From 39e5e0c7f85a73a56edb492e420a479a0f1b88b9 Mon Sep 17 00:00:00 2001
From: Markus Staab <maggus.staab@googlemail.com>
Date: Sun, 6 Feb 2022 12:16:07 +0100
Subject: [PATCH] modulo 1 is always zero

---
 src/Analyser/MutatingScope.php                | 20 ++++++++++---
 tests/PHPStan/Analyser/data/div-by-zero.php   |  5 ++++
 .../PHPStan/Analyser/data/modulo-operator.php | 28 +++++++++++++++++++
 3 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index fa70cc917a..7acab4ce1f 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -1051,12 +1051,24 @@ private function resolveType(Expr $node): Type
 			} 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) {
 
-			$rightTypes = TypeUtils::getConstantScalars($this->getType($right)->toNumber());
-			foreach ($rightTypes as $rightType) {
 				if (
-					$rightType->getValue() === 0
-					|| $rightType->getValue() === 0.0
+					$scalarType->getValue() === 0
+					|| $scalarType->getValue() === 0.0
 				) {
 					return new ErrorType();
 				}
diff --git a/tests/PHPStan/Analyser/data/div-by-zero.php b/tests/PHPStan/Analyser/data/div-by-zero.php
index 0c38a50c10..2dae4d4767 100644
--- a/tests/PHPStan/Analyser/data/div-by-zero.php
+++ b/tests/PHPStan/Analyser/data/div-by-zero.php
@@ -17,7 +17,12 @@ public function doFoo(int $range1, int $range2, int $int): void
 		assertType('(float|int)', 5 / $range2);
 		assertType('(float|int)', $range1 / $range2);
 		assertType('(float|int)', 5 / $int);
+
 		assertType('*ERROR*', 5 / 0);
+		assertType('*ERROR*', 5 / '0');
+		assertType('*ERROR*', 5 / 0.0);
+		assertType('*ERROR*', 5 / false);
+		assertType('*ERROR*', 5 / null);
 	}
 
 }
diff --git a/tests/PHPStan/Analyser/data/modulo-operator.php b/tests/PHPStan/Analyser/data/modulo-operator.php
index 6e432eb259..a4876e59f1 100644
--- a/tests/PHPStan/Analyser/data/modulo-operator.php
+++ b/tests/PHPStan/Analyser/data/modulo-operator.php
@@ -45,4 +45,32 @@ function doBar(int $i, int $j, $p, $range, $zeroOrMore, $intConst, $unionRange,
 
 		assertType('int', $j % $i);
 	}
+
+	function moduleOne(int $i, float $f) {
+		assertType('0', true % '1');
+		assertType('0', false % '1');
+		assertType('0', null % '1');
+		assertType('0', -1 % '1');
+		assertType('0', 0 % '1');
+		assertType('0', 1 % '1');
+		assertType('0', '1' % '1');
+		assertType('0', 1.24 % '1');
+
+		assertType('0', $i % 1.0);
+		assertType('0', $f % 1.0);
+
+		assertType('0', $i % '1.0');
+		assertType('0', $f % '1.0');
+
+		assertType('0', $i % '1');
+		assertType('0', $f % '1');
+
+		assertType('0', $i % true);
+		assertType('0', $f % true);
+
+		$i %= '1';
+		$f %= '1';
+		assertType('0', $i);
+		assertType('0', $f);
+	}
 }