Add `rewrite` support for `errorprone.refasterrules`

[Pankraz76]

Add rewrite support for errorprone.refasterrules

I propose integrating Google Error Prone with its Picnic extension (see Automating Away Bugs with Error Prone | PlatformCon 2023) to enable automated fixes via rewrite rules.
This would complement Checkstyle by addressing semantic bugs rather than just stylistic issues.

Motivation

Error Prone’s refaster/rewrite rules can:

• Fix common bug patterns (e.g., String.equals() misuse)
• Modernize code (e.g., JDK migration helpers)
• Enforce best practices (e.g., null-checks)

Adoption examples:

• Spotless #2641
• Maven #11159
• Maven Parent #496
• Checkstyle #17487
• Kafka #20219
• Spotless #2576

Proposal

1. Add support for errorprone.refasterrules rewrites
2. Make adoption opt-in (no breaking changes)
3. Provide suppression mechanisms for API constraints

Open Questions

• Scope of auto-fixes
• Preferred suppression strategy
• Integration approach

Next Steps

I can:

• Prepare a PoC
• Help design the implementation
• Address compatibility concerns

Most earlier objections have been resolved; from a technical perspective, there’s little reason not to automate this now—unless new concerns arise.