[ruby-core:122831] [Ruby Bug#21139] Prism and parse.y parses `it = it` differently
From:
"S_H_ (Shun Hiraoka) via ruby-core" <ruby-core@...>
Date:
2025-07-21 02:11:28 UTC
List:
ruby-core #122831
Issue #21139 has been updated by S_H_ (Shun Hiraoka).
I've created a pull request to fix this Prism behavior where `42.tap { it = it; p it }` returns `42` instead of `nil`.
https://github.com/ruby/prism/pull/3604
This change makes Prism treat the right-hand side `it` as a local variable in assignment context, matching parse.y's behavior.
I'm not entirely sure if there are other edge cases that need to be addressed. I would appreciate any feedback or suggestions.
----------------------------------------
Bug #21139: Prism and parse.y parses `it = it` differently
https://bugs.ruby-lang.org/issues/21139#change-114120
* Author: tompng (tomoya ishida)
* Status: Feedback
* Assignee: prism
* 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)
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