[red-knot] Add `Type::TypeVar` variant #17102

dcreager · 2025-03-31T21:50:47Z

This adds a new Type variant for holding an instance of a typevar inside of a generic function or class. We don't handle specializing the typevars yet, but this should implement most of the typing rules for inside the generic function/class, where we don't know yet which specific type the typevar will be specialized to.

This PR does not yet handle the constraint that multiple occurrences of the typevar must be specialized to the same time. (There is an existing test case for this in generics/functions.md which is still marked as TODO.)

github-actions · 2025-03-31T21:53:03Z

`mypy_primer` results

No ecosystem changes detected ✅

dcreager · 2025-03-31T21:51:38Z

crates/red_knot_python_semantic/src/types.rs

@@ -550,7 +552,7 @@ impl<'db> Type<'db> {

        match (self, target) {
            // We should have handled these immediately above.
-            (Type::Dynamic(_), _) | (_, Type::Dynamic(_)) => {
+            (Type::Dynamic(_) | Type::TypeVar(_), _) | (_, Type::Dynamic(_) | Type::TypeVar(_)) => {


I have implemented all of these Type functions with the interpretation that a typevar is not fully static, since it can be specialized to a dynamic type.

We are actually going to do a simple syntactic check to determine if a typevar is fully static. The typevar is not fully static iff it has a not-fully-static bound or constraint. This lines up nicely with the definition in the typing spec:

We will refer to types that do not contain a gradual form as a sub-part as fully static types.

crates/red_knot_python_semantic/src/types.rs

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md

crates/red_knot_python_semantic/src/types.rs

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md

crates/red_knot_python_semantic/src/types.rs

dcreager

Summarizing a discussion from Discord:

dcreager · 2025-04-01T17:51:53Z

crates/red_knot_python_semantic/src/types.rs

@@ -550,7 +552,7 @@ impl<'db> Type<'db> {

        match (self, target) {
            // We should have handled these immediately above.
-            (Type::Dynamic(_), _) | (_, Type::Dynamic(_)) => {
+            (Type::Dynamic(_) | Type::TypeVar(_), _) | (_, Type::Dynamic(_) | Type::TypeVar(_)) => {


We are actually going to do a simple syntactic check to determine if a typevar is fully static. The typevar is not fully static iff it has a not-fully-static bound or constraint. This lines up nicely with the definition in the typing spec:

We will refer to types that do not contain a gradual form as a sub-part as fully static types.

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md

carljm · 2025-04-01T18:00:14Z

(Currently planning to hold off on reviewing this until that fully-static change mentioned above is made, but please ping if there's anything it would be useful to get additional eyes on sooner.)

* main: [red-knot] Add property tests for callable types (#17006) [red-knot] Disjointness for callable types (#17094) [red-knot] Flatten `Type::Callable` into four `Type` variants (#17126) mdtest.py: do a full mdtest run immediately when the script is executed (#17128) [red-knot] Fix callable subtyping for standard parameters (#17125) [red-knot] Fix more `redundant-cast` false positives (#17119) Sync vendored typeshed stubs (#17106) [red-knot] support Any as a class in typeshed (#17107) Visit `Identifier` node as part of the `SourceOrderVisitor` (#17110) [red-knot] Don't infer Todo for quite so many tuple type expressions (#17116) CI: Run pre-commit on depot machine (#17120) Error instead of `panic!` when running Ruff from a deleted directory (#16903) (#17054) Control flow graph: setup (#17064) [red-knot] Playground improvements (#17109) [red-knot] IDE crate (#17045) Update dependency vite to v6.2.4 (#17104) [red-knot] Add redundant-cast error (#17100) [red-knot] Narrowing on `in tuple[...]` and `in str` (#17059)

dcreager · 2025-04-01T20:15:56Z

(Currently planning to hold off on reviewing this until that fully-static change mentioned above is made, but please ping if there's anything it would be useful to get additional eyes on sooner.)

Fully-static change is up, merge conflicts resolved. Should be good for another round of review!

crates/red_knot_python_semantic/src/types/type_ordering.rs

Co-authored-by: Alex Waygood <[email protected]>

carljm

This is fantastic! Great work. Sorry for all the comments 😆 I think almost all of them are fine to address just with TODO comments.

crates/red_knot_python_semantic/resources/mdtest/generics/functions.md

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md

crates/red_knot_python_semantic/src/types/infer.rs

crates/red_knot_python_semantic/src/types.rs

crates/red_knot_python_semantic/src/types/builder.rs

* origin/main: (35 commits) [red-knot] Callable types are disjoint from literals (#17160) [red-knot] Fix inference for `pow` between two literal integers (#17161) [red-knot] Add GitHub PR annotations when mdtests fail in CI (#17150) [red-knot] Fix equivalence of differently ordered unions that contain `Callable` types (#17145) [red-knot] Add initial set of tests for unreachable code (#17159) [`airflow`] Move `AIR302` to `AIR301` and `AIR303` to `AIR302` (#17151) ruff_db: simplify lifetimes on `DiagnosticDisplay` [red-knot] Detect division-by-zero in unions and intersections (#17157) [`airflow`] Add autofix infrastructure to `AIR302` name checks (#16965) [`flake8-bandit`] Mark `str` and `list[str]` literals as trusted input (`S603`) (#17136) [`airflow`] Add autofix for `AIR302` attribute checks (#16977) [`airflow`] Extend `AIR302` with additional symbols (#17085) [`airflow`] Move `AIR301` to `AIR002` (#16978) [`airflow`] Add autofix for `AIR302` method checks (#16976) ruff_db: switch diagnostic rendering over to `std::fmt::Display` [red-knot] Add 'Goto type definition' to the playground (#17055) red_knot_ide: update snapshots red_knot_python_semantic: remove comment about `TypeCheckDiagnostic` ruff_db: delete most of the old diagnostic code red_knot: use `Diagnostic` inside of red knot ...

…ager/typevar-type * origin/dcreager/typevar-type: Update crates/red_knot_python_semantic/src/types.rs

* origin/main: [red-knot] Fix more [redundant-cast] false positives (#17170) [red-knot] Three-argument type-calls take 'str' as the first argument (#17168) Control flow: `return` and `raise` (#17121) Bump 0.11.3 (#17173) [red-knot] Improve `Debug` implementation for `semantic_index::SymbolTable` (#17172) [red-knot] Fix `str(…)` calls (#17163) [red-knot] visibility_constraint analysis for match cases (#17077) [red-knot] Fix playground crashes when diagnostics are stale (#17165)

carljm

Awesome work. Ship it!

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md

crates/red_knot_python_semantic/src/types.rs

Co-authored-by: Carl Meyer <[email protected]>

* origin/main: [red-knot] Add `Type::TypeVar` variant (#17102) [red-knot] update to latest Salsa with fixpoint caching fix (#17179) Upgrade to Rust 1.86 and bump MSRV to 1.84 (#17171) [red-knot] Avoid unresolved-reference in unreachable code (#17169) Fix relative import resolution in `site-packages` packages when the `site-packages` search path is a subdirectory of the first-party search path (#17178) [DO NOT LAND] bump Salsa version (#17176) [syntax-errors] Detect duplicate keys in `match` mapping patterns (#17129)

This adds a new `Type` variant for holding an instance of a typevar inside of a generic function or class. We don't handle specializing the typevars yet, but this should implement most of the typing rules for inside the generic function/class, where we don't know yet which specific type the typevar will be specialized to. This PR does _not_ yet handle the constraint that multiple occurrences of the typevar must be specialized to the _same_ time. (There is an existing test case for this in `generics/functions.md` which is still marked as TODO.) --------- Co-authored-by: Alex Waygood <[email protected]> Co-authored-by: Carl Meyer <[email protected]>

dcreager added 2 commits March 31, 2025 17:04

Use union to hold typevar constraints

178ee89

Add Type::TypeVar variant

feb1ea9

dcreager added the ty Multi-file analysis & type inference label Mar 31, 2025

dcreager requested review from carljm, AlexWaygood and sharkdp as code owners March 31, 2025 21:50

dcreager commented Mar 31, 2025

View reviewed changes

Fix failing tests

3c1ad79

sharkdp reviewed Apr 1, 2025

View reviewed changes

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md Outdated Show resolved Hide resolved

sharkdp reviewed Apr 1, 2025

View reviewed changes

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md Outdated Show resolved Hide resolved

MichaReiser reviewed Apr 1, 2025

View reviewed changes

crates/red_knot_python_semantic/src/types.rs Show resolved Hide resolved

sharkdp reviewed Apr 1, 2025

View reviewed changes

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md Show resolved Hide resolved

doc Type::TypeVar

59430b6

dcreager commented Apr 1, 2025

View reviewed changes

crates/red_knot_python_semantic/src/types.rs Outdated Show resolved Hide resolved

dcreager added 4 commits April 1, 2025 10:24

More correct handling of final bounds/constraints

77ffa80

use list[T] so generic funcs are callable even with Never

6f86720

lint

cf81967

Add (currently failing) narrowing tests

6615df1

dcreager commented Apr 1, 2025

View reviewed changes

dcreager added 5 commits April 1, 2025 15:22

Typevars _can_ be fully static I guess

b2f5a2a

Simplify intersections with constrained typevars

590680c

Fix tests

debd60a

lint

aa391fd

AlexWaygood reviewed Apr 1, 2025

View reviewed changes

crates/red_knot_python_semantic/src/types/type_ordering.rs Show resolved Hide resolved

Update crates/red_knot_python_semantic/src/types/type_ordering.rs

e57e62e

Co-authored-by: Alex Waygood <[email protected]>

carljm approved these changes Apr 1, 2025

View reviewed changes

dcreager added 18 commits April 2, 2025 15:05

Simplify positive intersections too

9e07efe

Intersection of constraints is subtype of typevar

fb63c22

Better descriptions of intersections of constrained typevars

3459056

Add multiple narrowing example

71d425e

lint

233e938

Sort typevar constraints

9785202

Remove moot todo

c86af50

Fold typevar match arms back into main match statement

aa00895

Remove moot comment

d99d1d7

Remove moot todo

58f0995

Add more TODOs about OneOf connector

42fd54a

add todos for unary/binary ops

6bd69f1

Merge remote-tracking branch 'origin/dcreager/typevar-type' into dcre…

37692f1

…ager/typevar-type * origin/dcreager/typevar-type: Update crates/red_knot_python_semantic/src/types.rs

Fix tests

3869dc6

Fix tests better

0c1745b

Support unary and binary ops

8bdd9e2

carljm approved these changes Apr 3, 2025

View reviewed changes

dcreager and others added 7 commits April 3, 2025 13:55

add super checks

30172a0

remove parenthetical

7803ec3

use singleton bound

b4d2a0c

normalize upper bound

a3493cd

fix comment

d2c7647

Apply suggestions from code review

f70d565

Co-authored-by: Carl Meyer <[email protected]>

typo

f3afc91

dcreager merged commit 64e7e1a into main Apr 3, 2025
23 checks passed

dcreager deleted the dcreager/typevar-type branch April 3, 2025 18:36

[red-knot] Add Type::TypeVar variant #17102

[red-knot] Add Type::TypeVar variant #17102

Uh oh!

Conversation

dcreager commented Mar 31, 2025

Uh oh!

github-actions bot commented Mar 31, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

mypy_primer results

Uh oh!

dcreager Mar 31, 2025

Choose a reason for hiding this comment

Uh oh!

dcreager Apr 1, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

dcreager left a comment

Choose a reason for hiding this comment

Uh oh!

dcreager Apr 1, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

carljm commented Apr 1, 2025

Uh oh!

dcreager commented Apr 1, 2025

Uh oh!

Uh oh!

carljm left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

carljm left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

[red-knot] Add `Type::TypeVar` variant #17102

[red-knot] Add `Type::TypeVar` variant #17102

github-actions bot commented Mar 31, 2025 •

edited

Loading

`mypy_primer` results