Fix issue #66

src/Purl/Fragment.php

@@ -109,7 +109,12 @@ public function __toString() : string
     protected function doInitialize() : void
     {
         if ($this->fragment !== null) {
-            $this->data = array_merge($this->data, parse_url($this->fragment));
+            $data = parse_url($this->fragment);
+            if ($data === false) {
+                $data = ['path' => $this->fragment];
+            }
+
+            $this->data = array_merge($this->data, $data);
         }
 
         foreach ($this->data as $key => $value) {

tests/Purl/Test/UrlTest.php

@@ -362,6 +362,10 @@ public function testRelativeUrl() : void
         $url = new Url('/events');
         $url->query->set('param1', 'value1');
         $this->assertEquals('/events?param1=value1', (string) $url);
+
+        // test fragment with colon
+        $url = new Url('http://example.com/#hello:123');
+        $this->assertEquals('http://example.com/', (string) $url);
     }
 }