Issue #20952 has been updated by jeremyevans0 (Jeremy Evans). This is a bug in prism. The expected behavior is parse.y's behavior of raising a syntax error: ``` $ ruby34 -c -e "matrix[5, axis: :y] = 8" Syntax OK $ ruby34 --parser=parse.y -c -e "matrix[5, axis: :y] = 8" -e:1: keyword arg given in index assignment matrix[5, axis: :y] = 8 ruby34: compile error (SyntaxError) ``` ---------------------------------------- Bug #20952: A weird error message for []= with keyword arguments https://bugs.ruby-lang.org/issues/20952#change-110999 * Author: zverok (Victor Shepelev) * Status: Open * Backport: 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONTNEED ---------------------------------------- Trying to document the new deprecation of `#[]=` with keyword arguments, I wrote this sample code: ```ruby class MyMatrix # ...some implementation def []=(*args, **kwargs) p(args:, kwargs:) # ...some implementation end end matrix = MyMatrix.new matrix[5, axis: :y] = 8 ``` This fails as expected, but the error message is totally unexpected for me: ``` ruby3_4.rb:11:in '<main>': undefined method '[]=' for an instance of Integer (NoMethodError) matrix[5, axis: :y] = 8 ^^^^^^^^^^^^^^^ ``` Am I missing some interpretation peculiarity here?.. ``` $ ruby -v ruby 3.4.0dev (2024-12-11T19:50:20Z master 34e68548d4) +PRISM [x86_64-linux] ``` -- https://bugs.ruby-lang.org/