Bug #21805: Wrong "key not found" in NoMatchingPatternKeyError when destructuring Data

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: ruby 4.0.0 (2025-12-25 revision 553f1675f3) +PRISM [arm64-darwin24]
• Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN

[esad (Esad Hajdarevic)]

Consider

Foo = Data.define(:x)
Foo.new(1) => {x:, z:}

It raises #<data Foo x=1>: key not found: :x (NoMatchingPatternKeyError)

Clearly the message is misleading, as it is key :z that is missing.

[afurm (Andrii Furmanets)]

Thanks. The https://github.com/ruby/ruby/pull/15748 will fix the issue.