MSRV build is broken

[franziskuskiefer]

Running

cargo +nightly update -Z minimal-versions
cargo build

fails with

error[E0433]: failed to resolve: use of undeclared crate or module `syntax`
 --> ~/.cargo/registry/src/github.com-1ecc6299db9ec823/regex-1.5.0/src/literal/mod.rs:9:9
  |
9 |     use syntax::hir::literal::Literals;
  |         ^^^^^^ use of undeclared crate or module `syntax`

This blocks updating criterion in RustCrypto/formats#720.

[elpiel]

MSRV should be made > 1.59 based on the latest master branch

error: package async-global-executor v2.3.0 cannot be built because it requires rustc 1.59 or newer, while the currently active rustc version is 1.57.0

https://github.com/bheisler/criterion.rs/actions/runs/3028960427/jobs/4874098488

[dhardy]

rust-random/rand#1329 is currently blocked on our MSRV (1.60 in rand master branch).

Testing now wants at least 1.70:

error: package `clap_lex v0.6.0` cannot be built because it requires rustc 1.70.0 or newer, while the currently active rustc version is 1.60.0

Does Criterion have any particular policy here on the MSRV?

[elpiel]

@dhardy you can check - https://github.com/bheisler/criterion.rs#compatibility-policy

I believe msrv policy is less strict mainly because criterion is used primarily in dev-dependencies