typetools / typetools/checker-framework

More information in error messages relating to invariant type arguments

Open
#2,533 1 comment 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

enhancement
Dominant language
Java
Stars
1.1k
Forks
440
Avg merge
1d 12h
Merged PRs (30d)
134

Description

Users are sometimes confused why List<@NonNull String> is not a subtype of List<@Nullable String>. When a type error is issued, and the incompatibility is due to invariant type arguments, the Checker Framework could add an extra line to the error message, with a brief reference to a manual section such as a FAQ.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The issue names no files, tests, or entry points. Start by locating the type-error diagnostic logic and the handling of invariant type arguments, then identify where the relevant manual or FAQ section should be referenced. Done means affected errors include a brief additional line and coverage verifies the new diagnostic.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
compilers
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.