diff --git a/Contracts/UriRenderer.php b/Contracts/UriRenderer.php
index ddb746c..f01d454 100644
--- a/Contracts/UriRenderer.php
+++ b/Contracts/UriRenderer.php
@@ -45,7 +45,7 @@ public function toNormalizedString(): ?string;
      *
      * @see https://datatracker.ietf.org/doc/html/rfc3986#section-6.2
      */
-    public function toDisplayString(): ?string;
+    public function toDisplayString(): string;
 
     /**
      * Returns the string representation as a URI reference.
diff --git a/UriString.php b/UriString.php
index 4d0a6b2..e0ba6f4 100644
--- a/UriString.php
+++ b/UriString.php
@@ -338,40 +338,45 @@ public static function normalizeAuthority(Stringable|string $authority): string
      */
     public static function resolve(Stringable|string $uri, Stringable|string|null $baseUri = null): string
     {
+        $uri = (string) $uri;
         if ('' === $uri) {
             $uri = $baseUri ?? throw new SyntaxError('The uri can not be the empty string when there\'s no base URI.');
         }
 
-        $uri = self::parse($uri);
-        $baseUri = null !== $baseUri ? self::parse($baseUri) : $uri;
-        if (null === $baseUri['scheme']) {
+        $uriComponents = self::parse($uri);
+        $baseUriComponents = $uriComponents;
+        if (null !== $baseUri && (string) $uri !== (string) $baseUri) {
+            $baseUriComponents = self::parse($baseUri);
+        }
+
+        if (null === $baseUriComponents['scheme']) {
             throw new SyntaxError('The base URI must be an absolute URI or null; If the base URI is null the URI must be an absolute URI.');
         }
 
-        if (null !== $uri['scheme'] && '' !== $uri['scheme']) {
-            $uri['path'] = self::removeDotSegments($uri['path']);
+        if (null !== $uriComponents['scheme'] && '' !== $uriComponents['scheme']) {
+            $uriComponents['path'] = self::removeDotSegments($uriComponents['path']);
 
-            return UriString::build($uri);
+            return UriString::build($uriComponents);
         }
 
-        if (null !== self::buildAuthority($uri)) {
-            $uri['scheme'] = $baseUri['scheme'];
-            $uri['path'] = self::removeDotSegments($uri['path']);
+        if (null !== self::buildAuthority($uriComponents)) {
+            $uriComponents['scheme'] = $baseUriComponents['scheme'];
+            $uriComponents['path'] = self::removeDotSegments($uriComponents['path']);
 
-            return UriString::build($uri);
+            return UriString::build($uriComponents);
         }
 
-        [$path, $query] = self::resolvePathAndQuery($uri, $baseUri);
+        [$path, $query] = self::resolvePathAndQuery($uriComponents, $baseUriComponents);
         $path = UriString::removeDotSegments($path);
-        if ('' !== $path && '/' !== $path[0] && null !== self::buildAuthority($baseUri)) {
+        if ('' !== $path && '/' !== $path[0] && null !== self::buildAuthority($baseUriComponents)) {
             $path = '/'.$path;
         }
 
-        $baseUri['path'] = $path;
-        $baseUri['query'] = $query;
-        $baseUri['fragment'] = $uri['fragment'];
+        $baseUriComponents['path'] = $path;
+        $baseUriComponents['query'] = $query;
+        $baseUriComponents['fragment'] = $uriComponents['fragment'];
 
-        return UriString::build($baseUri);
+        return UriString::build($baseUriComponents);
     }
 
     /**
diff --git a/UriStringTest.php b/UriStringTest.php
index 6676ec6..2a0af99 100644
--- a/UriStringTest.php
+++ b/UriStringTest.php
@@ -1025,10 +1025,11 @@ public function it_fails_parsing_uri_string_with_whitespace(string $uri): void
 
     public static function invalidUriWithWhitespaceProvider(): iterable
     {
+        yield 'empty string' => ['uri' => ''];
         yield 'uri containing only whitespaces' => ['uri' => '     '];
-        yield 'uri stating with whitespace' => ['uri' => '    https://a/b?c'];
-        yield 'uri ending with whitespace' => ['uri' => 'https://a/b?c   '];
-        yield 'uri surrounded with whitespace' => ['uri' => '   https://a/b?c   '];
-        yield 'uri containing with whitespace' => ['uri' => 'https://a/b ?c'];
+        yield 'uri starting with whitespaces' => ['uri' => '    https://a/b?c'];
+        yield 'uri ending with whitespaces' => ['uri' => 'https://a/b?c   '];
+        yield 'uri surrounded by whitespaces' => ['uri' => '   https://a/b?c   '];
+        yield 'uri containing with whitespaces' => ['uri' => 'https://a/b ?c'];
     }
 }