Add Mixin attribute

README.md

@@ -103,6 +103,7 @@ These are the available attributes and their corresponding PHPDoc annotations:
 | [Internal](https://github.com/php-static-analysis/attributes/blob/main/doc/Internal.md)                           | `@internal`               |
 | [IsReadOnly](https://github.com/php-static-analysis/attributes/blob/main/doc/IsReadOnly.md)       | `@readonly`        |
 | [Method](https://github.com/php-static-analysis/attributes/blob/main/doc/Method.md)                               | `@method`                 |
+| [Mixin](https://github.com/php-static-analysis/attributes/blob/main/doc/Mixin.md)                                 | `@mixin`                  |
 | [Param](https://github.com/php-static-analysis/attributes/blob/main/doc/Param.md)                 | `@param`           |
 | [Property](https://github.com/php-static-analysis/attributes/blob/main/doc/Property.md)           | `@property` `@var` |
 | [PropertyRead](https://github.com/php-static-analysis/attributes/blob/main/doc/PropertyRead.md)   | `@property-read`   |

composer.json

@@ -26,8 +26,8 @@
     "require": {
         "php": ">=8.0",
         "ext-simplexml": "*",
-        "php-static-analysis/attributes": "^0.1.9 || dev-main",
-        "php-static-analysis/node-visitor": "^0.1.9 || dev-main",
+        "php-static-analysis/attributes": "^0.1.10 || dev-main",
+        "php-static-analysis/node-visitor": "^0.1.10 || dev-main",
         "vimeo/psalm": "^5"
     },
     "require-dev": {

tests/MixinAttributeTest.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace test\PhpStaticAnalysis\PsalmPlugin;
+
+class MixinAttributeTest extends BaseAttributeTestCase
+{
+    public function testClassMixinAttribute(): void
+    {
+        $errors = $this->analyzeTestFile( '/data/Mixin/ClassMixinAttribute.php');
+        $this->assertCount(0, $errors);
+    }
+
+    public function testInterfaceMixinAttribute(): void
+    {
+        $errors = $this->analyzeTestFile( '/data/Mixin/InterfaceMixinAttribute.php');
+        $this->assertCount(0, $errors);
+    }
+
+    public function testTraitMixinAttribute(): void
+    {
+        $errors = $this->analyzeTestFile( '/data/Mixin/TraitMixinAttribute.php');
+        $this->assertCount(0, $errors);
+    }
+
+    public function testInvalidClassMixinAttribute(): void
+    {
+        $errors = $this->analyzeTestFile( '/data/Mixin/InvalidClassMixinAttribute.php');
+
+        $expectedErrors = [
+            '@mixin annotation used without specifying class in docblock for test\PhpStaticAnalysis\PsalmPlugin\data\Mixin\InvalidClassMixinAttribute' => 9,
+            'Argument 1 of PhpStaticAnalysis\Attributes\Mixin::__construct expects string, but 0 provided' => 7,
+            'Attribute Mixin cannot be used on a method' => 11,
+        ];
+
+        $this->checkExpectedErrors($errors, $expectedErrors);
+    }
+}

tests/data/Mixin/ClassMixinAttribute.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace test\PhpStaticAnalysis\PsalmPlugin\data\Mixin;
+
+use PhpStaticAnalysis\Attributes\Mixin;
+
+class ClassMixinAttribute
+{
+    public function proxied(): void
+    {
+    }
+}
+
+class MyClass
+{
+}
+
+class Another
+{
+}
+
+#[Mixin('ClassMixinAttribute')] // this is the proxied class
+#[Mixin(
+    'MyClass',
+    'Another',
+)]
+class ClassMixinAttributeProxy
+{
+    public function __call(string $name, mixed ...$arguments): void
+    {
+        (new ClassMixinAttribute())->$name(...$arguments);
+    }
+}
+
+$proxy = new ClassMixinAttributeProxy();
+$proxy->proxied();

tests/data/Mixin/InterfaceMixinAttribute.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace test\PhpStaticAnalysis\PsalmPlugin\data\Mixin;
+
+use PhpStaticAnalysis\Attributes\Mixin;
+
+#[Mixin('AClass')]
+interface InterfaceMixinAttribute
+{
+}
+
+class AClass
+{
+}

tests/data/Mixin/InvalidClassMixinAttribute.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace test\PhpStaticAnalysis\PsalmPlugin\data\Mixin;
+
+use PhpStaticAnalysis\Attributes\Mixin;
+
+#[Mixin(0)]
+#[Mixin('count($a)')]
+class InvalidClassMixinAttribute
+{
+    #[Mixin('A')]
+    public function getName(): string
+    {
+        return "John";
+    }
+}

tests/data/Mixin/TraitMixinAttribute.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace test\PhpStaticAnalysis\PsalmPlugin\data\Mixin;
+
+use PhpStaticAnalysis\Attributes\Mixin;
+
+class Other
+{
+}
+
+#[Mixin('Other')]
+trait TraitMixinAttribute
+{
+}