diff --git a/lib/analyze-scope.js b/lib/analyze-scope.js
index fb9f4d4e..9b2a40d6 100644
--- a/lib/analyze-scope.js
+++ b/lib/analyze-scope.js
@@ -181,6 +181,11 @@ class Referencer extends OriginalReferencer {
     this._visitDeclareX(node);
   }
 
+  // visit OptionalMemberExpression as a MemberExpression.
+  OptionalMemberExpression(node) {
+    super.MemberExpression(node);
+  }
+
   _visitClassProperty(node) {
     this._visitTypeAnnotation(node.typeAnnotation);
     this.visitProperty(node);
diff --git a/package.json b/package.json
index 62977e54..1f449289 100644
--- a/package.json
+++ b/package.json
@@ -39,7 +39,7 @@
   "devDependencies": {
     "babel-eslint": "^8.0.0",
     "dedent": "^0.7.0",
-    "eslint": "npm:eslint@4.13.1",
+    "eslint": "npm:eslint@4.19.1",
     "eslint-config-babel": "^7.0.1",
     "eslint-old": "npm:eslint@4.13.1",
     "eslint-plugin-flowtype": "^2.30.3",
diff --git a/yarn.lock b/yarn.lock
index 53c3bced..35d31787 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -144,6 +144,10 @@ acorn@^5.4.0:
   version "5.4.1"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.4.1.tgz#fdc58d9d17f4a4e98d102ded826a9b9759125102"
 
+acorn@^5.5.0:
+  version "5.7.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.1.tgz#f095829297706a7c9776958c0afc8930a9b9d9d8"
+
 ajv-keywords@^2.1.0:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/ajv-keywords/-/ajv-keywords-2.1.1.tgz#617997fc5f60576894c435f940d819e135b80762"
@@ -434,7 +438,7 @@ doctrine@1.5.0:
     esutils "^2.0.2"
     isarray "^1.0.0"
 
-doctrine@^2.0.2:
+doctrine@^2.0.2, doctrine@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/doctrine/-/doctrine-2.1.0.tgz#5cd01fc101621b42c4cd7f5d1a66243716d3f39d"
   dependencies:
@@ -472,7 +476,7 @@ eslint-module-utils@^2.1.1:
     debug "^2.6.8"
     pkg-dir "^1.0.0"
 
-"eslint-old@npm:eslint@4.13.1", "eslint@npm:eslint@4.13.1":
+"eslint-old@npm:eslint@4.13.1":
   version "4.13.1"
   resolved "https://registry.yarnpkg.com/eslint/-/eslint-4.13.1.tgz#0055e0014464c7eb7878caf549ef2941992b444f"
   dependencies:
@@ -553,6 +557,49 @@ eslint-visitor-keys@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/eslint-visitor-keys/-/eslint-visitor-keys-1.0.0.tgz#3f3180fb2e291017716acb4c9d6d5b5c34a6a81d"
 
+"eslint@npm:eslint@4.19.1":
+  version "4.19.1"
+  resolved "https://registry.yarnpkg.com/eslint/-/eslint-4.19.1.tgz#32d1d653e1d90408854bfb296f076ec7e186a300"
+  dependencies:
+    ajv "^5.3.0"
+    babel-code-frame "^6.22.0"
+    chalk "^2.1.0"
+    concat-stream "^1.6.0"
+    cross-spawn "^5.1.0"
+    debug "^3.1.0"
+    doctrine "^2.1.0"
+    eslint-scope "^3.7.1"
+    eslint-visitor-keys "^1.0.0"
+    espree "^3.5.4"
+    esquery "^1.0.0"
+    esutils "^2.0.2"
+    file-entry-cache "^2.0.0"
+    functional-red-black-tree "^1.0.1"
+    glob "^7.1.2"
+    globals "^11.0.1"
+    ignore "^3.3.3"
+    imurmurhash "^0.1.4"
+    inquirer "^3.0.6"
+    is-resolvable "^1.0.0"
+    js-yaml "^3.9.1"
+    json-stable-stringify-without-jsonify "^1.0.1"
+    levn "^0.3.0"
+    lodash "^4.17.4"
+    minimatch "^3.0.2"
+    mkdirp "^0.5.1"
+    natural-compare "^1.4.0"
+    optionator "^0.8.2"
+    path-is-inside "^1.0.2"
+    pluralize "^7.0.0"
+    progress "^2.0.0"
+    regexpp "^1.0.1"
+    require-uncached "^1.0.3"
+    semver "^5.3.0"
+    strip-ansi "^4.0.0"
+    strip-json-comments "~2.0.1"
+    table "4.0.2"
+    text-table "~0.2.0"
+
 espree@^3.5.2:
   version "3.5.3"
   resolved "https://registry.yarnpkg.com/espree/-/espree-3.5.3.tgz#931e0af64e7fbbed26b050a29daad1fc64799fa6"
@@ -560,6 +607,13 @@ espree@^3.5.2:
     acorn "^5.4.0"
     acorn-jsx "^3.0.0"
 
+espree@^3.5.4:
+  version "3.5.4"
+  resolved "https://registry.yarnpkg.com/espree/-/espree-3.5.4.tgz#b0f447187c8a8bed944b815a660bddf5deb5d1a7"
+  dependencies:
+    acorn "^5.5.0"
+    acorn-jsx "^3.0.0"
+
 esprima@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/esprima/-/esprima-4.0.0.tgz#4499eddcd1110e0b218bacf2fa7f7f59f55ca804"
@@ -1378,6 +1432,10 @@ readable-stream@^2.2.2:
     string_decoder "~1.0.3"
     util-deprecate "~1.0.1"
 
+regexpp@^1.0.1:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/regexpp/-/regexpp-1.1.0.tgz#0e3516dd0b7904f413d2d4193dce4618c3a689ab"
+
 repeating@^2.0.0:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/repeating/-/repeating-2.0.1.tgz#5214c53a926d3552707527fbab415dbc08d06dda"
@@ -1592,7 +1650,7 @@ symbol-observable@^0.2.2:
   version "0.2.4"
   resolved "https://registry.yarnpkg.com/symbol-observable/-/symbol-observable-0.2.4.tgz#95a83db26186d6af7e7a18dbd9760a2f86d08f40"
 
-table@^4.0.1:
+table@4.0.2, table@^4.0.1:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/table/-/table-4.0.2.tgz#a33447375391e766ad34d3486e6e2aedc84d2e36"
   dependencies: