diff --git a/.makefile/e2e.file b/.makefile/e2e.file
index a19531a4..d6f5e7db 100644
--- a/.makefile/e2e.file
+++ b/.makefile/e2e.file
@@ -431,6 +431,24 @@ e2e_039: $(PHP_SCOPER_PHAR_BIN)
 		> build/set039/output || true
 	diff fixtures/set039-min-php-version/expected-output build/set039/output
 
+.PHONY: e2e_040
+e2e_040: # Runs end-to-end tests for the fixture set e2e_040 — Codebase using a polyfill
+e2e_040: $(PHP_SCOPER_PHAR_BIN)
+	rm -rf fixtures/set040-polyfills/vendor || true
+	composer --working-dir=fixtures/set040-polyfills dump-autoload
+
+	$(PHP_SCOPER_PHAR) add-prefix . \
+		--working-dir=fixtures/set040-polyfills \
+		--output-dir=../../build/set040 \
+		--force \
+		--no-interaction \
+		--stop-on-failure
+	composer --working-dir=build/set040 dump-autoload
+
+	php build/set040/index.php > build/set040/output || true
+
+	diff fixtures/set040-polyfills/expected-output build/set040/output
+
 
 #
 # Rules from files
diff --git a/fixtures/set040-polyfills/bootstrap.php b/fixtures/set040-polyfills/bootstrap.php
new file mode 100644
index 00000000..d2ef0fb5
--- /dev/null
+++ b/fixtures/set040-polyfills/bootstrap.php
@@ -0,0 +1,15 @@
+<?php declare(strict_types=1);
+
+use Set040\Php20;
+
+if (PHP_VERSION_ID >= 200_000) {
+    return;
+}
+
+if (!defined('NEW_PHP20_CONSTANT')) {
+    define('NEW_PHP20_CONSTANT', 42);
+}
+
+if (!function_exists('new_php20_function')) {
+    function new_php20_function(bool $echo = false): void { Php20::new_php20_function($echo); }
+}
diff --git a/fixtures/set040-polyfills/composer.json b/fixtures/set040-polyfills/composer.json
new file mode 100644
index 00000000..674008b2
--- /dev/null
+++ b/fixtures/set040-polyfills/composer.json
@@ -0,0 +1,11 @@
+{
+    "bin": "index.php",
+    "autoload": {
+        "files": ["bootstrap.php"],
+        "classmap": ["stubs"],
+        "psr-4": {
+            "Set040\\Polyfill\\": "src/",
+            "Set040\\": "src/"
+        }
+    }
+}
diff --git a/fixtures/set040-polyfills/composer.lock b/fixtures/set040-polyfills/composer.lock
new file mode 100644
index 00000000..ba6fe47d
--- /dev/null
+++ b/fixtures/set040-polyfills/composer.lock
@@ -0,0 +1,18 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "d751713988987e9331980363e24189ce",
+    "packages": [],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": [],
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": [],
+    "plugin-api-version": "2.6.0"
+}
diff --git a/fixtures/set040-polyfills/expected-output b/fixtures/set040-polyfills/expected-output
new file mode 100644
index 00000000..d5c32f4a
--- /dev/null
+++ b/fixtures/set040-polyfills/expected-output
@@ -0,0 +1 @@
+OK.
diff --git a/fixtures/set040-polyfills/index.php b/fixtures/set040-polyfills/index.php
new file mode 100644
index 00000000..69df1326
--- /dev/null
+++ b/fixtures/set040-polyfills/index.php
@@ -0,0 +1,27 @@
+<?php declare(strict_types=1);
+
+namespace App;
+
+use NewPhp20Interface;
+use NewPhp20Class;
+use function new_php20_function;
+use const NEW_PHP20_CONSTANT;
+use const PHP_EOL;
+
+require file_exists(__DIR__.'/vendor/scoper-autoload.php')
+    ? __DIR__.'/vendor/scoper-autoload.php'
+    : __DIR__.'/vendor/autoload.php';
+
+// This file mimics the execution of an app relying on a polyfill.
+//
+// From PHP-Scoper point of view, marking a symbol as excluded is
+// akin to say this is a PHP native symbol.
+
+// Consume the polyfilled code.
+
+class NewPhp20Child implements NewPhp20Interface {}
+new NewPhp20Class();
+new_php20_function();
+$x = NEW_PHP20_CONSTANT;
+
+echo "OK.".PHP_EOL;
diff --git a/fixtures/set040-polyfills/scoper.inc.php b/fixtures/set040-polyfills/scoper.inc.php
new file mode 100644
index 00000000..9de85229
--- /dev/null
+++ b/fixtures/set040-polyfills/scoper.inc.php
@@ -0,0 +1,14 @@
+<?php declare(strict_types=1);
+
+return [
+    'exclude-classes' => [
+        'NewPhp20Interface',
+        'NewPhp20Class',
+    ],
+    'exclude-functions' => [
+        'new_php20_function',
+    ],
+    'exclude-constants' => [
+        'NEW_PHP20_CONSTANT',
+    ],
+];
diff --git a/fixtures/set040-polyfills/src/Php20.php b/fixtures/set040-polyfills/src/Php20.php
new file mode 100644
index 00000000..fc794e0d
--- /dev/null
+++ b/fixtures/set040-polyfills/src/Php20.php
@@ -0,0 +1,17 @@
+<?php declare(strict_types=1);
+
+namespace Set040;
+
+final class Php20
+{
+    public static function new_php20_function(bool $echo = false): void
+    {
+        if ($echo) {
+            echo "Called `new_php20_function()`.";
+        }
+    }
+
+    private function __construct()
+    {
+    }
+}
\ No newline at end of file
diff --git a/fixtures/set040-polyfills/stubs/NewPhp20Class.php b/fixtures/set040-polyfills/stubs/NewPhp20Class.php
new file mode 100644
index 00000000..03d67238
--- /dev/null
+++ b/fixtures/set040-polyfills/stubs/NewPhp20Class.php
@@ -0,0 +1,7 @@
+<?php declare(strict_types=1);
+
+if (PHP_VERSION_ID < 200_000) {
+    final class NewPhp20Class
+    {
+    }
+}
\ No newline at end of file
diff --git a/fixtures/set040-polyfills/stubs/NewPhp20Interface.php b/fixtures/set040-polyfills/stubs/NewPhp20Interface.php
new file mode 100644
index 00000000..864c742f
--- /dev/null
+++ b/fixtures/set040-polyfills/stubs/NewPhp20Interface.php
@@ -0,0 +1,7 @@
+<?php declare(strict_types=1);
+
+if (PHP_VERSION_ID < 200_000) {
+    interface NewPhp20Interface
+    {
+    }
+}
\ No newline at end of file