typetools / typetools/checker-framework
Fine-grained errors when a subtype test fails for a compound type
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enhancement
- Dominant language
- Java
- Stars
- 1.1k
- Forks
- 440
- Avg merge
- 1d 12h
- Merged PRs (30d)
- 134
Description
Suppose that a subtyping test between two compound types occurs. The Checker Framework should report "the third type argument is not the same but needs to be" rather than just "A<B, C, D, E> is not a subtype of "A<B, C, D', E>".
Does using constraints help achieve this goal?
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
No files, tests, or entry points are named. Start by locating the subtype-checking diagnostics for compound types and reviewing how constraints are handled. Done means a failed subtype test identifies the differing type-argument position and explains the required relationship instead of showing only the full-type mismatch.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 25/100