1.18.1: allow(unused) incompatible with previous forbid

[mrtnzlml]

What happened?

It's all visible in the following automated PR: adeira/universe#4861

I started getting the following error:

error[E0453]: allow(unused) incompatible with previous forbid
  --> server/src/warp_server/models.rs:72:9
   |
72 | /         insta::assert_snapshot!(
73 | |             get_current_user(&pool, &Some(String::from("XYZ")))
74 | |             .await
75 | |             .err()
76 | |             .unwrap(),
77 | |              @"Unable to parse 'authorization' header (should be 'Bearer XYZ')."
78 | |         );
   | |_________^ overruled by previous forbid
   |
  ::: server/src/main.rs:3:11
   |
3  |   #![forbid(unused_must_use)]
   |             --------------- `forbid` level set here
   |
   = note: this error originates in the macro `$crate::assert_snapshot` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0453`.

Note: my project uses #![forbid(unused_must_use)] in main.rs

Reproduction steps

Check this PR: adeira/universe#4861

Insta Version

1.18.1

rustc Version

rustc 1.62.1 (e092d0b6b 2022-07-16)

What did you expect?

no error (or just errors related to the 1.18.0 breaking changes)

[mitsuhiko]

Thank you. This is fixed on both master and in 1.18.2

[mrtnzlml]

@mitsuhiko Awesome, thanks! I really appreciate that you put some effort into making the migration easy!

❤️ ❤️