leanprover / leanprover/lean4

`liftCommandElabM` breaks namespace resolution?

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bug P-medium
Dominant language
Lean
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Description

Prerequisites

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Description

When I use liftCommandElabM with elab and resolveGlobalConstNoOverload, it seems to break namespace resolution. It looks like a bug to me. Is the following expected?

import Lean

def Foo.ExampleDL := 42

elab "s3(" dl:ident ")" : term => do
  -- remove the `Lean.liftCommandElabM` to remove error below
  let _ ← Lean.liftCommandElabM (Lean.resolveGlobalConstNoOverload dl)
  return .const ``Nat []

#check s3(Foo.ExampleDL)

namespace Foo
-- "Unknown constant `ExampleDL`". Reproducible in https://live.lean-lang.org/
#check s3(ExampleDL)
Context

Zulip thread

Versions

4.24.0-rc1, live.lean-lang.org

Impact

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Contributor guide

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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 self-contained reproducer against the reported Lean nightly or live. Compare the two #check cases and inspect the interaction between liftCommandElabM, elab, and resolveGlobalConstNoOverload. Done means the unqualified ExampleDL resolves inside namespace Foo without removing liftCommandElabM.

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

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