Comment by tomsmeding

Egraphs fundamentally require a first-order language, i.e. no lambda functions, because they do not handle scoping well. There are workarounds that work in some circumstances, but no general solution (that I'm aware of).

Additionally, egraphs express rewrites on a single language. Compilers are fundamentally translators between different languages; how do you write typechecking as an egraph rewrite rule? Or conversion to assembly?