Use cache for DictExpr as well by ilevkivskyi · Pull Request #19536 · python/mypy
TBH examples in those issues are already sufficiently fast (probably because of combined effect of fast dict literals, and the fact that there are some lists and/or function calls in that examples, so some caching already kicks in). But this PR will probably make them even faster.
This has ~0 effect on self-check.