KotlinIsland/basedmypy

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Based Python static type checker with baseline, sane default settings and based typing features

Stars: 202
Forks: 6
Open beginner issues: 0
Indexed issues: 420

Dominant language: Python
License: No license data
Last GitHub push: Sep 10, 2025
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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420 open issues indexed

add zuban and pyrefly in the readme for alternative Open

documentation

Difficulty 1/5 Under an hour Newbie friendliness 65/100

KotlinIsland/basedmypy#881 · 1 comment · 2 reactions · Opened Sep 27, 2025
Tests fail because `_TypedDict.__closed__` is None at runtime (expected bool) Open

bug

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

KotlinIsland/basedmypy#879 · Opened Aug 3, 2025
don't report constrained `TypeVar` with variance if the constraints are assignable Open

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

KotlinIsland/basedmypy#876 · Opened May 29, 2025
generic bound of bare typevar can't resolve properly on callsite Open

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

KotlinIsland/basedmypy#872 · Opened Mar 21, 2025
false report of `helpful-string` on deleted variable Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

KotlinIsland/basedmypy#871 · Opened Mar 21, 2025
Incorrect inference of `Never`. Does not take into account type var default Open

bug

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

KotlinIsland/basedmypy#870 · Opened Mar 18, 2025
[arg-type] error in assignment of generic with unions Open

upstream

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

KotlinIsland/basedmypy#869 · Opened Mar 17, 2025
`Container.__contains__` should be generic Open

feature good first issue typeshed

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

KotlinIsland/basedmypy#866 · Opened Feb 21, 2025
nonsense error `"object & type" has no attribute "__init__"` Open

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

KotlinIsland/basedmypy#865 · Opened Feb 17, 2025
intersections don't work with `ParamSpec`s and `type` Open

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

KotlinIsland/basedmypy#864 · Opened Feb 17, 2025
daemon skitz moment - "Final must be initialized" false positive occasionally appears and disappears when unrelated changes are made Open

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

KotlinIsland/basedmypy#863 · Opened Jan 14, 2025
baseline doesn't cache properly Open

basedline

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

KotlinIsland/basedmypy#862 · Opened Jan 13, 2025
`no-any-explicit` false positive with type parameter default `Any` Open

bug topic-any upstream

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

KotlinIsland/basedmypy#861 · 4 comments · Opened Jan 12, 2025
overloads and intersections; research and analysis Open

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

KotlinIsland/basedmypy#860 · 4 comments · 1 reaction · Opened Jan 11, 2025
infer `async def` Open

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

KotlinIsland/basedmypy#859 · Opened Jan 8, 2025
bad narrowing with break in loop Open

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

KotlinIsland/basedmypy#858 · Opened Jan 7, 2025
issue with intersection compatibility with nested union Open

bug topic-intersection

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

KotlinIsland/basedmypy#856 · Opened Jan 6, 2025
sort out variadic and unknown/projected `*Ts`s and `**P`s Open

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

KotlinIsland/basedmypy#855 · Opened Jan 4, 2025
support simple builtins augumtation Open

basedpyright feature parity

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

KotlinIsland/basedmypy#853 · Opened Jan 2, 2025
Unpack instead of concatenate Open

feature

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

KotlinIsland/basedmypy#851 · Opened Dec 30, 2024
check type alias arguments Open

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

KotlinIsland/basedmypy#850 · Opened Dec 27, 2024
cmdline `--always-true` to override the config Open

feature

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

KotlinIsland/basedmypy#849 · 4 comments · Opened Dec 26, 2024
fail global that doesn't exist Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

KotlinIsland/basedmypy#848 · Opened Dec 20, 2024
return only generics dropped from higher order function Open

bug upstream

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

KotlinIsland/basedmypy#839 · Opened Dec 6, 2024
generic shorthand `def f(a) -> a` Open

feature

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

KotlinIsland/basedmypy#838 · Opened Dec 5, 2024
invalid class access on `NewType` Open

bug upstream

Difficulty 3/5 1-2 days Newbie friendliness 35/100

KotlinIsland/basedmypy#832 · Opened Dec 2, 2024
union distrubution of calls doesn't apply to constraints Open

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

KotlinIsland/basedmypy#831 · 7 comments · 1 reaction · Opened Dec 1, 2024
"def" in error messages about `FunctionType`/`Callable` etc is confusing Open

p-2 understandability

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

KotlinIsland/basedmypy#829 · 1 reaction · Opened Nov 29, 2024
parameter default value should be allowed to match typevar default value Open

bug

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

KotlinIsland/basedmypy#827 · Opened Nov 28, 2024
error messsages for typevars are inconsistent Open

Difficulty 3/5 1-2 days Newbie friendliness 38/100

KotlinIsland/basedmypy#825 · Opened Nov 27, 2024
add a "used by" section to the readme Open

documentation project

Difficulty 1/5 Under an hour Newbie friendliness 55/100

KotlinIsland/basedmypy#823 · Opened Nov 26, 2024
investigate crashes in primer Open

crash needs investigation

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

KotlinIsland/basedmypy#821 · Opened Nov 26, 2024
`UserList` etc have `__repr__` etc Open

typeshed

Difficulty 3/5 1-2 days Newbie friendliness 25/100

KotlinIsland/basedmypy#820 · Opened Nov 26, 2024
Recursive sequence type of `Sequence[NotAString]` should not accept `str` Open

bug needs investigation upstream

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

KotlinIsland/basedmypy#819 · 14 comments · Opened Nov 24, 2024
give all the invalid special form guys an error code Open

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

KotlinIsland/basedmypy#818 · Opened Nov 23, 2024
`_typeshed.MaybeNone` -> `None` Open

good first issue typeshed

Difficulty 5/5 Over a week Newbie friendliness 10/100

KotlinIsland/basedmypy#814 · Opened Nov 18, 2024
`--traceback` should be on by default, because mypy is so extremely unreliable Open

understandability

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

KotlinIsland/basedmypy#813 · Opened Nov 12, 2024
f-string types Open

feature

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

KotlinIsland/basedmypy#811 · 10 comments · 1 reaction · Opened Nov 7, 2024
disable the strictness for the stdlib/typeshed Open

typeshed

Difficulty 3/5 1-2 days Newbie friendliness 25/100

KotlinIsland/basedmypy#810 · Opened Nov 7, 2024
roadmap Open

project

Difficulty 5/5 Over a week Newbie friendliness 15/100

KotlinIsland/basedmypy#809 · Opened Nov 6, 2024
`type_check_only_generic` decorator Open

feature

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

KotlinIsland/basedmypy#808 · Opened Nov 6, 2024
put `optype` into typeshed Open

feature

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

KotlinIsland/basedmypy#806 · 1 comment · 1 reaction · Opened Nov 5, 2024
special forms that work with boolean context semantics `Truthy`/`Falsey` Open

feature

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

KotlinIsland/basedmypy#805 · Opened Nov 5, 2024
add `__bool__` overloads to `builtins` types Open

good first issue typeshed

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

KotlinIsland/basedmypy#804 · Opened Nov 5, 2024
`attrgetter` is generic, but not subscribable Open

Difficulty 3/5 1-2 days Newbie friendliness 25/100

KotlinIsland/basedmypy#802 · Opened Nov 4, 2024
type the `json` module better Open

typeshed

Difficulty 5/5 Over a week Newbie friendliness 15/100

KotlinIsland/basedmypy#801 · 1 reaction · Opened Nov 4, 2024
an `AttributeOf` form Open

feature

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

KotlinIsland/basedmypy#800 · 1 reaction · Opened Nov 4, 2024
`Ellipsis` should work as a bare literal, the same as `None` Open

p-3

Difficulty 3/5 1-2 days Newbie friendliness 35/100

KotlinIsland/basedmypy#799 · Opened Nov 1, 2024
inference fails with generic intersection of `Callable` Open

topic-intersection

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

KotlinIsland/basedmypy#798 · Opened Nov 1, 2024
union in string annotation invalid error Open

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

KotlinIsland/basedmypy#797 · Opened Nov 1, 2024

KotlinIsland/basedmypy

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