Add throw point for division

[rajyan]

fixes phpstan/phpstan#6349

Implemented throw point for zero value div/mod DivisionByZeroError.
I didn't implemented it for float, because currently there is no way to narrow float value as non-zero float.

I'm not satisfied enough with 01c2761
zero value ConstantScalarType would not be passed to calculateFromScalars because it's handled here

phpstan-src/src/Analyser/MutatingScope.php

Lines 989 to 1022 in 55b9952

	if (
	$node instanceof Node\Expr\BinaryOp\Div
	|| $node instanceof Node\Expr\AssignOp\Div
	|| $node instanceof Node\Expr\BinaryOp\Mod
	|| $node instanceof Node\Expr\AssignOp\Mod
	) {
	if ($node instanceof Node\Expr\AssignOp) {
	$right = $node->expr;
	} else {
	$right = $node->right;
	}
	$rightType = $this->getType($right);
	$integerType = $rightType->toInteger();
	if (
	$node instanceof Node\Expr\BinaryOp\Mod
	|| $node instanceof Node\Expr\AssignOp\Mod
	) {
	if ($integerType instanceof ConstantIntegerType && $integerType->getValue() === 1) {
	return new ConstantIntegerType(0);
	}
	}
	$rightScalarTypes = TypeUtils::getConstantScalars($rightType->toNumber());
	foreach ($rightScalarTypes as $scalarType) {
	if (
	$scalarType->getValue() === 0
	|| $scalarType->getValue() === 0.0
	) {
	return new ErrorType();
	}
	}
	}

Although, this commit might not be redundant, because using calculateFromScalars in other places may cause DivisionByZeroError.

[herndlm]

I'm too much out of context but would checking against PHP_FLOAT_EPSILON help with the float 0 detection?

[rajyan]

@herndlm
No. The problem for float is, division with 0.0 causes DivisionByZeroError but we can’t narrow down float.
https://phpstan.org/r/ff0c680f-2c75-46c3-b889-7e900e4609e1
so if I add a throw point for float, there is no way to make PHPStan not throw. (we need a type like float~ 0.0

[ondrejmirtes]

Thank you!