diff --git a/examples/tlsf/assembly/tlsf.ts b/examples/tlsf/assembly/tlsf.ts
index 74900310..ab606bcc 100644
--- a/examples/tlsf/assembly/tlsf.ts
+++ b/examples/tlsf/assembly/tlsf.ts
@@ -475,13 +475,15 @@ export function allocate_memory(size: usize): usize {
 
 /** Frees the chunk of memory at the specified address. */
 export function free_memory(data: usize): void {
-  var root = ROOT;
-  if (root && data) {
-    var block = changetype<Block>(data - Block.INFO);
-    var blockInfo = block.info;
-    assert(!(blockInfo & FREE)); // must be used
-    block.info = blockInfo | FREE;
-    root.insert(changetype<Block>(data - Block.INFO));
+  if (data) {
+    var root = ROOT;
+    if (root) {
+      var block = changetype<Block>(data - Block.INFO);
+      var blockInfo = block.info;
+      assert(!(blockInfo & FREE)); // must be used
+      block.info = blockInfo | FREE;
+      root.insert(changetype<Block>(data - Block.INFO));
+    }
   }
 }
 
diff --git a/package-lock.json b/package-lock.json
index 776f69d1..3991ff91 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -7,14 +7,12 @@
     "@types/strip-bom": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/@types/strip-bom/-/strip-bom-3.0.0.tgz",
-      "integrity": "sha1-FKjsOVbC6B7bdSB5CuzyHCkK69I=",
-      "dev": true
+      "integrity": "sha1-FKjsOVbC6B7bdSB5CuzyHCkK69I="
     },
     "@types/strip-json-comments": {
       "version": "0.0.30",
       "resolved": "https://registry.npmjs.org/@types/strip-json-comments/-/strip-json-comments-0.0.30.tgz",
-      "integrity": "sha512-7NQmHra/JILCd1QqpSzl8+mJRc8ZHz3uDm8YV1Ks9IhK0epEiTw8aIErbvH9PI+6XbqhyIQy3462nEsn7UVzjQ==",
-      "dev": true
+      "integrity": "sha512-7NQmHra/JILCd1QqpSzl8+mJRc8ZHz3uDm8YV1Ks9IhK0epEiTw8aIErbvH9PI+6XbqhyIQy3462nEsn7UVzjQ=="
     },
     "acorn": {
       "version": "4.0.13",
@@ -70,7 +68,6 @@
       "version": "3.2.0",
       "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-3.2.0.tgz",
       "integrity": "sha512-NnSOmMEYtVR2JVMIGTzynRkkaxtiq1xnFBcdQD/DnNCYPoEPsVJhM98BDyaoNOQIi7p4okdi3E27eN7GQbsUug==",
-      "dev": true,
       "requires": {
         "color-convert": "1.9.1"
       }
@@ -124,8 +121,7 @@
     "arrify": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/arrify/-/arrify-1.0.1.tgz",
-      "integrity": "sha1-iYUI2iIm84DfkEcoRWhJwVAaSw0=",
-      "dev": true
+      "integrity": "sha1-iYUI2iIm84DfkEcoRWhJwVAaSw0="
     },
     "asn1.js": {
       "version": "4.9.2",
@@ -228,7 +224,7 @@
         "component-emitter": "1.2.1",
         "define-property": "1.0.0",
         "isobject": "3.0.1",
-        "mixin-deep": "1.3.0",
+        "mixin-deep": "1.3.1",
         "pascalcase": "0.1.1"
       },
       "dependencies": {
@@ -259,9 +255,9 @@
       "dev": true
     },
     "binaryen": {
-      "version": "42.0.0-nightly.20180202",
-      "resolved": "https://registry.npmjs.org/binaryen/-/binaryen-42.0.0-nightly.20180202.tgz",
-      "integrity": "sha512-ieayH9pk3TRAIhx8CzWkt3YRvZvzXGqN3U8lihKQdsa/zDJBjQxbgCjKNX5GZGU0r4LLHSb8Epf/uRtKx86DbA=="
+      "version": "42.0.0-nightly.20180208",
+      "resolved": "https://registry.npmjs.org/binaryen/-/binaryen-42.0.0-nightly.20180208.tgz",
+      "integrity": "sha512-ydoTejdUpEAYmcH+wRBdYnlUQcFTVzh+9qDlcsNOwlR/ecUQb6G3CuIgXP4ns1VuPZVgShoK6aUhuxkyI/d0/Q=="
     },
     "bn.js": {
       "version": "4.11.8",
@@ -428,7 +424,6 @@
       "version": "2.3.0",
       "resolved": "https://registry.npmjs.org/chalk/-/chalk-2.3.0.tgz",
       "integrity": "sha512-Az5zJR2CBujap2rqXGaJKaPHyJ0IrUimvYNX+ncCy8PJP4ltOGTrHUIo097ZaL2zMeKYpiCdqDvS6zdrTFok3Q==",
-      "dev": true,
       "requires": {
         "ansi-styles": "3.2.0",
         "escape-string-regexp": "1.0.5",
@@ -585,7 +580,6 @@
       "version": "1.9.1",
       "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-1.9.1.tgz",
       "integrity": "sha512-mjGanIiwQJskCC18rPR6OmrZ6fm2Lc7PeGFYwCmy5J34wC6F1PzdGL6xeMfmgicfYcNLGuVFA3WzXtIDCQSZxQ==",
-      "dev": true,
       "requires": {
         "color-name": "1.1.3"
       }
@@ -593,8 +587,7 @@
     "color-name": {
       "version": "1.1.3",
       "resolved": "https://registry.npmjs.org/color-name/-/color-name-1.1.3.tgz",
-      "integrity": "sha1-p9BVi9icQveV3UIyj3QIMcpTvCU=",
-      "dev": true
+      "integrity": "sha1-p9BVi9icQveV3UIyj3QIMcpTvCU="
     },
     "commander": {
       "version": "2.13.0",
@@ -764,8 +757,7 @@
     "diff": {
       "version": "3.4.0",
       "resolved": "https://registry.npmjs.org/diff/-/diff-3.4.0.tgz",
-      "integrity": "sha512-QpVuMTEoJMF7cKzi6bvWhRulU1fZqZnvyVQgNhPaxxuTYwyjn/j1v9falseQ/uXWwPnO56RBfwtg4h/EQXmucA==",
-      "dev": true
+      "integrity": "sha512-QpVuMTEoJMF7cKzi6bvWhRulU1fZqZnvyVQgNhPaxxuTYwyjn/j1v9falseQ/uXWwPnO56RBfwtg4h/EQXmucA=="
     },
     "diffie-hellman": {
       "version": "5.0.2",
@@ -908,8 +900,7 @@
     "escape-string-regexp": {
       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz",
-      "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=",
-      "dev": true
+      "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ="
     },
     "escope": {
       "version": "3.6.0",
@@ -2069,8 +2060,7 @@
     "has-flag": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-2.0.0.tgz",
-      "integrity": "sha1-6CB68cx7MNRGzHC3NLXovhj4jVE=",
-      "dev": true
+      "integrity": "sha1-6CB68cx7MNRGzHC3NLXovhj4jVE="
     },
     "has-value": {
       "version": "1.0.0",
@@ -2166,7 +2156,6 @@
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/homedir-polyfill/-/homedir-polyfill-1.0.1.tgz",
       "integrity": "sha1-TCu8inWJmP7r9e1oWA921GdotLw=",
-      "dev": true,
       "requires": {
         "parse-passwd": "1.0.0"
       }
@@ -2562,8 +2551,7 @@
     "make-error": {
       "version": "1.3.2",
       "resolved": "https://registry.npmjs.org/make-error/-/make-error-1.3.2.tgz",
-      "integrity": "sha512-l9ra35l5VWLF24y75Tg8XgfGLX0ueRhph118WKM6H5denx4bB5QF59+4UAm9oJ2qsPQZas/CQUDdtDdfvYHBdQ==",
-      "dev": true
+      "integrity": "sha512-l9ra35l5VWLF24y75Tg8XgfGLX0ueRhph118WKM6H5denx4bB5QF59+4UAm9oJ2qsPQZas/CQUDdtDdfvYHBdQ=="
     },
     "map-cache": {
       "version": "0.2.2",
@@ -2684,9 +2672,9 @@
       "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ="
     },
     "mixin-deep": {
-      "version": "1.3.0",
-      "resolved": "https://registry.npmjs.org/mixin-deep/-/mixin-deep-1.3.0.tgz",
-      "integrity": "sha512-dgaCvoh6i1nosAUBKb0l0pfJ78K8+S9fluyIR2YvAeUD/QuMahnFnF3xYty5eYXMjhGSsB0DsW6A0uAZyetoAg==",
+      "version": "1.3.1",
+      "resolved": "https://registry.npmjs.org/mixin-deep/-/mixin-deep-1.3.1.tgz",
+      "integrity": "sha512-8ZItLHeEgaqEvd5lYBXfm4EZSFCX29Jb9K+lAHhDKzReKBQKj3R+7NOF6tjqYi9t4oI8VUfaWITJQm86wnXGNQ==",
       "dev": true,
       "requires": {
         "for-in": "1.0.2",
@@ -2708,7 +2696,6 @@
       "version": "0.5.1",
       "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
       "integrity": "sha1-MAV0OOrGz3+MR2fzhkjWaX11yQM=",
-      "dev": true,
       "requires": {
         "minimist": "0.0.8"
       },
@@ -2716,8 +2703,7 @@
         "minimist": {
           "version": "0.0.8",
           "resolved": "https://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
-          "integrity": "sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0=",
-          "dev": true
+          "integrity": "sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0="
         }
       }
     },
@@ -3060,8 +3046,7 @@
     "parse-passwd": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/parse-passwd/-/parse-passwd-1.0.0.tgz",
-      "integrity": "sha1-bVuTSkVpk7I9N/QKOC1vFmao5cY=",
-      "dev": true
+      "integrity": "sha1-bVuTSkVpk7I9N/QKOC1vFmao5cY="
     },
     "pascalcase": {
       "version": "0.1.1",
@@ -3546,12 +3531,6 @@
           "resolved": "https://registry.npmjs.org/kind-of/-/kind-of-5.1.0.tgz",
           "integrity": "sha512-NGEErnH6F2vUuXDh+OlbcKW7/wOcfdRHaZ7VWtqCztfHri/++YKmP51OdWeGPuqCOba6kk2OTe5d02VmTB80Pw==",
           "dev": true
-        },
-        "source-map": {
-          "version": "0.5.7",
-          "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.5.7.tgz",
-          "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
-          "dev": true
         }
       }
     },
@@ -3589,6 +3568,12 @@
       "integrity": "sha512-I2UmuJSRr/T8jisiROLU3A3ltr+swpniSmNPI4Ml3ZCX6tVnDsuZzK7F2hl5jTqbZBWCEKlj5HRQiPExXLgE8A==",
       "dev": true
     },
+    "source-map": {
+      "version": "0.5.7",
+      "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.5.7.tgz",
+      "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
+      "dev": true
+    },
     "source-map-resolve": {
       "version": "0.5.1",
       "resolved": "https://registry.npmjs.org/source-map-resolve/-/source-map-resolve-0.5.1.tgz",
@@ -3606,7 +3591,6 @@
       "version": "0.5.3",
       "resolved": "https://registry.npmjs.org/source-map-support/-/source-map-support-0.5.3.tgz",
       "integrity": "sha512-eKkTgWYeBOQqFGXRfKabMFdnWepo51vWqEdoeikaEPFiJC7MCU5j2h4+6Q8npkZTeLGbSyecZvRxiSoWl3rh+w==",
-      "dev": true,
       "requires": {
         "source-map": "0.6.1"
       },
@@ -3614,8 +3598,7 @@
         "source-map": {
           "version": "0.6.1",
           "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
-          "integrity": "sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==",
-          "dev": true
+          "integrity": "sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g=="
         }
       }
     },
@@ -3837,8 +3820,7 @@
     "strip-bom": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/strip-bom/-/strip-bom-3.0.0.tgz",
-      "integrity": "sha1-IzTBjpx1n3vdVv3vfprj1YjmjtM=",
-      "dev": true
+      "integrity": "sha1-IzTBjpx1n3vdVv3vfprj1YjmjtM="
     },
     "strip-eof": {
       "version": "1.0.0",
@@ -3849,14 +3831,12 @@
     "strip-json-comments": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-2.0.1.tgz",
-      "integrity": "sha1-PFMZQukIwml8DsNEhYwobHygpgo=",
-      "dev": true
+      "integrity": "sha1-PFMZQukIwml8DsNEhYwobHygpgo="
     },
     "supports-color": {
       "version": "4.5.0",
       "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-4.5.0.tgz",
       "integrity": "sha1-vnoN5ITexcXN34s9WRJQRJEvY1s=",
-      "dev": true,
       "requires": {
         "has-flag": "2.0.0"
       }
@@ -3983,9 +3963,9 @@
       }
     },
     "ts-loader": {
-      "version": "3.4.0",
-      "resolved": "https://registry.npmjs.org/ts-loader/-/ts-loader-3.4.0.tgz",
-      "integrity": "sha512-p5vExXYOj/yUEuW45kG643ufi1ynFleeeXFX4dhhVHbBpnrLqTx3VK0ZIMPfwBONIslYD4o2hyWb7JIquoL8tg==",
+      "version": "3.5.0",
+      "resolved": "https://registry.npmjs.org/ts-loader/-/ts-loader-3.5.0.tgz",
+      "integrity": "sha512-JTia3kObhTk36wPFgy0RnkZReiusYx7Le9IhcUWRrCTcFcr6Dy1zGsFd3x8DG4gevlbN65knI8W50FfoykXcng==",
       "dev": true,
       "requires": {
         "chalk": "2.3.0",
@@ -4198,7 +4178,6 @@
       "version": "4.1.0",
       "resolved": "https://registry.npmjs.org/ts-node/-/ts-node-4.1.0.tgz",
       "integrity": "sha512-xcZH12oVg9PShKhy3UHyDmuDLV3y7iKwX25aMVPt1SIXSuAfWkFiGPEkg+th8R4YKW/QCxDoW7lJdb15lx6QWg==",
-      "dev": true,
       "requires": {
         "arrify": "1.0.1",
         "chalk": "2.3.0",
@@ -4216,7 +4195,6 @@
       "version": "7.0.0",
       "resolved": "https://registry.npmjs.org/tsconfig/-/tsconfig-7.0.0.tgz",
       "integrity": "sha512-vZXmzPrL+EmC4T/4rVlT2jNVMWCi/O4DIiSj3UHg1OE5kCKbk4mfrXc6dZksLgRM/TZlKnousKH9bbTazUWRRw==",
-      "dev": true,
       "requires": {
         "@types/strip-bom": "3.0.0",
         "@types/strip-json-comments": "0.0.30",
@@ -4545,7 +4523,6 @@
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/v8flags/-/v8flags-3.0.1.tgz",
       "integrity": "sha1-3Oj8N5wX2fLJ6e142JzgAFKxt2s=",
-      "dev": true,
       "requires": {
         "homedir-polyfill": "1.0.1"
       }
@@ -4788,8 +4765,7 @@
     "yn": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/yn/-/yn-2.0.0.tgz",
-      "integrity": "sha1-5a2ryKz0CPY4X8dklWhMiOavaJo=",
-      "dev": true
+      "integrity": "sha1-5a2ryKz0CPY4X8dklWhMiOavaJo="
     }
   }
 }
diff --git a/package.json b/package.json
index 915703df..bca08bf4 100644
--- a/package.json
+++ b/package.json
@@ -11,17 +11,17 @@
     "url": "https://github.com/AssemblyScript/assemblyscript/issues"
   },
   "dependencies": {
-    "binaryen": "42.0.0-nightly.20180202",
+    "binaryen": "42.0.0-nightly.20180208",
     "glob": "^7.1.2",
-    "minimist": "^1.2.0"
+    "minimist": "^1.2.0",
+    "ts-node": "^4.1.0"
   },
   "devDependencies": {
     "chalk": "^2.3.0",
     "diff": "^3.4.0",
     "long": "^4.0.0",
     "source-map-support": "^0.5.3",
-    "ts-loader": "^3.4.0",
-    "ts-node": "^4.1.0",
+    "ts-loader": "^3.5.0",
     "tslint": "^5.9.1",
     "typescript": "^2.7.1",
     "webpack": "^3.10.0"