Improve handling of default extended params

src/Psalm/Internal/Analyzer/TypeAnalyzer.php

@@ -145,6 +145,7 @@ public static function isContainedBy(
 
                 if ($input_type_part instanceof TMixed
                     && $input_type->from_template_default
+                    && $input_type->from_docblock
                     && $atomic_comparison_result
                     && $atomic_comparison_result->type_coerced_from_mixed
                 ) {
@@ -250,7 +251,9 @@ public static function isContainedBy(
                 if ($all_type_coerced_from_mixed) {
                     $union_comparison_result->type_coerced_from_mixed = true;
 
-                    if ($input_type->from_template_default || $all_type_coerced_from_as_mixed) {
+                    if (($input_type->from_template_default && $input_type->from_docblock)
+                        || $all_type_coerced_from_as_mixed
+                    ) {
                         $union_comparison_result->type_coerced_from_as_mixed = true;
                     }
                 }
@@ -265,7 +268,9 @@ public static function isContainedBy(
                     if ($some_type_coerced_from_mixed) {
                         $union_comparison_result->type_coerced_from_mixed = true;
 
-                        if ($input_type->from_template_default || $all_type_coerced_from_as_mixed) {
+                        if (($input_type->from_template_default && $input_type->from_docblock)
+                            || $all_type_coerced_from_as_mixed
+                        ) {
                             $union_comparison_result->type_coerced_from_as_mixed = true;
                         }
                     }

src/Psalm/Internal/Codebase/Populator.php

@@ -403,8 +403,10 @@ private function populateDataFromTraits(
 
                     foreach ($trait_storage->template_types as $template_name => $template_type_map) {
                         foreach ($template_type_map as $template_type) {
+                            $default_param = clone $template_type[0];
+                            $default_param->from_docblock = false;
                             $storage->template_type_extends[$trait_storage->name][$template_name]
-                                = $template_type[0];
+                                = $default_param;
                         }
                     }
                 }
@@ -517,8 +519,10 @@ private function populateDataFromParentClass(
 
                     foreach ($parent_storage->template_types as $template_name => $template_type_map) {
                         foreach ($template_type_map as $template_type) {
+                            $default_param = clone $template_type[0];
+                            $default_param->from_docblock = false;
                             $storage->template_type_extends[$parent_storage->name][$template_name]
-                                = $template_type[0];
+                                = $default_param;
                         }
                     }
 
@@ -655,8 +659,10 @@ private function populateInterfaceDataFromParentInterfaces(
 
                     foreach ($parent_interface_storage->template_types as $template_name => $template_type_map) {
                         foreach ($template_type_map as $template_type) {
+                            $default_param = clone $template_type[0];
+                            $default_param->from_docblock = false;
                             $storage->template_type_extends[$parent_interface_storage->name][$template_name]
-                                = $template_type[0];
+                                = $default_param;
                         }
                     }
                 }
@@ -747,8 +753,10 @@ private function populateDataFromImplementedInterfaces(
 
                     foreach ($implemented_interface_storage->template_types as $template_name => $template_type_map) {
                         foreach ($template_type_map as $template_type) {
+                            $default_param = clone $template_type[0];
+                            $default_param->from_docblock = false;
                             $storage->template_type_extends[$implemented_interface_storage->name][$template_name]
-                                = $template_type[0];
+                                = $default_param;
                         }
                     }
                 }

tests/Template/ClassTemplateCovarianceTest.php

@@ -321,6 +321,64 @@ public function set($value): void {}
                     class CovariantFoo extends InvariantFoo {}',
                 'error_message' => 'InvalidTemplateParam',
             ],
+            'expectsTemplatedObject' => [
+                '<?php
+                    /**
+                     * @template T
+                     * @template-implements ArrayAccess<int,T>
+                     */
+                    class MyArray implements ArrayAccess, IteratorAggregate {
+                        /** @var array<int,T> */
+                        private $values = [];
+                        public function __construct() {
+                            $this->values = [];
+                        }
+
+                        /**
+                         * @param int $offset
+                         * @param T $value
+                         */
+                        public function offsetSet($offset, $value) {
+                            $this->values[$offset] = $value;
+                        }
+                        /**
+                         * @param int $offset
+                         * @return T
+                         */
+                        public function offsetGet($offset) {
+                            return $this->values[$offset];
+                        }
+                        /**
+                         * @param int $offset
+                         * @return bool
+                         */
+                        public function offsetExists($offset) {
+                            return isset($this->values[$offset]);
+                        }
+                        /**
+                         * @param int $offset
+                         */
+                        public function offsetUnset($offset) {
+                            unset($this->values[$offset]);
+                        }
+
+                        public function getIterator() : Traversable {
+                            return new ArrayObject($this->values);
+                        }
+                    }
+
+                    class A {}
+                    class AChild extends A {}
+
+                    /** @param IteratorAggregate<int, A> $i */
+                    function expectsIteratorAggregateOfA(IteratorAggregate $i) : void {}
+
+                    /** @param MyArray<AChild> $m */
+                    function takesMyArrayOfAChild(MyArray $m) : void {
+                        expectsIteratorAggregateOfA($m);
+                    }',
+                'error_message' => 'MixedArgumentTypeCoercion',
+            ],
         ];
     }
 }