[red-knot] Implement more types in binary and unary expressions (#13803)

Implemented some points from
https://github.com/astral-sh/ruff/issues/12701

- Handle Unknown and Any in Unary operation
- Handle Boolean in binary operations
- Handle instances in unary operation
- Consider division by False to be division by zero

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
This commit is contained in:
Shaygan Hooshyari
2024-10-20 03:57:21 +02:00
committed by GitHub
parent 2d2baeca23
commit 0f0fff4d5a
4 changed files with 161 additions and 5 deletions

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@@ -0,0 +1,48 @@
## Binary operations on booleans
## Basic Arithmetic
We try to be precise and all operations except for division will result in Literal type.
```py
a = True
b = False
reveal_type(a + a) # revealed: Literal[2]
reveal_type(a + b) # revealed: Literal[1]
reveal_type(b + a) # revealed: Literal[1]
reveal_type(b + b) # revealed: Literal[0]
reveal_type(a - a) # revealed: Literal[0]
reveal_type(a - b) # revealed: Literal[1]
reveal_type(b - a) # revealed: Literal[-1]
reveal_type(b - b) # revealed: Literal[0]
reveal_type(a * a) # revealed: Literal[1]
reveal_type(a * b) # revealed: Literal[0]
reveal_type(b * a) # revealed: Literal[0]
reveal_type(b * b) # revealed: Literal[0]
reveal_type(a % a) # revealed: Literal[0]
reveal_type(b % a) # revealed: Literal[0]
reveal_type(a // a) # revealed: Literal[1]
reveal_type(b // a) # revealed: Literal[0]
reveal_type(a**a) # revealed: Literal[1]
reveal_type(a**b) # revealed: Literal[1]
reveal_type(b**a) # revealed: Literal[0]
reveal_type(b**b) # revealed: Literal[1]
# Division
reveal_type(a / a) # revealed: float
reveal_type(b / a) # revealed: float
b / b # error: [division-by-zero] "Cannot divide object of type `Literal[False]` by zero"
a / b # error: [division-by-zero] "Cannot divide object of type `Literal[True]` by zero"
# bitwise OR
reveal_type(a | a) # revealed: Literal[True]
reveal_type(a | b) # revealed: Literal[True]
reveal_type(b | a) # revealed: Literal[True]
reveal_type(b | b) # revealed: Literal[False]
```

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@@ -11,6 +11,18 @@ reveal_type(-3 / 3) # revealed: float
reveal_type(5 % 3) # revealed: Literal[2]
```
## Power
For power if the result fits in the int literal type it will be a Literal type. Otherwise the
outcome is int.
```py
largest_u32 = 4_294_967_295
reveal_type(2**2) # revealed: Literal[4]
reveal_type(1 ** (largest_u32 + 1)) # revealed: int
reveal_type(2**largest_u32) # revealed: int
```
## Division by Zero
This error is really outside the current Python type system, because e.g. `int.__truediv__` and
@@ -38,6 +50,14 @@ reveal_type(c) # revealed: int
# revealed: float
reveal_type(int() / 0)
# error: "Cannot divide object of type `Literal[1]` by zero"
# revealed: float
reveal_type(1 / False)
# error: [division-by-zero] "Cannot divide object of type `Literal[True]` by zero"
True / False
# error: [division-by-zero] "Cannot divide object of type `Literal[True]` by zero"
bool(1) / False
# error: "Cannot divide object of type `float` by zero"
# revealed: float
reveal_type(1.0 / 0)