Fix #13023: function.alreadyNarrowedType and function.impossibleType after updates to 2.1.15

src/Rules/Comparison/ImpossibleCheckTypeHelper.php

@@ -299,6 +299,7 @@ public function findSpecifiedType(
 				}
 			}
 		}
+		$isInTrait = $scope->isInTrait();
 		foreach ($sureTypes as $sureType) {
 			if (self::isSpecified($typeSpecifierScope, $node, $sureType[0])) {
 				$results[] = TrinaryLogic::createMaybe();
@@ -322,6 +323,11 @@ public function findSpecifiedType(
 				$argumentType = $scope->getType($assignedInCallVar->expr);
 			}
 
+			if ($isInTrait && self::isThis($sureType[0]) && $resultType->getObjectClassNames() !== []) {
+				$results[] = TrinaryLogic::createMaybe();
+				continue;
+			}
+
 			$results[] = $resultType->isSuperTypeOf($argumentType)->result;
 		}
 
@@ -340,6 +346,11 @@ public function findSpecifiedType(
 			/** @var Type $resultType */
 			$resultType = $sureNotType[1];
 
+			if ($isInTrait && self::isThis($sureNotType[0]) && $resultType->getObjectClassNames() !== []) {
+				$results[] = TrinaryLogic::createMaybe();
+				continue;
+			}
+
 			$results[] = $resultType->isSuperTypeOf($argumentType)->negate()->result;
 		}
 
@@ -376,6 +387,11 @@ private static function isSpecified(Scope $scope, Expr $node, Expr $expr): bool
 		) && $scope->hasExpressionType($expr)->yes();
 	}
 
+	private static function isThis(Expr $expr): bool
+	{
+		return $expr instanceof Expr\Variable && $expr->name === 'this';
+	}
+
 	/**
 	 * @param Node\Arg[] $args
 	 */

tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php

@@ -1179,4 +1179,10 @@ public function testBug14177(): void
 		$this->analyse([__DIR__ . '/data/bug-14177.php'], []);
 	}
 
+	public function testBug13023(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-13023.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/bug-13023.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Bug13023;
+
+class SomeClass
+{
+	use MyTrait;
+}
+
+class SomeClass2
+{
+	use MyTrait;
+}
+
+trait MyTrait
+{
+	public function getRandom(): int
+	{
+		$value = random_int(1, 100);
+		if (is_a($this, SomeClass::class)) {
+			return $value * $value;
+		}
+		return $value;
+	}
+}