Bug #20991: Prism parses `"\C-\α"` into `"α"` which should be syntax error

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.5.0dev (2024-12-27T07:27:30Z master adbbc9109e) +YJIT +MN +PRISM [arm64-darwin22]
• Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[tompng (tomoya ishida)]

$ ./ruby -e 'p "\C-\α"'
"α"

I think it should raise Invalid escape character syntax just like "\C-α" does.

"\C-α"
# Invalid escape character syntax

"\C-\α"
# Prism: "α"
# parse.y:  invalid multibyte char (UTF-8), reported in #20990

[tompng (tomoya ishida)]

• Status changed from Open to Closed

Fixed by https://bugs.ruby-lang.org/projects/ruby-master/repository/git/revisions/e4ec2128ae9c5c2a43cd599759f19db21fc0238f
https://github.com/ruby/ruby/pull/12485