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ruff/crates/red_knot_python_semantic/resources/mdtest/expression/if.md
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[red-knot] Infer type of if-expression if test has statically known truthiness (#14048) 
## Summary

Detecting statically known truthy or falsy test in if expressions
(ternary).

## Test Plan

new mdtest
2024-11-01 12:23:18 -07:00

625 B
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If expression

Union

def bool_instance() -> bool:
    return True

reveal_type(1 if bool_instance() else 2)  # revealed: Literal[1, 2]

Statically known branches

reveal_type(1 if True else 2)  # revealed: Literal[1]
reveal_type(1 if "not empty" else 2)  # revealed: Literal[1]
reveal_type(1 if (1,) else 2)  # revealed: Literal[1]
reveal_type(1 if 1 else 2)  # revealed: Literal[1]

reveal_type(1 if False else 2)  # revealed: Literal[2]
reveal_type(1 if None else 2)  # revealed: Literal[2]
reveal_type(1 if "" else 2)  # revealed: Literal[2]
reveal_type(1 if 0 else 2)  # revealed: Literal[2]