Improve IntDivThrowTypeExtension to support integer ranges

Author: VincentLanglet

src/Type/Php/IntdivThrowTypeExtension.php

@@ -7,11 +7,10 @@
 use PhpParser\Node\Expr\FuncCall;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\DynamicFunctionThrowTypeExtension;
-use PHPStan\Type\NeverType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
-use PHPStan\Type\TypeCombinator;
 use function count;
 use const PHP_INT_MIN;
 
@@ -29,39 +28,19 @@ public function getThrowTypeFromFunctionCall(FunctionReflection $functionReflect
 			return $functionReflection->getThrowType();
 		}
 
-		$containsMin = false;
-		$valueType = $scope->getType($funcCall->getArgs()[0]->value);
-		foreach ($valueType->getConstantScalarTypes() as $constantScalarType) {
-			if ($constantScalarType->getValue() === PHP_INT_MIN) {
-				$containsMin = true;
-			}
-
-			$valueType = TypeCombinator::remove($valueType, $constantScalarType);
-		}
-
-		if (!$valueType instanceof NeverType) {
-			$containsMin = true;
-		}
+		$valueType = $scope->getType($funcCall->getArgs()[0]->value)->toInteger();
+		$containsMin = $valueType->isSuperTypeOf(new ConstantIntegerType(PHP_INT_MIN));
 
-		$divisionByZero = false;
-		$divisorType = $scope->getType($funcCall->getArgs()[1]->value);
-		foreach ($divisorType->getConstantScalarTypes() as $constantScalarType) {
-			if ($containsMin && $constantScalarType->getValue() === -1) {
+		$divisorType = $scope->getType($funcCall->getArgs()[1]->value)->toInteger();
+		if (!$containsMin->no()) {
+			$divisionByMinusOne = $divisorType->isSuperTypeOf(new ConstantIntegerType(-1));
+			if (!$divisionByMinusOne->no()) {
 				return new ObjectType(ArithmeticError::class);
 			}
-
-			if ($constantScalarType->getValue() === 0) {
-				$divisionByZero = true;
-			}
-
-			$divisorType = TypeCombinator::remove($divisorType, $constantScalarType);
-		}
-
-		if (!$divisorType instanceof NeverType) {
-			return new ObjectType($containsMin ? ArithmeticError::class : DivisionByZeroError::class);
 		}
 
-		if ($divisionByZero) {
+		$divisionByZero = $divisorType->isSuperTypeOf(new ConstantIntegerType(0));
+		if (!$divisionByZero->no()) {
 			return new ObjectType(DivisionByZeroError::class);
 		}
 

tests/PHPStan/Rules/Exceptions/CatchWithUnthrownExceptionRuleTest.php

@@ -137,6 +137,10 @@ public function testRule(): void
 				'Dead catch - InvalidArgumentException is never thrown in the try block.',
 				741,
 			],
+			[
+				'Dead catch - ArithmeticError is never thrown in the try block.',
+				762,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Exceptions/data/unthrown-exception.php

@@ -744,3 +744,49 @@ public function passCallableToMethod2(): void
 	}
 
 }
+
+class TestIntdivWithRange
+{
+	/**
+	 * @param int          $int
+	 * @param int<min, -1> $negativeInt
+	 * @param int<1, max>  $positiveInt
+	 */
+	public function doFoo(int $int, int $negativeInt, int $positiveInt): void
+	{
+		try {
+			intdiv($int, $positiveInt);
+			intdiv($positiveInt, $negativeInt);
+			intdiv($negativeInt, $positiveInt);
+			intdiv($positiveInt, $positiveInt);
+		} catch (\ArithmeticError $e) {
+
+		}
+		try {
+			intdiv($int, $negativeInt);
+		} catch (\ArithmeticError $e) {
+
+		}
+		try {
+			intdiv($negativeInt, $negativeInt);
+		} catch (\ArithmeticError $e) {
+
+		}
+		try {
+			intdiv($positiveInt, $int);
+		} catch (\ArithmeticError $e) {
+
+		}
+		try {
+			intdiv($negativeInt, $int);
+		} catch (\ArithmeticError $e) {
+
+		}
+		try {
+			intdiv($int, '-1,5');
+		} catch (\ArithmeticError $e) {
+
+		}
+	}
+
+}