Check conditional types in @param-out

src/Rules/PhpDoc/ConditionalReturnTypeRuleHelper.php

@@ -2,7 +2,7 @@
 
 namespace PHPStan\Rules\PhpDoc;
 
-use PHPStan\Reflection\ParametersAcceptor;
+use PHPStan\Reflection\ParametersAcceptorWithPhpDocs;
 use PHPStan\Rules\RuleError;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\ConditionalType;
@@ -23,7 +23,7 @@ class ConditionalReturnTypeRuleHelper
 	/**
 	 * @return RuleError[]
 	 */
-	public function check(ParametersAcceptor $acceptor): array
+	public function check(ParametersAcceptorWithPhpDocs $acceptor): array
 	{
 		$conditionalTypes = [];
 		$parametersByName = [];
@@ -36,6 +36,16 @@ public function check(ParametersAcceptor $acceptor): array
 				return $traverse($type);
 			});
 
+			if ($parameter->getOutType() !== null) {
+				TypeTraverser::map($parameter->getOutType(), static function (Type $type, callable $traverse) use (&$conditionalTypes): Type {
+					if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
+						$conditionalTypes[] = $type;
+					}
+
+					return $traverse($type);
+				});
+			}
+
 			$parametersByName[$parameter->getName()] = $parameter;
 		}
 

tests/PHPStan/Rules/PhpDoc/MethodConditionalReturnTypeRuleTest.php

@@ -63,6 +63,10 @@ public function testRule(): void
 				'Condition "array{foo: string} is array{foo: int}" in conditional return type is always false.',
 				156,
 			],
+			[
+				'Condition "int is int" in conditional return type is always true.',
+				185,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/PhpDoc/data/method-conditional-return-type.php

@@ -175,3 +175,15 @@ public function foo(): bool
 	}
 
 }
+
+class ParamOut
+{
+
+	/**
+	 * @param-out ($i is int ? 1 : 2) $out
+	 */
+	public function doFoo(int $i, &$out) {
+
+	}
+
+}