[ty] Model int and str enum value normalization

[charliermarsh]

Summary

Enum data types construct a member's _value_ before aliases are registered. Prior to this change, we used the declared right-hand side for both .value inference and alias detection, so constructor normalization could be lost and runtime aliases could remain separate canonical members.

This PR models the normalization performed when an enum's data type is the known built-in int or str:

from enum import Enum

class Number(int, Enum):
    FROM_BOOL = False
    FROM_INT = 0

reveal_type(Number.FROM_BOOL.value)  # Literal[0]
reveal_type(Number.FROM_INT)  # Literal[Number.FROM_BOOL]

We apply the same model through IntEnum, StrEnum, and memberless parent enum bases, recursively normalize union-valued members, and normalize generated auto() values. Aliased declarations still contribute their raw right-hand sides to the history used by a following _generate_next_value_ call.

User-defined data types remain opaque for .value inference and alias detection, even when they inherit from int or str without overriding methods. This avoids assuming that arbitrary construction, attribute access, equality, or hashing behavior matches the built-in scalar.

[astral-sh-bot]

Typing conformance results

No changes detected ✅

Current numbers

The percentage of diagnostics emitted that were expected errors held steady at 94.47%. The percentage of expected errors that received a diagnostic held steady at 89.19%. The number of fully passing files held steady at 95/134.

[astral-sh-bot]

Memory usage report

Memory usage unchanged ✅

[astral-sh-bot]

ecosystem-analyzer results

Lint rule	Added	Removed	Changed
invalid-argument-type	0	7	0
Total	0	7	0

Raw diff:

schemathesis (https://github.com/schemathesis/schemathesis)
- src/schemathesis/generation/overrides.py:75:59 error[invalid-argument-type] Argument to function `lookup_parameter` is incorrect: Expected `str`, found `Literal["query", "header", "path", "cookie", "body"] | None`
- src/schemathesis/generation/dictionaries.py:112:73 error[invalid-argument-type] Argument to function `_find_parameter_binding` is incorrect: Expected `str`, found `Literal["query", "header", "path", "cookie", "body"] | None`
- src/schemathesis/generation/dictionaries.py:115:97 error[invalid-argument-type] Argument to function `_find_parameter_binding` is incorrect: Expected `str`, found `Literal["query", "header", "path", "cookie", "body"] | None`
- src/schemathesis/generation/dictionaries.py:230:21 error[invalid-argument-type] Argument is incorrect: Expected `str`, found `Literal["query", "header", "path", "cookie", "body"] | None`
- src/schemathesis/specs/openapi/extra_data_source.py:181:9 error[invalid-argument-type] Argument is incorrect: Expected `str`, found `Literal["query", "header", "path", "cookie", "body"] | None`
- src/schemathesis/specs/openapi/extra_data_source.py:199:9 error[invalid-argument-type] Argument is incorrect: Expected `str`, found `Literal["query", "header", "path", "cookie", "body"] | None`
- src/schemathesis/specs/openapi/extra_data_source.py:645:38 error[invalid-argument-type] Argument to bound method `list.append` is incorrect: Expected `tuple[str, str]`, found `tuple[Literal["query", "header", "path", "cookie", "body"] | None, str]`

Full report with detailed diff (timing results)

[codspeed-hq]

Merging this PR will degrade performance by 4.57%

❌ 2 regressed benchmarks
✅ 83 untouched benchmarks
⏩ 64 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	WallTime	pandas	76.3 s	80.3 s	-4.96%
❌	WallTime	tanjun	2.9 s	3 s	-4.18%

Tip

Investigate this regression with the CodSpeed MCP and your agent.

---

_{Comparing charlie/normalize-built-in-enum-mixin-values (38fc949) with main (e9719d4)}

Footnotes

1. 64 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩