diff --git a/packages/babel-parser/src/plugins/typescript.js b/packages/babel-parser/src/plugins/typescript.js
index 3914611406..c23fd5d3c6 100644
--- a/packages/babel-parser/src/plugins/typescript.js
+++ b/packages/babel-parser/src/plugins/typescript.js
@@ -1849,7 +1849,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         return this.finishNode(typeCastNode, "TSTypeCastExpression");
       }
 
-      return node;
+      return this.finishNode(node, node.type);
     }
 
     parseExportDeclaration(node: N.ExportNamedDeclaration): ?N.Declaration {
diff --git a/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/input.js b/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/input.js
index 4b8fea779c..f3019ef4b6 100644
--- a/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/input.js
+++ b/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/input.js
@@ -1 +1,2 @@
-(x?: number): any => x;
\ No newline at end of file
+(x?: number): any => x;
+((k?) => k + 1)();
diff --git a/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/output.json b/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/output.json
index de4c8043c3..3a08e42c86 100644
--- a/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/arrow-function/optional-parameter/output.json
@@ -1,29 +1,29 @@
 {
   "type": "File",
   "start": 0,
-  "end": 23,
+  "end": 42,
   "loc": {
     "start": {
       "line": 1,
       "column": 0
     },
     "end": {
-      "line": 1,
-      "column": 23
+      "line": 2,
+      "column": 18
     }
   },
   "program": {
     "type": "Program",
     "start": 0,
-    "end": 23,
+    "end": 42,
     "loc": {
       "start": {
         "line": 1,
         "column": 0
       },
       "end": {
-        "line": 1,
-        "column": 23
+        "line": 2,
+        "column": 18
       }
     },
     "sourceType": "module",
@@ -158,6 +158,132 @@
             "name": "x"
           }
         }
+      },
+      {
+        "type": "ExpressionStatement",
+        "start": 24,
+        "end": 42,
+        "loc": {
+          "start": {
+            "line": 2,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 18
+          }
+        },
+        "expression": {
+          "type": "CallExpression",
+          "start": 24,
+          "end": 41,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 0
+            },
+            "end": {
+              "line": 2,
+              "column": 17
+            }
+          },
+          "callee": {
+            "type": "ArrowFunctionExpression",
+            "start": 25,
+            "end": 38,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 1
+              },
+              "end": {
+                "line": 2,
+                "column": 14
+              }
+            },
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start": 26,
+                "end": 28,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 2
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 4
+                  },
+                  "identifierName": "k"
+                },
+                "name": "k",
+                "optional": true
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start": 33,
+              "end": 38,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 9
+                },
+                "end": {
+                  "line": 2,
+                  "column": 14
+                }
+              },
+              "left": {
+                "type": "Identifier",
+                "start": 33,
+                "end": 34,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 9
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 10
+                  },
+                  "identifierName": "k"
+                },
+                "name": "k"
+              },
+              "operator": "+",
+              "right": {
+                "type": "NumericLiteral",
+                "start": 37,
+                "end": 38,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 13
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 14
+                  }
+                },
+                "extra": {
+                  "rawValue": 1,
+                  "raw": "1"
+                },
+                "value": 1
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 24
+            }
+          },
+          "arguments": []
+        }
       }
     ],
     "directives": []