feature: treat class-string<callable> as callable-object

Signed-off-by: Maximilian Bösing <2189546+boesing@users.noreply.github.com>

src/Psalm/Internal/Type/TypeParser.php

@@ -718,6 +718,10 @@ class TypeParser
                     continue;
                 }
 
+                if ($type instanceof TCallable) {
+                    $type = new TCallableObject($from_docblock, $type);
+                }
+
                 if ($type instanceof TCallableObject) {
                     $types[] = new TUnknownClassString($type, false, $from_docblock);
                     continue;

tests/IntersectionTypeTest.php

@@ -92,6 +92,29 @@ final class IntersectionTypeTest extends TestCase
                 'assertions' => [],
                 'ignored_issues' => ['UnsafeInstantiation', 'MixedMethodCall'],
             ],
+            'classStringOfCallableWillBeTreatedAsCallableObject' => [
+                'code' => '<?php
+                    /**
+                     * @param class-string<callable():int> $className
+                     */
+                    function takesCallableObject(string $className): int {
+                        $object = new $className();
+                        return $object();
+                    }
+
+                    class Foo
+                    {
+                        public function __invoke(): int
+                        {
+                            return 0;
+                        }
+                    }
+
+                    takesCallableObject(Foo::class);
+                    ',
+                'assertions' => [],
+                'ignored_issues' => ['UnsafeInstantiation', 'MixedMethodCall'],
+            ],
         ];
     }