leanprover / leanprover/lean4

term info missing in type ascriptions in patterns

Open
#3,955 1 comment 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

bug P-medium
Dominant language
Lean
Stars
9.2k
Forks
990
Avg merge
1d 17h
Merged PRs (30d)
175

Description

Example:

example (a : {n : Nat // n = 3}) : True :=
  --   v incorrectly marked as unused
  let ⟨n, (_h : n = 3)⟩ := a
  --            ^ not highlighted
  trivial

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

Start by running the supplied Lean example and inspect the term information and highlighting for the type ascription (_h : n = 3) in the pattern. Done means the relevant term information is available and the ascribed term is highlighted correctly rather than reported as unused.

Written by the indexing model from the issue text.

Assessment

Domain
compilers
Issue type
Bug
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.