diff --git a/src/Composer/Package/Loader/ValidatingArrayLoader.php b/src/Composer/Package/Loader/ValidatingArrayLoader.php
index e5d513c41b66..7e4318b85683 100644
--- a/src/Composer/Package/Loader/ValidatingArrayLoader.php
+++ b/src/Composer/Package/Loader/ValidatingArrayLoader.php
@@ -252,6 +252,7 @@ public function load(array $config, string $class = 'Composer\Package\CompletePa
         foreach (array_keys(BasePackage::$supportedLinkTypes) as $linkType) {
             if ($this->validateArray($linkType) && isset($this->config[$linkType])) {
                 foreach ($this->config[$linkType] as $package => $constraint) {
+                    $package = (string) $package;
                     if (0 === strcasecmp($package, $this->config['name'])) {
                         $this->errors[] = $linkType.'.'.$package.' : a package cannot set a '.$linkType.' on itself';
                         unset($this->config[$linkType][$package]);
diff --git a/tests/Composer/Test/Package/Loader/ValidatingArrayLoaderTest.php b/tests/Composer/Test/Package/Loader/ValidatingArrayLoaderTest.php
index e3d6103e1bdc..a7829ed14119 100644
--- a/tests/Composer/Test/Package/Loader/ValidatingArrayLoaderTest.php
+++ b/tests/Composer/Test/Package/Loader/ValidatingArrayLoaderTest.php
@@ -419,6 +419,13 @@ public function errorProvider(): array
                     'dist.url : must be present',
                 ),
             ),
+            array(
+                array(
+                    'name' => 'foo/bar',
+                    'replace' => array('acme/bar'),
+                ),
+                array('require.0 : invalid version constraint (Could not parse version constraint foo/Bar: Invalid version string "foo/Bar")')
+            ),
         ));
     }