`bool` is available even if `*constraints` of `TypeVar` is the exact types `int` and `float`

*Memo:

• mypy --strict test.py
• mypy 1.18.2
• Python 3.14.0
• Windows 11

The doc says 'Must be exactly str or bytes' about *constraints to make difference between bound and *constraints as shown below:

*Memo:

• From my understanding:
  • Setting bound, the type and the subtypes are available.
  • Setting *constraints, only the exact types are available but not the subtypes.

T = TypeVar('T') # Can be anything
S = TypeVar('S', bound=str) # Can be any subtype of str
A = TypeVar('A', str, bytes) # Must be exactly str or bytes

But bool is available even if *constraints is the exact types int and float as shown below:

<With TypeVar (Old syntax)>:

from typing import TypeVar, Generic

T = TypeVar('T', int, float)

class MyCls(Generic[T]):
    num: T

    def __init__(self, x: T) -> None:
        self.num = x

           # ↓↓↓↓↓↓↓↓↓↓↓↓
mycls = MyCls[bool](True)
# No error

<Without TypeVar (New syntax)>:

class MyCls[T: (int, float)]:
    num: T

    def __init__(self, x: T) -> None:
        self.num = x

           # ↓↓↓↓↓↓↓↓↓↓↓↓
mycls = MyCls[bool](True)
# No error

Inizia eseguendo la riproduzione fornita mypy --strict test.py con mypy 1.18.2 e confronta la sintassi vecchia e nuova di TypeVar. Traccia il comportamento del controllo dei tipi per i TypeVars vincolati di int/float; il lavoro è completato quando l'implementazione applica in modo coerente la semantica documentata dei vincoli e la copertura delle regressioni acquisisce il risultato.