diff --git a/src/Psalm/Type/ParseTree.php b/src/Psalm/Type/ParseTree.php
index 7c7147900..7a769722b 100644
--- a/src/Psalm/Type/ParseTree.php
+++ b/src/Psalm/Type/ParseTree.php
@@ -252,6 +252,10 @@ class ParseTree
                         throw new TypeParseTreeException('Unexpected LHS of property');
                     }
 
+                    if (!$current_parent instanceof ParseTree\ObjectLikeTree) {
+                        throw new TypeParseTreeException('Saw : outside of object-like array');
+                    }
+
                     $new_parent_leaf = new ParseTree\ObjectLikePropertyTree($current_leaf->value, $current_parent);
                     $new_parent_leaf->possibly_undefined = $last_token === '?';
                     $current_leaf->parent = $new_parent_leaf;
diff --git a/tests/TypeParseTest.php b/tests/TypeParseTest.php
index 8d9e1b432..783c6340d 100644
--- a/tests/TypeParseTest.php
+++ b/tests/TypeParseTest.php
@@ -493,6 +493,16 @@ class TypeParseTest extends TestCase
         Type::parseString('|array');
     }
 
+    /**
+     * @expectedException \Psalm\Exception\TypeParseTreeException
+     *
+     * @return void
+     */
+    public function testBadColonDash()
+    {
+        Type::parseString('array|string:-');
+    }
+
     /**
      * @expectedException \Psalm\Exception\TypeParseTreeException
      *