diff --git a/README.md b/README.md
index d7d354b6..b00ecc6e 100644
--- a/README.md
+++ b/README.md
@@ -2203,6 +2203,10 @@ The following patterns are not considered problems:
 ```js
 type foo = { foo: string, ... };
 
+interface Foo { foo: string }
+
+declare class Foo { foo: string }
+
 type foo = {| |};
 
 type foo = {| bar: string |};
diff --git a/src/rules/requireInexactType.js b/src/rules/requireInexactType.js
index 5486bd13..d048afe0 100644
--- a/src/rules/requireInexactType.js
+++ b/src/rules/requireInexactType.js
@@ -12,6 +12,10 @@ const create = (context) => {
     ObjectTypeAnnotation (node) {
       const {inexact, exact} = node;
 
+      if (!node.hasOwnProperty('inexact')) {
+        return;
+      }
+
       if (always && !inexact && !exact) {
         context.report({
           message: 'Type must be explicit inexact.',
diff --git a/tests/rules/assertions/requireInexactType.js b/tests/rules/assertions/requireInexactType.js
index 713ece6c..fac73491 100644
--- a/tests/rules/assertions/requireInexactType.js
+++ b/tests/rules/assertions/requireInexactType.js
@@ -65,6 +65,12 @@ export default {
     {
       code: 'type foo = { foo: string, ... };'
     },
+    {
+      code: 'interface Foo { foo: string }'
+    },
+    {
+      code: 'declare class Foo { foo: string }'
+    },
     {
       code: 'type foo = {| |};'
     },