diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 6356f5512b..5da3325cf8 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -5409,15 +5409,24 @@ private function integerRangeMath(Type $range, Expr $node, Type $operand): Type
 
 		if ($node instanceof Node\Expr\BinaryOp\Plus || $node instanceof Node\Expr\AssignOp\Plus) {
 			if ($operand instanceof ConstantIntegerType) {
+				/** @var int|float|null $min */
 				$min = $rangeMin !== null ? $rangeMin + $operand->getValue() : null;
+
+				/** @var int|float|null $max */
 				$max = $rangeMax !== null ? $rangeMax + $operand->getValue() : null;
 			} else {
+				/** @var int|float|null $min */
 				$min = $rangeMin !== null && $operand->getMin() !== null ? $rangeMin + $operand->getMin() : null;
+
+				/** @var int|float|null $max */
 				$max = $rangeMax !== null && $operand->getMax() !== null ? $rangeMax + $operand->getMax() : null;
 			}
 		} elseif ($node instanceof Node\Expr\BinaryOp\Minus || $node instanceof Node\Expr\AssignOp\Minus) {
 			if ($operand instanceof ConstantIntegerType) {
+				/** @var int|float|null $min */
 				$min = $rangeMin !== null ? $rangeMin - $operand->getValue() : null;
+
+				/** @var int|float|null $max */
 				$max = $rangeMax !== null ? $rangeMax - $operand->getValue() : null;
 			} else {
 				if ($rangeMin === $rangeMax && $rangeMin !== null
@@ -5429,8 +5438,10 @@ private function integerRangeMath(Type $range, Expr $node, Type $operand): Type
 						$min = null;
 					} elseif ($rangeMin !== null) {
 						if ($operand->getMax() !== null) {
+							/** @var int|float $min */
 							$min = $rangeMin - $operand->getMax();
 						} else {
+							/** @var int|float $min */
 							$min = $rangeMin - $operand->getMin();
 						}
 					} else {
@@ -5442,9 +5453,11 @@ private function integerRangeMath(Type $range, Expr $node, Type $operand): Type
 						$max = null;
 					} elseif ($rangeMax !== null) {
 						if ($rangeMin !== null && $operand->getMin() === null) {
+							/** @var int|float $min */
 							$min = $rangeMin - $operand->getMax();
 							$max = null;
 						} elseif ($operand->getMin() !== null) {
+							/** @var int|float $max */
 							$max = $rangeMax - $operand->getMin();
 						} else {
 							$max = null;
@@ -5460,10 +5473,16 @@ private function integerRangeMath(Type $range, Expr $node, Type $operand): Type
 			}
 		} elseif ($node instanceof Node\Expr\BinaryOp\Mul || $node instanceof Node\Expr\AssignOp\Mul) {
 			if ($operand instanceof ConstantIntegerType) {
+				/** @var int|float|null $min */
 				$min = $rangeMin !== null ? $rangeMin * $operand->getValue() : null;
+
+				/** @var int|float|null $max */
 				$max = $rangeMax !== null ? $rangeMax * $operand->getValue() : null;
 			} else {
+				/** @var int|float|null $min */
 				$min = $rangeMin !== null && $operand->getMin() !== null ? $rangeMin * $operand->getMin() : null;
+
+				/** @var int|float|null $max */
 				$max = $rangeMax !== null && $operand->getMax() !== null ? $rangeMax * $operand->getMax() : null;
 			}
 
@@ -5527,6 +5546,13 @@ private function integerRangeMath(Type $range, Expr $node, Type $operand): Type
 			}
 		}
 
+		if (is_float($min)) {
+			$min = null;
+		}
+		if (is_float($max)) {
+			$max = null;
+		}
+
 		return IntegerRangeType::fromInterval($min, $max);
 	}
 
diff --git a/tests/PHPStan/Analyser/AnalyserIntegrationTest.php b/tests/PHPStan/Analyser/AnalyserIntegrationTest.php
index ea2cc689e3..b54b16c461 100644
--- a/tests/PHPStan/Analyser/AnalyserIntegrationTest.php
+++ b/tests/PHPStan/Analyser/AnalyserIntegrationTest.php
@@ -500,6 +500,12 @@ public function testBug6300(): void
 		$this->assertSame(24, $errors[1]->getLine());
 	}
 
+	public function testBug6466(): void
+	{
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-6466.php');
+		$this->assertNoErrors($errors);
+	}
+
 	public function testBug6253(): void
 	{
 		$errors = $this->runAnalyse(
diff --git a/tests/PHPStan/Analyser/data/bug-6466.php b/tests/PHPStan/Analyser/data/bug-6466.php
new file mode 100644
index 0000000000..b529d7cbfc
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/bug-6466.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace Bug6466;
+
+class HelloWorld
+{
+	public function sayHello(\DateTimeImmutable $date): void
+	{
+		for ($i = 1; $i <= 1e18; $i *= 10) {
+		}
+	}
+}