I'm in the process of updating some dependencies and memfs is a transitive dependency on one of my project's dependencies. When I updated my dependency, the current version of memfs (4.56.10) was added and pnpm started reporting peer dependency warnings due to tslib.

 ERR_PNPM_PEER_DEP_ISSUES  Unmet peer dependencies

apps/app.admin
└─┬ @rspack/cli 1.7.5
  └─┬ @rspack/dev-server 1.1.5
    └─┬ webpack-dev-server 5.2.2
      └─┬ webpack-dev-middleware 7.4.2
        └─┬ memfs 4.56.10
          ├── ✕ missing peer tslib@2
<snip>
Peer dependencies that should be installed:
  tslib@">=2.0.0 <3.0.0-0"

Looking at the package.json for the memfs package it looks a little off. tslib is listed as a peer dependency with a version spec of "2" and also as a production dependency with a version spec of "^2.0.0".

It's possible that pnpm shouldn't report an unmet peer when the dependency specifying the peer also specifies it as a dependency. However, it seems unintentional for memfs to have tslib as both a dependency and a peer dependency as I can't think of a reason why you would need it to be both.