From bfd7b652df171ffe6868d8b11c3cf4aa1db00e74 Mon Sep 17 00:00:00 2001
From: Christopher Wosinski <christopher.wosinski@probelix.de>
Date: Tue, 12 Nov 2019 10:37:15 +0100
Subject: [PATCH] Fixes #1482: method_exists() with string

---
 .../MethodExistsTypeSpecifyingExtension.php   |  9 +++++
 ...mpossibleCheckTypeFunctionCallRuleTest.php | 34 +++++++------------
 .../data/check-type-function-call.php         |  3 ++
 3 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/src/Type/Php/MethodExistsTypeSpecifyingExtension.php b/src/Type/Php/MethodExistsTypeSpecifyingExtension.php
index e25e7d915e..53ba46461a 100644
--- a/src/Type/Php/MethodExistsTypeSpecifyingExtension.php
+++ b/src/Type/Php/MethodExistsTypeSpecifyingExtension.php
@@ -13,7 +13,9 @@
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\FunctionTypeSpecifyingExtension;
 use PHPStan\Type\IntersectionType;
+use PHPStan\Type\ObjectType;
 use PHPStan\Type\ObjectWithoutClassType;
+use PHPStan\Type\StringType;
 
 class MethodExistsTypeSpecifyingExtension implements FunctionTypeSpecifyingExtension, TypeSpecifierAwareExtension
 {
@@ -44,6 +46,13 @@ public function specifyTypes(
 		TypeSpecifierContext $context
 	): SpecifiedTypes
 	{
+		$objectType = $scope->getType($node->args[0]->value);
+		if (!$objectType instanceof ObjectType) {
+			if ((new StringType())->isSuperTypeOf($objectType)->yes()) {
+				return new SpecifiedTypes([], []);
+			}
+		}
+
 		$methodNameType = $scope->getType($node->args[1]->value);
 		if (!$methodNameType instanceof ConstantStringType) {
 			return new SpecifiedTypes([], []);
diff --git a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php
index 6935415a93..12ab5d3e61 100644
--- a/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php
+++ b/tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php
@@ -137,10 +137,6 @@ public function testImpossibleCheckTypeFunctionCall(): void
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'testWithStringFirst…\' will always evaluate to true.',
 					585,
 				],
-				[
-					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'undefinedMethod\' will always evaluate to false.',
-					588,
-				],
 				[
 					'Call to function method_exists() with \'UndefinedClass\' and string will always evaluate to false.',
 					594,
@@ -151,43 +147,43 @@ public function testImpossibleCheckTypeFunctionCall(): void
 				],
 				[
 					'Call to function method_exists() with CheckTypeFunctionCall\MethodExists and \'testWithNewObjectIn…\' will always evaluate to true.',
-					606,
+					609,
 				],
 				[
 					'Call to function method_exists() with $this(CheckTypeFunctionCall\MethodExistsWithTrait) and \'method\' will always evaluate to true.',
-					621,
+					624,
 				],
 				[
 					'Call to function method_exists() with $this(CheckTypeFunctionCall\MethodExistsWithTrait) and \'someAnother\' will always evaluate to true.',
-					624,
+					627,
 				],
 				[
 					'Call to function method_exists() with $this(CheckTypeFunctionCall\MethodExistsWithTrait) and \'unknown\' will always evaluate to false.',
-					627,
+					630,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'method\' will always evaluate to true.',
-					630,
+					633,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'someAnother\' will always evaluate to true.',
-					633,
+					636,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'unknown\' will always evaluate to false.',
-					636,
+					639,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'method\' will always evaluate to true.',
-					639,
+					642,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'someAnother\' will always evaluate to true.',
-					642,
+					645,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'unknown\' will always evaluate to false.',
-					645,
+					648,
 				],
 			]
 		);
@@ -259,10 +255,6 @@ public function testImpossibleCheckTypeFunctionCallWithoutAlwaysTrue(): void
 					'Call to function is_callable() with mixed will always evaluate to false.',
 					571,
 				],
-				[
-					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'undefinedMethod\' will always evaluate to false.',
-					588,
-				],
 				[
 					'Call to function method_exists() with \'UndefinedClass\' and string will always evaluate to false.',
 					594,
@@ -273,15 +265,15 @@ public function testImpossibleCheckTypeFunctionCallWithoutAlwaysTrue(): void
 				],
 				[
 					'Call to function method_exists() with $this(CheckTypeFunctionCall\MethodExistsWithTrait) and \'unknown\' will always evaluate to false.',
-					627,
+					630,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'unknown\' will always evaluate to false.',
-					636,
+					639,
 				],
 				[
 					'Call to function method_exists() with \'CheckTypeFunctionCa…\' and \'unknown\' will always evaluate to false.',
-					645,
+					648,
 				],
 			]
 		);
diff --git a/tests/PHPStan/Rules/Comparison/data/check-type-function-call.php b/tests/PHPStan/Rules/Comparison/data/check-type-function-call.php
index 7ca65409fe..6ea1bb6676 100644
--- a/tests/PHPStan/Rules/Comparison/data/check-type-function-call.php
+++ b/tests/PHPStan/Rules/Comparison/data/check-type-function-call.php
@@ -596,6 +596,9 @@ public function testWithStringFirstArgument(): void
 
 		if (method_exists('UndefinedClass', 'test')) {
 		}
+
+		if (method_exists($string, 'test')) {
+		}
 	}
 
 	public function testWithNewObjectInFirstArgument(): void