ruff/crates/ty_python_semantic
Douglas Creager b892e4548e
Some checks are pending
CI / Determine changes (push) Waiting to run
CI / cargo fmt (push) Waiting to run
CI / cargo clippy (push) Blocked by required conditions
CI / cargo test (linux) (push) Blocked by required conditions
CI / cargo test (linux, release) (push) Blocked by required conditions
CI / cargo test (windows) (push) Blocked by required conditions
CI / cargo test (wasm) (push) Blocked by required conditions
CI / cargo build (release) (push) Waiting to run
CI / cargo build (msrv) (push) Blocked by required conditions
CI / cargo fuzz build (push) Blocked by required conditions
CI / fuzz parser (push) Blocked by required conditions
CI / test scripts (push) Blocked by required conditions
CI / ecosystem (push) Blocked by required conditions
CI / Fuzz for new ty panics (push) Blocked by required conditions
CI / cargo shear (push) Blocked by required conditions
CI / python package (push) Waiting to run
CI / pre-commit (push) Waiting to run
CI / mkdocs (push) Waiting to run
CI / formatter instabilities and black similarity (push) Blocked by required conditions
CI / test ruff-lsp (push) Blocked by required conditions
CI / check playground (push) Blocked by required conditions
CI / benchmarks-instrumented (push) Blocked by required conditions
CI / benchmarks-walltime (push) Blocked by required conditions
[ty Playground] Release / publish (push) Waiting to run
[ty] Track when type variables are inferable or not (#19786)
`Type::TypeVar` now distinguishes whether the typevar in question is
inferable or not.

A typevar is _not inferable_ inside the body of the generic class or
function that binds it:

```py
def f[T](t: T) -> T:
    return t
```

The infered type of `t` in the function body is `TypeVar(T,
NotInferable)`. This represents how e.g. assignability checks need to be
valid for all possible specializations of the typevar. Most of the
existing assignability/etc logic only applies to non-inferable typevars.

Outside of the function body, the typevar is _inferable_:

```py
f(4)
```

Here, the parameter type of `f` is `TypeVar(T, Inferable)`. This
represents how e.g. assignability doesn't need to hold for _all_
specializations; instead, we need to find the constraints under which
this specific assignability check holds.

This is in support of starting to perform specialization inference _as
part of_ performing the assignability check at the call site.

In the [[POPL2015][]] paper, this concept is called _monomorphic_ /
_polymorphic_, but I thought _non-inferable_ / _inferable_ would be
clearer for us.

Depends on #19784 

[POPL2015]: https://doi.org/10.1145/2676726.2676991

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-08-16 18:25:03 -04:00
..
resources [ty] Track when type variables are inferable or not (#19786) 2025-08-16 18:25:03 -04:00
src [ty] Track when type variables are inferable or not (#19786) 2025-08-16 18:25:03 -04:00
tests [ty] Track open files in the server (#19264) 2025-07-18 19:33:35 +05:30
build.rs
Cargo.toml [ty] Avoid overcounting shared memory usage (#19773) 2025-08-06 15:32:02 -04:00
mdtest.py
mdtest.py.lock