diff --git a/.hhconfig b/.hhconfig
index 5e3b4da..498623e 100644
--- a/.hhconfig
+++ b/.hhconfig
@@ -7,3 +7,4 @@ decl_override_require_hint=true
 enable_experimental_tc_features=shape_field_check,sealed_classes
 user_attributes=
 disable_primitive_refinement=true
+disable_static_local_variables = true
diff --git a/composer.lock b/composer.lock
index c31ac96..8076e25 100644
--- a/composer.lock
+++ b/composer.lock
@@ -108,16 +108,16 @@
     "packages-dev": [
         {
             "name": "facebook/difflib",
-            "version": "v1.1",
+            "version": "v1.1.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/difflib.git",
-                "reference": "195502ecd77a691e91449a3b726c9c670a99addf"
+                "reference": "545adb5da05d342dad1bc45b75f6fb95aab3de4a"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/difflib/zipball/195502ecd77a691e91449a3b726c9c670a99addf",
-                "reference": "195502ecd77a691e91449a3b726c9c670a99addf",
+                "url": "https://api.github.com/repos/hhvm/difflib/zipball/545adb5da05d342dad1bc45b75f6fb95aab3de4a",
+                "reference": "545adb5da05d342dad1bc45b75f6fb95aab3de4a",
                 "shasum": ""
             },
             "require": {
@@ -139,7 +139,7 @@
             "license": [
                 "MIT"
             ],
-            "time": "2019-02-09T01:44:39+00:00"
+            "time": "2019-03-22T23:29:07+00:00"
         },
         {
             "name": "facebook/fbexpect",
@@ -175,16 +175,16 @@
         },
         {
             "name": "facebook/hh-clilib",
-            "version": "v2.1.0",
+            "version": "v2.1.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/hh-clilib.git",
-                "reference": "44f30c1f07b9d36430bfff721a119a0d43b15edd"
+                "reference": "9d6b1a8686951da24ab68ffeba25ae85d1788408"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/hh-clilib/zipball/44f30c1f07b9d36430bfff721a119a0d43b15edd",
-                "reference": "44f30c1f07b9d36430bfff721a119a0d43b15edd",
+                "url": "https://api.github.com/repos/hhvm/hh-clilib/zipball/9d6b1a8686951da24ab68ffeba25ae85d1788408",
+                "reference": "9d6b1a8686951da24ab68ffeba25ae85d1788408",
                 "shasum": ""
             },
             "require": {
@@ -195,7 +195,7 @@
             "require-dev": {
                 "facebook/fbexpect": "^2.1.0",
                 "hhvm/hacktest": "^1.0.0",
-                "hhvm/hhast": "^4.0"
+                "hhvm/hhast": "^4.0.2"
             },
             "type": "library",
             "extra": {
@@ -207,7 +207,7 @@
             "license": [
                 "MIT"
             ],
-            "time": "2019-02-12T20:14:07+00:00"
+            "time": "2019-03-26T18:31:27+00:00"
         },
         {
             "name": "hhvm/hacktest",
@@ -296,16 +296,16 @@
         },
         {
             "name": "hhvm/hhvm-autoload",
-            "version": "v2.0.5",
+            "version": "v2.0.6",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/hhvm-autoload.git",
-                "reference": "dbd50d7fb1856d1f6757e10bc30eb2bf5d17b3f1"
+                "reference": "4f510960e71adcad661c33ae355d0d9670d9c805"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/hhvm-autoload/zipball/dbd50d7fb1856d1f6757e10bc30eb2bf5d17b3f1",
-                "reference": "dbd50d7fb1856d1f6757e10bc30eb2bf5d17b3f1",
+                "url": "https://api.github.com/repos/hhvm/hhvm-autoload/zipball/4f510960e71adcad661c33ae355d0d9670d9c805",
+                "reference": "4f510960e71adcad661c33ae355d0d9670d9c805",
                 "shasum": ""
             },
             "require": {
@@ -339,7 +339,7 @@
                 ]
             },
             "notification-url": "https://packagist.org/downloads/",
-            "time": "2019-03-22T21:27:20+00:00"
+            "time": "2019-03-26T17:57:44+00:00"
         },
         {
             "name": "hhvm/type-assert",
diff --git a/src/router/BaseRouter.php b/src/router/BaseRouter.php
index ed918e2..3ffe2bd 100644
--- a/src/router/BaseRouter.php
+++ b/src/router/BaseRouter.php
@@ -56,11 +56,11 @@ final public function routeRequest(
     return $this->routeMethodAndPath($method, $request->getUri()->getPath());
   }
 
+  private ?IResolver<TResponder> $resolver = null;
+
   protected function getResolver(): IResolver<TResponder> {
-    // Don't use <<__Memoize>> because that can be surprising with subclassing
-    static $resolver = null;
-    if ($resolver !== null) {
-      return $resolver;
+    if ($this->resolver !== null) {
+      return $this->resolver;
     }
 
     if (is_dev()) {
@@ -84,6 +84,7 @@ protected function getResolver(): IResolver<TResponder> {
         \apc_store(__FILE__.'/cache', $routes);
       }
     }
-    return new PrefixMatchingResolver($routes);
+    $this->resolver = new PrefixMatchingResolver($routes);
+    return $this->resolver;
   }
 }