UselessCastRule - respect treatPhpDocTypesAsCertain

Author: ondrejmirtes

composer.json

@@ -7,7 +7,7 @@
 	],
 	"require": {
 		"php": "~7.1",
-		"phpstan/phpstan": "^0.12"
+		"phpstan/phpstan": "^0.12.6"
 	},
 	"require-dev": {
 		"consistence/coding-standard": "^3.0.1",

rules.neon

@@ -17,7 +17,6 @@ rules:
 	- PHPStan\Rules\BooleansInConditions\BooleanInElseIfConditionRule
 	- PHPStan\Rules\BooleansInConditions\BooleanInIfConditionRule
 	- PHPStan\Rules\BooleansInConditions\BooleanInTernaryOperatorRule
-	- PHPStan\Rules\Cast\UselessCastRule
 	- PHPStan\Rules\Classes\RequireParentConstructCallRule
 	- PHPStan\Rules\DisallowedConstructs\DisallowedEmptyRule
 	- PHPStan\Rules\DisallowedConstructs\DisallowedImplicitArrayCreationRule
@@ -45,6 +44,14 @@ rules:
 services:
 	-
 		class: PHPStan\Rules\BooleansInConditions\BooleanRuleHelper
+
+	-
+		class: PHPStan\Rules\Cast\UselessCastRule
+		arguments:
+			treatPhpDocTypesAsCertain: %treatPhpDocTypesAsCertain%
+		tags:
+			- phpstan.rules.rule
+
 	-
 		class: PHPStan\Rules\Operators\OperatorRuleHelper
 	-

src/Rules/Cast/UselessCastRule.php

@@ -5,13 +5,23 @@
 use PhpParser\Node;
 use PhpParser\Node\Expr\Cast;
 use PHPStan\Analyser\Scope;
+use PHPStan\Rules\RuleError;
+use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\TypeUtils;
 use PHPStan\Type\VerbosityLevel;
 
 class UselessCastRule implements \PHPStan\Rules\Rule
 {
 
+	/** @var bool */
+	private $treatPhpDocTypesAsCertain;
+
+	public function __construct(bool $treatPhpDocTypesAsCertain)
+	{
+		$this->treatPhpDocTypesAsCertain = $treatPhpDocTypesAsCertain;
+	}
+
 	public function getNodeType(): string
 	{
 		return Cast::class;
@@ -20,7 +30,7 @@ public function getNodeType(): string
 	/**
 	 * @param \PhpParser\Node\Expr\Cast $node
 	 * @param \PHPStan\Analyser\Scope $scope
-	 * @return string[] errors
+	 * @return RuleError[] errors
 	 */
 	public function processNode(Node $node, Scope $scope): array
 	{
@@ -30,14 +40,30 @@ public function processNode(Node $node, Scope $scope): array
 		}
 		$castType = TypeUtils::generalizeType($castType);
 
-		$expressionType = $scope->getType($node->expr);
+		if ($this->treatPhpDocTypesAsCertain) {
+			$expressionType = $scope->getType($node->expr);
+		} else {
+			$expressionType = $scope->getNativeType($node->expr);
+		}
 		if ($castType->isSuperTypeOf($expressionType)->yes()) {
+			$addTip = function (RuleErrorBuilder $ruleErrorBuilder) use ($scope, $node, $castType): RuleErrorBuilder {
+				if (!$this->treatPhpDocTypesAsCertain) {
+					return $ruleErrorBuilder;
+				}
+
+				$expressionTypeWithoutPhpDoc = $scope->getNativeType($node->expr);
+				if ($castType->isSuperTypeOf($expressionTypeWithoutPhpDoc)->yes()) {
+					return $ruleErrorBuilder;
+				}
+
+				return $ruleErrorBuilder->tip('Because the type is coming from a PHPDoc, you can turn off this check by setting <fg=cyan>treatPhpDocTypesAsCertain: false</> in your <fg=cyan>%configurationFile%</>.');
+			};
 			return [
-				sprintf(
+				$addTip(RuleErrorBuilder::message(sprintf(
 					'Casting to %s something that\'s already %s.',
 					$castType->describe(VerbosityLevel::typeOnly()),
 					$expressionType->describe(VerbosityLevel::typeOnly())
-				),
+				)))->build(),
 			];
 		}
 

tests/Rules/Cast/UselessCastRuleTest.php

@@ -5,14 +5,23 @@
 class UselessCastRuleTest extends \PHPStan\Testing\RuleTestCase
 {
 
+	/** @var bool */
+	private $treatPhpDocTypesAsCertain;
+
 	protected function getRule(): \PHPStan\Rules\Rule
 	{
-		return new UselessCastRule();
+		return new UselessCastRule($this->treatPhpDocTypesAsCertain);
+	}
+
+	protected function shouldTreatPhpDocTypesAsCertain(): bool
+	{
+		return $this->treatPhpDocTypesAsCertain;
 	}
 
 	public function testUselessCast(): void
 	{
 		require_once __DIR__ . '/data/useless-cast.php';
+		$this->treatPhpDocTypesAsCertain = true;
 		$this->analyse(
 			[__DIR__ . '/data/useless-cast.php'],
 			[
@@ -40,4 +49,31 @@ public function testUselessCast(): void
 		);
 	}
 
+	public function testDoNotReportPhpDoc(): void
+	{
+		$this->treatPhpDocTypesAsCertain = false;
+		$this->analyse([__DIR__ . '/data/useless-cast-not-phpdoc.php'], [
+			[
+				'Casting to int something that\'s already int.',
+				16,
+			],
+		]);
+	}
+
+	public function testReportPhpDoc(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/useless-cast-not-phpdoc.php'], [
+			[
+				'Casting to int something that\'s already int.',
+				16,
+			],
+			[
+				'Casting to int something that\'s already int.',
+				17,
+				'Because the type is coming from a PHPDoc, you can turn off this check by setting <fg=cyan>treatPhpDocTypesAsCertain: false</> in your <fg=cyan>%configurationFile%</>.',
+			],
+		]);
+	}
+
 }

tests/Rules/Cast/data/useless-cast-not-phpdoc.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace UselessCastNotPhpDoc;
+
+class Foo
+{
+
+	/**
+	 * @param int $phpDocInteger
+	 */
+	public function doFoo(
+		int $realInteger,
+		$phpDocInteger
+	): void
+	{
+		$foo = (int) $realInteger;
+		$bar = (int) $phpDocInteger;
+	}
+
+}