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Fixed bug in "literal math" logic for modulo and floor divide operato… #10168

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Merged
erictraut merged 1 commit into from
Mar 26, 2025
Merged

Fixed bug in "literal math" logic for modulo and floor divide operato… #10168

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17 changes: 9 additions & 8 deletions packages/pyright-internal/src/analyzer/operations.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1036,18 +1036,19 @@ function calcLiteralForBinaryOp(operator: OperatorType, leftType: Type, rightTyp
// BigInt rounds to zero, but floor divide rounds to negative
// infinity, so we need to adjust the result if the signs
// of the operands are different.
if (leftLiteralValue !== rightLiteralValue && leftLiteralValue !== BigInt(0)) {
if (
leftLiteralValue < BigInt(0) !== rightLiteralValue < BigInt(0) &&
leftLiteralValue !== rightLiteralValue * BigInt(-1)
) {
newValue -= BigInt(1);
}
if (
newValue * rightLiteralValue !== leftLiteralValue &&
leftLiteralValue < BigInt(0) !== rightLiteralValue < BigInt(0)
) {
newValue -= BigInt(1);
}
}
} else if (operator === OperatorType.Mod) {
if (rightLiteralValue !== BigInt(0)) {
newValue = leftLiteralValue % rightLiteralValue;
// BigInt always produces a remainder, but Python produces
// a modulo result whose sign is always the same as the
// right operand.
newValue = ((leftLiteralValue % rightLiteralValue) + rightLiteralValue) % rightLiteralValue;
}
} else if (operator === OperatorType.Power) {
if (rightLiteralValue >= BigInt(0)) {
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44 changes: 40 additions & 4 deletions packages/pyright-internal/src/tests/samples/operator8.py
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Original file line number Diff line number Diff line change
Expand Up @@ -77,11 +77,47 @@ def func1(a: Literal[1, 2], b: Literal[0, 4], c: Literal[3, 4]):
c12 = 6 // -6
reveal_type(c12, expected_text="Literal[-1]")

c13 = 1 << -1
reveal_type(c13, expected_text="int")
c13 = 6 // -3
reveal_type(c13, expected_text="Literal[-2]")

c14 = 1 >> -1
reveal_type(c14, expected_text="int")
c14 = 256 // -16
reveal_type(c14, expected_text="Literal[-16]")

c20 = 1 << -1
reveal_type(c20, expected_text="int")

c21 = 1 >> -1
reveal_type(c21, expected_text="int")

c30 = -129 % 16
reveal_type(c30, expected_text="Literal[15]")

c31 = -129 % 32
reveal_type(c31, expected_text="Literal[31]")

c32 = -129 % 100
reveal_type(c32, expected_text="Literal[71]")

c33 = 256 % -32678
reveal_type(c33, expected_text="Literal[-32422]")

c34 = 256 % -129
reveal_type(c34, expected_text="Literal[-2]")

c35 = 0 % -1
reveal_type(c35, expected_text="Literal[0]")

c36 = -1 % -1
reveal_type(c36, expected_text="Literal[0]")

c37 = 1 % 1
reveal_type(c37, expected_text="Literal[0]")

c38 = -2 % 1
reveal_type(c38, expected_text="Literal[0]")

c39 = 4 % -2
reveal_type(c39, expected_text="Literal[0]")


def func2(cond: bool):
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