Fix #3321 - allow interface methods to be mapped

src/Psalm/Internal/Provider/ReturnTypeProvider/ArrayMapReturnTypeProvider.php

@@ -313,7 +313,7 @@ class ArrayMapReturnTypeProvider implements \Psalm\Plugin\Hook\FunctionReturnTyp
                             continue;
                         }
 
-                        if (!$codebase->classlikes->classExists($callable_fq_class_name)) {
+                        if (!$codebase->classlikes->classOrInterfaceExists($callable_fq_class_name)) {
                             continue;
                         }
 

tests/ArrayFunctionCallTest.php

@@ -1348,6 +1348,20 @@ class ArrayFunctionCallTest extends TestCase
                 $a = [42, "A" => 42];
                 echo array_change_key_case($a, CASE_LOWER)[0];'
             ],
+            'mapInterfaceMethod' => [
+                '<?php
+                    interface MapperInterface {
+                        public function map(string $s): int;
+                    }
+
+                    /**
+                     * @param list<string> $strings
+                     * @return list<int>
+                     */
+                    function mapList(MapperInterface $m, array $strings): array {
+                        return array_map([$m, "map"], $strings);
+                    }'
+            ],
         ];
     }