diff --git a/package-lock.json b/package-lock.json
index 98679a65d..a5f3d3110 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,80 +10,25 @@
       "license": "MIT",
       "dependencies": {
         "commander": "^10.0.0",
+        "reflect-metadata": "^0.1.13",
         "source-map-support": "^0.5.21",
         "tslib": "^2.5.0",
         "yagl": "^0.5.1"
       },
       "bin": {
-        "bolt": "lib/bin/bolt.js"
+        "bolt": "lib/bin/bolt.js",
+        "bolt-self": "lib/bin/bolt-self.js"
       },
       "devDependencies": {
-        "@types/commonmark": "^0.27.6",
-        "@types/glob": "^8.1.0",
-        "@types/node": "^18.15.11",
-        "@types/yargs": "^17.0.24",
-        "commonmark": "^0.30.0",
-        "glob": "^10.0.0"
+        "@types/node": "^18.15.11"
       }
     },
-    "node_modules/@types/commonmark": {
-      "version": "0.27.6",
-      "resolved": "https://registry.npmjs.org/@types/commonmark/-/commonmark-0.27.6.tgz",
-      "integrity": "sha512-t3S2hOtSSuBp1H5PTFmekGFu9U9LBzGvHy93zHwusvj4RIGUrBQ4zHvw49CkJtAl6fZvsadKhYbv8WTxJLbBmw==",
-      "dev": true
-    },
-    "node_modules/@types/glob": {
-      "version": "8.1.0",
-      "resolved": "https://registry.npmjs.org/@types/glob/-/glob-8.1.0.tgz",
-      "integrity": "sha512-IO+MJPVhoqz+28h1qLAcBEH2+xHMK6MTyHJc7MTnnYb6wsoLR29POVGJ7LycmVXIqyy/4/2ShP5sUwTXuOwb/w==",
-      "dev": true,
-      "dependencies": {
-        "@types/minimatch": "^5.1.2",
-        "@types/node": "*"
-      }
-    },
-    "node_modules/@types/minimatch": {
-      "version": "5.1.2",
-      "resolved": "https://registry.npmjs.org/@types/minimatch/-/minimatch-5.1.2.tgz",
-      "integrity": "sha512-K0VQKziLUWkVKiRVrx4a40iPaxTUefQmjtkQofBkYRcoaaL/8rhwDWww9qWbrgicNOgnpIsMxyNIUM4+n6dUIA==",
-      "dev": true
-    },
     "node_modules/@types/node": {
       "version": "18.15.11",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-18.15.11.tgz",
       "integrity": "sha512-E5Kwq2n4SbMzQOn6wnmBjuK9ouqlURrcZDVfbo9ftDDTFt3nk7ZKK4GMOzoYgnpQJKcxwQw+lGaBvvlMo0qN/Q==",
       "dev": true
     },
-    "node_modules/@types/yargs": {
-      "version": "17.0.24",
-      "resolved": "https://registry.npmjs.org/@types/yargs/-/yargs-17.0.24.tgz",
-      "integrity": "sha512-6i0aC7jV6QzQB8ne1joVZ0eSFIstHsCrobmOtghM11yGlH0j43FKL2UhWdELkyps0zuf7qVTUVCCR+tgSlyLLw==",
-      "dev": true,
-      "dependencies": {
-        "@types/yargs-parser": "*"
-      }
-    },
-    "node_modules/@types/yargs-parser": {
-      "version": "20.2.1",
-      "resolved": "https://registry.npmjs.org/@types/yargs-parser/-/yargs-parser-20.2.1.tgz",
-      "integrity": "sha512-7tFImggNeNBVMsn0vLrpn1H1uPrUBdnARPTpZoitY37ZrdJREzf7I16tMrlK3hen349gr1NYh8CmZQa7CTG6Aw==",
-      "dev": true
-    },
-    "node_modules/balanced-match": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.2.tgz",
-      "integrity": "sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw==",
-      "dev": true
-    },
-    "node_modules/brace-expansion": {
-      "version": "2.0.1",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-2.0.1.tgz",
-      "integrity": "sha512-XnAIvQ8eM+kC6aULx6wuQiwVsnzsi9d3WxzV3FpWTGA19F621kwdbsAcFKXgKUHZWsy+mY6iL1sHTxWEFCytDA==",
-      "dev": true,
-      "dependencies": {
-        "balanced-match": "^1.0.0"
-      }
-    },
     "node_modules/buffer-from": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/buffer-from/-/buffer-from-1.1.2.tgz",
@@ -97,114 +42,10 @@
         "node": ">=14"
       }
     },
-    "node_modules/commonmark": {
-      "version": "0.30.0",
-      "resolved": "https://registry.npmjs.org/commonmark/-/commonmark-0.30.0.tgz",
-      "integrity": "sha512-j1yoUo4gxPND1JWV9xj5ELih0yMv1iCWDG6eEQIPLSWLxzCXiFoyS7kvB+WwU+tZMf4snwJMMtaubV0laFpiBA==",
-      "dev": true,
-      "dependencies": {
-        "entities": "~2.0",
-        "mdurl": "~1.0.1",
-        "minimist": ">=1.2.2",
-        "string.prototype.repeat": "^0.2.0"
-      },
-      "bin": {
-        "commonmark": "bin/commonmark"
-      },
-      "engines": {
-        "node": "*"
-      }
-    },
-    "node_modules/entities": {
-      "version": "2.0.3",
-      "resolved": "https://registry.npmjs.org/entities/-/entities-2.0.3.tgz",
-      "integrity": "sha512-MyoZ0jgnLvB2X3Lg5HqpFmn1kybDiIfEQmKzTb5apr51Rb+T3KdmMiqa70T+bhGnyv7bQ6WMj2QMHpGMmlrUYQ==",
-      "dev": true
-    },
-    "node_modules/fs.realpath": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
-      "integrity": "sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==",
-      "dev": true
-    },
-    "node_modules/glob": {
-      "version": "10.0.0",
-      "resolved": "https://registry.npmjs.org/glob/-/glob-10.0.0.tgz",
-      "integrity": "sha512-zmp9ZDC6NpDNLujV2W2n+3lH+BafIVZ4/ct+Yj3BMZTH/+bgm/eVjHzeFLwxJrrIGgjjS2eiQLlpurHsNlEAtQ==",
-      "dev": true,
-      "dependencies": {
-        "fs.realpath": "^1.0.0",
-        "minimatch": "^9.0.0",
-        "minipass": "^5.0.0",
-        "path-scurry": "^1.6.4"
-      },
-      "engines": {
-        "node": ">=16 || 14 >=14.17"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/isaacs"
-      }
-    },
-    "node_modules/lru-cache": {
-      "version": "9.0.1",
-      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-9.0.1.tgz",
-      "integrity": "sha512-C8QsKIN1UIXeOs3iWmiZ1lQY+EnKDojWd37fXy1aSbJvH4iSma1uy2OWuoB3m4SYRli5+CUjDv3Dij5DVoetmg==",
-      "dev": true,
-      "engines": {
-        "node": "14 || >=16.14"
-      }
-    },
-    "node_modules/mdurl": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/mdurl/-/mdurl-1.0.1.tgz",
-      "integrity": "sha512-/sKlQJCBYVY9Ers9hqzKou4H6V5UWc/M59TH2dvkt+84itfnq7uFOMLpOiOS4ujvHP4etln18fmIxA5R5fll0g==",
-      "dev": true
-    },
-    "node_modules/minimatch": {
-      "version": "9.0.0",
-      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-9.0.0.tgz",
-      "integrity": "sha512-0jJj8AvgKqWN05mrwuqi8QYKx1WmYSUoKSxu5Qhs9prezTz10sxAHGNZe9J9cqIJzta8DWsleh2KaVaLl6Ru2w==",
-      "dev": true,
-      "dependencies": {
-        "brace-expansion": "^2.0.1"
-      },
-      "engines": {
-        "node": ">=16 || 14 >=14.17"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/isaacs"
-      }
-    },
-    "node_modules/minimist": {
-      "version": "1.2.6",
-      "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.6.tgz",
-      "integrity": "sha512-Jsjnk4bw3YJqYzbdyBiNsPWHPfO++UGG749Cxs6peCu5Xg4nrena6OVxOYxrQTqww0Jmwt+Ref8rggumkTLz9Q==",
-      "dev": true
-    },
-    "node_modules/minipass": {
-      "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/minipass/-/minipass-5.0.0.tgz",
-      "integrity": "sha512-3FnjYuehv9k6ovOEbyOswadCDPX1piCfhV8ncmYtHOjuPwylVWsghTLo7rabjC3Rx5xD4HDx8Wm1xnMF7S5qFQ==",
-      "dev": true,
-      "engines": {
-        "node": ">=8"
-      }
-    },
-    "node_modules/path-scurry": {
-      "version": "1.6.4",
-      "resolved": "https://registry.npmjs.org/path-scurry/-/path-scurry-1.6.4.tgz",
-      "integrity": "sha512-Qp/9IHkdNiXJ3/Kon++At2nVpnhRiPq/aSvQN+H3U1WZbvNRK0RIQK/o4HMqPoXjpuGJUEWpHSs6Mnjxqh3TQg==",
-      "dev": true,
-      "dependencies": {
-        "lru-cache": "^9.0.0",
-        "minipass": "^5.0.0"
-      },
-      "engines": {
-        "node": ">=16 || 14 >=14.17"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/isaacs"
-      }
+    "node_modules/reflect-metadata": {
+      "version": "0.1.13",
+      "resolved": "https://registry.npmjs.org/reflect-metadata/-/reflect-metadata-0.1.13.tgz",
+      "integrity": "sha512-Ts1Y/anZELhSsjMcU605fU9RE4Oi3p5ORujwbIKXfWa+0Zxs510Qrmrce5/Jowq3cHSZSJqBjypxmHarc+vEWg=="
     },
     "node_modules/source-map": {
       "version": "0.6.1",
@@ -223,12 +64,6 @@
         "source-map": "^0.6.0"
       }
     },
-    "node_modules/string.prototype.repeat": {
-      "version": "0.2.0",
-      "resolved": "https://registry.npmjs.org/string.prototype.repeat/-/string.prototype.repeat-0.2.0.tgz",
-      "integrity": "sha512-1BH+X+1hSthZFW+X+JaUkjkkUPwIlLEMJBLANN3hOob3RhEk5snLWNECDnYbgn/m5c5JV7Ersu1Yubaf+05cIA==",
-      "dev": true
-    },
     "node_modules/tslib": {
       "version": "2.5.0",
       "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.5.0.tgz",
@@ -241,64 +76,12 @@
     }
   },
   "dependencies": {
-    "@types/commonmark": {
-      "version": "0.27.6",
-      "resolved": "https://registry.npmjs.org/@types/commonmark/-/commonmark-0.27.6.tgz",
-      "integrity": "sha512-t3S2hOtSSuBp1H5PTFmekGFu9U9LBzGvHy93zHwusvj4RIGUrBQ4zHvw49CkJtAl6fZvsadKhYbv8WTxJLbBmw==",
-      "dev": true
-    },
-    "@types/glob": {
-      "version": "8.1.0",
-      "resolved": "https://registry.npmjs.org/@types/glob/-/glob-8.1.0.tgz",
-      "integrity": "sha512-IO+MJPVhoqz+28h1qLAcBEH2+xHMK6MTyHJc7MTnnYb6wsoLR29POVGJ7LycmVXIqyy/4/2ShP5sUwTXuOwb/w==",
-      "dev": true,
-      "requires": {
-        "@types/minimatch": "^5.1.2",
-        "@types/node": "*"
-      }
-    },
-    "@types/minimatch": {
-      "version": "5.1.2",
-      "resolved": "https://registry.npmjs.org/@types/minimatch/-/minimatch-5.1.2.tgz",
-      "integrity": "sha512-K0VQKziLUWkVKiRVrx4a40iPaxTUefQmjtkQofBkYRcoaaL/8rhwDWww9qWbrgicNOgnpIsMxyNIUM4+n6dUIA==",
-      "dev": true
-    },
     "@types/node": {
       "version": "18.15.11",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-18.15.11.tgz",
       "integrity": "sha512-E5Kwq2n4SbMzQOn6wnmBjuK9ouqlURrcZDVfbo9ftDDTFt3nk7ZKK4GMOzoYgnpQJKcxwQw+lGaBvvlMo0qN/Q==",
       "dev": true
     },
-    "@types/yargs": {
-      "version": "17.0.24",
-      "resolved": "https://registry.npmjs.org/@types/yargs/-/yargs-17.0.24.tgz",
-      "integrity": "sha512-6i0aC7jV6QzQB8ne1joVZ0eSFIstHsCrobmOtghM11yGlH0j43FKL2UhWdELkyps0zuf7qVTUVCCR+tgSlyLLw==",
-      "dev": true,
-      "requires": {
-        "@types/yargs-parser": "*"
-      }
-    },
-    "@types/yargs-parser": {
-      "version": "20.2.1",
-      "resolved": "https://registry.npmjs.org/@types/yargs-parser/-/yargs-parser-20.2.1.tgz",
-      "integrity": "sha512-7tFImggNeNBVMsn0vLrpn1H1uPrUBdnARPTpZoitY37ZrdJREzf7I16tMrlK3hen349gr1NYh8CmZQa7CTG6Aw==",
-      "dev": true
-    },
-    "balanced-match": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.2.tgz",
-      "integrity": "sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw==",
-      "dev": true
-    },
-    "brace-expansion": {
-      "version": "2.0.1",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-2.0.1.tgz",
-      "integrity": "sha512-XnAIvQ8eM+kC6aULx6wuQiwVsnzsi9d3WxzV3FpWTGA19F621kwdbsAcFKXgKUHZWsy+mY6iL1sHTxWEFCytDA==",
-      "dev": true,
-      "requires": {
-        "balanced-match": "^1.0.0"
-      }
-    },
     "buffer-from": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/buffer-from/-/buffer-from-1.1.2.tgz",
@@ -309,84 +92,10 @@
       "resolved": "https://registry.npmjs.org/commander/-/commander-10.0.0.tgz",
       "integrity": "sha512-zS5PnTI22FIRM6ylNW8G4Ap0IEOyk62fhLSD0+uHRT9McRCLGpkVNvao4bjimpK/GShynyQkFFxHhwMcETmduA=="
     },
-    "commonmark": {
-      "version": "0.30.0",
-      "resolved": "https://registry.npmjs.org/commonmark/-/commonmark-0.30.0.tgz",
-      "integrity": "sha512-j1yoUo4gxPND1JWV9xj5ELih0yMv1iCWDG6eEQIPLSWLxzCXiFoyS7kvB+WwU+tZMf4snwJMMtaubV0laFpiBA==",
-      "dev": true,
-      "requires": {
-        "entities": "~2.0",
-        "mdurl": "~1.0.1",
-        "minimist": ">=1.2.2",
-        "string.prototype.repeat": "^0.2.0"
-      }
-    },
-    "entities": {
-      "version": "2.0.3",
-      "resolved": "https://registry.npmjs.org/entities/-/entities-2.0.3.tgz",
-      "integrity": "sha512-MyoZ0jgnLvB2X3Lg5HqpFmn1kybDiIfEQmKzTb5apr51Rb+T3KdmMiqa70T+bhGnyv7bQ6WMj2QMHpGMmlrUYQ==",
-      "dev": true
-    },
-    "fs.realpath": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
-      "integrity": "sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==",
-      "dev": true
-    },
-    "glob": {
-      "version": "10.0.0",
-      "resolved": "https://registry.npmjs.org/glob/-/glob-10.0.0.tgz",
-      "integrity": "sha512-zmp9ZDC6NpDNLujV2W2n+3lH+BafIVZ4/ct+Yj3BMZTH/+bgm/eVjHzeFLwxJrrIGgjjS2eiQLlpurHsNlEAtQ==",
-      "dev": true,
-      "requires": {
-        "fs.realpath": "^1.0.0",
-        "minimatch": "^9.0.0",
-        "minipass": "^5.0.0",
-        "path-scurry": "^1.6.4"
-      }
-    },
-    "lru-cache": {
-      "version": "9.0.1",
-      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-9.0.1.tgz",
-      "integrity": "sha512-C8QsKIN1UIXeOs3iWmiZ1lQY+EnKDojWd37fXy1aSbJvH4iSma1uy2OWuoB3m4SYRli5+CUjDv3Dij5DVoetmg==",
-      "dev": true
-    },
-    "mdurl": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/mdurl/-/mdurl-1.0.1.tgz",
-      "integrity": "sha512-/sKlQJCBYVY9Ers9hqzKou4H6V5UWc/M59TH2dvkt+84itfnq7uFOMLpOiOS4ujvHP4etln18fmIxA5R5fll0g==",
-      "dev": true
-    },
-    "minimatch": {
-      "version": "9.0.0",
-      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-9.0.0.tgz",
-      "integrity": "sha512-0jJj8AvgKqWN05mrwuqi8QYKx1WmYSUoKSxu5Qhs9prezTz10sxAHGNZe9J9cqIJzta8DWsleh2KaVaLl6Ru2w==",
-      "dev": true,
-      "requires": {
-        "brace-expansion": "^2.0.1"
-      }
-    },
-    "minimist": {
-      "version": "1.2.6",
-      "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.6.tgz",
-      "integrity": "sha512-Jsjnk4bw3YJqYzbdyBiNsPWHPfO++UGG749Cxs6peCu5Xg4nrena6OVxOYxrQTqww0Jmwt+Ref8rggumkTLz9Q==",
-      "dev": true
-    },
-    "minipass": {
-      "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/minipass/-/minipass-5.0.0.tgz",
-      "integrity": "sha512-3FnjYuehv9k6ovOEbyOswadCDPX1piCfhV8ncmYtHOjuPwylVWsghTLo7rabjC3Rx5xD4HDx8Wm1xnMF7S5qFQ==",
-      "dev": true
-    },
-    "path-scurry": {
-      "version": "1.6.4",
-      "resolved": "https://registry.npmjs.org/path-scurry/-/path-scurry-1.6.4.tgz",
-      "integrity": "sha512-Qp/9IHkdNiXJ3/Kon++At2nVpnhRiPq/aSvQN+H3U1WZbvNRK0RIQK/o4HMqPoXjpuGJUEWpHSs6Mnjxqh3TQg==",
-      "dev": true,
-      "requires": {
-        "lru-cache": "^9.0.0",
-        "minipass": "^5.0.0"
-      }
+    "reflect-metadata": {
+      "version": "0.1.13",
+      "resolved": "https://registry.npmjs.org/reflect-metadata/-/reflect-metadata-0.1.13.tgz",
+      "integrity": "sha512-Ts1Y/anZELhSsjMcU605fU9RE4Oi3p5ORujwbIKXfWa+0Zxs510Qrmrce5/Jowq3cHSZSJqBjypxmHarc+vEWg=="
     },
     "source-map": {
       "version": "0.6.1",
@@ -402,12 +111,6 @@
         "source-map": "^0.6.0"
       }
     },
-    "string.prototype.repeat": {
-      "version": "0.2.0",
-      "resolved": "https://registry.npmjs.org/string.prototype.repeat/-/string.prototype.repeat-0.2.0.tgz",
-      "integrity": "sha512-1BH+X+1hSthZFW+X+JaUkjkkUPwIlLEMJBLANN3hOob3RhEk5snLWNECDnYbgn/m5c5JV7Ersu1Yubaf+05cIA==",
-      "dev": true
-    },
     "tslib": {
       "version": "2.5.0",
       "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.5.0.tgz",
diff --git a/package.json b/package.json
index 7b55a400c..39dc94d7f 100644
--- a/package.json
+++ b/package.json
@@ -4,10 +4,11 @@
   "description": "A new programming language for the web",
   "main": "lib/index.js",
   "bin": {
-    "bolt": "lib/bin/bolt.js"
+    "bolt": "lib/bin/bolt.js",
+    "bolt-self": "lib/bin/bolt-self.js"
   },
   "scripts": {
-    "test": "node ./lib/bin/bolt-selftest.js run"
+    "test": "node ./lib/bin/bolt-self.js check"
   },
   "repository": {
     "type": "git",
@@ -23,16 +24,12 @@
   "license": "MIT",
   "dependencies": {
     "commander": "^10.0.0",
+    "reflect-metadata": "^0.1.13",
     "source-map-support": "^0.5.21",
     "tslib": "^2.5.0",
     "yagl": "^0.5.1"
   },
   "devDependencies": {
-    "@types/commonmark": "^0.27.6",
-    "@types/glob": "^8.1.0",
-    "@types/node": "^18.15.11",
-    "@types/yargs": "^17.0.24",
-    "commonmark": "^0.30.0",
-    "glob": "^10.0.0"
+    "@types/node": "^18.15.11"
   }
 }
diff --git a/src/bin/bolt-selftest.ts b/src/bin/bolt-selftest.ts
deleted file mode 100644
index 6f205356c..000000000
--- a/src/bin/bolt-selftest.ts
+++ /dev/null
@@ -1,61 +0,0 @@
-#!/usr/bin/env node
-
-import "source-map-support/register"
-
-import * as commonmark from "commonmark"
-import { sync as globSync } from "glob"
-import fs from "fs";
-import path from "path";
-import { Checker } from "../checker";
-import { TextFile } from "../cst";
-import { ConsoleDiagnostics } from "../diagnostics";
-import { parseSourceFile } from "..";
-import { Analyser } from "../analysis";
-import { Command } from "commander";
-
-const projectDir = path.resolve(__dirname, '..', '..');
-
-interface Test {
-  code: string;
-}
-
-const program = new Command()
-  .name('bolt-selftest');
-
-program
-  .command('run')
-  .option('-t', '--tag', 'Tag to add to test results')
-  .action(async (args) => {
-    for await (const test of loadTests()) {
-      console.log('--------');
-      console.log(test.code);
-      const diagnostics = new ConsoleDiagnostics();
-      const file = new TextFile("#<anonymous>", test.code);
-      let sourceFile = parseSourceFile(file, diagnostics);
-      if (sourceFile !== null) {
-        sourceFile.setParents();
-        const analyser = new Analyser();
-        analyser.addSourceFile(sourceFile);
-        const checker = new Checker(analyser, diagnostics);
-        checker.check(sourceFile);
-      }
-    }
-  });
-
-program.parse();
-
-async function* loadTests(): AsyncIterable<Test> {
-  for (const filename of globSync(path.join(projectDir, 'src', 'test', '**', '*.md'))) {
-    const text = await fs.promises.readFile(filename, 'utf-8');
-    const reader = new commonmark.Parser();
-    const root = reader.parse(text);
-    let child = root.firstChild;
-    while (child !== null) {
-      if (child.type === 'code_block') {
-        yield { code: child.literal! };
-      }
-      child = child.next;
-    }
-  }
-}
-
diff --git a/src/checker.ts b/src/checker.ts
index a15f07049..5d34b52e3 100644
--- a/src/checker.ts
+++ b/src/checker.ts
@@ -34,9 +34,10 @@ import {
   TypeclassNotFoundDiagnostic,
   TypeclassDeclaredTwiceDiagnostic,
 } from "./diagnostics";
-import { assert, assertNever, first, isEmpty, last, MultiMap, toStringTag, InspectFn } from "./util";
+import { assert, assertNever, first, isEmpty, last, MultiMap, toStringTag, InspectFn, JSONValue, ignore, deserializable } from "./util";
 import { Analyser } from "./analysis";
 import { InspectOptions } from "util";
+import { deserialize } from "v8";
 
 const MAX_TYPE_ERROR_COUNT = 5;
 
@@ -55,15 +56,13 @@ export enum TypeKind {
 
 abstract class TypeBase {
 
+  @ignore
   public abstract readonly kind: TypeKind;
 
+  @ignore
   public next: Type = this as any;
 
-  public constructor(
-    public node: Syntax | null = null
-  ) {
-
-  }
+  public abstract node: Syntax | null;
 
   public static join(a: Type, b: Type): void {
     const keep = a.next;
@@ -90,10 +89,18 @@ abstract class TypeBase {
 
 }
 
+export function isType(value: any): value is Type {
+  return value !== undefined
+      && value !== null
+      && value instanceof TypeBase;
+}
+
+@deserializable()
 class TVar extends TypeBase {
 
   public readonly kind = TypeKind.Var;
 
+  @ignore
   public context = new Set<ClassDeclaration>();
 
   public constructor(
@@ -127,6 +134,12 @@ export class TNil extends TypeBase {
 
   public readonly kind = TypeKind.Nil;
 
+  public constructor(
+    public node: Syntax | null = null
+  ) {
+    super();
+  }
+
   public substitute(_sub: TVSub): Type {
     return this;
   }
@@ -145,10 +158,17 @@ export class TNil extends TypeBase {
 
 }
 
+@deserializable()
 export class TAbsent extends TypeBase {
 
   public readonly kind = TypeKind.Absent;
 
+  public constructor(
+    public node: Syntax | null = null,
+  ) {
+    super();
+  }
+
   public substitute(_sub: TVSub): Type {
     return this;
   }
@@ -167,15 +187,16 @@ export class TAbsent extends TypeBase {
 
 }
 
+@deserializable()
 export class TPresent extends TypeBase {
 
   public readonly kind = TypeKind.Present;
 
   public constructor(
     public type: Type,
-    node: Syntax | null = null,
+    public node: Syntax | null = null,
   ) {
-    super(node);
+    super();
   }
 
   public substitute(sub: TVSub): Type {
@@ -196,6 +217,7 @@ export class TPresent extends TypeBase {
 
 }
 
+@deserializable()
 export class TArrow extends TypeBase {
 
   public readonly kind = TypeKind.Arrow;
@@ -203,9 +225,9 @@ export class TArrow extends TypeBase {
   public constructor(
     public paramType: Type,
     public returnType: Type,
-    node: Syntax | null = null,
+    public node: Syntax | null = null,
   ) {
-    super(node);
+    super();
   }
 
   public static build(paramTypes: Type[], returnType: Type, node: Syntax | null = null): Type {
@@ -248,6 +270,7 @@ export class TArrow extends TypeBase {
 
 }
 
+@deserializable()
 export class TCon extends TypeBase {
 
   public readonly kind = TypeKind.Con;
@@ -258,7 +281,7 @@ export class TCon extends TypeBase {
     public displayName: string,
     public node: Syntax | null = null,
   ) {
-    super(node);
+    super();
   }
 
   public *getTypeVars(): Iterable<TVar> {
@@ -295,6 +318,7 @@ export class TCon extends TypeBase {
 
 }
 
+@deserializable()
 class TTuple extends TypeBase {
 
   public readonly kind = TypeKind.Tuple;
@@ -303,7 +327,7 @@ class TTuple extends TypeBase {
     public elementTypes: Type[],
     public node: Syntax | null = null,
   ) {
-    super(node);
+    super();
   }
 
   public *getTypeVars(): Iterable<TVar> {
@@ -338,6 +362,7 @@ class TTuple extends TypeBase {
 
 }
 
+@deserializable()
 export class TField extends TypeBase {
 
   public readonly kind = TypeKind.Field;
@@ -348,7 +373,7 @@ export class TField extends TypeBase {
     public restType: Type,
     public node: Syntax | null = null,
   ) {
-    super(node);
+    super();
   }
 
   public getTypeVars(): Iterable<TVar> {
@@ -401,6 +426,7 @@ export class TField extends TypeBase {
 
 }
 
+@deserializable()
 export class TApp extends TypeBase {
 
   public readonly kind = TypeKind.App;
@@ -410,7 +436,7 @@ export class TApp extends TypeBase {
     public right: Type,
     public node: Syntax | null = null
   ) {
-    super(node);
+    super();
   }
 
   public static build(resultType: Type, types: Type[], node: Syntax | null = null): Type {
@@ -452,6 +478,7 @@ export class TApp extends TypeBase {
 
 }
 
+@deserializable()
 export class TNominal extends TypeBase {
 
   public readonly kind = TypeKind.Nominal;
@@ -460,7 +487,7 @@ export class TNominal extends TypeBase {
     public decl: StructDeclaration | EnumDeclaration,
     public node: Syntax | null = null,
   ) {
-    super(node);
+    super();
   }
 
   public *getTypeVars(): Iterable<TVar> {
diff --git a/src/cst.ts b/src/cst.ts
index 9e9a57aa1..dddbfbbe0 100644
--- a/src/cst.ts
+++ b/src/cst.ts
@@ -2,7 +2,7 @@
 import type stream from "stream";
 import path from "path"
 
-import { assert, implementationLimitation, IndentWriter, JSONObject, JSONValue, unreachable } from "./util";
+import { assert, deserializable, implementationLimitation, IndentWriter, JSONObject, JSONValue, nonenumerable, unreachable } from "./util";
 import { isNodeWithScope, Scope } from "./scope"
 import { InferContext, Kind, KindEnv, Scheme, Type, TypeEnv } from "./checker"
 import { Emitter } from "./emitter";
@@ -13,6 +13,7 @@ export type Value
   = bigint
   | string
 
+@deserializable()
 export class TextPosition {
 
   public constructor(
@@ -45,6 +46,7 @@ export class TextPosition {
 
 }
 
+@deserializable()
 export class TextRange {
 
   constructor(
@@ -63,6 +65,7 @@ export class TextRange {
 
 }
 
+@deserializable()
 export class TextFile {
 
   public constructor(
@@ -229,15 +232,21 @@ export type Syntax
   | StructExpressionElement
   | StructPatternElement
 
-function isIgnoredProperty(key: string): boolean {
+function isnonenumerabledProperty(key: string): boolean {
   return key === 'kind' || key === 'parent';
 }
 
 abstract class SyntaxBase {
 
+  @nonenumerable
+  public abstract readonly kind: SyntaxKind;
+
+  @nonenumerable
   public parent: Syntax | null = null;
 
+  @nonenumerable
   public inferredKind?: Kind;
+  @nonenumerable
   public inferredType?: Type;
 
   public abstract getFirstToken(): Token;
@@ -307,7 +316,7 @@ abstract class SyntaxBase {
     }
 
     for (const key of Object.getOwnPropertyNames(this)) {
-      if (isIgnoredProperty(key)) {
+      if (isnonenumerabledProperty(key)) {
         continue;
       }
       visit((this as any)[key]);
@@ -334,7 +343,7 @@ abstract class SyntaxBase {
 
   public *getFields(): Iterable<[string, any]> {
     for (const key of Object.getOwnPropertyNames(this)) {
-      if (!isIgnoredProperty(key)) {
+      if (!isnonenumerabledProperty(key)) {
         yield [key, (this as any)[key]];
       }
     }
@@ -368,7 +377,7 @@ abstract class SyntaxBase {
     const obj: JSONObject = {};
     obj['type'] = this.constructor.name;
     for (const [key, value] of this.getFields()) {
-      if (isIgnoredProperty(key)) {
+      if (isnonenumerabledProperty(key)) {
         continue;
       }
       obj[key] = encode(value);
@@ -417,7 +426,7 @@ abstract class SyntaxBase {
 export function forEachChild(node: Syntax, callback: (node: Syntax) => void): void {
 
   for (const key of Object.getOwnPropertyNames(node)) {
-    if (isIgnoredProperty(key)) {
+    if (isnonenumerabledProperty(key)) {
       continue;
     }
     visitField((node as any)[key]);
@@ -442,6 +451,7 @@ export function forEachChild(node: Syntax, callback: (node: Syntax) => void): vo
 
 abstract class TokenBase extends SyntaxBase {
 
+  @nonenumerable
   private endPos: TextPosition | null = null;
 
   public constructor(
@@ -505,6 +515,7 @@ abstract class VirtualTokenBase extends TokenBase {
   }
 }
 
+@deserializable()
 export class EndOfFile extends VirtualTokenBase {
 
   public readonly kind = SyntaxKind.EndOfFile;
@@ -515,6 +526,7 @@ export class EndOfFile extends VirtualTokenBase {
 
 }
 
+@deserializable()
 export class BlockEnd extends VirtualTokenBase {
 
   public readonly kind = SyntaxKind.BlockEnd;
@@ -525,6 +537,7 @@ export class BlockEnd extends VirtualTokenBase {
 
 }
 
+@deserializable()
 export class BlockStart extends VirtualTokenBase {
 
   public readonly kind = SyntaxKind.BlockStart;
@@ -535,6 +548,7 @@ export class BlockStart extends VirtualTokenBase {
 
 }
 
+@deserializable()
 export class LineFoldEnd extends VirtualTokenBase {
 
   public readonly kind = SyntaxKind.LineFoldEnd;
@@ -545,14 +559,15 @@ export class LineFoldEnd extends VirtualTokenBase {
 
 }
 
+@deserializable()
 export class Integer extends TokenBase {
 
   public readonly kind = SyntaxKind.Integer;
 
   public constructor(
+    startPos: TextPosition | null = null,
     public value: bigint,
     public radix: number,
-    startPos: TextPosition | null = null,
   ) {
     super(startPos);
   }
@@ -563,9 +578,9 @@ export class Integer extends TokenBase {
 
   public clone(): Integer {
     return new Integer(
+      this.startPos,
       this.value,
       this.radix,
-      this.startPos
     );
   }
 
@@ -586,13 +601,14 @@ export class Integer extends TokenBase {
 
 }
 
+@deserializable()
 export class StringLiteral extends TokenBase {
 
   public readonly kind = SyntaxKind.StringLiteral;
 
   public constructor(
-    public contents: string,
     startPos: TextPosition | null = null,
+    public contents: string,
   ) {
     super(startPos);
   }
@@ -603,8 +619,8 @@ export class StringLiteral extends TokenBase {
 
   public clone(): StringLiteral {
     return new StringLiteral(
+      this.startPos,
       this.contents,
-      this.startPos
     );
   }
 
@@ -626,61 +642,64 @@ export class StringLiteral extends TokenBase {
 
 }
 
+@deserializable()
 export class IdentifierAlt extends TokenBase {
 
   public readonly kind = SyntaxKind.IdentifierAlt;
 
   public constructor(
-    public text: string,
     startPos: TextPosition | null = null,
+    public text: string,
   ) {
     super(startPos);
   }
 
   public clone(): IdentifierAlt {
     return new IdentifierAlt(
+      this.startPos,
       this.text,
-      this.startPos
     );
   }
 
 }
 
+@deserializable()
 export class Identifier extends TokenBase {
 
   public readonly kind = SyntaxKind.Identifier;
 
   public constructor(
-    public text: string,
     startPos: TextPosition | null = null,
+    public text: string,
   ) {
     super(startPos);
   }
 
   public clone(): Identifier {
     return new Identifier(
+      this.startPos,
       this.text,
-      this.startPos
     );
   }
 
 }
 
+@deserializable()
 export class CustomOperator extends TokenBase {
 
   public readonly kind = SyntaxKind.CustomOperator;
 
   public constructor(
-    public text: string,
     startPos: TextPosition | null = null,
+    public text: string,
   ) {
     super(startPos);
   }
 
   public clone(): CustomOperator {
     return new CustomOperator(
-      this.text,
       this.startPos,
+      this.text,
     );
   }
 
@@ -695,26 +714,28 @@ export function isExprOperator(node: Syntax): node is ExprOperator {
       || node.kind === SyntaxKind.VBar
 }
 
+@deserializable()
 export class Assignment extends TokenBase {
 
   public readonly kind = SyntaxKind.Assignment;
 
   public constructor(
-    public text: string,
     startPos: TextPosition | null = null,
+    public text: string,
   ) {
     super(startPos);
   }
 
   public clone(): Assignment {
     return new Assignment(
+      this.startPos,
       this.text,
-      this.startPos
     );
   }
 
 }
 
+@deserializable()
 export class LParen extends TokenBase {
 
   public readonly kind = SyntaxKind.LParen;
@@ -729,6 +750,7 @@ export class LParen extends TokenBase {
 
 }
 
+@deserializable()
 export class RParen extends TokenBase {
 
   public readonly kind = SyntaxKind.RParen;
@@ -743,6 +765,7 @@ export class RParen extends TokenBase {
 
 }
 
+@deserializable()
 export class LBrace extends TokenBase {
 
   public readonly kind = SyntaxKind.LBrace;
@@ -757,6 +780,7 @@ export class LBrace extends TokenBase {
 
 }
 
+@deserializable()
 export class RBrace extends TokenBase {
 
   public readonly kind = SyntaxKind.RBrace;
@@ -771,6 +795,7 @@ export class RBrace extends TokenBase {
 
 }
 
+@deserializable()
 export class LBracket extends TokenBase {
 
   public readonly kind = SyntaxKind.LBracket;
@@ -785,6 +810,7 @@ export class LBracket extends TokenBase {
 
 }
 
+@deserializable()
 export class RBracket extends TokenBase {
 
   public readonly kind = SyntaxKind.RBracket;
@@ -799,6 +825,7 @@ export class RBracket extends TokenBase {
 
 }
 
+@deserializable()
 export class Dot extends TokenBase {
 
   public readonly kind = SyntaxKind.Dot;
@@ -813,6 +840,7 @@ export class Dot extends TokenBase {
 
 }
 
+@deserializable()
 export class Comma extends TokenBase {
 
   public readonly kind = SyntaxKind.Comma;
@@ -827,6 +855,7 @@ export class Comma extends TokenBase {
 
 }
 
+@deserializable()
 export class DotDot extends TokenBase {
 
   public readonly kind = SyntaxKind.DotDot;
@@ -841,6 +870,7 @@ export class DotDot extends TokenBase {
 
 }
 
+@deserializable()
 export class Colon extends TokenBase {
 
   public readonly kind = SyntaxKind.Colon;
@@ -855,6 +885,7 @@ export class Colon extends TokenBase {
 
 }
 
+@deserializable()
 export class Equals extends TokenBase {
 
   public readonly kind = SyntaxKind.Equals;
@@ -869,6 +900,7 @@ export class Equals extends TokenBase {
 
 }
 
+@deserializable()
 export class Backslash extends TokenBase {
 
   public readonly kind = SyntaxKind.Equals;
@@ -883,6 +915,7 @@ export class Backslash extends TokenBase {
 
 }
 
+@deserializable()
 export class IfKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.IfKeyword;
@@ -897,6 +930,7 @@ export class IfKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class ElseKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.ElseKeyword;
@@ -911,6 +945,7 @@ export class ElseKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class ElifKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.ElifKeyword;
@@ -925,6 +960,7 @@ export class ElifKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class StructKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.StructKeyword;
@@ -939,6 +975,7 @@ export class StructKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class EnumKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.EnumKeyword;
@@ -953,6 +990,7 @@ export class EnumKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class ReturnKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.ReturnKeyword;
@@ -967,6 +1005,7 @@ export class ReturnKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class MatchKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.MatchKeyword;
@@ -981,6 +1020,7 @@ export class MatchKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class ForeignKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.ForeignKeyword;
@@ -995,6 +1035,7 @@ export class ForeignKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class ModKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.ModKeyword;
@@ -1009,6 +1050,7 @@ export class ModKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class MutKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.MutKeyword;
@@ -1023,6 +1065,7 @@ export class MutKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class ImportKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.ImportKeyword;
@@ -1037,6 +1080,7 @@ export class ImportKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class ClassKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.ClassKeyword;
@@ -1051,6 +1095,7 @@ export class ClassKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class InstanceKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.InstanceKeyword;
@@ -1066,6 +1111,7 @@ export class InstanceKeyword extends TokenBase {
 }
 
 
+@deserializable()
 export class TypeKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.TypeKeyword;
@@ -1080,6 +1126,7 @@ export class TypeKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class PubKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.PubKeyword;
@@ -1094,6 +1141,7 @@ export class PubKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class LetKeyword extends TokenBase {
 
   public readonly kind = SyntaxKind.LetKeyword;
@@ -1108,6 +1156,7 @@ export class LetKeyword extends TokenBase {
 
 }
 
+@deserializable()
 export class RArrow extends TokenBase {
 
   public readonly kind = SyntaxKind.RArrow;
@@ -1122,6 +1171,7 @@ export class RArrow extends TokenBase {
 
 }
 
+@deserializable()
 export class RArrowAlt extends TokenBase {
 
   public readonly kind = SyntaxKind.RArrowAlt;
@@ -1136,6 +1186,7 @@ export class RArrowAlt extends TokenBase {
 
 }
 
+@deserializable()
 export class VBar extends TokenBase {
 
   public readonly kind = SyntaxKind.VBar;
@@ -1196,6 +1247,7 @@ export type Token
 export type TokenKind
   = Token['kind']
 
+@deserializable()
 export class ArrowTypeExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ArrowTypeExpression;
@@ -1227,6 +1279,7 @@ export class ArrowTypeExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class TupleTypeExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.TupleTypeExpression;
@@ -1257,6 +1310,7 @@ export class TupleTypeExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ReferenceTypeExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ReferenceTypeExpression;
@@ -1288,6 +1342,7 @@ export class ReferenceTypeExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class AppTypeExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.AppTypeExpression;
@@ -1319,6 +1374,7 @@ export class AppTypeExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class VarTypeExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.VarTypeExpression;
@@ -1343,6 +1399,7 @@ export class VarTypeExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class NestedTypeExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.NestedTypeExpression;
@@ -1381,6 +1438,7 @@ export type TypeExpression
   | NestedTypeExpression
   | TupleTypeExpression
 
+@deserializable()
 export class NamedPattern extends SyntaxBase {
 
   public readonly kind = SyntaxKind.NamedPattern;
@@ -1409,6 +1467,7 @@ export class NamedPattern extends SyntaxBase {
 
 }
 
+@deserializable()
 export class TuplePattern extends SyntaxBase {
 
   public readonly kind = SyntaxKind.TuplePattern;
@@ -1439,6 +1498,7 @@ export class TuplePattern extends SyntaxBase {
 
 }
 
+@deserializable()
 export class NamedTuplePattern extends SyntaxBase {
 
   public readonly kind = SyntaxKind.NamedTuplePattern;
@@ -1470,6 +1530,7 @@ export class NamedTuplePattern extends SyntaxBase {
 
 }
 
+@deserializable()
 export class StructPatternField extends SyntaxBase {
 
   public readonly kind = SyntaxKind.StructPatternField;
@@ -1500,6 +1561,7 @@ export class StructPatternField extends SyntaxBase {
 
 }
 
+@deserializable()
 export class VariadicStructPatternElement extends SyntaxBase {
 
   public readonly kind = SyntaxKind.VariadicStructPatternElement;
@@ -1531,6 +1593,7 @@ export class VariadicStructPatternElement extends SyntaxBase {
 
 }
 
+@deserializable()
 export class PunnedStructPatternField extends SyntaxBase {
 
   public readonly kind = SyntaxKind.PunnedStructPatternField;
@@ -1560,6 +1623,7 @@ export type StructPatternElement
   | PunnedStructPatternField
   | StructPatternField
 
+@deserializable()
 export class StructPattern extends SyntaxBase {
 
   public readonly kind = SyntaxKind.StructPattern;
@@ -1590,6 +1654,7 @@ export class StructPattern extends SyntaxBase {
 
 }
 
+@deserializable()
 export class NestedPattern extends SyntaxBase {
 
   public readonly kind = SyntaxKind.NestedPattern;
@@ -1620,6 +1685,7 @@ export class NestedPattern extends SyntaxBase {
 
 }
 
+@deserializable()
 export class DisjunctivePattern extends SyntaxBase {
 
   public readonly kind = SyntaxKind.DisjunctivePattern;
@@ -1651,6 +1717,7 @@ export class DisjunctivePattern extends SyntaxBase {
 }
 
 
+@deserializable()
 export class LiteralPattern extends SyntaxBase {
 
   public readonly kind = SyntaxKind.LiteralPattern;
@@ -1684,6 +1751,7 @@ export type Pattern
   | DisjunctivePattern
   | LiteralPattern
 
+@deserializable()
 export class TupleExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.TupleExpression;
@@ -1714,6 +1782,7 @@ export class TupleExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class NestedExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.NestedExpression;
@@ -1744,6 +1813,7 @@ export class NestedExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ConstantExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ConstantExpression;
@@ -1768,6 +1838,7 @@ export class ConstantExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class CallExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.CallExpression;
@@ -1799,6 +1870,7 @@ export class CallExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class StructExpressionField extends SyntaxBase {
 
   public readonly kind = SyntaxKind.StructExpressionField;
@@ -1829,6 +1901,7 @@ export class StructExpressionField extends SyntaxBase {
 
 }
 
+@deserializable()
 export class PunnedStructExpressionField extends SyntaxBase {
 
   public readonly kind = SyntaxKind.PunnedStructExpressionField;
@@ -1857,6 +1930,7 @@ export type StructExpressionElement
   = StructExpressionField
   | PunnedStructExpressionField;
 
+@deserializable()
 export class StructExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.StructExpression;
@@ -1887,6 +1961,7 @@ export class StructExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class MatchArm extends SyntaxBase {
 
   public readonly kind = SyntaxKind.MatchArm;
@@ -1917,6 +1992,7 @@ export class MatchArm extends SyntaxBase {
 
 }
 
+@deserializable()
 export class FunctionExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.FunctionExpression;
@@ -1948,6 +2024,7 @@ export class FunctionExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class MatchExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.MatchExpression;
@@ -1984,6 +2061,7 @@ export class MatchExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ReferenceExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ReferenceExpression;
@@ -2015,6 +2093,7 @@ export class ReferenceExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class MemberExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.MemberExpression;
@@ -2043,6 +2122,7 @@ export class MemberExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class PrefixExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.PrefixExpression;
@@ -2071,6 +2151,7 @@ export class PrefixExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class PostfixExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.PostfixExpression;
@@ -2099,6 +2180,7 @@ export class PostfixExpression extends SyntaxBase {
 
 }
 
+@deserializable()
 export class InfixExpression extends SyntaxBase {
 
   public readonly kind = SyntaxKind.InfixExpression;
@@ -2143,6 +2225,7 @@ export type Expression
   | PostfixExpression
   | FunctionExpression
 
+@deserializable()
 export class IfStatementCase extends SyntaxBase {
 
   public readonly kind = SyntaxKind.IfStatementCase;
@@ -2178,6 +2261,7 @@ export class IfStatementCase extends SyntaxBase {
 
 }
 
+@deserializable()
 export class IfStatement extends SyntaxBase {
 
   public readonly kind = SyntaxKind.IfStatement;
@@ -2204,6 +2288,7 @@ export class IfStatement extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ReturnStatement extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ReturnStatement;
@@ -2235,6 +2320,7 @@ export class ReturnStatement extends SyntaxBase {
 
 }
 
+@deserializable()
 export class AssignStatement extends SyntaxBase {
 
   public readonly kind = SyntaxKind.AssignStatement;
@@ -2265,6 +2351,7 @@ export class AssignStatement extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ExpressionStatement extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ExpressionStatement;
@@ -2295,6 +2382,7 @@ export type Statement
   | IfStatement
   | AssignStatement
 
+@deserializable()
 export class Param extends SyntaxBase {
 
   public readonly kind = SyntaxKind.Param;
@@ -2321,6 +2409,7 @@ export class Param extends SyntaxBase {
 
 }
 
+@deserializable()
 export class EnumDeclarationStructElement extends SyntaxBase {
 
   public readonly kind = SyntaxKind.EnumDeclarationStructElement;
@@ -2356,6 +2445,7 @@ export class EnumDeclarationStructElement extends SyntaxBase {
 
 }
 
+@deserializable()
 export class EnumDeclarationTupleElement extends SyntaxBase {
 
   public readonly kind = SyntaxKind.EnumDeclarationTupleElement;
@@ -2391,10 +2481,12 @@ export type EnumDeclarationElement
   = EnumDeclarationStructElement
   | EnumDeclarationTupleElement
 
+@deserializable()
 export class EnumDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.EnumDeclaration;
 
+  @nonenumerable
   public typeEnv?: TypeEnv;
 
   public constructor(
@@ -2433,6 +2525,7 @@ export class EnumDeclaration extends SyntaxBase {
 
 }
 
+@deserializable()
 export class StructDeclarationField extends SyntaxBase {
 
   public readonly kind = SyntaxKind.StructDeclarationField;
@@ -2463,10 +2556,12 @@ export class StructDeclarationField extends SyntaxBase {
 
 }
 
+@deserializable()
 export class StructDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.StructDeclaration;
 
+  @nonenumerable
   public typeEnv?: TypeEnv;
 
   public constructor(
@@ -2505,6 +2600,7 @@ export class StructDeclaration extends SyntaxBase {
 
 }
 
+@deserializable()
 export class TypeAssert extends SyntaxBase {
 
   public readonly kind = SyntaxKind.TypeAssert;
@@ -2537,6 +2633,7 @@ export type Body
   = ExprBody
   | BlockBody
 
+@deserializable()
 export class ExprBody extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ExprBody;
@@ -2569,6 +2666,7 @@ export type LetBodyElement
   = LetDeclaration
   | Statement
 
+@deserializable()
 export class BlockBody extends SyntaxBase {
 
   public readonly kind = SyntaxKind.BlockBody;
@@ -2600,6 +2698,7 @@ export class BlockBody extends SyntaxBase {
 
 }
 
+@deserializable()
 export class WrappedOperator extends SyntaxBase {
 
   public readonly kind = SyntaxKind.WrappedOperator;
@@ -2630,10 +2729,12 @@ export class WrappedOperator extends SyntaxBase {
 
 }
 
+@deserializable()
 export class TypeDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.TypeDeclaration;
 
+  @nonenumerable
   public typeEnv?: TypeEnv;
 
   public constructor(
@@ -2671,14 +2772,21 @@ export class TypeDeclaration extends SyntaxBase {
 
 }
 
+@deserializable()
 export class LetDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.LetDeclaration;
 
+  @nonenumerable
   public scope?: Scope;
+
+  @nonenumerable
   public typeEnv?: TypeEnv;
 
+  @nonenumerable
   public activeCycle?: boolean;
+
+  @nonenumerable
   public context?: InferContext;
 
   public constructor(
@@ -2741,6 +2849,7 @@ export class LetDeclaration extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ImportDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ImportDeclaration;
@@ -2776,6 +2885,7 @@ export type Declaration
   | EnumDeclaration
   | TypeDeclaration
 
+@deserializable()
 export class Initializer extends SyntaxBase {
 
   public readonly kind = SyntaxKind.Initializer;
@@ -2804,6 +2914,7 @@ export class Initializer extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ClassConstraint extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ClassConstraint;
@@ -2832,6 +2943,7 @@ export class ClassConstraint extends SyntaxBase {
 
 }
 
+@deserializable()
 export class ClassConstraintClause extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ClassConstraintClause;
@@ -2867,10 +2979,12 @@ export type ClassDeclarationElement
   = LetDeclaration
   | TypeDeclaration
 
+@deserializable()
 export class ClassDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ClassDeclaration;
 
+  @nonenumerable
   public typeEnv?: TypeEnv;
 
   public constructor(
@@ -2970,10 +3084,12 @@ export type InstanceDeclarationElement
   = LetDeclaration
   | TypeDeclaration
 
+@deserializable()
 export class InstanceDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.InstanceDeclaration;
 
+  @nonenumerable
   public typeEnv?: TypeEnv;
 
   public constructor(
@@ -3016,11 +3132,14 @@ export class InstanceDeclaration extends SyntaxBase {
   }
 
 }
+@deserializable()
 export class ModuleDeclaration extends SyntaxBase {
 
   public readonly kind = SyntaxKind.ModuleDeclaration;
 
+  @nonenumerable
   public typeEnv?: TypeEnv;
+  @nonenumerable
   public kindEnv?: KindEnv;
 
   public constructor(
@@ -3066,12 +3185,16 @@ export type SourceFileElement
   | InstanceDeclaration
   | ModuleDeclaration
 
+@deserializable()
 export class SourceFile extends SyntaxBase {
 
   public readonly kind = SyntaxKind.SourceFile;
 
+  @nonenumerable
   public scope?: Scope;
+  @nonenumerable
   public typeEnv?: TypeEnv;
+  @nonenumerable
   public kindEnv?: KindEnv;
 
   public constructor(
diff --git a/src/diagnostics.ts b/src/diagnostics.ts
index 3824e3c18..744720d1b 100644
--- a/src/diagnostics.ts
+++ b/src/diagnostics.ts
@@ -1,7 +1,7 @@
 
 import { TypeKind, type Type, Kind, KindType } from "./checker";
 import { ClassConstraint, ClassDeclaration, IdentifierAlt, InstanceDeclaration, Syntax, SyntaxKind, TextFile, TextPosition, TextRange, Token } from "./cst";
-import { assertNever, countDigits, IndentWriter } from "./util";
+import { assertNever, countDigits, deserializable, IndentWriter } from "./util";
 
 const ANSI_RESET = "\u001b[0m"
 const ANSI_BOLD = "\u001b[1m"
@@ -47,12 +47,16 @@ const enum DiagnosticKind {
   FieldNotFound,
 }
 
-interface DiagnosticBase {
-  level: Level;
-  readonly kind: DiagnosticKind;
+abstract class DiagnosticBase {
+
+  public abstract readonly kind: DiagnosticKind;
+
+  public abstract level: Level;
+
 }
 
-export class UnexpectedCharDiagnostic implements DiagnosticBase {
+@deserializable()
+export class UnexpectedCharDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.UnexpectedChar;
 
@@ -63,13 +67,14 @@ export class UnexpectedCharDiagnostic implements DiagnosticBase {
     public position: TextPosition,
     public actual: string,
   ) {
-
+    super();
   }
 
 }
 
 
-export class UnexpectedTokenDiagnostic implements DiagnosticBase {
+@deserializable()
+export class UnexpectedTokenDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.UnexpectedToken;
 
@@ -80,12 +85,13 @@ export class UnexpectedTokenDiagnostic implements DiagnosticBase {
     public actual: Token,
     public expected: SyntaxKind[],
   ) {
-
+    super();
   }
 
 }
 
-export class TypeclassDeclaredTwiceDiagnostic implements DiagnosticBase {
+@deserializable()
+export class TypeclassDeclaredTwiceDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.TypeclassDecaredTwice;
   
@@ -95,12 +101,13 @@ export class TypeclassDeclaredTwiceDiagnostic implements DiagnosticBase {
     public name: IdentifierAlt,
     public origDecl: ClassDeclaration,
   ) {
-
+    super();
   } 
 
 }
 
-export class TypeclassNotFoundDiagnostic implements DiagnosticBase {
+@deserializable()
+export class TypeclassNotFoundDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.TypeclassNotFound;
 
@@ -110,12 +117,13 @@ export class TypeclassNotFoundDiagnostic implements DiagnosticBase {
     public name: IdentifierAlt,
     public origin: InstanceDeclaration | ClassConstraint | null = null,
   ) {
-
+    super();
   }
 
 }
 
-export class BindingNotFoundDiagnostic implements DiagnosticBase {
+@deserializable()
+export class BindingNotFoundDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.BindingNotFound;
 
@@ -126,12 +134,13 @@ export class BindingNotFoundDiagnostic implements DiagnosticBase {
     public name: string,
     public node: Syntax,
   ) {
-
+    super();
   }
 
 }
 
-export class TypeMismatchDiagnostic implements DiagnosticBase {
+@deserializable()
+export class TypeMismatchDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.TypeMismatch;
 
@@ -143,12 +152,13 @@ export class TypeMismatchDiagnostic implements DiagnosticBase {
     public trace: Syntax[],
     public fieldPath: string[],
   ) {
-
+    super();
   }
 
 }
 
-export class FieldNotFoundDiagnostic implements DiagnosticBase {
+@deserializable()
+export class FieldNotFoundDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.FieldNotFound;
 
@@ -160,12 +170,13 @@ export class FieldNotFoundDiagnostic implements DiagnosticBase {
     public present: Syntax | null,
     public cause: Syntax | null = null,
   ) {
-
+    super();
   }
 
 }
 
-export class KindMismatchDiagnostic implements DiagnosticBase {
+@deserializable()
+export class KindMismatchDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.KindMismatch;
 
@@ -176,12 +187,13 @@ export class KindMismatchDiagnostic implements DiagnosticBase {
     public right: Kind,
     public origin: Syntax | null,
   ) {
-  
+    super();
   }
 
 }
 
-export class ModuleNotFoundDiagnostic implements DiagnosticBase {
+@deserializable()
+export class ModuleNotFoundDiagnostic extends DiagnosticBase {
 
   public readonly kind = DiagnosticKind.ModuleNotFound;
 
@@ -191,7 +203,7 @@ export class ModuleNotFoundDiagnostic implements DiagnosticBase {
     public modulePath: string[],
     public node: Syntax,
   ) {
-
+    super();
   }
 
 }
diff --git a/src/scanner.ts b/src/scanner.ts
index 0c33c8f4d..58ce79dc4 100644
--- a/src/scanner.ts
+++ b/src/scanner.ts
@@ -212,7 +212,7 @@ export class Scanner extends BufferedStream<Token> {
               }
             }
           }
-          return new StringLiteral(contents, startPos);
+          return new StringLiteral(startPos, contents);
         }
 
         case EOF:
@@ -233,7 +233,7 @@ export class Scanner extends BufferedStream<Token> {
           if (text === '') {
             return new Colon(startPos);
           } else if (text === '=') {
-            return new Assignment(':', startPos);
+            return new Assignment(startPos, ':');
           } else {
             throw new ScanError(this.file, startPos, ':' + text);
           }
@@ -273,9 +273,9 @@ export class Scanner extends BufferedStream<Token> {
           } else if (text === '=') {
             return new Equals(startPos);
           } else if (text.endsWith('=') && text[text.length-2] !== '=') {
-            return new Assignment(text.substring(0, text.length-1), startPos);
+            return new Assignment(startPos, text.substring(0, text.length-1));
           } else {
-            return new CustomOperator(text, startPos);
+            return new CustomOperator(startPos, text);
           }
         }
 
@@ -307,7 +307,7 @@ export class Scanner extends BufferedStream<Token> {
             this.getChar();
             value = value * BigInt(10) + BigInt(toDecimal(c1));
           }
-          return new Integer(value, 10, startPos);
+          return new Integer(startPos, value, 10);
         }
 
         case 'a':
@@ -385,9 +385,9 @@ export class Scanner extends BufferedStream<Token> {
             case 'mod': return new ModKeyword(startPos);
             default:
               if (isUpper(text[0])) {
-                return new IdentifierAlt(text, startPos);
+                return new IdentifierAlt(startPos, text);
               } else {
-                return new Identifier(text, startPos);
+                return new Identifier(startPos, text);
               }
           }
         }
diff --git a/src/util.ts b/src/util.ts
index b57e55986..80bd19b8b 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -1,4 +1,5 @@
 
+import "reflect-metadata"
 import path from "path"
 import stream from "stream"
 import { InspectOptions } from "util";
@@ -242,3 +243,56 @@ export class MultiMap<K, V> {
 
 }
 
+export const classes = new Map<string, any>;
+
+export function deserializable() {
+  return (constructor: Function) => {
+    if (classes.has(constructor.name)) {
+      throw new Error(`A class with the name '${constructor.name}' has already been registered.`);
+    }
+    classes.set(constructor.name, constructor);
+  }
+}
+
+export function getIgnoredFields(target: any): Set<string> {
+  const fields = Reflect.getOwnMetadata('ignoredFields', target) ?? new Set;
+  for (;;) {
+    target = Object.getPrototypeOf(target);
+    if (target === null) {
+      break;
+    }
+    const otherFields = Reflect.getOwnMetadata('ignoredFields', target);
+    if (otherFields !== undefined) {
+      for (const field of otherFields) {
+        fields.add(field);
+      }
+    }
+  }
+  return fields;
+}
+
+export function ignore(target: any, propertyKey: string) {
+  if (!Reflect.hasOwnMetadata('ignoredFields', target.constructor)) {
+    Reflect.defineMetadata('ignoredFields', new Set([ propertyKey ]), target.constructor);
+  }
+  Reflect.getOwnMetadata('ignoredFields', target.constructor).add(propertyKey);
+}
+
+export const nonenumerable: {
+    (target: any, name: string): void;
+    (target: any, name: string, desc: PropertyDescriptor): PropertyDescriptor;
+} = (target: any, name: string, desc?: any) => {
+    if (desc) {
+        desc.enumerable = false;
+        return desc;
+    }
+    Object.defineProperty(target, name,  {
+        set(value) {
+            Object.defineProperty(this, name, {
+                value, writable: true, configurable: true,
+            });
+        },
+        configurable: true,
+    });
+};
+
diff --git a/tsconfig.json b/tsconfig.json
index b61a9b28b..120e849c9 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -12,7 +12,8 @@
     "esModuleInterop": true,
     "forceConsistentCasingInFileNames": true,
     "strict": true,
-    "skipLibCheck": true
+    "skipLibCheck": true,
+    "experimentalDecorators": true
   },
   "include": ["src"]
 }