diff --git a/.phan/config.php b/.phan/config.php
new file mode 100644
index 0000000..40fe568
--- /dev/null
+++ b/.phan/config.php
@@ -0,0 +1,247 @@
+<?php
+
+use \Phan\Issue;
+
+/**
+ * This configuration will be read and overlayed on top of the
+ * default configuration. Command line arguments will be applied
+ * after this file is read.
+ *
+ * @see src/Phan/Config.php
+ * See Config for all configurable options.
+ *
+ * A Note About Paths
+ * ==================
+ *
+ * Files referenced from this file should be defined as
+ *
+ * ```
+ *   Config::projectPath('relative_path/to/file')
+ * ```
+ *
+ * where the relative path is relative to the root of the
+ * project which is defined as either the working directory
+ * of the phan executable or a path passed in via the CLI
+ * '-d' flag.
+ */
+return [
+
+    // If true, missing properties will be created when
+    // they are first seen. If false, we'll report an
+    // error message.
+    "allow_missing_properties" => false,
+
+    // Allow null to be cast as any type and for any
+    // type to be cast to null.
+    "null_casts_as_any_type" => false,
+
+    // If enabled, scalars (int, float, bool, string, null)
+    // are treated as if they can cast to each other.
+    'scalar_implicit_cast' => false,
+
+    // If true, seemingly undeclared variables in the global
+    // scope will be ignored. This is useful for projects
+    // with complicated cross-file globals that you have no
+    // hope of fixing.
+    'ignore_undeclared_variables_in_global_scope' => false,
+
+    // Backwards Compatibility Checking
+    'backward_compatibility_checks' => false,
+
+    // If enabled, check all methods that override a
+    // parent method to make sure its signature is
+    // compatible with the parent's. This check
+    // can add quite a bit of time to the analysis.
+    'analyze_signature_compatibility' => true,
+
+    // Set to true in order to attempt to detect dead
+    // (unreferenced) code. Keep in mind that the
+    // results will only be a guess given that classes,
+    // properties, constants and methods can be referenced
+    // as variables (like `$class->$property` or
+    // `$class->$method()`) in ways that we're unable
+    // to make sense of.
+    'dead_code_detection' => false,
+
+    // Run a quick version of checks that takes less
+    // time
+    "quick_mode" => false,
+
+    // Enable or disable support for generic templated
+    // class types.
+    'generic_types_enabled' => true,
+
+    // By default, Phan will not analyze all node types
+    // in order to save time. If this config is set to true,
+    // Phan will dig deeper into the AST tree and do an
+    // analysis on all nodes, possibly finding more issues.
+    //
+    // See \Phan\Analysis::shouldVisit for the set of skipped
+    // nodes.
+    'should_visit_all_nodes' => true,
+
+    'runkit_superglobals' => ['_DATE', '_RK'],
+
+    'globals_type_map' => [
+        '_DATE' => '\\DateTime',
+        '_RK'  => '\\RunkitGlobal',
+    ],
+
+    // The minimum severity level to report on. This can be
+    // set to Issue::SEVERITY_LOW, Issue::SEVERITY_NORMAL or
+    // Issue::SEVERITY_CRITICAL.
+    'minimum_severity' => Issue::SEVERITY_LOW,
+
+    // Add any issue types (such as 'PhanUndeclaredMethod')
+    // here to inhibit them from being reported
+    'suppress_issue_types' => [
+        // 'PhanUndeclaredMethod',
+    ],
+
+    // If empty, no filter against issues types will be applied.
+    // If non-empty, only issues within the list will be emitted
+    // by Phan.
+    'whitelist_issue_types' => [
+        // 'PhanAccessMethodPrivate',
+        // 'PhanAccessMethodProtected',
+        // 'PhanAccessNonStaticToStatic',
+        // 'PhanAccessPropertyPrivate',
+        // 'PhanAccessPropertyProtected',
+        // 'PhanAccessSignatureMismatch',
+        // 'PhanAccessSignatureMismatchInternal',
+        // 'PhanAccessStaticToNonStatic',
+        // 'PhanCompatibleExpressionPHP7',
+        // 'PhanCompatiblePHP7',
+        // 'PhanContextNotObject',
+        // 'PhanDeprecatedClass',
+        // 'PhanDeprecatedFunction',
+        // 'PhanDeprecatedProperty',
+        // 'PhanEmptyFile',
+        // 'PhanNonClassMethodCall',
+        // 'PhanNoopArray',
+        // 'PhanNoopClosure',
+        // 'PhanNoopConstant',
+        // 'PhanNoopProperty',
+        // 'PhanNoopVariable',
+        // 'PhanParamRedefined',
+        // 'PhanParamReqAfterOpt',
+        // 'PhanParamSignatureMismatch',
+        // 'PhanParamSignatureMismatchInternal',
+        // 'PhanParamSpecial1',
+        // 'PhanParamSpecial2',
+        // 'PhanParamSpecial3',
+        // 'PhanParamSpecial4',
+        // 'PhanParamTooFew',
+        // 'PhanParamTooFewInternal',
+        // 'PhanParamTooMany',
+        // 'PhanParamTooManyInternal',
+        // 'PhanParamTypeMismatch',
+        // 'PhanParentlessClass',
+        // 'PhanRedefineClass',
+        // 'PhanRedefineClassInternal',
+        // 'PhanRedefineFunction',
+        // 'PhanRedefineFunctionInternal',
+        // 'PhanStaticCallToNonStatic',
+        // 'PhanSyntaxError',
+        // 'PhanTraitParentReference',
+        // 'PhanTypeArrayOperator',
+        // 'PhanTypeArraySuspicious',
+        // 'PhanTypeComparisonFromArray',
+        // 'PhanTypeComparisonToArray',
+        // 'PhanTypeConversionFromArray',
+        // 'PhanTypeInstantiateAbstract',
+        // 'PhanTypeInstantiateInterface',
+        // 'PhanTypeInvalidLeftOperand',
+        // 'PhanTypeInvalidRightOperand',
+        // 'PhanTypeMismatchArgument',
+        // 'PhanTypeMismatchArgumentInternal',
+        // 'PhanTypeMismatchDefault',
+        // 'PhanTypeMismatchForeach',
+        // 'PhanTypeMismatchProperty',
+        // 'PhanTypeMismatchReturn',
+        // 'PhanTypeMissingReturn',
+        // 'PhanTypeNonVarPassByRef',
+        // 'PhanTypeParentConstructorCalled',
+        // 'PhanTypeVoidAssignment',
+        // 'PhanUnanalyzable',
+        // 'PhanUndeclaredClass',
+        // 'PhanUndeclaredClassCatch',
+        // 'PhanUndeclaredClassConstant',
+        // 'PhanUndeclaredClassInstanceof',
+        // 'PhanUndeclaredClassMethod',
+        // 'PhanUndeclaredClassReference',
+        // 'PhanUndeclaredConstant',
+        // 'PhanUndeclaredExtendedClass',
+        // 'PhanUndeclaredFunction',
+        // 'PhanUndeclaredInterface',
+        // 'PhanUndeclaredMethod',
+        // 'PhanUndeclaredProperty',
+        // 'PhanUndeclaredStaticMethod',
+        // 'PhanUndeclaredStaticProperty',
+        // 'PhanUndeclaredTrait',
+        // 'PhanUndeclaredTypeParameter',
+        // 'PhanUndeclaredTypeProperty',
+        // 'PhanUndeclaredVariable',
+        // 'PhanUnreferencedClass',
+        // 'PhanUnreferencedConstant',
+        // 'PhanUnreferencedMethod',
+        // 'PhanUnreferencedProperty',
+        // 'PhanVariableUseClause',
+    ],
+
+    // A list of files to include in analysis
+    'file_list' => [
+        // 'vendor/phpunit/phpunit/src/Framework/TestCase.php',
+    ],
+
+    // A file list that defines files that will be excluded
+    // from parsing and analysis and will not be read at all.
+    //
+    // This is useful for excluding hopelessly unanalyzable
+    // files that can't be removed for whatever reason.
+    'exclude_file_list' => [],
+
+    // The number of processes to fork off during the analysis
+    // phase.
+    'processes' => 1,
+
+    // A list of directories that should be parsed for class and
+    // method information. After excluding the directories
+    // defined in exclude_analysis_directory_list, the remaining
+    // files will be statically analyzed for errors.
+    //
+    // Thus, both first-party and third-party code being used by
+    // your application should be included in this list.
+    'directory_list' => [
+        'src',
+        'vendor/nikic/php-parser/lib',
+    ],
+
+    // A directory list that defines files that will be excluded
+    // from static analysis, but whose class and method
+    // information should be included.
+    //
+    // Generally, you'll want to include the directories for
+    // third-party code (such as "vendor/") in this list.
+    //
+    // n.b.: If you'd like to parse but not analyze 3rd
+    //       party code, directories containing that code
+    //       should be added to the `directory_list` as
+    //       to `exclude_analysis_directory_list`.
+    "exclude_analysis_directory_list" => [
+        'vendor/nikic/php-parser/lib',
+    ],
+
+    // A list of plugin files to execute
+    'plugins' => [
+        // NOTE: src/Phan/Language/Internal/FunctionSignatureMap.php mixes value without key as return type with values having keys deliberately.
+        'vendor/etsy/phan/.phan/plugins/AlwaysReturnPlugin.php',  // (TODO: make BlockExitStatus more reliable)
+        'vendor/etsy/phan/.phan/plugins/DollarDollarPlugin.php',
+        'vendor/etsy/phan/.phan/plugins/DuplicateArrayKeyPlugin.php',
+        'vendor/etsy/phan/.phan/plugins/UnreachableCodePlugin.php',  // (TODO: make BlockExitStatus more reliable)
+        // NOTE: This plugin only produces correct results when
+        //       Phan is run on a single core (-j1).
+        // '.phan/plugins/UnusedSuppressionPlugin.php',
+    ],
+
+];
diff --git a/.travis.yml b/.travis.yml
index b358602..78a3dc2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,4 +15,5 @@ install:
   - composer --prefer-dist install
 
 script:
+  - vendor/bin/phan
   - ./test
diff --git a/README.md b/README.md
index 18c3700..d850ccf 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,14 @@ PHP-Parser to php-ast
 
 [![Build Status](https://travis-ci.org/TysonAndre/php-parser-to-php-ast.svg?branch=master)](https://travis-ci.org/TysonAndre/php-parser-to-php-ast)
 
+This converts ASTs(Abstract Syntax Trees) from [PHP-Parser](https://github.com/nikic/PHP-Parser) to [php-ast](https://github.com/nikic/php-ast/).
+It can be used as a PHP-only implementation of php-ast.
+
+Supported [php-ast AST versions](https://github.com/nikic/php-ast#version-changelog): 40, 50
+
+Current Status
+--------------
+
 No tests are failing
 
 - This is 90% done
@@ -31,7 +39,7 @@ Using it as an error-tolerant substitute for php-ast (e.g. for use in IDEs)
 Running unit tests
 ------------------
 
-To run unit tests, you must install [nikic/php-ast](https://github.com/nikic/php-ast)
+To run unit tests, you must install [nikic/php-ast](https://github.com/nikic/php-ast). A version supporting AST versions 40 and/or 50 should be installed (`~0.1.5` is preferred)
 
 - Then run `vendor/bin/phpunit`
 
diff --git a/composer.json b/composer.json
index 250ed54..d26fa94 100644
--- a/composer.json
+++ b/composer.json
@@ -1,15 +1,16 @@
 {
-    "name": "tysonandre/php-parser",
-    "description": "A php-parser to php-ast converter written in php",
+    "name": "tysonandre/php-parser-to-php-ast",
+    "description": "A php-parser to php-ast converter written in php. Can be used to test out projects using php-ast without compiling php-ast.",
     "require": {
         "php": ">=7.1",
-        "nikic/PHP-Parser": "3.0.5"
+        "nikic/PHP-Parser": "~3.1.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.7"
+        "phpunit/phpunit": "^5.7",
+        "etsy/phan": "~0.9.4"
     },
     "suggest": {
-        "ext-ast": "~0.1.4"
+        "ext-ast": "~0.1.5"
     },
     "autoload": {
         "psr-4": {"ASTConverter\\": "src/ASTConverter"}
diff --git a/composer.lock b/composer.lock
index 3cf070f..c643581 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,20 +4,20 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "content-hash": "cf0e7bee43429609880fc658e9b0c017",
+    "content-hash": "7beae8f069e15b813586fa101cbd1f35",
     "packages": [
         {
             "name": "nikic/php-parser",
-            "version": "v3.0.5",
+            "version": "v3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/nikic/PHP-Parser.git",
-                "reference": "2b9e2f71b722f7c53918ab0c25f7646c2013f17d"
+                "reference": "4d4896e553f2094e657fe493506dc37c509d4e2b"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/nikic/PHP-Parser/zipball/2b9e2f71b722f7c53918ab0c25f7646c2013f17d",
-                "reference": "2b9e2f71b722f7c53918ab0c25f7646c2013f17d",
+                "url": "https://api.github.com/repos/nikic/PHP-Parser/zipball/4d4896e553f2094e657fe493506dc37c509d4e2b",
+                "reference": "4d4896e553f2094e657fe493506dc37c509d4e2b",
                 "shasum": ""
             },
             "require": {
@@ -55,7 +55,7 @@
                 "parser",
                 "php"
             ],
-            "time": "2017-03-05T18:23:57+00:00"
+            "time": "2017-07-28T14:45:09+00:00"
         }
     ],
     "packages-dev": [
@@ -113,6 +113,59 @@
             ],
             "time": "2017-07-22T11:58:36+00:00"
         },
+        {
+            "name": "etsy/phan",
+            "version": "0.9.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phan/phan.git",
+                "reference": "d2f3fbd719cb9236f1d85fb6018f9c8b7e41ffaa"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phan/phan/zipball/d2f3fbd719cb9236f1d85fb6018f9c8b7e41ffaa",
+                "reference": "d2f3fbd719cb9236f1d85fb6018f9c8b7e41ffaa",
+                "shasum": ""
+            },
+            "require": {
+                "ext-ast": "^0.1.4",
+                "php": "~7.1.0",
+                "symfony/console": "~2.3|~3.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^6.2.1"
+            },
+            "bin": [
+                "phan",
+                "phan_client",
+                "tocheckstyle"
+            ],
+            "type": "project",
+            "autoload": {
+                "psr-4": {
+                    "Phan\\": "src/Phan"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Rasmus Lerdorf"
+                },
+                {
+                    "name": "Andrew S. Morrison"
+                }
+            ],
+            "description": "A static analyzer for PHP",
+            "keywords": [
+                "analyzer",
+                "php",
+                "static"
+            ],
+            "time": "2017-08-15T19:31:44+00:00"
+        },
         {
             "name": "myclabs/deep-copy",
             "version": "1.6.1",
@@ -754,6 +807,53 @@
             ],
             "time": "2017-06-30T09:13:00+00:00"
         },
+        {
+            "name": "psr/log",
+            "version": "1.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/log.git",
+                "reference": "4ebe3a8bf773a19edfe0a84b6585ba3d401b724d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/log/zipball/4ebe3a8bf773a19edfe0a84b6585ba3d401b724d",
+                "reference": "4ebe3a8bf773a19edfe0a84b6585ba3d401b724d",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Log\\": "Psr/Log/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "http://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for logging libraries",
+            "homepage": "https://github.com/php-fig/log",
+            "keywords": [
+                "log",
+                "psr",
+                "psr-3"
+            ],
+            "time": "2016-10-10T12:19:37+00:00"
+        },
         {
             "name": "sebastian/code-unit-reverse-lookup",
             "version": "1.0.1",
@@ -1267,6 +1367,189 @@
             "homepage": "https://github.com/sebastianbergmann/version",
             "time": "2016-10-03T07:35:21+00:00"
         },
+        {
+            "name": "symfony/console",
+            "version": "v3.3.8",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/console.git",
+                "reference": "d6596cb5022b6a0bd940eae54a1de78646a5fda6"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/console/zipball/d6596cb5022b6a0bd940eae54a1de78646a5fda6",
+                "reference": "d6596cb5022b6a0bd940eae54a1de78646a5fda6",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.5.9|>=7.0.8",
+                "symfony/debug": "~2.8|~3.0",
+                "symfony/polyfill-mbstring": "~1.0"
+            },
+            "conflict": {
+                "symfony/dependency-injection": "<3.3"
+            },
+            "require-dev": {
+                "psr/log": "~1.0",
+                "symfony/config": "~3.3",
+                "symfony/dependency-injection": "~3.3",
+                "symfony/event-dispatcher": "~2.8|~3.0",
+                "symfony/filesystem": "~2.8|~3.0",
+                "symfony/process": "~2.8|~3.0"
+            },
+            "suggest": {
+                "psr/log": "For using the console logger",
+                "symfony/event-dispatcher": "",
+                "symfony/filesystem": "",
+                "symfony/process": ""
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.3-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Component\\Console\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony Console Component",
+            "homepage": "https://symfony.com",
+            "time": "2017-08-27T14:52:21+00:00"
+        },
+        {
+            "name": "symfony/debug",
+            "version": "v3.3.8",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/debug.git",
+                "reference": "084d804fe35808eb2ef596ec83d85d9768aa6c9d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/debug/zipball/084d804fe35808eb2ef596ec83d85d9768aa6c9d",
+                "reference": "084d804fe35808eb2ef596ec83d85d9768aa6c9d",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.5.9|>=7.0.8",
+                "psr/log": "~1.0"
+            },
+            "conflict": {
+                "symfony/http-kernel": ">=2.3,<2.3.24|~2.4.0|>=2.5,<2.5.9|>=2.6,<2.6.2"
+            },
+            "require-dev": {
+                "symfony/http-kernel": "~2.8|~3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.3-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Component\\Debug\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony Debug Component",
+            "homepage": "https://symfony.com",
+            "time": "2017-08-27T14:52:21+00:00"
+        },
+        {
+            "name": "symfony/polyfill-mbstring",
+            "version": "v1.5.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-mbstring.git",
+                "reference": "7c8fae0ac1d216eb54349e6a8baa57d515fe8803"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/7c8fae0ac1d216eb54349e6a8baa57d515fe8803",
+                "reference": "7c8fae0ac1d216eb54349e6a8baa57d515fe8803",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "suggest": {
+                "ext-mbstring": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.5-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Mbstring\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill for the Mbstring extension",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "mbstring",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "time": "2017-06-14T15:44:48+00:00"
+        },
         {
             "name": "symfony/yaml",
             "version": "v3.3.8",
diff --git a/src/ASTConverter/ASTConverter.php b/src/ASTConverter/ASTConverter.php
index e4f14db..5eabc28 100644
--- a/src/ASTConverter/ASTConverter.php
+++ b/src/ASTConverter/ASTConverter.php
@@ -12,9 +12,21 @@
  */
 class ASTConverter {
     // The latest stable version of php-ast.
-    // For something > 40, update the library's release.
+    // For something > 50, update the library's release.
     // For something < 40, there are no releases.
-    const AST_VERSION = 40;
+    const AST_VERSION = 50;
+    // The versions that this supports
+    const SUPPORTED_AST_VERSIONS = [40, 50];
+
+    /**
+     * @var int - A version in SUPPORTED_AST_VERSIONS
+     */
+    private static $ast_version = self::AST_VERSION;
+
+    /**
+     * @var int - A version in SUPPORTED_AST_VERSIONS
+     */
+    private static $decl_id = 0;
 
     private static $should_add_placeholders = false;
 
@@ -23,8 +35,8 @@ public static function set_should_add_placeholders(bool $value) : void {
     }
 
     public static function ast_parse_code_fallback(string $source, int $version, bool $suppressErrors = false, array &$errors = null) {
-        if ($version !== self::AST_VERSION) {
-            throw new \InvalidArgumentException(sprintf("Unexpected version: want %d, got %d", self::AST_VERSION, $version));
+        if (!\in_array($version, self::SUPPORTED_AST_VERSIONS)) {
+            throw new \InvalidArgumentException(sprintf("Unexpected version: want %d, got %d", implode(', ', self::SUPPORTED_AST_VERSIONS), $version));
         }
         // Aside: this can be implemented as a stub.
         $parserNode = self::phpparser_parse($source, $suppressErrors, $errors);
@@ -46,17 +58,25 @@ public static function phpparser_parse(string $source, bool $suppressErrors = fa
     /**
      * @param PhpParser\Node|PhpParser\Node[] $parserNode
      * @param int $version
+     * @return \ast\Node
      */
     public static function phpparser_to_phpast($parserNode, int $version) {
-        if ($version !== self::AST_VERSION) {
-            throw new \InvalidArgumentException(sprintf("Unexpected version: want %d, got %d", self::AST_VERSION, $version));
+        if (!\in_array($version, self::SUPPORTED_AST_VERSIONS)) {
+            throw new \InvalidArgumentException(sprintf("Unexpected version: want %s, got %d", implode(', ', self::SUPPORTED_AST_VERSIONS), $version));
         }
+        self::_start_parsing($version);
         if (is_array($parserNode)) {
             return self::_phpparser_stmtlist_to_ast_node($parserNode, 1);
         }
+        // Unreachable?
         return self::_phpparser_node_to_ast_node($parserNode);
     }
 
+    private static function _start_parsing(int $ast_version) {
+        self::$ast_version = $ast_version;
+        self::$decl_id = 0;
+    }
+
     private static function _phpparser_stmtlist_to_ast_node(array $parserNodes, ?int $lineno) : \ast\Node {
         $stmts = new \ast\Node();
         $stmts->kind = \ast\AST_STMT_LIST;
@@ -110,7 +130,7 @@ private static function _phpparser_expr_list_to_expr_list(array $exprs, int $lin
                 break;
             }
         }
-        return astnode(
+        return new \ast\Node(
             \ast\AST_EXPR_LIST,
             0,
             $children,
@@ -149,7 +169,7 @@ private static final function _phpparser_node_to_ast_node($n) {
      * - In php <= 7.1, the interpreter would loop through all possible cases, and compare against the value one by one.
      * - There are a lot of local variables to look at.
      *
-     * @return Closure[]
+     * @return \Closure[]
      */
     private static function _init_handle_map() : array {
         $closures = [
@@ -160,7 +180,7 @@ private static function _init_handle_map() : array {
                 return self::_phpparser_array_to_ast_array($n, $startLine);
             },
             'PhpParser\Node\Expr\ArrayDimFetch'            => function(PhpParser\Node\Expr\ArrayDimFetch $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_DIM, 0, [
+                return new \ast\Node(\ast\AST_DIM, 0, [
                     'expr' => self::_phpparser_node_to_ast_node($n->var),
                     'dim' => $n->dim !== null ? self::_phpparser_node_to_ast_node($n->dim) : null,
                 ], $startLine);
@@ -345,16 +365,16 @@ private static function _init_handle_map() : array {
                 return self::_phpparser_classconstfetch_to_ast_classconstfetch($n, $startLine);
             },
             'PhpParser\Node\Expr\Clone_' => function(PhpParser\Node\Expr\Clone_ $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_CLONE, 0, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], $startLine);
+                return new \ast\Node(\ast\AST_CLONE, 0, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], $startLine);
             },
             'PhpParser\Node\Expr\ConstFetch' => function(PhpParser\Node\Expr\ConstFetch $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_CONST, 0, ['name' => self::_phpparser_node_to_ast_node($n->name)], $startLine);
+                return new \ast\Node(\ast\AST_CONST, 0, ['name' => self::_phpparser_node_to_ast_node($n->name)], $startLine);
             },
             'PhpParser\Node\Expr\ErrorSuppress' => function(PhpParser\Node\Expr\ErrorSuppress $n, int $startLine) : \ast\Node {
                 return self::_ast_node_unary_op(\ast\flags\UNARY_SILENCE, self::_phpparser_node_to_ast_node($n->expr), $startLine);
             },
             'PhpParser\Node\Expr\Empty_' => function(PhpParser\Node\Expr\Empty_ $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_EMPTY, 0, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], $startLine);
+                return new \ast\Node(\ast\AST_EMPTY, 0, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], $startLine);
             },
             'PhpParser\Node\Expr\Eval_' => function(PhpParser\Node\Expr\Eval_ $n, int $startLine) : \ast\Node {
                 return self::_ast_node_eval(
@@ -368,7 +388,7 @@ private static function _init_handle_map() : array {
                 return null;
             },
             'PhpParser\Node\Expr\Exit_' => function(PhpParser\Node\Expr\Exit_ $n, int $startLine) {
-                return astnode(\ast\AST_EXIT, 0, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], $startLine);
+                return new \ast\Node(\ast\AST_EXIT, 0, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], $startLine);
             },
             'PhpParser\Node\Expr\FuncCall' => function(PhpParser\Node\Expr\FuncCall $n, int $startLine) : \ast\Node {
                 return self::_ast_node_call(
@@ -385,7 +405,7 @@ private static function _init_handle_map() : array {
                 );
             },
             'PhpParser\Node\Expr\Instanceof_' => function(PhpParser\Node\Expr\Instanceof_ $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_INSTANCEOF, 0, [
+                return new \ast\Node(\ast\AST_INSTANCEOF, 0, [
                     'expr'  => self::_phpparser_node_to_ast_node($n->expr),
                     'class' => self::_phpparser_node_to_ast_node($n->class),
                 ], $startLine);
@@ -393,14 +413,14 @@ private static function _init_handle_map() : array {
             'PhpParser\Node\Expr\Isset_' => function(PhpParser\Node\Expr\Isset_ $n, int $startLine) : \ast\Node {
                 $astIssets = [];
                 foreach ($n->vars as $var) {
-                    $astIssets[] = astnode(\ast\AST_ISSET, 0, [
+                    $astIssets[] = new \ast\Node(\ast\AST_ISSET, 0, [
                         'var' => self::_phpparser_node_to_ast_node($var),
                     ], $startLine);
                 }
                 $e = $astIssets[0];
                 for ($i = 1; $i < \count($astIssets); $i++) {
                     $right = $astIssets[$i];
-                    $e = astnode(
+                    $e = new \ast\Node(
                         \ast\AST_BINARY_OP,
                         \ast\flags\BINARY_BOOL_AND,
                         [
@@ -424,25 +444,25 @@ private static function _init_handle_map() : array {
                 );
             },
             'PhpParser\Node\Expr\New_' => function(PhpParser\Node\Expr\New_ $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_NEW, 0, [
+                return new \ast\Node(\ast\AST_NEW, 0, [
                     'class' => self::_phpparser_node_to_ast_node($n->class),
                     'args' => self::_phpparser_arg_list_to_ast_arg_list($n->args, $startLine),
                 ], $startLine);
             },
             'PhpParser\Node\Expr\PreInc' => function(PhpParser\Node\Expr\PreInc $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_PRE_INC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
+                return new \ast\Node(\ast\AST_PRE_INC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
             },
             'PhpParser\Node\Expr\PreDec' => function(PhpParser\Node\Expr\PreDec $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_PRE_DEC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
+                return new \ast\Node(\ast\AST_PRE_DEC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
             },
             'PhpParser\Node\Expr\PostInc' => function(PhpParser\Node\Expr\PostInc $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_POST_INC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
+                return new \ast\Node(\ast\AST_POST_INC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
             },
             'PhpParser\Node\Expr\PostDec' => function(PhpParser\Node\Expr\PostDec $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_POST_DEC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
+                return new \ast\Node(\ast\AST_POST_DEC, 0, ['var' => self::_phpparser_node_to_ast_node($n->var)], $startLine);
             },
             'PhpParser\Node\Expr\Print_' => function(PhpParser\Node\Expr\Print_ $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_PRINT,
                     0,
                     ['expr' => self::_phpparser_node_to_ast_node($n->expr)],
@@ -458,9 +478,9 @@ private static function _init_handle_map() : array {
                     $value = $parts[0]->value;
                 } else {
                     $value_inner = array_map(function(PhpParser\Node $node) { return self::_phpparser_node_to_ast_node($node); }, $parts);
-                    $value = astnode(\ast\AST_ENCAPS_LIST, 0, $value_inner, $startLine);
+                    $value = new \ast\Node(\ast\AST_ENCAPS_LIST, 0, $value_inner, $startLine);
                 }
-                return astnode(\ast\AST_SHELL_EXEC, 0, ['expr' => $value], $startLine);
+                return new \ast\Node(\ast\AST_SHELL_EXEC, 0, ['expr' => $value], $startLine);
             },
             'PhpParser\Node\Expr\StaticCall' => function(PhpParser\Node\Expr\StaticCall $n, int $startLine) : \ast\Node {
                 return self::_ast_node_static_call(
@@ -471,7 +491,7 @@ private static function _init_handle_map() : array {
                 );
             },
             'PhpParser\Node\Expr\StaticPropertyFetch' => function(PhpParser\Node\Expr\StaticPropertyFetch $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_STATIC_PROP,
                     0,
                     [
@@ -482,7 +502,7 @@ private static function _init_handle_map() : array {
                 );
             },
             'PhpParser\Node\Expr\Ternary' => function(PhpParser\Node\Expr\Ternary $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_CONDITIONAL,
                     0,
                     [
@@ -503,7 +523,7 @@ private static function _init_handle_map() : array {
                 return self::_ast_node_variable($n->name, $startLine);
             },
             'PhpParser\Node\Expr\Yield_' => function(PhpParser\Node\Expr\Yield_ $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_YIELD,
                     0,
                     [
@@ -514,7 +534,7 @@ private static function _init_handle_map() : array {
                 );
             },
             'PhpParser\Node\Expr\YieldFrom' => function(PhpParser\Node\Expr\YieldFrom $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_YIELD_FROM,
                     0,
                     ['expr' => self::_phpparser_node_to_ast_node($n->expr)],
@@ -527,9 +547,6 @@ private static function _init_handle_map() : array {
                     $startLine
                 );
             },
-            /**
-             * @suppress PhanDeprecatedProperty TODO: figure out alternative
-             */
             'PhpParser\Node\Name\FullyQualified' => function(PhpParser\Node\Name\FullyQualified $n, int $startLine) : \ast\Node {
                 return self::_ast_node_name_fullyqualified(
                     implode('\\', $n->parts),
@@ -555,7 +572,7 @@ private static function _init_handle_map() : array {
                 );
             },
             'PhpParser\Node\Scalar\Encapsed' => function(PhpParser\Node\Scalar\Encapsed $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_ENCAPS_LIST,
                     0,
                     array_map(function(PhpParser\Node $n) { return self::_phpparser_node_to_ast_node($n); }, $n->parts),
@@ -599,7 +616,7 @@ private static function _init_handle_map() : array {
                 return self::_ast_magic_const(\ast\flags\MAGIC_TRAIT, $startLine);
             },
             'PhpParser\Node\Stmt\Break_' => function(PhpParser\Node\Stmt\Break_ $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_BREAK, 0, ['depth' => isset($n->num) ? self::_phpparser_node_to_ast_node($n->num) : null], $startLine);
+                return new \ast\Node(\ast\AST_BREAK, 0, ['depth' => isset($n->num) ? self::_phpparser_node_to_ast_node($n->num) : null], $startLine);
             },
             'PhpParser\Node\Stmt\Catch_' => function(PhpParser\Node\Stmt\Catch_ $n, int $startLine) : \ast\Node {
                 return self::_ast_stmt_catch(
@@ -626,7 +643,7 @@ private static function _init_handle_map() : array {
                 return self::_phpparser_class_const_to_ast_node($n, $startLine);
             },
             'PhpParser\Node\Stmt\ClassMethod' => function(PhpParser\Node\Stmt\ClassMethod $n, int $startLine) : \ast\Node {
-                return astdecl(
+                return self::_new_ast_decl(
                     \ast\AST_METHOD,
                     self::_phpparser_visibility_to_ast_visibility($n->flags) | ($n->byRef ? \ast\flags\RETURNS_REF : 0),
                     [
@@ -638,18 +655,19 @@ private static function _init_handle_map() : array {
                     $startLine,
                     self::_extract_phpdoc_comment($n->getAttribute('comments')),
                     $n->name,
-                    $n->getAttribute('endLine')
+                    $n->getAttribute('endLine'),
+                    self::_next_decl_id()
                 );
             },
             'PhpParser\Node\Stmt\Const_' => function(PhpParser\Node\Stmt\Const_ $n, int $startLine) : \ast\Node {
                 return self::_phpparser_const_to_ast_node($n, $startLine);
             },
             'PhpParser\Node\Stmt\Continue_' => function(PhpParser\Node\Stmt\Continue_ $n, int $startLine) : \ast\Node {
-                return astnode(\ast\AST_CONTINUE, 0, ['depth' => isset($n->num) ? self::_phpparser_node_to_ast_node($n->num) : null], $startLine);
+                return new \ast\Node(\ast\AST_CONTINUE, 0, ['depth' => isset($n->num) ? self::_phpparser_node_to_ast_node($n->num) : null], $startLine);
             },
             'PhpParser\Node\Stmt\Declare_' => function(PhpParser\Node\Stmt\Declare_ $n, int $startLine) : \ast\Node {
                 return self::_ast_stmt_declare(
-                    self::_phpparser_declare_list_to_ast_declares($n->declares, $startLine),
+                    self::_phpparser_declare_list_to_ast_declares($n->declares, $startLine, self::_extract_phpdoc_comment($n->getAttribute('comments'))),
                     is_array($n->stmts) ? self::_phpparser_stmtlist_to_ast_node($n->stmts, $startLine) : null,
                     $startLine
                 );
@@ -677,14 +695,14 @@ private static function _init_handle_map() : array {
             'PhpParser\Node\Stmt\Foreach_' => function(PhpParser\Node\Stmt\Foreach_ $n, int $startLine) : \ast\Node {
                 $value = self::_phpparser_node_to_ast_node($n->valueVar);
                 if ($n->byRef) {
-                    $value = astnode(
+                    $value = new \ast\Node(
                         \ast\AST_REF,
                         0,
                         ['var' => $value],
                         $value->lineno ?? $startLine
                     );
                 }
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_FOREACH,
                     0,
                     [
@@ -722,7 +740,7 @@ private static function _init_handle_map() : array {
             'PhpParser\Node\Stmt\Global_' => function(PhpParser\Node\Stmt\Global_ $n, int $startLine) {
                 $globalNodes = [];
                 foreach ($n->vars as $var) {
-                    $globalNodes[] = astnode(\ast\AST_GLOBAL, 0, ['var' => self::_phpparser_node_to_ast_node($var)], sl($var) ?: $startLine);
+                    $globalNodes[] = new \ast\Node(\ast\AST_GLOBAL, 0, ['var' => self::_phpparser_node_to_ast_node($var)], sl($var) ?: $startLine);
                 }
                 return \count($globalNodes) === 1 ? $globalNodes[0] : $globalNodes;
             },
@@ -746,7 +764,7 @@ private static function _init_handle_map() : array {
                 );
             },
             'PhpParser\Node\Stmt\For_' => function(PhpParser\Node\Stmt\For_ $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_FOR,
                     0,
                     [
@@ -771,7 +789,7 @@ private static function _init_handle_map() : array {
                     'dumpComments' => true,
                     'dumpPositions' => true,
                 ]);
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_NAMESPACE,
                     0,
                     [
@@ -795,8 +813,8 @@ private static function _init_handle_map() : array {
             'PhpParser\Node\Stmt\Static_' => function(PhpParser\Node\Stmt\Static_ $n, int $startLine) {
                 $staticNodes = [];
                 foreach ($n->vars as $var) {
-                    $staticNodes[] = astnode(\ast\AST_STATIC, 0, [
-                        'var' => astnode(\ast\AST_VAR, 0, ['name' => $var->name], sl($var) ?: $startLine),
+                    $staticNodes[] = new \ast\Node(\ast\AST_STATIC, 0, [
+                        'var' => new \ast\Node(\ast\AST_VAR, 0, ['name' => $var->name], sl($var) ?: $startLine),
                         'default' => $var->default !== null ? self::_phpparser_node_to_ast_node($var->default) : null,
                     ], sl($var) ?: $startLine);
                 }
@@ -806,7 +824,7 @@ private static function _init_handle_map() : array {
                 return self::_phpparser_switch_list_to_ast_switch($n);
             },
             'PhpParser\Node\Stmt\Throw_' => function(PhpParser\Node\Stmt\Throw_ $n, int $startLine) : \ast\Node {
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_THROW,
                     0,
                     ['expr' => self::_phpparser_node_to_ast_node($n->expr)],
@@ -831,11 +849,11 @@ private static function _init_handle_map() : array {
                     $adaptations_inner = array_map(function(PhpParser\Node\Stmt\TraitUseAdaptation $n) : \ast\Node {
                         return self::_phpparser_node_to_ast_node($n);
                     }, $n->adaptations);
-                    $adaptations = astnode(\ast\AST_TRAIT_ADAPTATIONS, 0, $adaptations_inner, $adaptations_inner[0]->lineno ?: $startLine);
+                    $adaptations = new \ast\Node(\ast\AST_TRAIT_ADAPTATIONS, 0, $adaptations_inner, $adaptations_inner[0]->lineno ?: $startLine);
                 } else {
                     $adaptations = null;
                 }
-                return astnode(
+                return new \ast\Node(
                     \ast\AST_USE_TRAIT,
                     0,
                     [
@@ -849,8 +867,8 @@ private static function _init_handle_map() : array {
                 $old_class = $n->trait !== null ? self::_phpparser_node_to_ast_node($n->trait) : null;
                 $flags = ($n->trait instanceof PhpParser\Node\Name\FullyQualified) ? \ast\flags\NAME_FQ : \ast\flags\NAME_NOT_FQ;
                 // TODO: flags for visibility
-                return astnode(\ast\AST_TRAIT_ALIAS, self::_phpparser_visibility_to_ast_visibility($n->newModifier ?? 0, false), [
-                    'method' => astnode(\ast\AST_METHOD_REFERENCE, 0, [
+                return new \ast\Node(\ast\AST_TRAIT_ALIAS, self::_phpparser_visibility_to_ast_visibility($n->newModifier ?? 0, false), [
+                    'method' => new \ast\Node(\ast\AST_METHOD_REFERENCE, 0, [
                         'class' => $old_class,
                         'method' => $n->method,
                     ], $startLine),
@@ -861,9 +879,9 @@ private static function _init_handle_map() : array {
                 $old_class = $n->trait !== null ? self::_phpparser_name_to_string($n->trait) : null;
                 $flags = ($n->trait instanceof PhpParser\Node\Name\FullyQualified) ? \ast\flags\NAME_FQ : \ast\flags\NAME_NOT_FQ;
                 // TODO: flags for visibility
-                return astnode(\ast\AST_TRAIT_PRECEDENCE, 0, [
-                    'method' => astnode(\ast\AST_METHOD_REFERENCE, 0, [
-                        'class' => astnode(\ast\AST_NAME, $flags, ['name' => $old_class], $startLine),
+                return new \ast\Node(\ast\AST_TRAIT_PRECEDENCE, 0, [
+                    'method' => new \ast\Node(\ast\AST_METHOD_REFERENCE, 0, [
+                        'class' => new \ast\Node(\ast\AST_NAME, $flags, ['name' => $old_class], $startLine),
                         'method' => $n->method,
                     ], $startLine),
                     'insteadof' => self::_phpparser_name_list_to_ast_name_list($n->insteadof, $startLine),
@@ -884,7 +902,7 @@ private static function _init_handle_map() : array {
             'PhpParser\Node\Stmt\Unset_' => function(PhpParser\Node\Stmt\Unset_ $n, int $startLine) {
                 $stmts = [];
                 foreach ($n->vars as $var) {
-                    $stmts[] = astnode(\ast\AST_UNSET, 0, ['var' => self::_phpparser_node_to_ast_node($var)], sl($var) ?: $startLine);
+                    $stmts[] = new \ast\Node(\ast\AST_UNSET, 0, ['var' => self::_phpparser_node_to_ast_node($var)], sl($var) ?: $startLine);
                 }
                 return \count($stmts) === 1 ? $stmts[0] : $stmts;
             },
@@ -939,7 +957,7 @@ private static function _ast_stmt_catch($types, string $var, $stmts, int $lineno
         $node->flags = 0;
         $node->children = [
             'class' => $types,
-            'var' => astnode(\ast\AST_VAR, 0, ['name' => $var], end($types->children)->lineno),  // FIXME AST_VAR
+            'var' => new \ast\Node(\ast\AST_VAR, 0, ['name' => $var], end($types->children)->lineno),  // FIXME AST_VAR
             'stmts' => $stmts,
         ];
         return $node;
@@ -963,11 +981,11 @@ private static function _phpparser_name_list_to_ast_name_list(array $types, int
         foreach ($types as $type) {
             $astTypes[] = self::_phpparser_node_to_ast_node($type);
         }
-        return astnode(\ast\AST_NAME_LIST, 0, $astTypes, $line);
+        return new \ast\Node(\ast\AST_NAME_LIST, 0, $astTypes, $line);
     }
 
     private static function _ast_node_while($cond, $stmts, int $startLine) : \ast\Node {
-        return astnode(
+        return new \ast\Node(
             \ast\AST_WHILE,
             0,
             [
@@ -979,7 +997,7 @@ private static function _ast_node_while($cond, $stmts, int $startLine) : \ast\No
     }
 
     private static function _ast_node_do_while($cond, $stmts, int $startLine) : \ast\Node {
-        return astnode(
+        return new \ast\Node(
             \ast\AST_DO_WHILE,
             0,
             [
@@ -998,27 +1016,22 @@ private static function _ast_node_assign($var, $expr, int $line, bool $ref) : ?\
                 return null;
             }
         }
-        $node = new \ast\Node();
-        $node->kind = $ref ? \ast\AST_ASSIGN_REF : \ast\AST_ASSIGN;
-        $node->flags = 0;
-        $node->children = [
+        return new \ast\Node($ref ? \ast\AST_ASSIGN_REF : \ast\AST_ASSIGN, 0, [
             'var'  => $var,
             'expr' => $expr,
-        ];
-        $node->lineno = $line;
-        return $node;
+        ], $line);
     }
 
     private static function _ast_node_unary_op(int $flags, $expr, int $line) : \ast\Node {
-        return astnode(\ast\AST_UNARY_OP, $flags, ['expr' => $expr], $line);
+        return new \ast\Node(\ast\AST_UNARY_OP, $flags, ['expr' => $expr], $line);
     }
 
     private static function _ast_node_cast(int $flags, PhpParser\Node\Expr\Cast $n, int $line) : \ast\Node {
-        return astnode(\ast\AST_CAST, $flags, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], sl($n) ?: $line);
+        return new \ast\Node(\ast\AST_CAST, $flags, ['expr' => self::_phpparser_node_to_ast_node($n->expr)], sl($n) ?: $line);
     }
 
     private static function _ast_node_eval($expr, int $line) : \ast\Node {
-        return astnode(\ast\AST_INCLUDE_OR_EVAL, \ast\flags\EXEC_EVAL, ['expr' => $expr], $line);
+        return new \ast\Node(\ast\AST_INCLUDE_OR_EVAL, \ast\flags\EXEC_EVAL, ['expr' => $expr], $line);
     }
 
     private static function _phpparser_include_flags_to_ast_include_flags(int $type) : int {
@@ -1037,7 +1050,7 @@ private static function _phpparser_include_flags_to_ast_include_flags(int $type)
     }
     private static function _ast_node_include($expr, int $line, int $type) : \ast\Node {
         $flags = self::_phpparser_include_flags_to_ast_include_flags($type);
-        return astnode(\ast\AST_INCLUDE_OR_EVAL, $flags, ['expr' => $expr], $line);
+        return new \ast\Node(\ast\AST_INCLUDE_OR_EVAL, $flags, ['expr' => $expr], $line);
     }
 
     /**
@@ -1063,7 +1076,18 @@ private static function _phpparser_type_to_ast_node($type, int $line) {
             case 'array':
                 $flags = \ast\flags\TYPE_ARRAY; break;
             case 'object':
-                $flags = \ast\flags\TYPE_OBJECT; break;
+                if (self::$ast_version >= 45) {
+                    $flags = \ast\flags\TYPE_OBJECT; break;
+                } else {
+                    return new \ast\Node(
+                        \ast\AST_NAME,
+                        substr($type, 0, 1) === '\\' ? \ast\flags\NAME_FQ : \ast\flags\NAME_NOT_FQ,  // FIXME wrong.
+                        [
+                            'name' => $type,
+                        ],
+                        $line
+                    );
+                }
             case 'callable':
                 $flags = \ast\flags\TYPE_CALLABLE; break;
             case 'void':
@@ -1071,14 +1095,14 @@ private static function _phpparser_type_to_ast_node($type, int $line) {
             case 'iterable':
                 $flags = \ast\flags\TYPE_ITERABLE; break;
             default:
-                $node = new \ast\Node();
-                $node->kind = \ast\AST_NAME;
-                $node->flags = substr($type, 0, 1) === '\\' ? \ast\flags\NAME_FQ : \ast\flags\NAME_NOT_FQ;  // FIXME wrong.
-                $node->lineno = $line;
-                $node->children = [
-                    'name' => $type,
-                ];
-                return $node;
+                return new \ast\Node(
+                    \ast\AST_NAME,
+                    substr($type, 0, 1) === '\\' ? \ast\flags\NAME_FQ : \ast\flags\NAME_NOT_FQ,  // FIXME wrong.
+                    [
+                        'name' => $type,
+                    ],
+                    $line
+                );
             }
             $node = new \ast\Node();
             $node->kind = \ast\AST_TYPE;
@@ -1119,11 +1143,11 @@ private static function _ast_node_nullable_type(\ast\Node $type, int $line) {
     }
 
     private static function _ast_node_name(string $name, int $line) : \ast\Node {
-        return astnode(\ast\AST_NAME, \ast\flags\NAME_NOT_FQ, ['name' => $name], $line);
+        return new \ast\Node(\ast\AST_NAME, \ast\flags\NAME_NOT_FQ, ['name' => $name], $line);
     }
 
     private static function _ast_node_name_fullyqualified(string $name, int $line) : \ast\Node {
-        return astnode(\ast\AST_NAME, \ast\flags\NAME_FQ, ['name' => $name], $line);
+        return new \ast\Node(\ast\AST_NAME, \ast\flags\NAME_FQ, ['name' => $name], $line);
     }
 
     private static function _ast_node_variable($expr, int $line) : ?\ast\Node {
@@ -1147,7 +1171,7 @@ private static function _ast_node_variable($expr, int $line) : ?\ast\Node {
     }
 
     private static function _ast_magic_const(int $flags, int $line) {
-        return astnode(\ast\AST_MAGIC_CONST, $flags, [], $line);
+        return new \ast\Node(\ast\AST_MAGIC_CONST, $flags, [], $line);
     }
 
     private static function _phpparser_params_to_ast_params(array $parserParams, int $line) : \ast\Node {
@@ -1194,9 +1218,9 @@ private static function _phpparser_closure_uses_to_ast_closure_uses(
         }
         $astUses = [];
         foreach ($uses as $use) {
-            $astUses[] = astnode(\ast\AST_CLOSURE_VAR, $use->byRef ? 1 : 0, ['name' => $use->var], $use->getAttribute('startLine'));
+            $astUses[] = new \ast\Node(\ast\AST_CLOSURE_VAR, $use->byRef ? 1 : 0, ['name' => $use->var], $use->getAttribute('startLine'));
         }
-        return astnode(\ast\AST_CLOSURE_USES, 0, $astUses, $astUses[0]->lineno ?? $line);
+        return new \ast\Node(\ast\AST_CLOSURE_USES, 0, $astUses, $astUses[0]->lineno ?? $line);
 
     }
 
@@ -1210,21 +1234,22 @@ private static function _ast_decl_closure(
         int $startLine,
         int $endLine,
         ?string $docComment
-    ) : \ast\Node\Decl {
-        $node = new \ast\Node\Decl;
-        $node->kind = \ast\AST_CLOSURE;
-        $node->flags = ($byRef ? \ast\flags\RETURNS_REF : 0) | ($static ? \ast\flags\MODIFIER_STATIC : 0);
-        $node->lineno = $startLine;
-        $node->endLineno = $endLine;
-        if ($docComment) { $node->docComment = $docComment; }
-        $node->children = [
-            'params' => $params,
-            'uses' => $uses,
-            'stmts' => $stmts,
-            'returnType' => $returnType,
-        ];
-        $node->name = '{closure}';
-        return $node;
+    ) : \ast\Node {
+        return self::_new_ast_decl(
+            \ast\AST_CLOSURE,
+            ($byRef ? \ast\flags\RETURNS_REF : 0) | ($static ? \ast\flags\MODIFIER_STATIC : 0),
+            [
+                'params' => $params,
+                'uses' => $uses,
+                'stmts' => $stmts,
+                'returnType' => $returnType,
+            ],
+            $startLine,
+            $docComment,
+            '{closure}',
+            $endLine,
+            self::_next_decl_id()
+        );
     }
 
     /**
@@ -1240,21 +1265,22 @@ private static function _ast_decl_function(
         int $line,
         int $endLine,
         ?string $docComment
-    ) : \ast\Node\Decl {
-        $node = new \ast\Node\Decl;
-        $node->kind = \ast\AST_FUNC_DECL;
-        $node->flags = 0;
-        $node->lineno = $line;
-        $node->endLineno = $endLine;
-        $node->children = [
-            'params' => $params,
-            'uses' => $uses,
-            'stmts' => $stmts,
-            'returnType' => $returnType,
-        ];
-        $node->name = $name;
-        $node->docComment = $docComment;
-        return $node;
+    ) : \ast\Node {
+        return self::_new_ast_decl(
+            \ast\AST_FUNC_DECL,
+            0,
+            [
+                'params' => $params,
+                'uses' => $uses,
+                'stmts' => $stmts,
+                'returnType' => $returnType,
+            ],
+            $line,
+            $docComment,
+            $name,
+            $endLine,
+            self::_next_decl_id()
+        );
     }
 
     private static function _phpparser_class_flags_to_ast_class_flags(int $flags) {
@@ -1287,7 +1313,7 @@ private static function _ast_stmt_class(
         int $line,
         int $endLine,
         ?string $docComment
-    ) : \ast\Node\Decl {
+    ) : \ast\Node {
         if ($name === null) {
             $flags |= \ast\flags\CLASS_ANONYMOUS;
         }
@@ -1302,12 +1328,12 @@ private static function _ast_stmt_class(
             foreach ($implements as $implement) {
                 $ast_implements_inner[] = self::_phpparser_node_to_ast_node($implement);
             }
-            $ast_implements = astnode(\ast\AST_NAME_LIST, 0, $ast_implements_inner, $ast_implements_inner[0]->lineno);
+            $ast_implements = new \ast\Node(\ast\AST_NAME_LIST, 0, $ast_implements_inner, $ast_implements_inner[0]->lineno);
         } else {
             $ast_implements = null;
         }
 
-        return astdecl(
+        return self::_new_ast_decl(
             \ast\AST_CLASS,
             $flags,
             [
@@ -1318,7 +1344,8 @@ private static function _ast_stmt_class(
             $line,
             $docComment,
             $name,
-            $endLine
+            $endLine,
+            self::_next_decl_id()
         );
     }
 
@@ -1412,7 +1439,7 @@ private static function _ast_stmt_return($expr, int $line) : \ast\Node {
     }
 
     private static function _ast_if_elem($cond, $stmts, int $line) : \ast\Node {
-        return astnode(\ast\AST_IF_ELEM, 0, ['cond' => $cond, 'stmts' => $stmts], $line);
+        return new \ast\Node(\ast\AST_IF_ELEM, 0, ['cond' => $cond, 'stmts' => $stmts], $line);
     }
 
     private static function _phpparser_switch_list_to_ast_switch(PhpParser\Node\Stmt\Switch_ $node) {
@@ -1420,7 +1447,7 @@ private static function _phpparser_switch_list_to_ast_switch(PhpParser\Node\Stmt
         $nodeLine = sl($node) ?? 0;
         foreach ($node->cases as $case) {
             $caseLine = sl($case);
-            $stmts[] = astnode(
+            $stmts[] = new \ast\Node(
                 \ast\AST_SWITCH_CASE,
                 0,
                 [
@@ -1430,9 +1457,9 @@ private static function _phpparser_switch_list_to_ast_switch(PhpParser\Node\Stmt
                 $caseLine ?? $nodeLine
             );
         }
-        return astnode(\ast\AST_SWITCH, 0, [
+        return new \ast\Node(\ast\AST_SWITCH, 0, [
             'cond' => self::_phpparser_node_to_ast_node($node->cond),
-            'stmts' => astnode(\ast\AST_SWITCH_LIST, 0, $stmts, $stmts[0]->lineno ?? $nodeLine),
+            'stmts' => new \ast\Node(\ast\AST_SWITCH_LIST, 0, $stmts, $stmts[0]->lineno ?? $nodeLine),
         ], $nodeLine);
     }
 
@@ -1464,7 +1491,7 @@ private static function _phpparser_if_stmt_to_ast_if_stmt(PhpParser\Node $node)
                 $parserElseLine
             );
         }
-        return astnode(\ast\AST_IF, 0, $ifElems, $startLine);
+        return new \ast\Node(\ast\AST_IF, 0, $ifElems, $startLine);
 
     }
 
@@ -1472,7 +1499,7 @@ private static function _phpparser_if_stmt_to_ast_if_stmt(PhpParser\Node $node)
      * @suppress PhanUndeclaredProperty
      */
     private static function _ast_node_assignop(int $flags, PhpParser\Node $node, int $startLine) {
-        return astnode(
+        return new \ast\Node(
             \ast\AST_ASSIGN_OP,
             $flags,
             [
@@ -1487,7 +1514,7 @@ private static function _ast_node_assignop(int $flags, PhpParser\Node $node, int
      * @suppress PhanUndeclaredProperty
      */
     private static function _ast_node_binaryop(int $flags, PhpParser\Node $n, int $startLine) {
-        return astnode(
+        return new \ast\Node(
             \ast\AST_BINARY_OP,
             $flags,
             self::_phpparser_nodes_to_left_right_children($n->left, $n->right),
@@ -1510,7 +1537,7 @@ private static function _phpparser_propelem_to_ast_propelem(PhpParser\Node\Stmt\
 
         $startLine = $n->getAttribute('startLine');
 
-        return astnode(\ast\AST_PROP_ELEM, 0, $children, $startLine, self::_extract_phpdoc_comment($n->getAttribute('comments') ?? $docComment));
+        return self::_new_ast_node(\ast\AST_PROP_ELEM, 0, $children, $startLine, self::_extract_phpdoc_comment($n->getAttribute('comments') ?? $docComment));
     }
 
     private static function _phpparser_constelem_to_ast_constelem(PhpParser\Node\Const_ $n, ?string $docComment) : \ast\Node{
@@ -1521,7 +1548,7 @@ private static function _phpparser_constelem_to_ast_constelem(PhpParser\Node\Con
 
         $startLine = $n->getAttribute('startLine');
 
-        return astnode(\ast\AST_CONST_ELEM, 0, $children, $startLine, self::_extract_phpdoc_comment($n->getAttribute('comments') ?? $docComment));
+        return self::_new_ast_node(\ast\AST_CONST_ELEM, 0, $children, $startLine, self::_extract_phpdoc_comment($n->getAttribute('comments') ?? $docComment));
     }
 
     private static function _phpparser_visibility_to_ast_visibility(int $visibility, bool $automatically_add_public = true) : int {
@@ -1559,7 +1586,7 @@ private static function _phpparser_property_to_ast_node(PhpParser\Node $n, int $
         }
         $flags = self::_phpparser_visibility_to_ast_visibility($n->flags);
 
-        return astnode(\ast\AST_PROP_DECL, $flags, $propElems, $propElems[0]->lineno ?: $startLine);
+        return new \ast\Node(\ast\AST_PROP_DECL, $flags, $propElems, $propElems[0]->lineno ?: $startLine);
     }
 
     private static function _phpparser_class_const_to_ast_node(PhpParser\Node\Stmt\ClassConst $n, int $startLine) : \ast\Node {
@@ -1570,7 +1597,7 @@ private static function _phpparser_class_const_to_ast_node(PhpParser\Node\Stmt\C
         }
         $flags = self::_phpparser_visibility_to_ast_visibility($n->flags);
 
-        return astnode(\ast\AST_CLASS_CONST_DECL, $flags, $constElems, $constElems[0]->lineno ?: $startLine);
+        return new \ast\Node(\ast\AST_CLASS_CONST_DECL, $flags, $constElems, $constElems[0]->lineno ?: $startLine);
     }
 
     private static function _phpparser_const_to_ast_node(PhpParser\Node\Stmt\Const_ $n, int $startLine) : \ast\Node {
@@ -1580,19 +1607,31 @@ private static function _phpparser_const_to_ast_node(PhpParser\Node\Stmt\Const_
             $constElems[] = self::_phpparser_constelem_to_ast_constelem($prop, $i === 0 ? $docComment : null);
         }
 
-        return astnode(\ast\AST_CONST_DECL, 0, $constElems, $constElems[0]->lineno ?: $startLine);
+        return new \ast\Node(\ast\AST_CONST_DECL, 0, $constElems, $constElems[0]->lineno ?: $startLine);
     }
 
-    private static function _phpparser_declare_list_to_ast_declares(array $declares, int $startLine) : \ast\Node {
+    /**
+     * @suppress PhanUndeclaredProperty
+     */
+    private static function _phpparser_declare_list_to_ast_declares(array $declares, int $startLine, string $firstDocComment = null) : \ast\Node {
         $astDeclareElements = [];
         foreach ($declares as $declare) {
             $children = [
                 'name' => $declare->key,
                 'value' => self::_phpparser_node_to_ast_node($declare->value),
             ];
-            $astDeclareElements[] = astnode(\ast\AST_CONST_ELEM, 0, $children, $declare->getAttribute('startLine'));
+            $docComment = self::_extract_phpdoc_comment($declare->getAttribute('comments')) ?? $firstDocComment;
+            $firstDocComment = null;
+            if (self::$ast_version >= 50) {
+                $children['docComment'] = $docComment;
+            }
+            $node = new \ast\Node(\ast\AST_CONST_ELEM, 0, $children, $declare->getAttribute('startLine'));
+            if (self::$ast_version < 50 && is_string($docComment)) {
+                $node->docComment = $docComment;
+            }
+            $astDeclareElements[] = $node;
         }
-        return astnode(\ast\AST_CONST_DECL, 0, $astDeclareElements, $startLine);
+        return new \ast\Node(\ast\AST_CONST_DECL, 0, $astDeclareElements, $startLine);
 
     }
 
@@ -1601,7 +1640,7 @@ private static function _ast_stmt_declare(\ast\Node $declares, ?\ast\Node $stmts
             'declares' => $declares,
             'stmts' => $stmts,
         ];
-        return astnode(\ast\AST_DECLARE, 0, $children, $startLine);
+        return new \ast\Node(\ast\AST_DECLARE, 0, $children, $startLine);
     }
 
     private static function _ast_node_call($expr, $args, int $startLine) : \ast\Node{
@@ -1609,13 +1648,13 @@ private static function _ast_node_call($expr, $args, int $startLine) : \ast\Node
             if (substr($expr, 0, 1) === '\\') {
                 $expr = substr($expr, 1);
             }
-            $expr = astnode(\ast\AST_NAME, \ast\flags\NAME_FQ, ['name' => $expr], $startLine);
+            $expr = new \ast\Node(\ast\AST_NAME, \ast\flags\NAME_FQ, ['name' => $expr], $startLine);
         }
-        return astnode(\ast\AST_CALL, 0, ['expr' => $expr, 'args' => $args], $startLine);
+        return new \ast\Node(\ast\AST_CALL, 0, ['expr' => $expr, 'args' => $args], $startLine);
     }
 
     private static function _ast_node_method_call($expr, $method, \ast\Node $args, int $startLine) : \ast\Node {
-        return astnode(\ast\AST_METHOD_CALL, 0, ['expr' => $expr, 'method' => $method, 'args' => $args], $startLine);
+        return new \ast\Node(\ast\AST_METHOD_CALL, 0, ['expr' => $expr, 'method' => $method, 'args' => $args], $startLine);
     }
 
     private static function _ast_node_static_call($class, $method, \ast\Node $args, int $startLine) : \ast\Node {
@@ -1624,9 +1663,9 @@ private static function _ast_node_static_call($class, $method, \ast\Node $args,
             if (substr($class, 0, 1) === '\\') {
                 $expr = substr($class, 1);
             }
-            $class = astnode(\ast\AST_NAME, \ast\flags\NAME_FQ, ['name' => $class], $startLine);
+            $class = new \ast\Node(\ast\AST_NAME, \ast\flags\NAME_FQ, ['name' => $class], $startLine);
         }
-        return astnode(\ast\AST_STATIC_CALL, 0, ['class' => $class, 'method' => $method, 'args' => $args], $startLine);
+        return new \ast\Node(\ast\AST_STATIC_CALL, 0, ['class' => $class, 'method' => $method, 'args' => $args], $startLine);
     }
 
     private static function _extract_phpdoc_comment($comments) : ?string {
@@ -1657,13 +1696,13 @@ private static function _phpparser_list_to_ast_list(PhpParser\Node\Expr\List_ $n
             if ($item === null) {
                 $astItems[] = null;
             } else {
-                $astItems[] = astnode(\ast\AST_ARRAY_ELEM, 0, [
+                $astItems[] = new \ast\Node(\ast\AST_ARRAY_ELEM, 0, [
                     'value' => self::_phpparser_node_to_ast_node($item->value),
                     'key' => $item->key !== null ? self::_phpparser_node_to_ast_node($item->key) : null,
                 ], $item->getAttribute('startLine'));
             }
         }
-        return astnode(\ast\AST_ARRAY, \ast\flags\ARRAY_SYNTAX_LIST, $astItems, $startLine);
+        return new \ast\Node(\ast\AST_ARRAY, \ast\flags\ARRAY_SYNTAX_LIST, $astItems, $startLine);
     }
 
     private static function _phpparser_array_to_ast_array(PhpParser\Node\Expr\Array_ $n, int $startLine) : \ast\Node {
@@ -1672,13 +1711,13 @@ private static function _phpparser_array_to_ast_array(PhpParser\Node\Expr\Array_
             if ($item === null) {
                 $astItems[] = null;
             } else {
-                $astItems[] = astnode(\ast\AST_ARRAY_ELEM, 0, [
+                $astItems[] = new \ast\Node(\ast\AST_ARRAY_ELEM, 0, [
                     'value' => self::_phpparser_node_to_ast_node($item->value),
                     'key' => $item->key !== null ? self::_phpparser_node_to_ast_node($item->key) : null,
                 ], $item->getAttribute('startLine'));
             }
         }
-        return astnode(\ast\AST_ARRAY, \ast\flags\ARRAY_SYNTAX_SHORT, $astItems, $startLine);
+        return new \ast\Node(\ast\AST_ARRAY, \ast\flags\ARRAY_SYNTAX_SHORT, $astItems, $startLine);
     }
 
     private static function _phpparser_propertyfetch_to_ast_prop(PhpParser\Node\Expr\PropertyFetch $n, int $startLine) : ?\ast\Node {
@@ -1693,7 +1732,7 @@ private static function _phpparser_propertyfetch_to_ast_prop(PhpParser\Node\Expr
                 return null;
             }
         }
-        return astnode(\ast\AST_PROP, 0, [
+        return new \ast\Node(\ast\AST_PROP, 0, [
             'expr'  => self::_phpparser_node_to_ast_node($n->var),
             'prop'  => is_object($name) ?  : $name,
         ], $startLine);
@@ -1711,58 +1750,85 @@ private static function _phpparser_classconstfetch_to_ast_classconstfetch(PhpPar
                 return null;
             }
         }
-        return astnode(\ast\AST_CLASS_CONST, 0, [
+        return new \ast\Node(\ast\AST_CLASS_CONST, 0, [
             'class' => self::_phpparser_node_to_ast_node($n->class),
             'const' => $name,
         ], $startLine);
     }
 
-    /**
-     * @suppress PhanDeprecatedProperty TODO: figure out alternative
-     */
     private static function _phpparser_name_to_string(PhpParser\Node\Name $name) : string {
         return implode('\\', $name->parts);
     }
-}
 
-/**
- * @suppress PhanTypeMismatchProperty https://github.com/etsy/phan/issues/609
- * @suppress PhanUndeclaredProperty - docComment really exists.
- * NOTE: this may be removed in the future.
- *
- * Phan was used while developing this. The asserts can be cleaned up in the future.
- */
-function astnode(int $kind, int $flags, ?array $children, int $lineno, ?string $docComment = null) : \ast\Node {
-    $node = new \ast\Node();
-    $node->kind = $kind;
-    $node->flags = $flags;
-    $node->lineno = $lineno;
-    $node->children = $children;
-    if (\is_string($docComment)) {
-        $node->docComment = $docComment;
-    }
-    return $node;
-}
+    const _NODES_WITH_NULL_DOC_COMMENT = [
+        \ast\AST_CONST_ELEM => true,
+        \ast\AST_PROP_ELEM => true,
+    ];
+
+    /**
+     * @suppress PhanTypeMismatchProperty https://github.com/etsy/phan/issues/609
+     * @suppress PhanUndeclaredProperty - docComment really exists.
+     * NOTE: this may be removed in the future.
+     *
+     * Phan was used while developing this. The asserts can be cleaned up in the future.
+     *
+     * NOTE: in AST version <= 40, may creates docComment as a property, but in version >= 45, adds it to $children
+     *
+     * @return \ast\Node
+     */
+    private static function _new_ast_node(int $kind, int $flags, array $children, int $lineno, string $docComment = null) : \ast\Node {
+        if (self::$ast_version >= 45) {
+            if (is_string($docComment) || array_key_exists($kind, self::_NODES_WITH_NULL_DOC_COMMENT)) {
+                $children['docComment'] = $docComment;
+            }
+            return new \ast\Node($kind, $flags, $children, $lineno);
+        }
+        $node = new \ast\Node($kind, $flags, $children, $lineno);
+        if (is_string($docComment)) {
+            $node->docComment = $docComment;
+        }
+        return $node;
+    }
+
+    /**
+     * @suppress PhanTypeMismatchProperty https://github.com/etsy/phan/issues/609
+     * @suppress PhanUndeclaredProperty - docComment really exists.
+     * NOTE: this may be removed in the future.
+     *
+     * Phan was used while developing this. The asserts can be cleaned up in the future.
+     *
+     * NOTE: in AST version >= 45, this returns Node, but in version <=40, this returns Decl
+     *
+     * @return \ast\Node|\ast\Node\Decl
+     */
+    private static function _new_ast_decl(int $kind, int $flags, array $children, int $lineno, string $docComment = null, string $name = null, int $endLineno = 0, int $declId = -1) : \ast\Node {
+        if (self::$ast_version >= 45) {
+            $children45 = [];
+            $children45['name'] = $name;
+            $children45['docComment'] = $docComment;
+            $children45 += $children;
+            if ($declId >= 0 && self::$ast_version >= 50) {
+                $children45['__declId'] = $declId;
+            }
+            $node = new \ast\Node($kind, $flags, $children45, $lineno);
+            if (is_int($endLineno)) {
+                $node->endLineno = $endLineno;
+            }
+            return $node;
+        }
+        $decl = new \ast\Node\Decl($kind, $flags, $children, $lineno);
+        if (\is_string($docComment)) {
+            $decl->docComment = $docComment;
+        }
+        $decl->name = $name;
+        $decl->endLineno = $endLineno;
+        return $decl;
+    }
+
+    private static function _next_decl_id() : int {
+        return self::$decl_id++;
+    }
 
-/**
- * @suppress PhanTypeMismatchProperty https://github.com/etsy/phan/issues/609
- * @suppress PhanUndeclaredProperty - docComment really exists.
- * NOTE: this may be removed in the future.
- *
- * Phan was used while developing this. The asserts can be cleaned up in the future.
- */
-function astdecl(int $kind, int $flags, ?array $children, int $lineno, string $docComment = null, string $name = null, int $endLineno = 0) : \ast\Node\Decl {
-    $node = new \ast\Node\Decl();
-    $node->kind = $kind;
-    $node->flags = $flags;
-    $node->lineno = $lineno;
-    $node->children = $children;
-    if (\is_string($docComment)) {
-        $node->docComment = $docComment;
-    }
-    $node->name = $name;
-    $node->endLineno = $endLineno;
-    return $node;
 }
 
 function sl($node) : ?int {
diff --git a/src/ASTConverter/Bootstrap.php b/src/ASTConverter/Bootstrap.php
index a968e25..f494627 100644
--- a/src/ASTConverter/Bootstrap.php
+++ b/src/ASTConverter/Bootstrap.php
@@ -13,7 +13,6 @@
     __DIR__.'/../../../../../vendor/autoload.php', // autoloader is in parent project
     ] as $file) {
     if (file_exists($file)) {
-        echo "Found the autoloader at $file\n";
         require_once($file);
         break;
     }
diff --git a/src/util.php b/src/util.php
index 5b75f32..d3a177e 100644
--- a/src/util.php
+++ b/src/util.php
@@ -1,4 +1,5 @@
 <?php declare(strict_types=1);
+// TODO: update for version 50 and 40
 
 use ast\flags;
 
@@ -164,7 +165,10 @@ function format_flags(int $kind, int $flags) : string {
     return (string) $flags;
 }
 
-/** Dumps abstract syntax tree */
+/**
+ * Dumps abstract syntax tree
+ * @suppress PhanUndeclaredProperty some properties of Decl aren't part of Node.
+ */
 function ast_dump($ast, int $options = 0) : string {
     if ($ast instanceof ast\Node) {
         $result = ast\get_kind_name($ast->kind);
@@ -179,13 +183,20 @@ function ast_dump($ast, int $options = 0) : string {
         if (ast\kind_uses_flags($ast->kind)) {
             $result .= "\n    flags: " . format_flags($ast->kind, $ast->flags);
         }
-        if (isset($ast->name)) {
-            $result .= "\n    name: $ast->name";
+        $name = $ast->name ?? $ast->children['name'] ?? null;
+        if (is_string($name)) {
+            $result .= "\n    name: $name";
         }
-        if (isset($ast->docComment)) {
-            $result .= "\n    docComment: $ast->docComment";
+        $docComment = $ast->docComment ?? $ast->children['docComment'] ?? null;
+        if ($docComment !== null) {
+            $result .= "\n    docComment: $docComment";
         }
         foreach ($ast->children as $i => $child) {
+            if ($i === 'name' && $child === $name) {
+                continue;
+            } else if ($i === 'docComment' && $child === $docComment) {
+                continue;
+            }
             $result .= "\n    $i: " . str_replace("\n", "\n    ", ast_dump($child, $options));
         }
         return $result;
diff --git a/test_files/src/stmt_list.php b/test_files/src/stmt_list.php
index aa43e63..1de1c6e 100644
--- a/test_files/src/stmt_list.php
+++ b/test_files/src/stmt_list.php
@@ -4,4 +4,5 @@
 while ($a) { $b; }
 
 declare(ticks=1);
+/** Doc comment on decl */
 declare(ticks=1) {}
diff --git a/test_files/src/type_hints.php b/test_files/src/type_hints.php
index 67c8e82..ef6a057 100644
--- a/test_files/src/type_hints.php
+++ b/test_files/src/type_hints.php
@@ -1,2 +1,2 @@
 <?php
-function test(A $a, array $b, callable $c, INT $d, Float $e, string $f, bool $g, iterable $h) : void { }
+function test(A $a, array $b, callable $c, INT $d, Float $e, string $f, bool $g, iterable $h, object $j) : void { }
diff --git a/tests/ASTConverter/ConversionTest.php b/tests/ASTConverter/ConversionTest.php
index d8ff5ca..4cd2759 100644
--- a/tests/ASTConverter/ConversionTest.php
+++ b/tests/ASTConverter/ConversionTest.php
@@ -22,12 +22,38 @@ function($filename) {
         return array_values($files);
     }
 
+    /**
+     * @return bool
+     */
+    public static function hasNativeASTSupport(int $astVersion) {
+        try {
+            $x = \ast\parse_code('', $astVersion);
+            return true;
+        } catch (\LogicException $e) {
+            return false;
+        }
+    }
+
+    /**
+     * @return string[]|int[] [string $filePath, int $astVersion]
+     */
     public function astValidFileExampleProvider() {
         $tests = [];
         $sourceDir = dirname(dirname(realpath(__DIR__))) . '/test_files/src';
         $files = $this->_scanSourceDirForPHP($sourceDir);
+        $supports40 = self::hasNativeASTSupport(40);
+        $supports50 = self::hasNativeASTSupport(50);
+        if (!($supports40 || $supports50)) {
+            throw new RuntimeException("Neither AST version 40 nor 50 are natively supported");
+        }
         foreach ($files as $file) {
-            $tests[] = [$sourceDir . '/' . $file];
+            $path = $sourceDir . '/' . $file;
+            if ($supports40) {
+                $tests[] = [$path, 40];
+            }
+            if ($supports50) {
+                $tests[] = [$path, 50];
+            }
         }
         return $tests;
     }
@@ -52,15 +78,15 @@ private static function normalizeOriginalAST($node) {
     }
 
     /** @dataProvider astValidFileExampleProvider */
-    public function testFallbackFromParser(string $fileName) {
+    public function testFallbackFromParser(string $fileName, int $astVersion) {
         $contents = file_get_contents($fileName);
         if ($contents === false) {
             $this->fail("Failed to read $fileName");
         }
-        $ast = \ast\parse_code($contents, ASTConverter::AST_VERSION);
+        $ast = \ast\parse_code($contents, $astVersion);
         self::normalizeOriginalAST($ast);
         $this->assertInstanceOf('\ast\Node', $ast, 'Examples must be syntactically valid PHP parseable by php-ast');
-        $fallback_ast = \ASTConverter\ASTConverter::ast_parse_code_fallback($contents, ASTConverter::AST_VERSION);
+        $fallback_ast = \ASTConverter\ASTConverter::ast_parse_code_fallback($contents, $astVersion);
         $this->assertInstanceOf('\ast\Node', $fallback_ast, 'The fallback must also return a tree of php-ast nodes');
         $fallbackASTRepr = var_export($fallback_ast, true);
         $originalASTRepr = var_export($ast, true);
diff --git a/tests/ASTConverter/ErrorTolerantConversionTest.php b/tests/ASTConverter/ErrorTolerantConversionTest.php
index 52e8644..e663f7c 100644
--- a/tests/ASTConverter/ErrorTolerantConversionTest.php
+++ b/tests/ASTConverter/ErrorTolerantConversionTest.php
@@ -177,11 +177,25 @@ function foo() {
     }
 
     private function _testFallbackFromParser(string $incompleteContents, string $validContents) {
-        $ast = \ast\parse_code($validContents, ASTConverter::AST_VERSION);
+        $supports40 = ConversionTest::hasNativeASTSupport(40);
+        $supports50 = ConversionTest::hasNativeASTSupport(50);
+        if (!($supports40 || $supports50)) {
+            $this->fail('No supported AST versions to test');
+        }
+        if ($supports40) {
+            $this->_testFallbackFromParserForASTVersion($incompleteContents, $validContents, 40);
+        }
+        if ($supports50) {
+            $this->_testFallbackFromParserForASTVersion($incompleteContents, $validContents, 50);
+        }
+    }
+
+    private function _testFallbackFromParserForASTVersion(string $incompleteContents, string $validContents, int $astVersion) {
+        $ast = \ast\parse_code($validContents, $astVersion);
         $this->assertInstanceOf('\ast\Node', $ast, 'Examples(for validContents) must be syntactically valid PHP parseable by php-ast');
         $errors = [];
         $phpParserNode = ASTConverter::phpparser_parse($incompleteContents, true, $errors);
-        $fallback_ast = ASTConverter::phpparser_to_phpast($phpParserNode, ASTConverter::AST_VERSION);
+        $fallback_ast = ASTConverter::phpparser_to_phpast($phpParserNode, $astVersion);
         $this->assertInstanceOf('\ast\Node', $fallback_ast, 'The fallback must also return a tree of php-ast nodes');
         $fallbackASTRepr = var_export($fallback_ast, true);
         $originalASTRepr = var_export($ast, true);
@@ -197,7 +211,7 @@ private function _testFallbackFromParser(string $incompleteContents, string $val
             } catch (\PhpParser\Error $e) {
             }
             $original_ast_dump = \ast_dump($ast);
-            $parser_export = var_export($phpParserNode, true);
+            // $parser_export = var_export($phpParserNode, true);
             $this->assertSame($originalASTRepr, $fallbackASTRepr,  <<<EOT
 The fallback must return the same tree of php-ast nodes
 Code:
diff --git a/tests/setup.sh b/tests/setup.sh
index a43d5fa..9d8b3ad 100755
--- a/tests/setup.sh
+++ b/tests/setup.sh
@@ -1,67 +1,6 @@
 #!/usr/bin/env bash
-# php-ast installation and configuration script, taken from Etsy/Phan
-
-function build {
-    phpize
-    ./configure
-    make
-}
-
-function cleanBuild {
-    make clean
-    build
-}
-
-function install {
-    make install
-    echo "extension=ast.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
-}
-
-# Ensure the build directory exists
-[[ -d "build" ]] || mkdir build
-
-# Ensure that the PHP version hasn't changed under us. If it has, we'll have to
-# rebuild the extension.
-if [[ -e "build/phpversion.txt" ]]; then
-  if ! diff -q build/phpversion.txt <(php -r "echo PHP_VERSION_ID;"); then
-    # Something has changed, so nuke the build/ast directory if it exists.
-    echo "New version of PHP detected. Removing build/ast so we can do a fresh build."
-    rm -rf build/ast
-  fi
-fi
-
-# Ensure that we have a copy of the ast extension source code.
-if [[ ! -e "build/ast/config.m4" ]]; then
-    # If build/ast exists, but build/ast/config.m4 doesn't, nuke it and start over.
-    [[ ! -d "build/ast" ]] || rm -rf build/ast
-    git clone --depth 1 https://github.com/nikic/php-ast.git build/ast
-fi
-
-# Install the ast extension
-pushd ./build/ast
-  # If we don't have ast.so, we have to build it.
-  if [[ ! -e "modules/ast.so" ]]; then
-      echo "No cached extension found. Building..."
-      build
-  else
-      # If there are new commits, we need to rebuild the extension.
-      git fetch origin master
-      newCommits=$(git rev-list HEAD...origin/master --count)
-      if [[ "$newCommits" != "0" ]]; then
-          echo "New commits found upstream. Updating and rebuilding..."
-          git pull origin master
-          cleanBuild
-      else
-          echo "Using cached extension."
-      fi
-  fi
-
-  # No matter what, we still have to move the .so into place and enable it.
-  install
-popd
-
-# Note the PHP version for later builds.
-php -r "echo PHP_VERSION_ID;" > build/phpversion.txt
+# This has been tested with 0.1.5 but not any other versions
+pecl install -f ast-0.1.5
 
 # Disable xdebug, since we aren't currently gathering code coverage data and
 # having xdebug slows down Composer a bit.