diff --git a/compiler/pipes/final-check.cpp b/compiler/pipes/final-check.cpp
index 91937fa3f1..5461bf12e8 100644
--- a/compiler/pipes/final-check.cpp
+++ b/compiler/pipes/final-check.cpp
@@ -1,23 +1,21 @@
 // Compiler for PHP (aka KPHP)
-// Copyright (c) 2020 LLC «V Kontakte»
+// Copyright (c) 2025 LLC «V Kontakte»
 // Distributed under the GPL v3 License, see LICENSE.notice.txt
 
 #include "compiler/pipes/final-check.h"
 
-
-#include "common/termformat/termformat.h"
-#include "common/algorithms/string-algorithms.h"
 #include "common/algorithms/contains.h"
-
+#include "common/algorithms/find.h"
+#include "common/algorithms/string-algorithms.h"
+#include "common/termformat/termformat.h"
 #include "compiler/compiler-core.h"
 #include "compiler/data/kphp-json-tags.h"
 #include "compiler/data/kphp-tracing-tags.h"
-#include "compiler/data/src-file.h"
 #include "compiler/data/var-data.h"
 #include "compiler/inferring/primitive-type.h"
-#include "compiler/vertex-util.h"
+#include "compiler/kphp_assert.h"
 #include "compiler/type-hint.h"
-#include "compiler/phpdoc.h"
+#include "compiler/vertex-util.h"
 
 namespace {
 void check_class_immutableness(ClassPtr klass) {
@@ -899,6 +897,17 @@ void FinalCheckPass::check_op_func_call(VertexAdaptor<op_func_call> call) {
       kphp_error(vk::none_of_equal(elem_type->ptype(), tp_Class, tp_tuple, tp_shape),
                  fmt_format("{} is not comparable and cannot be sorted", elem_type->as_human_readable()));
     }
+
+    // TODO: get rid of this when rewrite array_diff_impl with some hash set container
+    if (vk::any_of_equal(function_name, "array_diff")) {
+      // Forbid arrays with elements that would be rejected by key projection function.
+      for (const auto arg: call->args()) {
+        const TypeData *array_type = tinf::get_type(arg);
+        const auto *elem_type = array_type->lookup_at_any_key();
+        kphp_error(vk::none_of_equal(elem_type->ptype(), tp_tuple, tp_shape),
+                   fmt_format("{} in {}() is not supported", elem_type->as_human_readable(), function_name));
+      }
+    }
   }
 
   check_func_call_params(call);
diff --git a/runtime-common/stdlib/array/array-functions.h b/runtime-common/stdlib/array/array-functions.h
index 6ff9812214..28992f58ca 100644
--- a/runtime-common/stdlib/array/array-functions.h
+++ b/runtime-common/stdlib/array/array-functions.h
@@ -30,17 +30,17 @@ auto transform_to_vector(const array<T> &a, const F &op) noexcept {
 }
 
 template<class T, class T1, class Proj>
-array<T> array_diff(const array<T> &a1, const array<T1> &a2, const Proj &projector) noexcept {
+array<T> array_diff(const array<T> &a1, const array<T1> &a2, const Proj &key_projector) noexcept {
   array<T> result(a1.size());
 
   array<int64_t> values{array_size{a2.count(), false}};
 
   for (const auto &it : a2) {
-    values.set_value(projector(it.get_value()), 1);
+    values.set_value(key_projector(it.get_value()), 1);
   }
 
   for (const auto &it : a1) {
-    if (!values.has_key(projector(it.get_value()))) {
+    if (!values.has_key(key_projector(it.get_value()))) {
       result.set_value(it);
     }
   }
diff --git a/tests/phpt/shapes/107_array_diff_1.php b/tests/phpt/shapes/107_array_diff_1.php
new file mode 100644
index 0000000000..2b5adaebd0
--- /dev/null
+++ b/tests/phpt/shapes/107_array_diff_1.php
@@ -0,0 +1,10 @@
+@kphp_should_fail
+/shape\(bar:int, foo:int\) in array_diff\(\) is not supported/
+<?php
+
+function test_array_diff() {
+    $arr = [shape(["foo" => 1, "bar" => 2])];
+    $x = array_diff($arr, $arr);
+}
+
+test_array_diff();
diff --git a/tests/phpt/shapes/107_array_diff_2.php b/tests/phpt/shapes/107_array_diff_2.php
new file mode 100644
index 0000000000..f2146dc836
--- /dev/null
+++ b/tests/phpt/shapes/107_array_diff_2.php
@@ -0,0 +1,10 @@
+@kphp_should_fail
+/shape\(bar:int, foo:int\) in array_diff\(\) is not supported/
+<?php
+
+function test_array_diff() {
+    $arr = [shape(["foo" => 1, "bar" => 2])];
+    $x = array_diff([["foo" => 1, "bar" => 2]], $arr);
+}
+
+test_array_diff();
diff --git a/tests/phpt/tup/112_array_diff_1.php b/tests/phpt/tup/112_array_diff_1.php
new file mode 100644
index 0000000000..8b592ae214
--- /dev/null
+++ b/tests/phpt/tup/112_array_diff_1.php
@@ -0,0 +1,10 @@
+@kphp_should_fail
+/tuple\(int, int\) in array_diff\(\) is not supported/
+<?php
+
+function test_array_diff() {
+    $arr = [tuple(1, 2)];
+    $x = array_diff($arr, $arr);
+}
+
+test_array_diff();
diff --git a/tests/phpt/tup/112_array_diff_2.php b/tests/phpt/tup/112_array_diff_2.php
new file mode 100644
index 0000000000..9a99e2f222
--- /dev/null
+++ b/tests/phpt/tup/112_array_diff_2.php
@@ -0,0 +1,10 @@
+@kphp_should_fail
+/tuple\(int, int\) in array_diff\(\) is not supported/
+<?php
+
+function test_array_diff() {
+    $arr = [tuple(1, 2)];
+    $x = array_diff([[1, 2]], $arr);
+}
+
+test_array_diff();