diff --git a/src/rules/typeColonSpacing/reporter.js b/src/rules/typeColonSpacing/reporter.js
index e1c92870..bfa80bb6 100644
--- a/src/rules/typeColonSpacing/reporter.js
+++ b/src/rules/typeColonSpacing/reporter.js
@@ -14,6 +14,13 @@ export default (direction, context, {always, allowLineBreak}) => {
   return ({colon, node, name = '', type = 'type annotation'}) => {
     let spaces;
 
+    // Support optional names
+    // type X = { [string]: a }
+    // type X = string => string
+    if (colon.value !== ':') {
+      return;
+    }
+
     const data = {
       direction,
       name,
diff --git a/tests/rules/assertions/spaceAfterTypeColon.js b/tests/rules/assertions/spaceAfterTypeColon.js
index a354cc95..4733a60c 100644
--- a/tests/rules/assertions/spaceAfterTypeColon.js
+++ b/tests/rules/assertions/spaceAfterTypeColon.js
@@ -453,6 +453,41 @@ const FUNCTION_TYPE_PARAMS = {
     {
       code: 'type TArrayPredicate = (el:T, i?:number) => boolean',
       options: ['never']
+    },
+    {
+      code: 'type X = (number) => string;'
+    },
+    {
+      code: 'type X = (?number) => string;'
+    },
+    {
+      code: 'type X = number => string;'
+    },
+    {
+      code: 'type X = ?number => string;'
+    },
+    {
+      code: 'type X = ({ foo: bar }) => string;'
+    },
+    {
+      code: 'type X = (number) => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = (?number) => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = number => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = ?number => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = ({ foo: bar }) => string;',
+      options: ['always']
     }
   ]
 };
@@ -948,6 +983,14 @@ const OBJECT_TYPE_INDEXERS = {
     {
       code: 'type X = { +[a:b]:c }',
       options: ['never']
+    },
+    {
+      code: 'type X = { [string]: c }',
+      options: ['always']
+    },
+    {
+      code: 'type X = { [string]:c }',
+      options: ['never']
     }
   ]
 };
diff --git a/tests/rules/assertions/spaceBeforeTypeColon.js b/tests/rules/assertions/spaceBeforeTypeColon.js
index aa1fe022..80fe4460 100644
--- a/tests/rules/assertions/spaceBeforeTypeColon.js
+++ b/tests/rules/assertions/spaceBeforeTypeColon.js
@@ -338,6 +338,41 @@ const FUNCTION_TYPE_PARAMS = {
     {
       code: 'type X = (foo? : ?string) => number',
       options: ['always']
+    },
+    {
+      code: 'type X = (number) => string;'
+    },
+    {
+      code: 'type X = (?number) => string;'
+    },
+    {
+      code: 'type X = number => string;'
+    },
+    {
+      code: 'type X = ?number => string;'
+    },
+    {
+      code: 'type X = ({ foo: bar }) => string;'
+    },
+    {
+      code: 'type X = (number) => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = (?number) => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = number => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = ?number => string;',
+      options: ['always']
+    },
+    {
+      code: 'type X = ({ foo : bar }) => string;',
+      options: ['always']
     }
   ]
 };
@@ -749,6 +784,14 @@ const OBJECT_TYPE_INDEXERS = {
       code: 'type X = { [a:b]:c }',
       options: ['never']
     },
+    {
+      code: 'type X = { [string] : c }',
+      options: ['always']
+    },
+    {
+      code: 'type X = { [string]:c }',
+      options: ['never']
+    },
     {
       code: 'type X = { +[a : b] : c }',
       options: ['always']