leanprover-community/lean

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Lean 3 Theorem Prover (community fork)

Stars: 434
Forks: 79
Open beginner issues: 0
Indexed issues: 107

Dominant language: C++
License: Apache-2.0
Last GitHub push: Oct 12, 2023
Latest indexed: Sep 18, 2026
Contributing guide: Contributing guide
Code of conduct: No code of conduct
Beginner labels: good first issue
PR merge metrics: No merged PRs in 30d

Beginner friendly Everything

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107 open issues indexed

leanittest_complete_trailing_period.lean test fails (99% tests passed, 1 tests failed out of 1441) Open

Difficulty 2/5 1-3 hours Newbie friendliness 50/100

leanprover-community/lean#816 · Opened Sep 3, 2024
Segmentation fault when using `get_env` with `run_tactic` Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#803 · 1 comment · Opened Mar 15, 2023
"Invalid return type" error when definining inductive propositions can be attached to more suitable text range Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#802 · 1 comment · Opened Feb 25, 2023
pp.links handles unit.star badly Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover-community/lean#789 · Opened Dec 2, 2022
opening a namespace can affect elaboration Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#776 · Opened Oct 26, 2022
local notation can change explicitness of arguments Open

bug

Difficulty 5/5 Over a week Newbie friendliness 20/100

leanprover-community/lean#772 · Opened Sep 26, 2022
clang prints warnings: use reference type ... to prevent copying Open

Difficulty 2/5 1-3 hours Newbie friendliness 48/100

leanprover-community/lean#767 · Opened Sep 5, 2022
Simple programs run for many seconds Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#765 · 8 comments · Opened Sep 1, 2022
Failures in get_peak_rss() should fail the application instead of silently returning 0 Open

Difficulty 3/5 1-2 days Newbie friendliness 42/100

leanprover-community/lean#763 · Opened Aug 31, 2022
Kernel failed to type-check due to name collision involving `include` Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#751 · Opened Jul 29, 2022
exceptions when saving oleans are not user-visible Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

leanprover-community/lean#750 · Opened Jul 29, 2022
`is_bi_equal` use of BinderInfo-unaware hashes causes many collisions (a.k.a. timeout when saving oleans) Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

leanprover-community/lean#749 · Opened Jul 29, 2022
Assertion failure in local_context_adapter.cpp Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover-community/lean#748 · 1 comment · Opened Jul 29, 2022
`native.rb_map.insert` not working as expected Open

Difficulty 3/5 1-2 days Newbie friendliness 50/100

leanprover-community/lean#738 · 2 comments · Opened Jul 10, 2022
invalid synthesis of `reflected` instances Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover-community/lean#731 · Opened Jun 16, 2022
Cannot build .olean file on NFS Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#718 · 6 comments · 1 reaction · Opened May 21, 2022
Test failure on i686 (32 bit) Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#685 · Opened Feb 19, 2022
"kernel failed to type check declaration" in presence of implicit coercion to Sort Open

Difficulty 4/5 3-5 days Newbie friendliness 28/100

leanprover-community/lean#672 · Opened Jan 25, 2022
universe error in definition generated by the equation compiler Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#655 · Opened Dec 10, 2021
apply tactic produces incorrect proof Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#644 · 1 comment · Opened Nov 1, 2021
segfault in badly typed pattern match Open

Difficulty 4/5 3-5 days Newbie friendliness 32/100

leanprover-community/lean#625 · Opened Sep 22, 2021
CI: Flaky test on macos debug runs Open

Difficulty 4/5 3-5 days Newbie friendliness 32/100

leanprover-community/lean#624 · Opened Sep 22, 2021
simp ignores direction of equation lemmas Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#623 · Opened Sep 21, 2021
(No equational lemmas)/(Mistaken as field notation) when using a `namespace` inside a `section` with universe polymorphism Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

leanprover-community/lean#613 · Opened Sep 6, 2021
Repeat tactic does not terminate instead of giving an error or functioning as it should. Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#584 · 1 comment · Opened Jun 20, 2021
Universe levels are ignored when using projection notation Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

leanprover-community/lean#576 · Opened May 14, 2021
Deep recursion error depending on order of multiplication Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

leanprover-community/lean#563 · Opened Apr 12, 2021
When /proc isn't mounted lean aborts: please catch exceptions and print messages from them Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover-community/lean#559 · 2 comments · Opened Mar 28, 2021
The after_set field of user attributes does not have access to current options Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 20/100

leanprover-community/lean#546 · Opened Mar 5, 2021
Leanchecker crashes on `@has_add.add (has_coe_to_fun.F ...) pi.has_add` Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 15/100

leanprover-community/lean#543 · Opened Mar 2, 2021
French quotes can lead to unexpected evaluation. Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

leanprover-community/lean#542 · Opened Feb 26, 2021
λ with ⟨⟩ consumes following implicit arguments Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

leanprover-community/lean#529 · Opened Feb 3, 2021
Instance cache not always preserved between simp invocations Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#521 · Opened Jan 26, 2021
nested congr doesn't work in converter mode Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#516 · Opened Jan 5, 2021
widget docs need to be updated for #501 Open

leanprover-community/lean#515 · 1 assignee · Opened Jan 4, 2021
Unknown identifier in `do` block inside tactic mode Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#500 · Opened Nov 13, 2020
Implicit arguments in structure fields are not respected when using projection notation Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#492 · Opened Oct 28, 2020
Equivalent of `add_key_equivalence` for simp Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

leanprover-community/lean#489 · Opened Oct 27, 2020
API to set decl_pos Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 20/100

leanprover-community/lean#486 · 1 comment · Opened Oct 25, 2020
lean[pkg build and test] should have a way to turn warnings into errors Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

leanprover-community/lean#478 · Opened Oct 11, 2020
Running `leanpkg <command> --help` runs <command> Open

Difficulty 2/5 1-3 hours Newbie friendliness 52/100

leanprover-community/lean#477 · Opened Oct 11, 2020
elaborator doesn't unify universe metavariable Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#474 · Opened Oct 6, 2020
constant/axiom in sections Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

leanprover-community/lean#470 · 3 comments · Opened Sep 25, 2020
`[ ... ] tactics produce output in other files Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 25/100

leanprover-community/lean#468 · 1 comment · Opened Sep 14, 2020
more possible type class caching opportunities Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

leanprover-community/lean#467 · Opened Sep 14, 2020
a flag to stop `lean --make` at the first error Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover-community/lean#454 · Opened Aug 23, 2020
neither computable nor noncomputable Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

leanprover-community/lean#451 · 3 comments · Opened Aug 20, 2020
segfault with `by {using}` Open

crash

Difficulty 4/5 3-5 days Newbie friendliness 40/100

leanprover-community/lean#450 · 3 comments · Opened Aug 18, 2020
segfault on inductive type with binder starting with `_` Open

crash

Difficulty 4/5 3-5 days Newbie friendliness 38/100

leanprover-community/lean#447 · 2 comments · Opened Aug 15, 2020
don't use "standalone" .olean files by default Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover-community/lean#441 · 6 comments · Opened Aug 14, 2020

leanprover-community/lean

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