From 25b01ce3a3e0602e5dd60432f480c4e829bf79a7 Mon Sep 17 00:00:00 2001
From: kkmuffme <11071985+kkmuffme@users.noreply.github.com>
Date: Mon, 17 Oct 2022 15:36:08 +0200
Subject: [PATCH] ensure callbacks have the required number of params

Fix https://github.com/vimeo/psalm/issues/8593
---
 .../Type/Comparator/UnionTypeComparator.php   | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/Psalm/Internal/Type/Comparator/UnionTypeComparator.php b/src/Psalm/Internal/Type/Comparator/UnionTypeComparator.php
index c997199d650..1906fc938f1 100644
--- a/src/Psalm/Internal/Type/Comparator/UnionTypeComparator.php
+++ b/src/Psalm/Internal/Type/Comparator/UnionTypeComparator.php
@@ -6,6 +6,7 @@
 use Psalm\Internal\Type\TypeExpander;
 use Psalm\Type\Atomic;
 use Psalm\Type\Atomic\TArrayKey;
+use Psalm\Type\Atomic\TCallable;
 use Psalm\Type\Atomic\TClassConstant;
 use Psalm\Type\Atomic\TFalse;
 use Psalm\Type\Atomic\TIntRange;
@@ -21,6 +22,10 @@
 use function array_pop;
 use function array_push;
 use function array_reverse;
+use function count;
+use function is_array;
+
+use const PHP_INT_MAX;
 
 /**
  * @internal
@@ -134,6 +139,39 @@ public static function isContainedBy(
                     continue;
                 }
 
+                // if params are specified
+                if ($container_type_part instanceof TCallable
+                    && is_array($container_type_part->params)
+                    && $input_type_part instanceof TCallable
+                ) {
+                    $container_required_param_count = 0;
+                    foreach ($container_type_part->params as $index => $container_param) {
+                        if ($container_param->is_optional === false) {
+                            $container_required_param_count = $index + 1;
+                        }
+                    }
+
+                    $input_required_param_count = 0;
+                    if (!is_array($input_type_part->params)) {
+                        // it's not declared, there can be an arbitrary number of params
+                        $input_all_param_count = PHP_INT_MAX;
+                    } else {
+                        $input_all_param_count = count($input_type_part->params);
+                        foreach ($input_type_part->params as $index => $input_param) {
+                            if ($input_param->is_optional === false) {
+                                $input_required_param_count = $index + 1;
+                            }
+                        }
+                    }
+
+                    // too few or too many non-optional params provided in callback
+                    if ($container_required_param_count > $input_all_param_count
+                        || count($container_type_part->params) < $input_required_param_count
+                    ) {
+                        return false;
+                    }
+                }
+
                 if ($union_comparison_result) {
                     $atomic_comparison_result = new TypeComparisonResult();
                 } else {