Unrolled build for #142240

Rollup merge of #142240 - fee1-dead-contrib:push-zkkzoxlymslv, r=oli-obk

deduplicate the rest of AST walker functions

After this, we can tidy things up and deduplicate the visitor traits themselves too.

Fixes #139825, apparently

r? ``@oli-obk``

Author: rust-timer