[WIP] Prototype AST rewrite for parameterless witness method

[Copilot]

Implementation Plan: AST Rewrite for Parameterless witness()

• Understand the current architecture and resolve() method
• Add javac tools dependency for AST manipulation (JCTree)
• Create a function to translate InstantiationPlan to JCTree method calls
• Created WitnessResolutionPlugin as compiler plugin
• Configure Maven to enable the compiler plugin
• Add parameterless witness() method
• Update plugin to handle parameterless witness()
• Simplify plugin implementation
• Add test for parameterless witness()
• Document the new functionality
• Address code review feedback
• Verify the implementation compiles and runs correctly

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Prototype compiler AST rewrite for parameterless witness()</issue_title>
<issue_description>It should be possible to expose a parameterless T witness() static method that gets rewritten into the expected witness constructor calls after witness resolution.

We only need the new Ty<>() {} "trick" because of type erasure. And of course because we can only resolve witnesses at runtime currently.

We can modify the AST as explained here: https://www.baeldung.com/java-build-compiler-plugin

In the current checker code, we ignore the success branch from the resolve() call. It contains an InstantiationPlan which describes the tree of WitnessConstructor that should be invoked to build the witness instance.

Roughly:

• Write a function that translates an InstantiationPlan tree into a JCTree of method call invocations. Each InstantiationPlan contains a WitnessConstructor which contains a ExecutableElement. This should be enough to build the JCTree?
• Then update the success branch of the resolve() call in the checker to replace the current AST node with the tree build from the function above. </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Implement compiler AST rewrite for parameterless witness() #20

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.11%. Comparing base (8d575fa) to head (ad166c4).

Additional details and impacted files

@@            Coverage Diff            @@
##               main      #23   +/-   ##
=========================================
  Coverage     66.11%   66.11%           
  Complexity      320      320           
=========================================
  Files            55       55           
  Lines           782      782           
  Branches         65       65           
=========================================
  Hits            517      517           
  Misses          219      219           
  Partials         46       46           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.