[ty] Infer type of self as typing.Self in method body (with updated salsa, micha playground)

[MichaReiser]

This is #18473 but my own version where I play with an updated Salsa version.

I don't plan on merging this PR. It's just to get perf numbers, see if mypy primer passes etc.

[github-actions]

Diagnostic diff on typing conformance tests

Changes were detected when running ty on typing conformance tests

--- old-output.txt	2025-10-11 16:27:50.031016480 +0000
+++ new-output.txt	2025-10-11 16:27:53.409029431 +0000
@@ -1,6 +1,6 @@
 WARN ty is pre-release software and not ready for production use. Expect to encounter bugs, missing features, and fatal errors.
-fatal[panic] Panicked at /home/runner/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/29ab321/src/function/execute.rs:217:25 when checking `/home/runner/work/ruff/ruff/typing/conformance/tests/aliases_type_statement.py`: `PEP695TypeAliasType < 'db >::value_type_(Id(cc17)): execute: too many cycle iterations`
-fatal[panic] Panicked at /home/runner/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/29ab321/src/function/execute.rs:217:25 when checking `/home/runner/work/ruff/ruff/typing/conformance/tests/aliases_typealiastype.py`: `infer_definition_types(Id(1603f)): execute: too many cycle iterations`
+fatal[panic] Panicked at /home/runner/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/f89c430/src/function/execute.rs:401:17 when checking `/home/runner/work/ruff/ruff/typing/conformance/tests/aliases_type_statement.py`: `PEP695TypeAliasType < 'db >::value_type_(Id(cc17)): execute: too many cycle iterations`
+fatal[panic] Panicked at /home/runner/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/f89c430/src/function/execute.rs:401:17 when checking `/home/runner/work/ruff/ruff/typing/conformance/tests/aliases_typealiastype.py`: `infer_definition_types(Id(1643f)): execute: too many cycle iterations`
 _directives_deprecated_library.py:15:31: error[invalid-return-type] Function always implicitly returns `None`, which is not assignable to return type `int`
 _directives_deprecated_library.py:30:26: error[invalid-return-type] Function always implicitly returns `None`, which is not assignable to return type `str`
 _directives_deprecated_library.py:36:41: error[invalid-return-type] Function always implicitly returns `None`, which is not assignable to return type `Self@__add__`
@@ -346,6 +346,7 @@
 enums_member_names.py:30:5: error[type-assertion-failure] Argument does not have asserted type `Literal["RED", "BLUE", "GREEN"]`
 enums_member_values.py:30:5: error[type-assertion-failure] Argument does not have asserted type `Literal[1, 2, 3]`
 enums_member_values.py:54:1: error[type-assertion-failure] Argument does not have asserted type `Literal[1]`
+enums_member_values.py:85:9: error[invalid-assignment] Object of type `int` is not assignable to attribute `_value_` of type `str`
 enums_member_values.py:96:1: error[type-assertion-failure] Argument does not have asserted type `int`
 enums_members.py:128:21: info[revealed-type] Revealed type: `Unknown | Literal[2]`
 enums_members.py:129:9: error[type-assertion-failure] Argument does not have asserted type `Unknown`
@@ -437,7 +438,6 @@
 generics_self_advanced.py:18:1: error[type-assertion-failure] Argument does not have asserted type `ParentA`
 generics_self_advanced.py:19:1: error[type-assertion-failure] Argument does not have asserted type `ChildA`
 generics_self_advanced.py:28:25: error[invalid-return-type] Function always implicitly returns `None`, which is not assignable to return type `Self@method1`
-generics_self_advanced.py:35:9: error[type-assertion-failure] Argument does not have asserted type `Self@method2`
 generics_self_advanced.py:36:9: error[type-assertion-failure] Argument does not have asserted type `list[Self@method2]`
 generics_self_advanced.py:37:9: error[type-assertion-failure] Argument does not have asserted type `Self@method2`
 generics_self_advanced.py:38:9: error[type-assertion-failure] Argument does not have asserted type `Self@method2`
@@ -447,7 +447,6 @@
 generics_self_attributes.py:26:33: error[invalid-argument-type] Argument is incorrect: Expected `typing.Self | None`, found `LinkedList[int]`
 generics_self_attributes.py:29:5: error[invalid-assignment] Object of type `OrdinalLinkedList` is not assignable to attribute `next` of type `typing.Self | None`
 generics_self_attributes.py:32:5: error[invalid-assignment] Object of type `LinkedList[int]` is not assignable to attribute `next` of type `typing.Self | None`
-generics_self_basic.py:14:9: error[type-assertion-failure] Argument does not have asserted type `Self@set_scale`
 generics_self_basic.py:20:16: error[invalid-return-type] Return type does not match returned value: expected `Self@method2`, found `Shape`
 generics_self_basic.py:33:16: error[invalid-return-type] Return type does not match returned value: expected `Self@cls_method2`, found `Shape`
 generics_self_basic.py:54:1: error[type-assertion-failure] Argument does not have asserted type `Shape`
@@ -491,6 +490,7 @@
 generics_syntax_infer_variance.py:46:1: error[invalid-assignment] Object of type `ShouldBeCovariant3[int | float]` is not assignable to `ShouldBeCovariant3[int]`
 generics_syntax_infer_variance.py:74:1: error[invalid-assignment] Object of type `ShouldBeCovariant5[int]` is not assignable to `ShouldBeCovariant5[int | float]`
 generics_syntax_infer_variance.py:75:1: error[invalid-assignment] Object of type `ShouldBeCovariant5[int | float]` is not assignable to `ShouldBeCovariant5[int]`
+generics_syntax_infer_variance.py:82:9: error[invalid-assignment] Cannot assign to final attribute `x` on type `Self@__init__`
 generics_syntax_infer_variance.py:85:1: error[invalid-assignment] Object of type `ShouldBeCovariant6[int]` is not assignable to `ShouldBeCovariant6[int | float]`
 generics_syntax_infer_variance.py:86:1: error[invalid-assignment] Object of type `ShouldBeCovariant6[int | float]` is not assignable to `ShouldBeCovariant6[int]`
 generics_syntax_infer_variance.py:102:1: error[invalid-assignment] Object of type `ShouldBeInvariant1[int]` is not assignable to `ShouldBeInvariant1[int | float]`
@@ -756,6 +756,8 @@
 protocols_definition.py:287:1: error[invalid-assignment] Object of type `Concrete5_Bad3` is not assignable to `Template5`
 protocols_definition.py:288:1: error[invalid-assignment] Object of type `Concrete5_Bad4` is not assignable to `Template5`
 protocols_definition.py:289:1: error[invalid-assignment] Object of type `Concrete5_Bad5` is not assignable to `Template5`
+protocols_explicit.py:56:9: error[invalid-assignment] Object of type `tuple[int, int, str]` is not assignable to attribute `rgb` of type `tuple[int, int, int]`
+protocols_explicit.py:85:9: error[invalid-attribute-access] Cannot assign to ClassVar `cm1` from an instance of type `Self@__init__`
 protocols_generic.py:40:1: error[invalid-assignment] Object of type `Concrete1` is not assignable to `Proto1[int, str]`
 protocols_generic.py:56:5: error[invalid-assignment] Object of type `Box[int | float]` is not assignable to `Box[int]`
 protocols_generic.py:66:5: error[invalid-assignment] Object of type `Sender[int]` is not assignable to `Sender[int | float]`
@@ -800,6 +802,11 @@
 qualifiers_annotated.py:64:8: error[invalid-type-form] Special form `typing.Annotated` expected at least 2 arguments (one type and at least one metadata element)
 qualifiers_annotated.py:91:1: error[call-non-callable] Object of type `typing.Annotated` is not callable
 qualifiers_final_annotation.py:18:7: error[invalid-type-form] Type qualifier `typing.Final` expected exactly 1 argument, got 2
+qualifiers_final_annotation.py:52:9: error[invalid-assignment] Cannot assign to final attribute `ID4` on type `Self@__init__`
+qualifiers_final_annotation.py:54:9: error[invalid-assignment] Cannot assign to final attribute `ID5` on type `Self@__init__`
+qualifiers_final_annotation.py:57:13: error[invalid-assignment] Cannot assign to final attribute `ID6` on type `Self@__init__`
+qualifiers_final_annotation.py:59:13: error[invalid-assignment] Cannot assign to final attribute `ID6` on type `Self@__init__`
+qualifiers_final_annotation.py:65:9: error[invalid-assignment] Cannot assign to final attribute `ID7` on type `Self@method1`
 qualifiers_final_annotation.py:71:1: error[invalid-assignment] Reassignment of `Final` symbol `RATE` is not allowed: Symbol later reassigned here
 qualifiers_final_annotation.py:81:1: error[invalid-assignment] Cannot assign to final attribute `DEFAULT_ID` on type `<class 'ClassB'>`
 qualifiers_final_annotation.py:118:9: error[invalid-type-form] Type qualifier `typing.Final` is not allowed in type expressions (only in annotation expressions)
@@ -897,5 +904,5 @@
 typeddicts_usage.py:28:17: error[missing-typed-dict-key] Missing required key 'name' in TypedDict `Movie` constructor
 typeddicts_usage.py:28:18: error[invalid-key] Invalid key access on TypedDict `Movie`: Unknown key "title"
 typeddicts_usage.py:40:24: error[invalid-type-form] The special form `typing.TypedDict` is not allowed in type expressions. Did you mean to use a concrete TypedDict or `collections.abc.Mapping[str, object]` instead?
-Found 898 diagnostics
+Found 905 diagnostics
 WARN A fatal error occurred while checking some files. Not all project files were analyzed. See the diagnostics list above for details.

[github-actions]

ecosystem-analyzer results

Failing projects:

Project	Old Status	New Status	Old Return Code	New Return Code
zulip	success	abnormal exit	1	101
setuptools	success	abnormal exit	1	101
pandas	success	abnormal exit	1	101
bokeh	success	abnormal exit	1	101

Diagnostic changes:

Lint rule	Added	Removed	Changed
unresolved-attribute	5,120	0	0
possibly-missing-attribute	3,148	8	21
invalid-argument-type	1,725	5	135
unused-ignore-comment	0	1,052	0
unsupported-operator	929	2	7
invalid-assignment	427	6	15
invalid-super-argument	430	4	1
invalid-return-type	331	64	11
non-subscriptable	404	0	0
call-non-callable	204	0	0
missing-argument	192	0	0
too-many-positional-arguments	173	0	0
no-matching-overload	109	0	0
not-iterable	105	0	0
possibly-missing-implicit-call	85	4	11
deprecated	28	0	0
unknown-argument	25	0	0
parameter-already-assigned	17	4	0
possibly-unresolved-reference	0	18	0
redundant-cast	13	0	0
division-by-zero	6	4	0
index-out-of-bounds	4	0	0
invalid-await	3	0	1
invalid-context-manager	3	0	0
type-assertion-failure	0	3	0
invalid-key	2	0	0
missing-typed-dict-key	2	0	0
unsupported-base	2	0	0
invalid-parameter-default	1	0	0
invalid-type-form	1	0	0
Total	13,489	1,174	202

Full report with detailed diff (timing results)

[codspeed-hq]

CodSpeed Performance Report

Merging #20812 will degrade performances by 15.96%

_{Comparing micha/typing-self-function-scope (cbc7305) with main (dc64c08)}

Summary

❌ 7 regressions
✅ 44 untouched

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Mode	Benchmark	BASE	HEAD	Change
❌	Instrumentation	anyio	905.5 ms	992.8 ms	-8.79%
❌	WallTime	large[sympy]	42.6 s	46.1 s	-7.53%
❌	WallTime	medium[pandas]	34.5 s	39.1 s	-11.84%
❌	WallTime	medium[static-frame]	9.5 s	10.5 s	-9.4%
❌	WallTime	small[freqtrade]	5 s	5.6 s	-10.95%
❌	WallTime	small[pydantic]	2.6 s	2.8 s	-6.79%
❌	WallTime	small[tanjun]	1.7 s	2 s	-15.96%

[MichaReiser]

Setuptools now panics with too many iterations for setuptools/_vendor/jaraco/collections/__init__.py. This seems correct as we now end up with a pretty ridiculous type. The other project also fail because of too many iteration errors. This seems no longer salsa-related but is an issue with our convergence functions.