[GROOVY-8722] final modifier for non-abstract methods in traits is ignored

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.15, 2.5.1
• Fix Version/s: 2.5.2
• Component/s: Compiler, Documentation
• Labels: breaking documentation
• Assignee: Paul King
• Reporter: Dmytro Buryak
• Created: 30/Jul/18 14:29
• Updated: 14/Aug/18 08:05
• Resolved: 06/Aug/18 22:35

Description

When using the final modifier in a trait non-abstract method signature, then:

• compiler successfully compiles trait and class that implements it
• final method of trait may be overridden in class that implements trait
• if class implements trait and doesn't override trait final method, then this method is available as non-final method in class
• documentation says absolutely nothing about this

In other words, final modifier is ignored in trait methods: code works the same with or without it. Even if this behavior is expected, there's nothing about it in the documentation.

Here's simple example gradle groovy project to demonstrate the issue: https://github.com/dburyak/groovy-bug-trait-final

Issue Links

• links to: GitHub Pull Request #780