Fix supertype checks between int range and constant int union

src/Type/UnionType.php

@@ -137,6 +137,13 @@ public function isSuperTypeOf(Type $otherType): TrinaryLogic
 			return $otherType->isSubTypeOf($this);
 		}
 
+		if ($otherType instanceof IntegerRangeType) {
+			$remainingType = TypeCombinator::remove($otherType, $this);
+			if ($remainingType instanceof NeverType) {
+				return TrinaryLogic::createYes();
+			}
+		}
+
 		$result = TrinaryLogic::createNo()->lazyOr($this->getTypes(), static fn (Type $innerType) => $innerType->isSuperTypeOf($otherType));
 		if ($result->yes()) {
 			return $result;

tests/PHPStan/Rules/Properties/TypesAssignedToPropertiesRuleTest.php

@@ -445,4 +445,10 @@ public function testBug4680(): void
 		$this->analyse([__DIR__ . '/data/bug-4680.php'], []);
 	}
 
+	public function testBug3383(): void
+	{
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-3383.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Properties/data/bug-3383.php

@@ -0,0 +1,13 @@
+<?php declare(strict_types = 1);
+
+namespace Bug3383;
+
+class HelloWorld
+{
+	/** @var 0|1|2|3 */
+	public int $classification = 0;
+
+	public function test(): void {
+		$this->classification = random_int(0, 3);
+	}
+}