diff --git a/RoboFile.php b/RoboFile.php
deleted file mode 100644
index 966c3d3..0000000
--- a/RoboFile.php
+++ /dev/null
@@ -1,150 +0,0 @@
-<?php
-/** @license MIT
- * Copyright 2017 , Dustin Wilson, J. King et al.
- * See LICENSE and AUTHORS files for details */
-
-
-use Robo\Result;
-
-const BASE = __DIR__.\DIRECTORY_SEPARATOR;
-const BASE_TEST = BASE."tests".\DIRECTORY_SEPARATOR;
-define("IS_WIN", defined("PHP_WINDOWS_VERSION_MAJOR"));
-define("IS_MAC", php_uname("s") === "Darwin");
-error_reporting(0);
-
-function norm(string $path): string {
-    $out = realpath($path);
-    if (!$out) {
-        $out = str_replace(["/", "\\"], \DIRECTORY_SEPARATOR, $path);
-    }
-    return $out;
-}
-
-class RoboFile extends \Robo\Tasks {
-    /** Runs the typical test suite
-     *
-     * Arguments passed to the task are passed on to PHPUnit. Thus one may, for
-     * example, run the following command and get the expected results:
-     *
-     * ./robo test --testsuite Tokenizer --exclude-group slow --testdox
-     *
-     * Please see the PHPUnit documentation for available options.
-    */
-    public function test(array $args): Result {
-        return $this->runTests(escapeshellarg(\PHP_BINARY), "typical", $args);
-    }
-
-    /** Runs the full test suite
-     *
-     * This includes pedantic tests which may help to identify problems.
-     * See help for the "test" task for more details.
-    */
-    public function testFull(array $args): Result {
-        return $this->runTests(escapeshellarg(\PHP_BINARY), "full", $args);
-    }
-
-    /**
-     * Runs a quick subset of the test suite
-     *
-     * See help for the "test" task for more details.
-    */
-    public function testQuick(array $args): Result {
-        return $this->runTests(escapeshellarg(\PHP_BINARY), "quick", $args);
-    }
-
-    /** Manually updates the imported html5lib test suite */
-    public function testUpdate(): Result {
-        $dir = BASE_TEST."html5lib-tests";
-        if (is_dir($dir)) {
-            return $this->taskGitStack()->dir($dir)->pull()->run();
-        } else {
-            return $this->taskGitStack()->cloneRepo("https://github.com/html5lib/html5lib-tests", $dir)->run();
-        }
-    }
-
-    /** Produces a code coverage report
-     *
-     * By default this task produces an HTML-format coverage report in
-     * tests/coverage/. Additional reports may be produced by passing
-     * arguments to this task as one would to PHPUnit.
-    */
-    public function coverage(array $args): Result {
-        // run tests with code coverage reporting enabled
-        $exec = $this->findCoverageEngine();
-        return $this->runTests($exec, "coverage", array_merge(["--coverage-html", BASE_TEST."coverage"], $args));
-    }
-
-    /** Produces a code coverage report, with redundant tests
-     *
-     * Depending on the environment, some tests that normally provide
-     * coverage may be skipped, while working alternatives are normally
-     * suppressed for reasons of time. This coverage report will try to
-     * run all tests which may cover code.
-     *
-     * See also help for the "coverage" task for more details.
-    */
-    public function coverageFull(array $args): Result {
-        // run tests with code coverage reporting enabled
-        $exec = $this->findCoverageEngine();
-        return $this->runTests($exec, "typical", array_merge(["--coverage-html", BASE_TEST."coverage"], $args));
-    }
-
-    protected function findCoverageEngine(): string {
-        $dir = rtrim(ini_get("extension_dir"), "/").\DIRECTORY_SEPARATOR;
-        $ext = IS_WIN ? "dll" : "so";
-        $php = escapeshellarg(\PHP_BINARY);
-        $code = escapeshellarg(BASE."lib");
-        if (extension_loaded("pcov")) {
-            return "$php -d opcache.enable_cli=0 -d pcov.enabled=1 -d pcov.directory=$code";
-        } elseif (extension_loaded("xdebug")) {
-            return "$php -d opcache.enable_cli=0 -d xdebug.mode=coverage";
-        } elseif (file_exists($dir."pcov.$ext")) {
-            return "$php -d opcache.enable_cli=0 -d extension=pcov.$ext -d pcov.enabled=1 -d pcov.directory=$code";
-        } elseif (file_exists($dir."xdebug.$ext")) {
-            return "$php -d opcache.enable_cli=0 -d zend_extension=xdebug.$ext -d xdebug.mode=coverage";
-        } else {
-            if (IS_WIN) {
-                $dbg = dirname(\PHP_BINARY)."\\phpdbg.exe";
-                $dbg = file_exists($dbg) ? $dbg : "";
-            } else {
-                $dbg = trim(`which phpdbg 2>/dev/null`);
-            }
-            if ($dbg) {
-                return escapeshellarg($dbg)." -qrr";
-            } else {
-                return $php;
-            }
-        }
-    }
-
-    protected function blackhole(bool $all = false): string {
-        $hole = IS_WIN ? "nul" : "/dev/null";
-        return $all ? ">$hole 2>&1" : "2>$hole";
-    }
-
-    protected function runTests(string $executor, string $set, array $args) : Result {
-        switch ($set) {
-            case "typical":
-                $set = ["--exclude-group", "optional"];
-                break;
-            case "quick":
-                $set = ["--exclude-group", "optional,slow"];
-                break;
-            case "coverage":
-                $set = ["--exclude-group", "optional,coverageOptional"];
-                break;
-            case "full":
-                $set = [];
-                break;
-            default:
-                throw new \Exception;
-        }
-        $execpath = norm(BASE."vendor-bin/phpunit/vendor/phpunit/phpunit/phpunit");
-        $confpath = realpath(BASE_TEST."phpunit.dist.xml") ?: norm(BASE_TEST."phpunit.xml");
-        // clone the html5lib test suite if it's not already present
-        if (!is_dir(BASE_TEST."html5lib-tests")) {
-            $this->testUpdate();
-        }
-        return $this->taskExec($executor)->option("-d", "zend.assertions=1")->arg($execpath)->option("-c", $confpath)->args(array_merge($set, $args))->run();
-    }
-}
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 7462af5..8ce4733 100644
--- a/composer.json
+++ b/composer.json
@@ -1,22 +1,14 @@
 {
     "name": "mensbeam/html-dom",
-    "description": "Modern DOM library written in PHP for HTML documents",
-    "type": "library",
-    "require": {
-        "php": ">=8.0.2",
-        "ext-dom": "*",
-        "mensbeam/html-parser": ">=1.2.1",
-        "symfony/css-selector": ">=5.3",
-        "mensbeam/getters-and-setters": ">=1.1"
-    },
-    "require-dev": {
-        "bamarni/composer-bin-plugin": "^1.3",
-        "mikey179/vfsstream": "^1.6",
-        "nikic/php-parser": "^4.13"
-    },
-    "scripts": {
-        "post-install-cmd": ["@composer bin all install"],
-        "post-update-cmd": ["@composer bin all update"]
+    "autoload": {
+        "psr-4": {
+            "MensBeam\\HTML\\DOM\\": [
+                "lib/",
+                "lib/DOMException",
+                "lib/Exception",
+                "lib/HTMLElement"
+            ]
+        }
     },
     "license": "MIT",
     "authors": [
@@ -31,27 +23,9 @@
             "homepage": "https://jkingweb.ca/"
         }
     ],
-    "autoload": {
-        "psr-4": {
-            "MensBeam\\HTML\\DOM\\": [
-                "lib/",
-                "lib/HTMLElement"
-            ]
-        }
-    },
-    "autoload-dev": {
-        "psr-4": {
-            "MensBeam\\HTML\\DOM\\Test\\": "tests/lib/",
-            "MensBeam\\HTML\\DOM\\TestCase\\": [
-                "tests/cases/",
-                "tests/cases/Document",
-                "tests/cases/Serializer"
-            ]
-        }
-    },
-    "config": {
-        "allow-plugins": {
-            "bamarni/composer-bin-plugin": true
-        }
+    "require": {
+        "mensbeam/html-parser": "^1.3",
+        "symfony/css-selector": "^6.3",
+        "mensbeam/getters-and-setters": "^1.1"
     }
 }
diff --git a/composer.lock b/composer.lock
index d10c45b..6f10a26 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "dc49ff7a1b170e6b1f368a4f5145543e",
+    "content-hash": "b4a731d7d5cb3bb8b0520670bb74f4c5",
     "packages": [
         {
             "name": "mensbeam/getters-and-setters",
@@ -51,16 +51,16 @@
         },
         {
             "name": "mensbeam/html-parser",
-            "version": "1.2.6",
+            "version": "1.3.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/mensbeam/HTML-Parser.git",
-                "reference": "fa0591bd9ce241631894bda290cb99f30b7c288d"
+                "reference": "2b8a31ce472190013faab710f6f7ad41a486a740"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/mensbeam/HTML-Parser/zipball/fa0591bd9ce241631894bda290cb99f30b7c288d",
-                "reference": "fa0591bd9ce241631894bda290cb99f30b7c288d",
+                "url": "https://api.github.com/repos/mensbeam/HTML-Parser/zipball/2b8a31ce472190013faab710f6f7ad41a486a740",
+                "reference": "2b8a31ce472190013faab710f6f7ad41a486a740",
                 "shasum": ""
             },
             "require": {
@@ -115,10 +115,9 @@
                 "parsing"
             ],
             "support": {
-                "issues": "https://github.com/mensbeam/HTML-Parser/issues",
-                "source": "https://github.com/mensbeam/HTML-Parser/tree/1.2.6"
+                "source": "https://github.com/mensbeam/HTML-Parser/tree/1.3.1"
             },
-            "time": "2023-01-25T22:49:58+00:00"
+            "time": "2023-04-20T19:55:47+00:00"
         },
         {
             "name": "mensbeam/intl",
@@ -228,25 +227,25 @@
         },
         {
             "name": "psr/http-message",
-            "version": "1.0.1",
+            "version": "1.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/php-fig/http-message.git",
-                "reference": "f6561bf28d520154e4b0ec72be95418abe6d9363"
+                "reference": "cb6ce4845ce34a8ad9e68117c10ee90a29919eba"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/php-fig/http-message/zipball/f6561bf28d520154e4b0ec72be95418abe6d9363",
-                "reference": "f6561bf28d520154e4b0ec72be95418abe6d9363",
+                "url": "https://api.github.com/repos/php-fig/http-message/zipball/cb6ce4845ce34a8ad9e68117c10ee90a29919eba",
+                "reference": "cb6ce4845ce34a8ad9e68117c10ee90a29919eba",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.0"
+                "php": "^7.2 || ^8.0"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.0.x-dev"
+                    "dev-master": "1.1.x-dev"
                 }
             },
             "autoload": {
@@ -275,22 +274,22 @@
                 "response"
             ],
             "support": {
-                "source": "https://github.com/php-fig/http-message/tree/master"
+                "source": "https://github.com/php-fig/http-message/tree/1.1"
             },
-            "time": "2016-08-06T14:39:51+00:00"
+            "time": "2023-04-04T09:50:52+00:00"
         },
         {
             "name": "symfony/css-selector",
-            "version": "v6.2.5",
+            "version": "v6.3.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/css-selector.git",
-                "reference": "bf1b9d4ad8b1cf0dbde8b08e0135a2f6259b9ba1"
+                "reference": "883d961421ab1709877c10ac99451632a3d6fa57"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/css-selector/zipball/bf1b9d4ad8b1cf0dbde8b08e0135a2f6259b9ba1",
-                "reference": "bf1b9d4ad8b1cf0dbde8b08e0135a2f6259b9ba1",
+                "url": "https://api.github.com/repos/symfony/css-selector/zipball/883d961421ab1709877c10ac99451632a3d6fa57",
+                "reference": "883d961421ab1709877c10ac99451632a3d6fa57",
                 "shasum": ""
             },
             "require": {
@@ -326,7 +325,7 @@
             "description": "Converts CSS selectors to XPath expressions",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/css-selector/tree/v6.2.5"
+                "source": "https://github.com/symfony/css-selector/tree/v6.3.2"
             },
             "funding": [
                 {
@@ -342,184 +341,16 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2023-01-01T08:38:09+00:00"
-        }
-    ],
-    "packages-dev": [
-        {
-            "name": "bamarni/composer-bin-plugin",
-            "version": "1.8.2",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/bamarni/composer-bin-plugin.git",
-                "reference": "92fd7b1e6e9cdae19b0d57369d8ad31a37b6a880"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/bamarni/composer-bin-plugin/zipball/92fd7b1e6e9cdae19b0d57369d8ad31a37b6a880",
-                "reference": "92fd7b1e6e9cdae19b0d57369d8ad31a37b6a880",
-                "shasum": ""
-            },
-            "require": {
-                "composer-plugin-api": "^2.0",
-                "php": "^7.2.5 || ^8.0"
-            },
-            "require-dev": {
-                "composer/composer": "^2.0",
-                "ext-json": "*",
-                "phpstan/extension-installer": "^1.1",
-                "phpstan/phpstan": "^1.8",
-                "phpstan/phpstan-phpunit": "^1.1",
-                "phpunit/phpunit": "^8.5 || ^9.5",
-                "symfony/console": "^2.8.52 || ^3.4.35 || ^4.4 || ^5.0 || ^6.0",
-                "symfony/finder": "^2.8.52 || ^3.4.35 || ^4.4 || ^5.0 || ^6.0",
-                "symfony/process": "^2.8.52 || ^3.4.35 || ^4.4 || ^5.0 || ^6.0"
-            },
-            "type": "composer-plugin",
-            "extra": {
-                "class": "Bamarni\\Composer\\Bin\\BamarniBinPlugin"
-            },
-            "autoload": {
-                "psr-4": {
-                    "Bamarni\\Composer\\Bin\\": "src"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "description": "No conflicts for your bin dependencies",
-            "keywords": [
-                "composer",
-                "conflict",
-                "dependency",
-                "executable",
-                "isolation",
-                "tool"
-            ],
-            "support": {
-                "issues": "https://github.com/bamarni/composer-bin-plugin/issues",
-                "source": "https://github.com/bamarni/composer-bin-plugin/tree/1.8.2"
-            },
-            "time": "2022-10-31T08:38:03+00:00"
-        },
-        {
-            "name": "mikey179/vfsstream",
-            "version": "v1.6.11",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/bovigo/vfsStream.git",
-                "reference": "17d16a85e6c26ce1f3e2fa9ceeacdc2855db1e9f"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/bovigo/vfsStream/zipball/17d16a85e6c26ce1f3e2fa9ceeacdc2855db1e9f",
-                "reference": "17d16a85e6c26ce1f3e2fa9ceeacdc2855db1e9f",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.3.0"
-            },
-            "require-dev": {
-                "phpunit/phpunit": "^4.5|^5.0"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.6.x-dev"
-                }
-            },
-            "autoload": {
-                "psr-0": {
-                    "org\\bovigo\\vfs\\": "src/main/php"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Frank Kleine",
-                    "homepage": "http://frankkleine.de/",
-                    "role": "Developer"
-                }
-            ],
-            "description": "Virtual file system to mock the real file system in unit tests.",
-            "homepage": "http://vfs.bovigo.org/",
-            "support": {
-                "issues": "https://github.com/bovigo/vfsStream/issues",
-                "source": "https://github.com/bovigo/vfsStream/tree/master",
-                "wiki": "https://github.com/bovigo/vfsStream/wiki"
-            },
-            "time": "2022-02-23T02:02:42+00:00"
-        },
-        {
-            "name": "nikic/php-parser",
-            "version": "v4.15.3",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/nikic/PHP-Parser.git",
-                "reference": "570e980a201d8ed0236b0a62ddf2c9cbb2034039"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/nikic/PHP-Parser/zipball/570e980a201d8ed0236b0a62ddf2c9cbb2034039",
-                "reference": "570e980a201d8ed0236b0a62ddf2c9cbb2034039",
-                "shasum": ""
-            },
-            "require": {
-                "ext-tokenizer": "*",
-                "php": ">=7.0"
-            },
-            "require-dev": {
-                "ircmaxell/php-yacc": "^0.0.7",
-                "phpunit/phpunit": "^6.5 || ^7.0 || ^8.0 || ^9.0"
-            },
-            "bin": [
-                "bin/php-parse"
-            ],
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "4.9-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "PhpParser\\": "lib/PhpParser"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Nikita Popov"
-                }
-            ],
-            "description": "A PHP parser written in PHP",
-            "keywords": [
-                "parser",
-                "php"
-            ],
-            "support": {
-                "issues": "https://github.com/nikic/PHP-Parser/issues",
-                "source": "https://github.com/nikic/PHP-Parser/tree/v4.15.3"
-            },
-            "time": "2023-01-16T22:05:37+00:00"
+            "time": "2023-07-12T16:00:22+00:00"
         }
     ],
+    "packages-dev": [],
     "aliases": [],
     "minimum-stability": "stable",
     "stability-flags": [],
     "prefer-stable": false,
     "prefer-lowest": false,
-    "platform": {
-        "php": ">=8.0.2",
-        "ext-dom": "*"
-    },
+    "platform": [],
     "platform-dev": [],
-    "plugin-api-version": "2.3.0"
+    "plugin-api-version": "2.6.0"
 }
diff --git a/lib/ArgumentCountError.php b/lib/ArgumentCountError.php
new file mode 100644
index 0000000..8c7ec82
--- /dev/null
+++ b/lib/ArgumentCountError.php
@@ -0,0 +1,11 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class ArgumentCountError extends \ArgumentCountError {}
\ No newline at end of file
diff --git a/lib/Attr.php b/lib/Attr.php
index 5447fb0..9dcda95 100644
--- a/lib/Attr.php
+++ b/lib/Attr.php
@@ -9,7 +9,10 @@ declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 
 
+/** @property \DOMAttr $_innerNode */
 class Attr extends Node {
+    protected \DOMAttr $_innerNode;
+
     protected function __get_localName(): string {
         // PHP's DOM does this correctly already.
         // Need to uncoerce string if necessary.
@@ -37,7 +40,9 @@ class Attr extends Node {
             return null;
         }
 
-        return $this->_innerNode->ownerDocument->getWrapperNode($this->_innerNode->ownerElement);
+        /** @var MensBeam\HTML\DOM\Inner\Document $innerOwnerDocument */
+        $innerOwnerDocument = $this->_innerNode->ownerDocument;
+        return $innerOwnerDocument->getWrapperNode($this->_innerNode->ownerElement);
     }
 
     protected function __get_prefix(): string {
diff --git a/lib/CharacterData.php b/lib/CharacterData.php
index 489c833..2ff7b4b 100644
--- a/lib/CharacterData.php
+++ b/lib/CharacterData.php
@@ -9,6 +9,7 @@ declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 
 
+/** @property \DOMCharacterData $_innerNode */
 abstract class CharacterData extends Node {
     use ChildNode, NonDocumentTypeChildNode;
 
diff --git a/lib/ChildNode.php b/lib/ChildNode.php
index b30802f..6a9fdb8 100644
--- a/lib/ChildNode.php
+++ b/lib/ChildNode.php
@@ -7,10 +7,6 @@
 
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
-use MensBeam\HTML\DOM\Inner\{
-    Document as InnerDocument,
-    Reflection
-};
 
 
 trait ChildNode {
diff --git a/lib/DOMException.php b/lib/DOMException.php
index 67635ac..71bd3a7 100644
--- a/lib/DOMException.php
+++ b/lib/DOMException.php
@@ -8,46 +8,4 @@
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 
-
-class DOMException extends Exception {
-    // DEVIATION (kinda): The specification states clearly that using the old
-    // integer values for exceptions has been deprecated, but all the browsers
-    // continue to honor them even if they're not explicitly used. Besides, it's
-    // bonkers to create numerous exception classes for each error type.
-    public const INDEX_SIZE_ERROR = 1;
-    public const HIERARCHY_REQUEST_ERROR = 3;
-    public const WRONG_DOCUMENT = 4;
-    public const INVALID_CHARACTER = 5;
-    public const NO_MODIFICATION_ALLOWED = 7;
-    public const NOT_FOUND = 8;
-    public const NOT_SUPPORTED = 9;
-    public const IN_USE_ATTRIBUTE = 10;
-    public const SYNTAX_ERROR = 12;
-    public const INVALID_MODIFICATION = 13;
-    public const NAMESPACE_ERROR = 14;
-    public const INVALID_ACCESS = 15;
-
-    public const FILE_NOT_FOUND = 301;
-
-
-    public function __construct(int $code, ...$args) {
-        self::$messages = array_replace(parent::$messages, [
-              1 => 'Invalid index size',
-              3 => 'Hierarchy request error',
-              4 => 'Supplied node does not belong to this document',
-              5 => 'Invalid character',
-              7 => 'Modification not allowed here',
-              8 => 'Not found error',
-              9 => 'Feature is not supported',
-             10 => 'The attribute is in use',
-             12 => 'Syntax error',
-             13 => 'Invalid modification error',
-             14 => 'Namespace error',
-             15 => 'Invalid access error',
-
-             301 => 'File not found'
-        ]);
-
-        parent::__construct($code, ...$args);
-    }
-}
+abstract class DOMException extends \Exception {}
\ No newline at end of file
diff --git a/lib/DOMException/HierarchyRequestError.php b/lib/DOMException/HierarchyRequestError.php
new file mode 100644
index 0000000..5e70f6d
--- /dev/null
+++ b/lib/DOMException/HierarchyRequestError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class HierarchyRequestError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The requested operation would yield an incorrect node tree', 3, $previous);
+    }
+}
\ No newline at end of file
diff --git a/lib/DOMException/InUseAttributeError.php b/lib/DOMException/InUseAttributeError.php
new file mode 100644
index 0000000..138949a
--- /dev/null
+++ b/lib/DOMException/InUseAttributeError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class InUseAttributeError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The attribute is in use by another element', 10, $previous);
+    }
+}
diff --git a/lib/DOMException/InvalidCharacterError.php b/lib/DOMException/InvalidCharacterError.php
new file mode 100644
index 0000000..4173a0e
--- /dev/null
+++ b/lib/DOMException/InvalidCharacterError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class InvalidCharacterError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The string contains invalid characters', 5, $previous);
+    }
+}
diff --git a/lib/DOMException/NamespaceError.php b/lib/DOMException/NamespaceError.php
new file mode 100644
index 0000000..6d6de2f
--- /dev/null
+++ b/lib/DOMException/NamespaceError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class NamespaceError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The operation is not allowed by namespaces', 14, $previous);
+    }
+}
diff --git a/lib/DOMException/NoModificationAllowedError.php b/lib/DOMException/NoModificationAllowedError.php
new file mode 100644
index 0000000..f8814af
--- /dev/null
+++ b/lib/DOMException/NoModificationAllowedError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class NoModificationAllowedError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The object can not be modified', 7, $previous);
+    }
+}
diff --git a/lib/DOMException/NotFoundError.php b/lib/DOMException/NotFoundError.php
new file mode 100644
index 0000000..399f180
--- /dev/null
+++ b/lib/DOMException/NotFoundError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class NotFoundError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The object can not be found here', 8, $previous);
+    }
+}
diff --git a/lib/DOMException/NotSupportedError.php b/lib/DOMException/NotSupportedError.php
new file mode 100644
index 0000000..bb80df3
--- /dev/null
+++ b/lib/DOMException/NotSupportedError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class NotSupportedError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The operation is not supported', 9, $previous);
+    }
+}
diff --git a/lib/DOMException/SyntaxError.php b/lib/DOMException/SyntaxError.php
new file mode 100644
index 0000000..9741c85
--- /dev/null
+++ b/lib/DOMException/SyntaxError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class SyntaxError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The string did not match the expected pattern', 12, $previous);
+    }
+}
diff --git a/lib/DOMException/WrongDocumentError.php b/lib/DOMException/WrongDocumentError.php
new file mode 100644
index 0000000..90c8e1f
--- /dev/null
+++ b/lib/DOMException/WrongDocumentError.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class WrongDocumentError extends DOMException {
+    public function __construct(?\Throwable $previous = null) {
+        parent::__construct('The object is in the wrong document', 4, $previous);
+    }
+}
diff --git a/lib/DOMImplementation.php b/lib/DOMImplementation.php
index 6658667..434fe7a 100644
--- a/lib/DOMImplementation.php
+++ b/lib/DOMImplementation.php
@@ -82,7 +82,7 @@ class DOMImplementation {
                 $contentType = 'application/xml';
         }
 
-        Reflection::setProtectedProperties($document, ['_contentType' => $contentType ]);
+        Reflection::setProtectedProperties($document, [ '_contentType' => $contentType ]);
 
         # 8. Return document.
         return $document;
@@ -95,7 +95,7 @@ class DOMImplementation {
         #    To validate a qualifiedName, throw an "InvalidCharacterError" DOMException if
         #    qualifiedName does not match the QName production.
         if (!preg_match(InnerDocument::QNAME_PRODUCTION_REGEX, $qualifiedName)) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 2. Return a new doctype, with qualifiedName as its name, publicId as its
@@ -145,7 +145,7 @@ class DOMImplementation {
         $documentElement->appendChild($doc->createElement('body'));
 
         # 8. doc’s origin is this’s associated document’s origin.
-        // Not necessary. No scripting in this implementation.
+        // DEVIATION: There is no scripting in this implementation.
 
         # 9. Return doc.
         return $doc;
diff --git a/lib/DOMTokenList.php b/lib/DOMTokenList.php
index ada7ce6..1b6a2d6 100644
--- a/lib/DOMTokenList.php
+++ b/lib/DOMTokenList.php
@@ -8,8 +8,7 @@
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 use MensBeam\HTML\Parser\Data,
-    MensBeam\GettersAndSetters,
-    MensBeam\HTML\DOM\Inner\Reflection;
+    MensBeam\GettersAndSetters;
 
 
 class DOMTokenList implements \ArrayAccess, \Countable, \Iterator {
@@ -95,13 +94,13 @@ class DOMTokenList implements \ArrayAccess, \Countable, \Iterator {
         foreach ($tokens as $token) {
             # 1. If token is the empty string, then throw a "SyntaxError" DOMException.
             if ($token === '') {
-                throw new DOMException(DOMException::SYNTAX_ERROR);
+                throw new SyntaxError();
             }
 
             # 2. If token contains any ASCII whitespace, then throw an
             # "InvalidCharacterError" DOMException.
             if (preg_match(Data::WHITESPACE_REGEX, $token)) {
-                throw new DOMException(DOMException::INVALID_CHARACTER);
+                throw new InvalidCharacterError();
             }
         }
 
@@ -176,13 +175,13 @@ class DOMTokenList implements \ArrayAccess, \Countable, \Iterator {
         foreach ($tokens as $token) {
             # 1. If token is the empty string, then throw a "SyntaxError" DOMException.
             if ($token === '') {
-                throw new DOMException(DOMException::SYNTAX_ERROR);
+                throw new SyntaxError();
             }
 
             # 2. If token contains any ASCII whitespace, then throw an
             # "InvalidCharacterError" DOMException.
             if (preg_match(Data::WHITESPACE_REGEX, $token)) {
-                throw new DOMException(DOMException::INVALID_CHARACTER);
+                throw new InvalidCharacterError();
             }
         }
 
@@ -210,13 +209,13 @@ class DOMTokenList implements \ArrayAccess, \Countable, \Iterator {
         # 1. If either token or newToken is the empty string, then throw a "SyntaxError"
         # DOMException.
         if ($token === '' || $newToken === '') {
-            throw new DOMException(DOMException::SYNTAX_ERROR);
+            throw new SyntaxError();
         }
 
         # 2. If either token or newToken contains any ASCII whitespace, then throw an
         # "InvalidCharacterError" DOMException.
         if (preg_match(Data::WHITESPACE_REGEX, $token) || preg_match(Data::WHITESPACE_REGEX, $newToken)) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 3. If this’s token set does not contain token, then return false.
@@ -268,13 +267,13 @@ class DOMTokenList implements \ArrayAccess, \Countable, \Iterator {
     public function toggle(string $token, ?bool $force = null): bool {
         # 1. If token is the empty string, then throw a "SyntaxError" DOMException.
         if ($token === '') {
-            throw new DOMException(DOMException::SYNTAX_ERROR);
+            throw new SyntaxError();
         }
 
         # 2. If token contains any ASCII whitespace, then throw an
         # "InvalidCharacterError" DOMException.
         if (preg_match(Data::WHITESPACE_REGEX, $token)) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 3. If this’s token set[token] exists, then:
diff --git a/lib/Document.php b/lib/Document.php
index 3126208..26b8ccb 100644
--- a/lib/Document.php
+++ b/lib/Document.php
@@ -20,6 +20,7 @@ use MensBeam\HTML\Parser\{
 };
 
 
+/** @property InnerDocument $_innerNode */
 class Document extends Node implements \ArrayAccess {
     use DocumentOrElement, NonElementParentNode, ParentNode, XPathEvaluatorBase;
 
@@ -45,7 +46,7 @@ class Document extends Node implements \ArrayAccess {
         if ($n !== null) {
             do {
                 if ($n instanceof \DOMElement && $n->namespaceURI === null && ($n->nodeName === 'body' || $n->nodeName === 'frameset')) {
-                    return $n->ownerDocument->getWrapperNode($n);
+                    return $this->_innerNode->getWrapperNode($n);
                 }
             } while ($n = $n->nextSibling);
         }
@@ -328,19 +329,19 @@ class Document extends Node implements \ArrayAccess {
                 $element = $title;
             }
             # 3. Otherwise:
-            else {
+            elseif ($head !== null) {
                 # 1. Let element be the result of creating an element given the document
                 #   element's node document, title, and the HTML namespace.
                 $element = $this->_innerNode->createElementNS(Node::SVG_NAMESPACE, 'title');
 
                 # 2. Append element to the head element.
                 $head->appendChild($element);
-            }
 
-            # 4. String replace all with the given value within element.
-            // This is basically what textContent will do for us...
-            if ($element !== null) {
-                $element->textContent = $value;
+                # 4. String replace all with the given value within element.
+                // This is basically what textContent will do for us...
+                if ($element !== null) {
+                    $element->textContent = $value;
+                }
             }
         }
 
@@ -380,7 +381,7 @@ class Document extends Node implements \ArrayAccess {
         #
         # 1. If node is a document, then throw a "NotSupportedError" DOMException.
         if ($node instanceof Document) {
-            throw new DOMException(DOMException::NOT_SUPPORTED);
+            throw new NotSupportedError();
         }
 
         # 2. If node is a shadow root, then throw a "HierarchyRequestError" DOMException.
@@ -390,7 +391,7 @@ class Document extends Node implements \ArrayAccess {
         // DEVIATION: One can't just return here?
         if ($node instanceof DocumentFragment) {
             $host = Reflection::getProtectedProperty($node, 'host');
-            if ($host !== null || $host->get() !== null) {
+            if ($host instanceof \WeakReference && $host->get() !== null || $host !== null) {
                 return $node;
             }
         }
@@ -419,7 +420,7 @@ class Document extends Node implements \ArrayAccess {
         # 1. If localName does not match the Name production in XML, then throw an
         #    "InvalidCharacterError" DOMException.
         if (preg_match(InnerDocument::NAME_PRODUCTION_REGEX, $localName) !== 1) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 2. If this is an HTML document, then set localName to localName in ASCII
@@ -509,13 +510,13 @@ class Document extends Node implements \ArrayAccess {
         #
         # 1. If this is an HTML document, then throw a "NotSupportedError" DOMException.
         if (!$this instanceof XMLDocument) {
-            throw new DOMException(DOMException::NOT_SUPPORTED);
+            throw new NotSupportedError();
         }
 
         # 2. If data contains the string "]]>", then throw an "InvalidCharacterError"
         #    DOMException.
         if (str_contains(needle: ']]>', haystack: $data)) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 3. Return a new CDATASection node with its data set to data and node document
@@ -539,12 +540,12 @@ class Document extends Node implements \ArrayAccess {
         # 1. If localName does not match the Name production, then throw an
         #    "InvalidCharacterError" DOMException.
         if (!preg_match(InnerDocument::NAME_PRODUCTION_REGEX, $localName)) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 2. If this is an HTML document, then set localName to localName in ASCII
         #    lowercase.
-        if (!$this instanceof XMLElement) {
+        if (!$this instanceof XMLDocument) {
             $localName = strtolower($localName);
         }
 
@@ -642,7 +643,7 @@ class Document extends Node implements \ArrayAccess {
         #    DOMException.
         // Because this can import from PHP's DOM we must check for more stuff.
         if ($node instanceof Document || $node instanceof \DOMDocument || ($node instanceof \DOMNode && $node->ownerDocument::class !== 'DOMDocument') || $node instanceof \DOMEntityReference) {
-            throw new DOMException(DOMException::NOT_SUPPORTED);
+            throw new NotSupportedError();
         }
 
         # 2. Return a clone of node, with this and the clone children flag set if deep
@@ -652,7 +653,7 @@ class Document extends Node implements \ArrayAccess {
 
     public function load(string $source = null, ?string $charset = null): void {
         if ($this->hasChildNodes()) {
-            throw new DOMException(DOMException::NO_MODIFICATION_ALLOWED);
+            throw new NoModificationAllowedError();
         }
 
         $config = new ParserConfig();
@@ -675,7 +676,7 @@ class Document extends Node implements \ArrayAccess {
     public function loadFile(string $filename, ?string $charset = null): void {
         $f = @fopen($filename, 'r');
         if (!$f) {
-            throw new DOMException(DOMException::FILE_NOT_FOUND);
+            throw new FileNotFoundException();
         }
 
         $data = stream_get_contents($f);
@@ -810,7 +811,7 @@ class Document extends Node implements \ArrayAccess {
     public function serialize(?Node $node = null, array $config = []): string {
         $node = $node ?? $this;
         if ($node !== $this && $node->ownerDocument !== $this) {
-            throw new DOMException(DOMException::WRONG_DOCUMENT);
+            throw new WrongDocumentError();
         }
 
         return Serializer::serialize($node->innerNode, $config);
@@ -819,7 +820,7 @@ class Document extends Node implements \ArrayAccess {
     public function serializeInner(?Node $node = null, array $config = []): string {
         $node = $node ?? $this;
         if ($node !== $this && $node->ownerDocument !== $this) {
-            throw new DOMException(DOMException::WRONG_DOCUMENT);
+            throw new WrongDocumentError();
         }
 
         return Serializer::serializeInner($node->innerNode, $config);
diff --git a/lib/DocumentOrElement.php b/lib/DocumentOrElement.php
index 5d1bf58..681e3af 100644
--- a/lib/DocumentOrElement.php
+++ b/lib/DocumentOrElement.php
@@ -160,7 +160,7 @@ trait DocumentOrElement {
         #    To validate a qualifiedName, throw an "InvalidCharacterError" DOMException if
         #    qualifiedName does not match the QName production.
         if (preg_match(InnerDocument::QNAME_PRODUCTION_REGEX, $qualifiedName) !== 1) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 3. Let prefix be null.
@@ -190,7 +190,7 @@ trait DocumentOrElement {
             (($qualifiedName === 'xmlns' || $prefix === 'xmlns') && $namespace !== self::XMLNS_NAMESPACE) ||
             ($namespace === self::XMLNS_NAMESPACE && $qualifiedName !== 'xmlns' && $prefix !== 'xmlns')
         ) {
-            throw new DOMException(DOMException::NAMESPACE_ERROR);
+            throw new NamespaceError();
         }
 
         # 10. Return namespace, prefix, and localName.
diff --git a/lib/DocumentType.php b/lib/DocumentType.php
index c233fdd..f2a70e0 100644
--- a/lib/DocumentType.php
+++ b/lib/DocumentType.php
@@ -9,6 +9,7 @@ declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 
 
+/** @property \DOMDocumentType $_innerNode */
 class DocumentType extends Node {
     use ChildNode;
 
diff --git a/lib/Element.php b/lib/Element.php
index d77a82a..8b58e4d 100644
--- a/lib/Element.php
+++ b/lib/Element.php
@@ -16,6 +16,7 @@ use MensBeam\HTML\Parser,
     Symfony\Component\CssSelector\Exception\SyntaxErrorException as SymfonySyntaxErrorException;
 
 
+/** @property \DOMElement $_innerNode */
 class Element extends Node {
     use ChildNode, DocumentOrElement, NonDocumentTypeChildNode, ParentNode;
 
@@ -76,11 +77,13 @@ class Element extends Node {
         // object.
         $context = $this;
         $innerContext = $this->_innerNode;
+        /** @var InnerDocument */
+        $innerOwnerDocument = $innerContext->ownerDocument;
 
         # 2. Let fragment be the result of invoking the fragment parsing algorithm with
         #    the new value as markup, and with context element.
         $innerFragment = Parser::parseFragment($innerContext, Parser::NO_QUIRKS_MODE, $value, 'UTF-8');
-        $fragment = $innerContext->ownerDocument->getWrapperNode($innerFragment);
+        $fragment = $innerOwnerDocument->getWrapperNode($innerFragment);
         $this->postParsingTemplatesFix($innerFragment);
 
         # 3. If the context object is a template element, then let context object be the
@@ -136,6 +139,8 @@ class Element extends Node {
         # 1. Let parent be the context object's parent.
         $parent = $this->parentNode;
         $innerParent = $this->_innerNode->parentNode;
+        /** @var InnerDocument */
+        $innerOwnerDocument = $this->_innerNode->ownerDocument;
 
         # 2. If parent is null, terminate these steps. There would be no way to obtain a
         #    reference to the nodes created even if the remaining steps were run.
@@ -145,7 +150,7 @@ class Element extends Node {
 
         # 3. If parent is a Document, throw a "NoModificationAllowedError" DOMException.
         if ($innerParent instanceof \DOMDocument) {
-            throw new DOMException(DOMException::NO_MODIFICATION_ALLOWED);
+            throw new NoModificationAllowedError();
         }
 
         # 4. If parent is a DocumentFragment, let parent be a new Element with:
@@ -153,13 +158,13 @@ class Element extends Node {
         #       • The HTML namespace as its namespace, and
         #       • The context object's node document as its node document.
         if ($innerParent instanceof \DOMDocumentFragment) {
-            $innerParent = $this->_innerNode->ownerDocument->createElement('body');
+            $innerParent = $innerOwnerDocument->createElement('body');
         }
 
         # 5. Let fragment be the result of invoking the fragment parsing algorithm with
         #    the new value as markup, and parent as the context element.
         $innerFragment = Parser::parseFragment($innerParent, Parser::NO_QUIRKS_MODE, $value, 'UTF-8');
-        $fragment = $this->_innerNode->ownerDocument->getWrapperNode($innerFragment);
+        $fragment = $innerOwnerDocument->getWrapperNode($innerFragment);
         $this->postParsingTemplatesFix($innerFragment);
 
         # 6. Replace the context object with fragment within the context object's
@@ -192,7 +197,7 @@ class Element extends Node {
         } catch (\Exception $e) {
             # 2. If s is failure, throw a "SyntaxError" DOMException.
             if ($e instanceof SymfonySyntaxErrorException) {
-                throw new DOMException(DOMException::SYNTAX_ERROR);
+                throw new SyntaxError();
             }
         }
 
@@ -276,6 +281,8 @@ class Element extends Node {
         }
 
         $qualifiedName = $this->coerceName($qualifiedName);
+        /** @var InnerDocument */
+        $innerOwnerDocument = $this->_innerNode->ownerDocument;
 
         # 2. Return the first attribute in element’s attribute list whose qualified name is
         #    qualifiedName; otherwise null.
@@ -285,7 +292,7 @@ class Element extends Node {
         $attributes = $this->_innerNode->attributes;
         foreach ($attributes as $attr) {
             if ($attr->nodeName === $qualifiedName) {
-                return $this->_innerNode->ownerDocument->getWrapperNode($attr);
+                return $innerOwnerDocument->getWrapperNode($attr);
             }
         }
 
@@ -307,6 +314,8 @@ class Element extends Node {
         }
 
         $localName = $this->coerceName($localName);
+        /** @var InnerDocument */
+        $innerOwnerDocument = $this->_innerNode->ownerDocument;
 
         # 2. Return the attribute in element’s attribute list whose namespace is namespace
         #    and local name is localName, if any; otherwise null.
@@ -316,7 +325,7 @@ class Element extends Node {
         $attributes = $this->_innerNode->attributes;
         foreach ($attributes as $attr) {
             if ($attr->namespaceURI === $namespace && $attr->localName === $localName) {
-                return $this->_innerNode->ownerDocument->getWrapperNode($attr);
+                return $innerOwnerDocument->getWrapperNode($attr);
             }
         }
 
@@ -419,7 +428,7 @@ class Element extends Node {
 
                 # If context is null or a Document, throw a "NoModificationAllowedError" DOMException.
                 if ($context === null || $context instanceof Document) {
-                    throw new DOMException(DOMException::NO_MODIFICATION_ALLOWED);
+                    throw new NoModificationAllowedError();
                 }
             break;
             case 'afterbegin':
@@ -428,7 +437,7 @@ class Element extends Node {
                 $context = $this;
                 $innerContext = $this->_innerNode;
             break;
-            default: throw new DOMException(DOMException::SYNTAX_ERROR);
+            default: throw new SyntaxError();
         }
 
         # 2. If context is not an Element or the following are all true:
@@ -495,7 +504,7 @@ class Element extends Node {
         } catch (\Exception $e) {
             # 2. If s is failure, throw a "SyntaxError" DOMException.
             if ($e instanceof SymfonySyntaxErrorException) {
-                throw new DOMException(DOMException::SYNTAX_ERROR);
+                throw new SyntaxError();
             }
         }
 
@@ -503,9 +512,11 @@ class Element extends Node {
         #    :scope element this, returns success, then return true; otherwise, return
         #    false. [SELECTORS4]
         $innerNode = $this->_innerNode;
+        /** @var InnerDocument */
+        $innerOwnerDocument = $innerNode->ownerDocument;
         // Query the parent as the context node, yes. This is due to how the XPath
         // queries are generated from Symfony.
-        return ($innerNode->ownerDocument->xpath->query($s, $innerNode->parentNode)->item(0) === $innerNode);
+        return ($innerOwnerDocument->xpath->query($s, $innerNode->parentNode)->item(0) === $innerNode);
     }
 
     public function removeAttribute(string $qualifiedName): void {
@@ -527,14 +538,20 @@ class Element extends Node {
         # The removeAttributeNode(attr) method steps are:
         # 1. If this’s attribute list does not contain attr, then throw a
         #    "NotFoundError" DOMException.
-        // PHP's DOM does this already. Will catch its exception and rethrow as HTML-DOM
+        // PHP's DOM does this already. Will catch its exceptions and rethrow as HTML-DOM
         // DOMException.
 
         # 2. Remove attr.
         try {
             $this->_innerNode->removeAttributeNode($attr->innerNode);
         } catch (\DOMException $e) {
-            throw new DOMException($e->code);
+            switch ($e->getCode()) {
+                case 8: throw new NotFoundError();
+                break;
+                case 9: throw new NotSupportedError();
+                break;
+                default: throw new UnknownException();
+            }
         }
 
         # 3. Return attr.
@@ -560,7 +577,7 @@ class Element extends Node {
         # 1. If qualifiedName does not match the Name production in XML, then throw an
         #    "InvalidCharacterError" DOMException.
         if (!preg_match(InnerDocument::NAME_PRODUCTION_REGEX, $qualifiedName)) {
-            throw new DOMException(DOMException::INVALID_CHARACTER);
+            throw new InvalidCharacterError();
         }
 
         # 2. If this is in the HTML namespace and its node document is an HTML document,
@@ -603,7 +620,7 @@ class Element extends Node {
         #    "InUseAttributeError" DOMException.
         $ownerElement = $attr->ownerElement;
         if ($ownerElement !== null && $ownerElement !== $this) {
-            throw new DOMException(DOMException::IN_USE_ATTRIBUTE);
+            throw new InUseAttributeError();
         }
 
         // PHP's DOM doesn't do this method correctly. It returns the old node if it is
@@ -756,7 +773,7 @@ class Element extends Node {
                 return $element->parentNode->insertBefore($node, $element->nextSibling);
             break;
 
-            default: throw new DOMException(DOMException::SYNTAX_ERROR);
+            default: throw new SyntaxError();
         }
     }
 }
\ No newline at end of file
diff --git a/lib/Exception.php b/lib/Exception.php
deleted file mode 100644
index 7dcb04a..0000000
--- a/lib/Exception.php
+++ /dev/null
@@ -1,73 +0,0 @@
-<?php
-/**
- * @license MIT
- * Copyright 2021, Dustin Wilson, J. King et al.
- * See LICENSE and AUTHORS files for details
- */
-
-declare(strict_types=1);
-namespace MensBeam\HTML\DOM;
-
-
-class Exception extends \Exception {
-    const INVALID_CODE = 100;
-    const UNKNOWN_ERROR = 101;
-    const INCORRECT_PARAMETERS_FOR_MESSAGE = 102;
-    const UNREACHABLE_CODE = 103;
-
-    const NONEXISTENT_PROPERTY = 201;
-    const READONLY_PROPERTY = 202;
-    const ARGUMENT_TYPE_ERROR = 203;
-    const UNDEFINED_METHOD = 204;
-    const RETURN_TYPE_ERROR = 205;
-
-
-    protected static $messages = [
-        100 => 'Invalid error code',
-        101 => 'Unknown error; escaping',
-        102 => 'Incorrect number of parameters for Exception message; %s expected',
-        103 => 'Unreachable code',
-
-        201 => 'Property %s does not exist',
-        202 => 'Cannot write readonly property %s',
-        203 => 'Argument #%s ($%s) must be of type %s, %s given',
-        204 => 'Call to undefined method %s::%s()',
-        205 => 'Function should return type %s, %s given'
-    ];
-
-    public function __construct(int $code, ...$args) {
-        if (!isset(self::$messages[$code])) {
-            throw new Exception(Exception::INVALID_CODE);
-        }
-
-        $message = self::$messages[$code];
-        $previous = null;
-
-        // @codeCoverageIgnoreStart
-        if ($args) {
-            // Grab a previous exception if there is one.
-            if ($args[0] instanceof \Throwable) {
-                $previous = array_shift($args);
-            } elseif (end($args) instanceof \Throwable) {
-                $previous = array_pop($args);
-            }
-        }
-        // @codeCoverageIgnoreEnd
-
-        // Count the number of replacements needed in the message.
-        preg_match_all('/(\%(?:\d+\$)?s)/', $message, $matches);
-        $count = count($matches[1]);
-
-        // If the number of replacements don't match the arguments then oops.
-        if (count($args) !== $count) {
-            throw new Exception(Exception::INCORRECT_PARAMETERS_FOR_MESSAGE, $count);
-        }
-
-        if ($count > 0) {
-            // Go through each of the arguments and run sprintf on the strings.
-            $message = call_user_func_array('sprintf', array_merge([$message], $args));
-        }
-
-        parent::__construct($message, $code, $previous);
-    }
-}
diff --git a/lib/FileNotFoundException.php b/lib/FileNotFoundException.php
new file mode 100644
index 0000000..dd175a0
--- /dev/null
+++ b/lib/FileNotFoundException.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class FileNotFoundException extends IOException {
+    public function __construct(int $code = 0, \Throwable $previous = null, string $path = null) {
+        parent::__construct(($path === null) ? 'File could not be found' : sprintf('File "%s" could not be found', $path), $code, $previous);
+    }
+}
\ No newline at end of file
diff --git a/lib/HTMLCollection.php b/lib/HTMLCollection.php
index eb8aa81..c254bf3 100644
--- a/lib/HTMLCollection.php
+++ b/lib/HTMLCollection.php
@@ -7,7 +7,6 @@
 
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
-use MensBeam\HTML\Parser;
 
 
 # An HTMLCollection object is a collection of elements.
diff --git a/lib/HTMLElement.php b/lib/HTMLElement.php
index 9fb0852..cf5e24a 100644
--- a/lib/HTMLElement.php
+++ b/lib/HTMLElement.php
@@ -104,7 +104,7 @@ class HTMLElement extends Element {
             case 'false':
                 $this->setAttribute('contenteditable', $value);
             break;
-            default: throw new DOMException(DOMException::SYNTAX_ERROR);
+            default: throw new SyntaxError();
         }
     }
 
@@ -225,9 +225,10 @@ class HTMLElement extends Element {
         }
 
         $n = $this->_innerNode;
+        /** @var InnerDocument */
         $doc = $n->ownerDocument;
         while ($n = $n->parentNode) {
-            if ($doc->getWrapperNode($n) instanceof HTMLElement && $n->hasAttribute('hidden')) {
+            if ($doc->getWrapperNode($n) instanceof HTMLElement && $n instanceof \DOMElement && $n->hasAttribute('hidden')) {
                 return true;
             }
         }
@@ -334,7 +335,9 @@ class HTMLElement extends Element {
         $n = $this->_innerNode;
         while ($n = $n->parentNode) {
             if ($n instanceof \DOMElement) {
-                if ($n->getAttribute('contenteditable') === 'true' && $n->ownerDocument->getWrapperNode($n) instanceof HTMLElement) {
+                /** @var InnerDocument */
+                $ownerDocument = $n->ownerDocument;
+                if ($n->getAttribute('contenteditable') === 'true' && $ownerDocument->getWrapperNode($n) instanceof HTMLElement) {
                     return true;
                 }
             }
@@ -366,7 +369,7 @@ class HTMLElement extends Element {
         # DOMException.
         $innerNode = $this->_innerNode;
         if ($this->parentNode === null) {
-            throw new DOMException(DOMException::NO_MODIFICATION_ALLOWED);
+            throw new NoModificationAllowedError();
         }
 
         # 2. Let next be this's next sibling.
@@ -391,9 +394,14 @@ class HTMLElement extends Element {
         #    with the next text node given next's previous sibling.
         if ($next !== null && $next->previousSibling instanceof \DOMText) {
             # To merge with the next text node given a Text node node:
+            // This gets confusing because this is a process that's in another section of
+            // the spec, but in this situation _node_ is next's previous sibling, so _node's
+            // next sibling_ will be next.
             # 1. Let next be node's next sibling.
             # 2. If next is not a Text node, then return.
-            // Already checked for
+            if (!$next instanceof \DOMText) {
+                return;
+            }
 
             # 3. Replace data with node, node's data's length, 0, and next's data.
             $next->previousSibling->data .= $next->data;
@@ -476,11 +484,13 @@ class HTMLElement extends Element {
         }
 
         $n = $this->_innerNode;
+        /** @var InnerDocument */
         $doc = $n->ownerDocument;
         while ($n = $n->parentNode) {
             // This looks weird but it's faster to check for the method here first because
             // getting a wrapper node causes a wrapper element to be created if it doesn't
             // already exist. Don't want to create unnecessary wrappers.
+            /** @var \DOMElement $n */
             if (method_exists($n, 'getAttribute') && $n->getAttribute('translate') === 'yes' && $doc->getWrapperNode($n) instanceof HTMLElement) {
                 return true;
             }
@@ -519,7 +529,9 @@ class HTMLElement extends Element {
 
             $n = $element;
             while ($n = $n->parentNode) {
-                if ($n->tagName === 'form' && $n->ownerDocument->getWrapperNode($n) instanceof HTMLElement) {
+                /** @var InnerDocumente */
+                $ownerDocument = $n->ownerDocument;
+                if ($ownerDocument->getWrapperNode($n) instanceof HTMLElement && $n instanceof \DOMElement && $n->tagName === 'form') {
                     return $this->autoCapitalizationHint($n);
                 }
             }
diff --git a/lib/IOException.php b/lib/IOException.php
new file mode 100644
index 0000000..46ed791
--- /dev/null
+++ b/lib/IOException.php
@@ -0,0 +1,11 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class IOException extends \RuntimeException {}
\ No newline at end of file
diff --git a/lib/Inner/Document.php b/lib/Inner/Document.php
index 7b80e2b..4e25d69 100644
--- a/lib/Inner/Document.php
+++ b/lib/Inner/Document.php
@@ -68,7 +68,7 @@ class Document extends \DOMDocument {
         }
 
         if ($node instanceof \DOMDocument) {
-            throw new DOMException(DOMException::NOT_SUPPORTED);
+            throw new NotSupportedError();
         }
 
         // There's no way to see whether unappended doctypes are owned by a document in
@@ -76,7 +76,7 @@ class Document extends \DOMDocument {
         // document. This is worked around in the wrapper DOM but a problem here when
         // creating the wrapper node.
         if (!$node instanceof \DOMDocumentType && $node->ownerDocument !== $this) {
-            throw new DOMException(DOMException::WRONG_DOCUMENT);
+            throw new WrongDocumentError();
         }
 
         // If the wrapper node already exists then return that.
diff --git a/lib/NamedNodeMap.php b/lib/NamedNodeMap.php
index 2ed616b..e2309f6 100644
--- a/lib/NamedNodeMap.php
+++ b/lib/NamedNodeMap.php
@@ -7,11 +7,8 @@
 
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
-use MensBeam\HTML\DOM\Inner\{
-    Document as InnerDocument,
-    Reflection
-};
-use MensBeam\HTML\Parser\NameCoercion;
+use MensBeam\HTML\DOM\Inner\Document as InnerDocument,
+    MensBeam\HTML\Parser\NameCoercion;
 
 
 class NamedNodeMap extends Collection {
@@ -124,7 +121,7 @@ class NamedNodeMap extends Collection {
 
         # 2. If attr is null, then throw a "NotFoundError" DOMException.
         if ($attr === null) {
-            throw new DOMException(DOMException::NOT_FOUND);
+            throw new NotFoundError();
         }
 
         # 3. Return attr.
diff --git a/lib/Node.php b/lib/Node.php
index 606a86b..8d62161 100644
--- a/lib/Node.php
+++ b/lib/Node.php
@@ -8,7 +8,6 @@
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 use MensBeam\GettersAndSetters,
-    MensBeam\HTML\Parser,
     MensBeam\HTML\Parser\NameCoercion;
 use MensBeam\HTML\DOM\Inner\{
     Document as InnerDocument,
@@ -227,11 +226,12 @@ abstract class Node implements \Stringable {
         # otherwise this’s node document.
         // PHP's DOM does this correctly on everything but document types. That's taken
         // care of in DocumentType.
-        if ($this instanceof Document || !$ownerDocument = $this->_innerNode->ownerDocument) {
+        /** @var InnerDocument $ownerDocument */
+        if ($this instanceof Document || !($ownerDocument = $this->_innerNode->ownerDocument)) {
             return null;
         }
 
-        return $this->_innerNode->ownerDocument->getWrapperNode($ownerDocument);
+        return $ownerDocument->getWrapperNode($ownerDocument);
     }
 
     protected function __get_parentElement(): ?Element {
@@ -376,6 +376,7 @@ abstract class Node implements \Stringable {
         # 5. If node2 is an attribute, then:
         if ($node2 instanceof Attr) {
             # 1. Set attr2 to node2 and node2 to attr2’s element.
+            /** @var \DOMAttr $innerNode2 */
             $attr2 = $innerNode2;
             $node2 = $attr2->ownerElement;
             $innerNode2 = $innerNode2->ownerElement;
@@ -480,7 +481,13 @@ abstract class Node implements \Stringable {
         while ($n = $n->parentNode) {
             $root = $n;
         }
-        return (!$root instanceof InnerDocument) ? $root->ownerDocument->getWrapperNode($root) : $root->wrapperNode;
+
+        if (!$root instanceof InnerDocument) {
+            /** @var Node $root */
+            return $root->ownerDocument->getWrapperNode($root);
+        }
+
+        return $root->wrapperNode;
     }
 
     public function hasChildNodes(): bool {
@@ -612,7 +619,7 @@ abstract class Node implements \Stringable {
         # 1. If parent is not a Document, DocumentFragment, or Element node, then throw
         #    a "HierarchyRequestError" DOMException.
         if (!$inner instanceof InnerDocument && !$inner instanceof \DOMDocumentFragment && !$inner instanceof \DOMElement) {
-            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+            throw new HierarchyRequestError();
         }
 
         # 2. If node is a host-including inclusive ancestor of parent, then throw a
@@ -621,25 +628,25 @@ abstract class Node implements \Stringable {
         // host-including inclusive ancestor of child, but it should. All browsers check
         // for this.
         if ($this->containsInner($node, $inner) || $this->containsInner($node, $child)) {
-            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+            throw new HierarchyRequestError();
         }
 
         # 3. If child’s parent is not parent, then throw a "NotFoundError" DOMException.
         if ($child->parentNode !== $inner) {
-            throw new DOMException(DOMException::NOT_FOUND);
+            throw new NotFoundError();
         }
 
         # 4. If node is not a DocumentFragment, DocumentType, Element, or CharacterData
         #    node, then throw a "HierarchyRequestError" DOMException.
         if (!$node instanceof \DOMDocumentFragment && !$node instanceof \DOMDocumentType && !$node instanceof \DOMElement && !$node instanceof \DOMCharacterData) {
-            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+            throw new HierarchyRequestError();
         }
 
         # 5. If either node is a Text node and parent is a document, or node is a
         #    doctype and parent is not a document, then throw a "HierarchyRequestError"
         #    DOMException.
         if (($node instanceof \DOMText && $inner instanceof InnerDocument) || ($node instanceof \DOMDocumentType && !$inner instanceof InnerDocument)) {
-            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+            throw new HierarchyRequestError();
         }
 
         # 6. If parent is a document, and any of the statements below, switched on the
@@ -653,14 +660,14 @@ abstract class Node implements \Stringable {
             if ($node instanceof \DOMDocumentFragment) {
                 $nodeChildElementCount = $node->childElementCount;
                 if ($nodeChildElementCount > 1) {
-                    throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                    throw new HierarchyRequestError();
                 }
 
                 $n = $node->firstChild;
                 if ($n !== null) {
                     do {
                         if ($n instanceof \DOMText) {
-                            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                            throw new HierarchyRequestError();
                         }
                     } while ($n = $n->nextSibling);
                 }
@@ -671,7 +678,7 @@ abstract class Node implements \Stringable {
                         $beforeChild = ($n !== $child);
                         do {
                             if (($n instanceof \DOMElement && $n !== $child) || (!$beforeChild && $n instanceof \DOMDocumentType)) {
-                                throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                                throw new HierarchyRequestError();
                             } elseif ($n === $child) {
                                 $beforeChild = false;
                             }
@@ -689,7 +696,7 @@ abstract class Node implements \Stringable {
                     $beforeChild = ($n !== $child);
                     do {
                         if (($n instanceof \DOMElement && $n !== $child) || (!$beforeChild && $n instanceof \DOMDocumentType)) {
-                            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                            throw new HierarchyRequestError();
                         } elseif ($n === $child) {
                             $beforeChild = false;
                         }
@@ -706,7 +713,7 @@ abstract class Node implements \Stringable {
                     $beforeChild = ($n !== $child);
                     do {
                         if (($n instanceof \DOMDocumentType && $n !== $child) || $beforeChild && $n instanceof \DOMElement) {
-                            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                            throw new HierarchyRequestError();
                         } elseif ($n === $child) {
                             $beforeChild = false;
                         }
@@ -824,14 +831,18 @@ abstract class Node implements \Stringable {
                 #    with the clone children flag set.
                 # 3. Append copied contents to copy's template contents.
                 // Template contents are stored in the wrapper nodes.
-                $copyWrapperContent = $copy->ownerDocument->getWrapperNode($copy)->content;
+                /** @var InnerDocument */
+                $copyOwnerDocument = $copy->ownerDocument;
+                $copyWrapperContent = $copyOwnerDocument->getWrapperNode($copy)->content;
 
                 // If the cloning is called for as a result of parsing serialized markup the
                 // contents of the node should be appended to the wrapper element's content
                 // document fragment. Otherwise, clone the content document fragment instead.
                 if (!$parsing) {
                     $copyWrapperContentInner = $copyWrapperContent->innerNode;
-                    $nodeWrapperContent = $node->ownerDocument->getWrapperNode($node)->content->innerNode;
+                    /** @var InnerDocument */
+                    $nodeWrapperOwnerDocument = $node->ownerDocument;
+                    $nodeWrapperContent = $nodeWrapperOwnerDocument->getWrapperNode($node)->content->innerNode;
                     $childNodes = $nodeWrapperContent->childNodes;
                     if ($childNodes->length > 0) {
                         // This garbage is necessary because the appendChildInner method
@@ -1063,6 +1074,7 @@ abstract class Node implements \Stringable {
         # ↪ DocumentType
         #      Its name, public ID, and system ID.
         if ($thisNode instanceof \DOMDocumentType) {
+            /** @var \DOMDocumentType $otherNode */
             if ($thisNode->name !== $otherNode->name || $thisNode->publicId !== $otherNode->publicId || $thisNode->systemId !== $thisNode->publicId) {
                 return false;
             }
@@ -1070,6 +1082,7 @@ abstract class Node implements \Stringable {
         # ↪ Element
         #      Its namespace, namespace prefix, local name, and its attribute list’s size.
         elseif ($thisNode instanceof \DOMElement) {
+            /** @var \DOMElement $otherNode */
             $otherAttributes = $otherNode->attributes;
             if ($thisNode->namespaceURI !== $otherNode->namespaceURI || $thisNode->prefix !== $otherNode->prefix || $thisNode->localName !== $otherNode->localName || $thisNode->attributes->length !== $otherAttributes->length) {
                 return false;
@@ -1091,6 +1104,7 @@ abstract class Node implements \Stringable {
         # ↪ Attr
         #       Its namespace, local name, and value.
         elseif ($thisNode instanceof \DOMAttr) {
+            /** @var \DOMAttr $otherNode */
             if ($thisNode->namespaceURI !== $otherNode->namespaceURI || $thisNode->localName !== $otherNode->localName || $thisNode->value !== $otherNode->value) {
                 return false;
             }
@@ -1099,12 +1113,14 @@ abstract class Node implements \Stringable {
         # ↪ Comment
         #      Its data.
         elseif ($thisNode instanceof \DOMText || $thisNode instanceof \DOMComment) {
+            /** @var \DOMText|\DOMComment $otherNode */
             if ($thisNode->data !== $otherNode->data) {
                 return false;
             }
         }
 
         if ($thisNode instanceof \DOMDocument || $thisNode instanceof \DOMDocumentFragment || $thisNode instanceof \DOMElement) {
+            /** @var \DOMDocument|\DOMDocumentFragment|\DOMElement $otherNode */
             # • A and B have the same number of children.
             if ($thisNode->childNodes->length !== $otherNode->childNodes->length) {
                 return false;
@@ -1129,7 +1145,9 @@ abstract class Node implements \Stringable {
         # ↪ Element
         if ($node instanceof \DOMElement) {
             // Work around PHP DOM HTML namespace bug
-            if ($node->namespaceURI === null && !$node->ownerDocument->getWrapperNode($node->ownerDocument) instanceof XMLDocument) {
+            /** @var \InnerDocument */
+            $ownerDocument = $node->ownerDocument;
+            if ($node->namespaceURI === null && !$ownerDocument->getWrapperNode($ownerDocument) instanceof XMLDocument) {
                 $namespace = self::HTML_NAMESPACE;
             } else {
                 $namespace = $node->namespaceURI;
@@ -1289,7 +1307,9 @@ abstract class Node implements \Stringable {
         // below walks through this node and temporarily replaces foreign descendants
         // with bullshit elements which are then replaced once the node is inserted.
         if ($element->namespaceURI === null && ($this instanceof DocumentFragment || $this->getRootNode() !== null) && $element->hasChildNodes()) {
-            $foreign = $element->ownerDocument->xpath->query('.//*[parent::*[namespace-uri()=""] and not(namespace-uri()="") and name()=local-name()]', $element);
+            /** @var InnerDocument */
+            $ownerDocument = $element->ownerDocument;
+            $foreign = $ownerDocument->xpath->query('.//*[parent::*[namespace-uri()=""] and not(namespace-uri()="") and name()=local-name()]', $element);
             $this->bullshitReplacements = [];
             if ($foreign->length > 0) {
                 $count = 0;
@@ -1317,7 +1337,7 @@ abstract class Node implements \Stringable {
         # 1. If parent is not a Document, DocumentFragment, or Element node, then throw
         #    a "HierarchyRequestError" Exception.
         if (!$parent instanceof InnerDocument && !$parent instanceof \DOMDocumentFragment && !$parent instanceof \DOMElement) {
-            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+            throw new HierarchyRequestError();
         }
 
         # 2. If node is a host-including inclusive ancestor of parent, then throw a
@@ -1328,7 +1348,7 @@ abstract class Node implements \Stringable {
         # host-including inclusive ancestor of B’s root’s host.
         if ($node->parentNode !== null) {
             if ($parent->parentNode !== null && ($parent === $node || $this->containsInner($node, $parent))) {
-                throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                throw new HierarchyRequestError();
             } else {
                 $n = $parent;
                 do {
@@ -1336,10 +1356,12 @@ abstract class Node implements \Stringable {
                 } while ($n = $n->parentNode);
 
                 if ($parentRoot instanceof \DOMDocumentFragment) {
-                    $wrappedParentRoot = $parentRoot->ownerDocument->getWrapperNode($parentRoot);
+                    /** @var InnerDocument */
+                    $ownerDocument = $parentRoot->ownerDocument;
+                    $wrappedParentRoot = $ownerDocument->getWrapperNode($parentRoot);
                     $parentRootHost = Reflection::getProtectedProperty($wrappedParentRoot, 'host');
                     if ($parentRootHost !== null && ($parentRootHost === $node || $this->containsInner($node, $parentRootHost->get()->innerNode))) {
-                        throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                        throw new HierarchyRequestError();
                     }
                 }
             }
@@ -1348,21 +1370,21 @@ abstract class Node implements \Stringable {
         # 3. If child is non-null and its parent is not parent, then throw a
         #    "NotFoundError" Exception.
         if ($child !== null && ($child->parentNode === null || $child->parentNode !== $parent)) {
-            throw new DOMException(DOMException::NOT_FOUND);
+            throw new NotFoundError();
         }
 
         # 4. If node is not a DocumentFragment, DocumentType, Element, Text,
         #    ProcessingInstruction, or Comment node, then throw a "HierarchyRequestError"
         #    Exception.
         if (!$node instanceof \DOMDocumentFragment && !$node instanceof \DOMDocumentType && !$node instanceof \DOMElement && !$node instanceof \DOMText && !$node instanceof \DOMProcessingInstruction && !$node instanceof \DOMComment) {
-            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+            throw new HierarchyRequestError();
         }
 
         # 5. If either node is a Text node and parent is a document, or node is a
         #    doctype and parent is not a document, then throw a "HierarchyRequestError"
         #    Exception.
         if (($node instanceof \DOMText && $parent instanceof \DOMDocument) || ($node instanceof \DOMDocumentType && !$parent instanceof InnerDocument)) {
-            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+            throw new HierarchyRequestError();
         }
 
         # 6. If parent is a document, and any of the statements below, switched on the
@@ -1377,13 +1399,13 @@ abstract class Node implements \Stringable {
             if ($node instanceof \DOMDocumentFragment) {
                 $nodeChildElementCount = $node->childElementCount;
                 if ($nodeChildElementCount > 1) {
-                    throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                    throw new HierarchyRequestError();
                 } else {
                     $n = $node->firstChild;
                     if ($n !== null) {
                         do {
                             if ($n instanceof \DOMText) {
-                                throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                                throw new HierarchyRequestError();
                             }
                         } while ($n = $n->nextSibling);
                     }
@@ -1391,14 +1413,14 @@ abstract class Node implements \Stringable {
 
                 if ($nodeChildElementCount === 1) {
                     if ($parent->childElementCount > 0 || $child instanceof \DOMDocumentType) {
-                        throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                        throw new HierarchyRequestError();
                     }
 
                     if ($child !== null) {
                         $n = $child;
                         while ($n = $n->nextSibling) {
                             if ($n instanceof \DOMDocumentType) {
-                                throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                                throw new HierarchyRequestError();
                             }
                         }
                     }
@@ -1410,14 +1432,14 @@ abstract class Node implements \Stringable {
             #      doctype is following child.
             elseif ($node instanceof \DOMElement) {
                 if ($child instanceof \DOMDocumentType) {
-                    throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                    throw new HierarchyRequestError();
                 }
 
                 if ($child !== null) {
                     $n = $child;
                     while ($n = $n->nextSibling) {
                         if ($n instanceof \DOMDocumentType) {
-                            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                            throw new HierarchyRequestError();
                         }
                     }
                 }
@@ -1426,7 +1448,7 @@ abstract class Node implements \Stringable {
                     $n = $parent->firstChild;
                     do {
                         if ($n instanceof \DOMElement) {
-                            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                            throw new HierarchyRequestError();
                         }
                     } while ($n = $n->nextSibling);
                 }
@@ -1441,7 +1463,7 @@ abstract class Node implements \Stringable {
                     $n = $firstChild;
                     do {
                         if ($n instanceof \DOMDocumentType || ($child === null && $n instanceof \DOMElement)) {
-                            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                            throw new HierarchyRequestError();
                         }
                     } while ($n = $n->nextSibling);
                 }
@@ -1450,7 +1472,7 @@ abstract class Node implements \Stringable {
                     $n = $child;
                     while ($n = $n->previousSibling) {
                         if ($n instanceof \DOMElement) {
-                            throw new DOMException(DOMException::HIERARCHY_REQUEST_ERROR);
+                            throw new HierarchyRequestError();
                         }
                     }
                 }
diff --git a/lib/NonDocumentTypeChildNode.php b/lib/NonDocumentTypeChildNode.php
index 9bbc256..5cd5285 100644
--- a/lib/NonDocumentTypeChildNode.php
+++ b/lib/NonDocumentTypeChildNode.php
@@ -7,10 +7,6 @@
 
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
-use MensBeam\HTML\DOM\Inner\{
-    Document as InnerDocument,
-    Reflection
-};
 
 
 trait NonDocumentTypeChildNode {
diff --git a/lib/NonElementParentNode.php b/lib/NonElementParentNode.php
index 4d59902..ed508a9 100644
--- a/lib/NonElementParentNode.php
+++ b/lib/NonElementParentNode.php
@@ -7,11 +7,6 @@
 
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
-use MensBeam\HTML\DOM\Inner\{
-    Document as InnerDocument,
-    Reflection
-};
-use MensBeam\HTML\Parser;
 
 
 trait NonElementParentNode {
diff --git a/lib/OutOfBoundsException.php b/lib/OutOfBoundsException.php
new file mode 100644
index 0000000..7187e2d
--- /dev/null
+++ b/lib/OutOfBoundsException.php
@@ -0,0 +1,11 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class OutOfBoundsException extends \OutOfBoundsException {}
diff --git a/lib/ParentNode.php b/lib/ParentNode.php
index 97b1efa..480cd16 100644
--- a/lib/ParentNode.php
+++ b/lib/ParentNode.php
@@ -7,10 +7,7 @@
 
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
-use MensBeam\HTML\DOM\Inner\{
-    Document as InnerDocument,
-    Reflection
-};
+use MensBeam\HTML\DOM\Inner\Reflection;
 use Symfony\Component\CssSelector\CssSelectorConverter,
     Symfony\Component\CssSelector\Exception\SyntaxErrorException as SymfonySyntaxErrorException;
 
@@ -121,7 +118,7 @@ trait ParentNode {
                     continue 2;
                     case Node::WALK_REJECT:
                     break;
-                    default: throw new DOMException(DOMException::SYNTAX_ERROR);
+                    default: throw new SyntaxError();
                 }
 
                 if ($node->parentNode !== null && $node->hasChildNodes()) {
@@ -146,7 +143,7 @@ trait ParentNode {
             // so only throw exception when an actual syntax error, otherwise return an
             // empty nodelist.
             if ($e instanceof SymfonySyntaxErrorException) {
-                throw new DOMException(DOMException::SYNTAX_ERROR);
+                throw new SyntaxError();
             }
 
             return new \DOMNodeList;
diff --git a/lib/ProcessingInstruction.php b/lib/ProcessingInstruction.php
index 8dc305c..f0b430b 100644
--- a/lib/ProcessingInstruction.php
+++ b/lib/ProcessingInstruction.php
@@ -9,6 +9,7 @@ declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 
 
+/** @property \DOMProcessingInstruction $_innerNode */
 class ProcessingInstruction extends CharacterData {
     protected function __get_target(): string {
         // Need to uncoerce string if necessary.
diff --git a/lib/Serializer.php b/lib/Serializer.php
index 4699ea2..fc008c0 100644
--- a/lib/Serializer.php
+++ b/lib/Serializer.php
@@ -8,20 +8,21 @@
 declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 use MensBeam\HTML\DOM\Inner\Reflection,
-    MensBeam\HTML\Parser;
-use MensBeam\HTML\Parser\{
-    Config,
-    Serializer as ParserSerializer
-};
+    MensBeam\HTML\Parser,
+    MensBeam\HTML\Parser\Serializer as ParserSerializer;
 
 
 class Serializer extends ParserSerializer {
     protected static function fragmentHasHost(\DOMDocumentFragment $fragment): bool {
-        return (Reflection::getProtectedProperty($fragment->ownerDocument->getWrapperNode($fragment), 'host') !== null);
+        /** @var InnerDocument */
+        $ownerDocument = $fragment->ownerDocument;
+        return (Reflection::getProtectedProperty($ownerDocument->getWrapperNode($fragment), 'host') !== null);
     }
 
     protected static function getTemplateContent(\DOMElement $node): \DOMNode {
-        return $node->ownerDocument->getWrapperNode($node)->content->innerNode;
+        /** @var InnerDocument */
+        $ownerDocument = $node->ownerDocument;
+        return $ownerDocument->getWrapperNode($node)->content->innerNode;
     }
 
     protected static function isPreformattedContent(\DOMNode $node): bool {
@@ -32,7 +33,9 @@ class Serializer extends ParserSerializer {
                     return true;
                 }
             } elseif ($n instanceof \DOMDocumentFragment) {
-                $host = Reflection::getProtectedProperty($node->ownerDocument->getWrapperNode($n), 'host');
+                /** @var InnerDocument */
+                $ownerDocument = $node->ownerDocument;
+                $host = Reflection::getProtectedProperty($ownerDocument->getWrapperNode($n), 'host');
                 if ($host !== null) {
                     $n = $host->get()->innerNode;
                 }
@@ -43,6 +46,7 @@ class Serializer extends ParserSerializer {
     }
 
     protected static function treatAsBlockWithTemplates(\DOMNode $node): bool {
+        /** @var InnerDocument */
         $document = $node->ownerDocument;
         $xpath = $document->xpath;
         $templates = $xpath->query('.//template[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"][not(ancestor::iframe[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::listing[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::noembed[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::noframes[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::noscript[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::plaintext[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::pre[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::style[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::script[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::textarea[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::title[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"] or ancestor::xmp[namespace-uri()="" or namespace-uri()="http://www.w3.org/1999/xhtml"])]', $node);
diff --git a/lib/Text.php b/lib/Text.php
index 0538f52..5586f03 100644
--- a/lib/Text.php
+++ b/lib/Text.php
@@ -9,6 +9,7 @@ declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 
 
+/** @property \DOMText $_innerNode */
 class Text extends CharacterData {
     protected function __get_wholeText(): string {
         // PHP's DOM does this correctly already.
@@ -19,11 +20,21 @@ class Text extends CharacterData {
     public function splitText(int $offset): Text {
         // PHP DOM mostly handles this correctly with the exception of not throwing an
         // exception when the offset is greater than the length, so let's fix that.
-        if ($offset > $this->length) {
-            throw new DOMException(DOMException::INDEX_SIZE_ERROR);
+        // DEVIATION?: All browsers error when supplying negative numbers here, so let's check for that, too.
+        if ($offset < 0 || $offset > $this->length) {
+            # 2. If offset is greater than length, then throw an "IndexSizeError" DOMException.
+            // DEVIATION?: WebIDL standard
+            // (https://webidl.spec.whatwg.org/#idl-DOMException-error-names) says
+            // IndexSizeError is deprecated and to use RangeError instead which isn't a
+            // DOMException but specified to be an analog of ECMAScript's built-in errors.
+            // Because of this we're going to use OutOfBoundsException which is PHP's
+            // equivalent.
+            throw new OutOfBoundsException(sprintf('Offset %s is outside of Text node\'s range of %s to %s', $offset, 0, $this->length));
         }
 
-        return $this->_innerNode->ownerDocument->getWrapperNode($this->_innerNode->splitText($offset));
+        /** @var \MensBeam\HTML\DOM\Inner\Document */
+        $ownerDocument = $this->_innerNode->ownerDocument;
+        return $ownerDocument->getWrapperNode($this->_innerNode->splitText($offset));
     }
 
 
diff --git a/lib/UnknownException.php b/lib/UnknownException.php
new file mode 100644
index 0000000..d4a5ace
--- /dev/null
+++ b/lib/UnknownException.php
@@ -0,0 +1,15 @@
+<?php
+/**
+ * @license MIT
+ * Copyright 2017 Dustin Wilson, J. King, et al.
+ * See LICENSE and AUTHORS files for details
+ */
+
+declare(strict_types=1);
+namespace MensBeam\HTML\DOM;
+
+class UnknownException extends \LogicException {
+    public function __construct(int $code = 0, ?\Throwable $previous = null) {
+        parent::__construct('The program reached an invalid state; this error should be reported', $code, $previous);
+    }
+}
\ No newline at end of file
diff --git a/lib/XMLDocument.php b/lib/XMLDocument.php
index bc5679f..1b5fdb2 100644
--- a/lib/XMLDocument.php
+++ b/lib/XMLDocument.php
@@ -16,7 +16,7 @@ class XMLDocument extends Document {
 
     public function load(string $source = null, ?string $charset = null): void {
         if ($this->hasChildNodes()) {
-            throw new DOMException(DOMException::NO_MODIFICATION_ALLOWED);
+            throw new NoModificationAllowedError();
         }
 
         $this->_innerNode->encoding = Charset::fromCharset((string)$charset) ?? 'UTF-8';
diff --git a/lib/XPathEvaluate.php b/lib/XPathEvaluate.php
index 073daad..8c0c66d 100644
--- a/lib/XPathEvaluate.php
+++ b/lib/XPathEvaluate.php
@@ -82,7 +82,7 @@ trait XPathEvaluate {
                     $resultType = XPathResult::ORDERED_NODE_ITERATOR_TYPE;
                 break;
                 default:
-                    throw new DOMException(DOMException::NOT_SUPPORTED);
+                    throw new NotSupportedError();
             }
         } else {
             switch ($type) {
@@ -148,7 +148,7 @@ trait XPathEvaluate {
                     $result = $result->item(0);
                 break;
 
-                default: throw new DOMException(DOMException::NOT_SUPPORTED);
+                default: throw new NotSupportedError();
             }
 
             $resultType = $type;
diff --git a/lib/XPathException.php b/lib/XPathException.php
index 7165751..64e7348 100644
--- a/lib/XPathException.php
+++ b/lib/XPathException.php
@@ -9,18 +9,22 @@ declare(strict_types=1);
 namespace MensBeam\HTML\DOM;
 
 
-class XPathException extends Exception {
+class XPathException extends \Exception {
     public const INVALID_EXPRESSION = 51;
     public const TYPE_ERROR = 52;
     public const UNRESOLVABLE_NAMESPACE_PREFIX = 53;
 
-    public function __construct(int $code, ...$args) {
-        self::$messages = array_replace(parent::$messages, [
-              51 => 'Invalid expression error',
-              52 => 'Expression cannot be converted to the specified type',
-              53 => 'Unresolvable namespace prefix'
-        ]);
+    public function __construct(int $code = 0, ?\Throwable $previous = null) {
+        switch ($code) {
+            case self::INVALID_EXPRESSION: $message = 'Invalid expression error';
+            break;
+            case self::TYPE_ERROR: $message = 'Expression cannot be converted to the specified type';
+            break;
+            case self::UNRESOLVABLE_NAMESPACE_PREFIX: $message = 'Unresolvable namespace prefix';
+            break;
+            default: throw new UnknownException();
+        }
 
-        parent::__construct($code, ...$args);
+        parent::__construct($message, $code, $previous);
     }
 }
diff --git a/robo b/robo
deleted file mode 100755
index e096c36..0000000
--- a/robo
+++ /dev/null
@@ -1,14 +0,0 @@
-#! /bin/sh
-base=`dirname "$0"`
-roboCommand="$1"
-if [ $# -eq 0 ]; then
-    "$base/vendor/bin/robo"
-else
-    shift
-    ulimit -n 2048
-    if [ "$1" = "clean" ]; then
-        "$base/vendor/bin/robo" "$roboCommand" "$@"
-    else
-        "$base/vendor/bin/robo" "$roboCommand" -- "$@"
-    fi
-fi
diff --git a/robo.bat b/robo.bat
deleted file mode 100644
index d50b8a7..0000000
--- a/robo.bat
+++ /dev/null
@@ -1,21 +0,0 @@
-@echo off
-setlocal
-set base=%~dp0
-set roboCommand=%1
-
-rem get all arguments except the first
-shift
-set "args="
-:parse
-if "%~1" neq "" (
-  set args=%args% %1
-  shift
-  goto :parse
-)
-if defined args set args=%args:~1%
-
-if "%1"=="clean" (
-    call "%base%vendor\bin\robo" "%roboCommand%" %args%
-) else (
-    call "%base%vendor\bin\robo" "%roboCommand%" -- %args%
-)