeytonT @pierreN @Redblueflame @RobbieClarken @RobertoSnap @robjtede @SarthakSingh31 @senden9 @shekohex @sinato @spastorino @turboladen @woshilapin @yerke

[tmiasko]

Reverting implicates #72388, cc @Aaron1011.

[Aaron1011]

Minimized:

pub(crate) struct Time;

use proc_macro_hack::proc_macro_hack;

macro_rules! impl_macros {
    ($($name:ident : $type:ty),* $(,)?) => {
        $(
            #[proc_macro_hack]
            #[allow(clippy::unimplemented)]
            pub fn $name(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
                panic!()
            }
        )*
    };
}

impl_macros! {
    time: Time,
}