Fails to build with the latest nightly

[kornelski]

https://crater-reports.s3.amazonaws.com/pr-72622/master%237726070fa755f660b5da3f82f46e07d9c6866f69/reg/cargo-crev-0.17.0/log.txt

[INFO] [stderr]    Compiling ifmt-impl v0.3.0
[INFO] [stderr] error: expected identifier
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.tiyicn.workers.dev-1ecc6299db9ec823/ifmt-impl-0.3.0/src/lib.rs:87:16
[INFO] [stderr]    |
[INFO] [stderr] 87 |         pub fn $name(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
[INFO] [stderr]    |                ^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 97 | def_ifmt_macro!(iformat, format);
[INFO] [stderr]    | --------------------------------- in this macro invocation
[INFO] [stderr]    |
[INFO] [stderr]    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] error: expected identifier
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.tiyicn.workers.dev-1ecc6299db9ec823/ifmt-impl-0.3.0/src/lib.rs:87:16
[INFO] [stderr]    |
[INFO] [stderr] 87 |         pub fn $name(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
[INFO] [stderr]    |                ^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 99 | def_ifmt_macro!(iprint, print);
[INFO] [stderr]    | ------------------------------- in this macro invocation
[INFO] [stderr]    |
[INFO] [stderr]    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] error: expected identifier
[INFO] [stderr]    --> /opt/rustwide/cargo-home/registry/src/github.tiyicn.workers.dev-1ecc6299db9ec823/ifmt-impl-0.3.0/src/lib.rs:87:16
[INFO] [stderr]     |
[INFO] [stderr] 87  |         pub fn $name(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
[INFO] [stderr]     |                ^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 101 | def_ifmt_macro!(iprintln, println);
[INFO] [stderr]     | ----------------------------------- in this macro invocation
[INFO] [stderr]     |
[INFO] [stderr]     = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] error: expected identifier
[INFO] [stderr]    --> /opt/rustwide/cargo-home/registry/src/github.tiyicn.workers.dev-1ecc6299db9ec823/ifmt-impl-0.3.0/src/lib.rs:87:16
[INFO] [stderr]     |
[INFO] [stderr] 87  |         pub fn $name(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
[INFO] [stderr]     |                ^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 103 | def_ifmt_macro!(ieprint, eprint);
[INFO] [stderr]     | --------------------------------- in this macro invocation
[INFO] [stderr]     |
[INFO] [stderr]     = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] error: expected identifier
[INFO] [stderr]    --> /opt/rustwide/cargo-home/registry/src/github.tiyicn.workers.dev-1ecc6299db9ec823/ifmt-impl-0.3.0/src/lib.rs:87:16
[INFO] [stderr]     |
[INFO] [stderr] 87  |         pub fn $name(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
[INFO] [stderr]     |                ^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 105 | def_ifmt_macro!(ieprintln, eprintln);
[INFO] [stderr]     | ------------------------------------- in this macro invocation
[INFO] [stderr]     |
[INFO] [stderr]     = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] error: expected identifier
[INFO] [stderr]    --> /opt/rustwide/cargo-home/registry/src/github.tiyicn.workers.dev-1ecc6299db9ec823/ifmt-impl-0.3.0/src/lib.rs:87:16
[INFO] [stderr]     |
[INFO] [stderr] 87  |         pub fn $name(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
[INFO] [stderr]     |                ^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 107 | def_ifmt_macro!(iformat_args, format_args);
[INFO] [stderr]     | ------------------------------------------- in this macro invocation
[INFO] [stderr]     |
[INFO] [stderr]     = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] error: expected identifier
[INFO] [stderr]    --> /opt/rustwide/cargo-home/registry/src/github.tiyicn.workers.dev-1ecc6299db9ec823/ifmt-impl-0.3.0/src/lib.rs:87:16
[INFO] [stderr]     |
[INFO] [stderr] 87  |         pub fn $name(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
[INFO] [stderr]     |                ^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 109 | def_ifmt_macro!(ipanic, panic);
[INFO] [stderr]     | ------------------------------- in this macro invocation
[INFO] [stderr]     |
[INFO] [stderr]     = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 7 previous errors
[INFO] [stderr] 
[INFO] [stderr] error: could not compile `ifmt-impl`.

From: rust-lang/rust#72622 (comment)

[dtolnay]

This was fixed by proc-macro-hack 0.5.16.