Too wide return type - report for conditional return types

Author: ondrejmirtes

src/Rules/TooWideTypehints/TooWideFunctionReturnTypehintRule.php

@@ -9,6 +9,7 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\TypeUtils;
 use PHPStan\Type\UnionType;
 use PHPStan\Type\VerbosityLevel;
 use function count;
@@ -30,6 +31,7 @@ public function processNode(Node $node, Scope $scope): array
 		$function = $node->getFunctionReflection();
 
 		$functionReturnType = ParametersAcceptorSelector::selectSingle($function->getVariants())->getReturnType();
+		$functionReturnType = TypeUtils::resolveLateResolvableTypes($functionReturnType);
 		if (!$functionReturnType instanceof UnionType) {
 			return [];
 		}

src/Rules/TooWideTypehints/TooWideMethodReturnTypehintRule.php

@@ -10,6 +10,7 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\TypeUtils;
 use PHPStan\Type\UnionType;
 use PHPStan\Type\VerbosityLevel;
 use function count;
@@ -56,6 +57,7 @@ public function processNode(Node $node, Scope $scope): array
 		}
 
 		$methodReturnType = ParametersAcceptorSelector::selectSingle($method->getVariants())->getReturnType();
+		$methodReturnType = TypeUtils::resolveLateResolvableTypes($methodReturnType);
 		if (!$methodReturnType instanceof UnionType) {
 			return [];
 		}

tests/PHPStan/Rules/TooWideTypehints/TooWideFunctionReturnTypehintRuleTest.php

@@ -44,6 +44,10 @@ public function testRule(): void
 				'Function TooWideFunctionReturnType\dolor6() never returns null so it can be removed from the return type.',
 				79,
 			],
+			[
+				'Function TooWideFunctionReturnType\conditionalType() never returns string so it can be removed from the return type.',
+				90,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/TooWideTypehints/TooWideMethodReturnTypehintRuleTest.php

@@ -48,6 +48,10 @@ public function testPrivate(): void
 				'Method TooWideMethodReturnType\Foo::dolor6() never returns null so it can be removed from the return type.',
 				86,
 			],
+			[
+				'Method TooWideMethodReturnType\ConditionalTypeClass::conditionalType() never returns string so it can be removed from the return type.',
+				119,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/TooWideTypehints/data/tooWideFunctionReturnType.php

@@ -83,3 +83,11 @@ function dolor6() {
 
 	return 'bar';
 }
+
+/**
+ * @return ($flag is 1 ? string : int)
+ */
+function conditionalType(int $flag)
+{
+	return $flag;
+}

tests/PHPStan/Rules/TooWideTypehints/data/tooWideMethodReturnType-private.php

@@ -109,3 +109,17 @@ class UsesFooTrait
 	use FooTrait;
 
 }
+
+class ConditionalTypeClass
+{
+
+	/**
+	 * @return ($flag is 1 ? int : string)
+	 */
+	private function conditionalType(int $flag)
+	{
+		return $flag;
+	}
+
+
+}