Support better mixin handling

vimeo · May 27, 2020 · 3c60609 · 3c60609
1 parent 203ed6d
commit 3c60609
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Showing 2 changed files with 69 additions and 1 deletion.
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/AtomicMethodCallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/AtomicMethodCallAnalyzer.php
@@ -344,6 +344,20 @@ public static function analyze(
                     $codebase
                 );
 
+                $lhs_type_expanded = \Psalm\Internal\Type\TypeExpander::expandUnion(
+                    $codebase,
+                    new Type\Union([$lhs_type_part]),
+                    $mixin_declaring_class_storage->name,
+                    $fq_class_name,
+                    $class_storage->parent_class
+                );
+
+                $new_lhs_type_part = array_values($lhs_type_expanded->getAtomicTypes())[0];
+
+                if ($new_lhs_type_part instanceof Type\Atomic\TNamedObject) {
+                    $lhs_type_part = $new_lhs_type_part;
+                }
+
                 $mixin_class_storage = $codebase->classlike_storage_provider->get($class_storage->mixin->value);
 
                 $fq_class_name = $mixin_class_storage->name;

diff --git a/tests/MixinAnnotationTest.php b/tests/MixinAnnotationTest.php
@@ -224,7 +224,7 @@ function toArray(B $b) : string {
                         return $b->foo;
                     }'
             ],
-            'inheritTemplatedMixin' => [
+            'inheritTemplatedMixinWithStatic' => [
                 '<?php
                     /**
                      * @template T
@@ -316,6 +316,60 @@ class A {}
                     (new A)->foo();',
                 'error_message' => 'UndefinedMethod'
             ],
+            'inheritTemplatedMixinWithSelf' => [
+                '<?php
+                    /**
+                     * @template T
+                     */
+                    class Mixin {
+                        /**
+                         * @psalm-var T
+                         */
+                        private $var;
+
+                        /**
+                         * @psalm-param T $var
+                         */
+                        public function __construct ($var) {
+                            $this->var = $var;
+                        }
+
+                        /**
+                         * @psalm-return T
+                         */
+                        public function type() {
+                            return $this->var;
+                        }
+                    }
+
+                    /**
+                     * @template T as object
+                     * @mixin Mixin<T>
+                     */
+                    abstract class Foo {
+                        /** @var Mixin<T> */
+                        public object $obj;
+
+                        public function __call(string $name, array $args) {
+                            return $this->obj->$name(...$args);
+                        }
+                    }
+
+                    /**
+                     * @extends Foo<self>
+                     */
+                    abstract class FooChild extends Foo{}
+
+                    /**
+                     * @psalm-suppress MissingConstructor
+                     */
+                    final class FooGrandChild extends FooChild {}
+
+                    function test() : FooGrandChild {
+                        return (new FooGrandChild)->type();
+                    }',
+                'error_message' => 'LessSpecificReturnStatement'
+            ],
         ];
     }
 }