report invalid % operator usage

Author: schlndh

src/Reflection/InitializerExprTypeResolver.php

@@ -856,6 +856,10 @@ public function getModType(Expr $left, Expr $right, callable $getTypeCallback):
 			return $this->getNeverType($leftType, $rightType);
 		}
 
+		if ($leftType->toNumber() instanceof ErrorType || $rightType->toNumber() instanceof ErrorType) {
+			return new ErrorType();
+		}
+
 		$leftTypes = $leftType->getConstantScalarTypes();
 		$rightTypes = $rightType->getConstantScalarTypes();
 		$leftTypesCount = count($leftTypes);

tests/PHPStan/Rules/Operators/InvalidBinaryOperationRuleTest.php

@@ -251,6 +251,22 @@ public function testRule(): void
 				'Binary operation "+" between int and array{} results in an error.',
 				259,
 			],
+			[
+				'Binary operation "%" between array and 3 results in an error.',
+				267,
+			],
+			[
+				'Binary operation "%" between 3 and array results in an error.',
+				268,
+			],
+			[
+				'Binary operation "%" between object and 3 results in an error.',
+				270,
+			],
+			[
+				'Binary operation "%" between 3 and object results in an error.',
+				271,
+			],
 		]);
 	}
 
@@ -313,7 +329,10 @@ public function testBinaryMixed(): void
 				'Binary operation "/" between T and 2 results in an error.',
 				17,
 			],
-			// % is not handled yet
+			[
+				'Binary operation "%" between T and 2 results in an error.',
+				18,
+			],
 			[
 				'Binary operation "+" between T and 2 results in an error.',
 				19,
@@ -358,7 +377,10 @@ public function testBinaryMixed(): void
 				'Binary operation "/=" between 5 and T results in an error.',
 				38,
 			],
-			// %= is not handled yet
+			[
+				'Binary operation "%=" between 5 and T results in an error.',
+				41,
+			],
 			[
 				'Binary operation "&=" between 5 and T results in an error.',
 				44,
@@ -399,6 +421,10 @@ public function testBinaryMixed(): void
 				'Binary operation "/" between mixed and 2 results in an error.',
 				67,
 			],
+			[
+				'Binary operation "%" between mixed and 2 results in an error.',
+				68,
+			],
 			[
 				'Binary operation "+" between mixed and 2 results in an error.',
 				69,
@@ -443,6 +469,10 @@ public function testBinaryMixed(): void
 				'Binary operation "/=" between 5 and mixed results in an error.',
 				88,
 			],
+			[
+				'Binary operation "%=" between 5 and mixed results in an error.',
+				91,
+			],
 			[
 				'Binary operation "&=" between 5 and mixed results in an error.',
 				94,
@@ -483,6 +513,10 @@ public function testBinaryMixed(): void
 				'Binary operation "/" between mixed and 2 results in an error.',
 				117,
 			],
+			[
+				'Binary operation "%" between mixed and 2 results in an error.',
+				118,
+			],
 			[
 				'Binary operation "+" between mixed and 2 results in an error.',
 				119,
@@ -527,6 +561,10 @@ public function testBinaryMixed(): void
 				'Binary operation "/=" between 5 and mixed results in an error.',
 				138,
 			],
+			[
+				'Binary operation "%=" between 5 and mixed results in an error.',
+				141,
+			],
 			[
 				'Binary operation "&=" between 5 and mixed results in an error.',
 				144,

tests/PHPStan/Rules/Operators/data/invalid-binary.php

@@ -258,3 +258,15 @@ function benevolentPlus(array $a, int $i): void {
 function (int $int) {
 	$int + [];
 };
+
+function testMod(array $a, object $o): void {
+	echo 4 % 3;
+	echo '4' % 3;
+	echo 4 % '3';
+
+	echo $a % 3;
+	echo 3 % $a;
+
+	echo $o % 3;
+	echo 3 % $o;
+}