Issue #21139 has been updated by matz (Yukihiro Matsumoto). I said I prefer Prism behavior to `parse.y`. But It was due to my misunderstanding. `it = it` should initialize the local variable named `it` and the value should be `nil`, just like other `x = x` assignment in Ruby. In the future, all assignment to `it` could be prohibited, maybe. Matz. ---------------------------------------- Bug #21139: Prism and parse.y parses `it = it` differently https://bugs.ruby-lang.org/issues/21139#change-112308 * Author: tompng (tomoya ishida) * Status: Open * ruby -v: ruby 3.5.0dev (2025-02-14T16:49:52Z master ee181d1bb7) +PRISM [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- ~~~ # ruby --parser=parse.y -e "42.tap { it = it; p it }" nil # ruby --parser=prism -e "42.tap { it = it; p it }" 42 ~~~ ---Files-------------------------------- clipboard-202503081702-idzz2.png (22.6 KB) -- https://bugs.ruby-lang.org/