diff --git a/packages/babel-parser/test/fixtures/flow/type-alias/6/input.js b/packages/babel-parser/test/fixtures/flow/type-alias/6/input.js
new file mode 100644
index 0000000000..099757ca3f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/type-alias/6/input.js
@@ -0,0 +1 @@
+type a = ??string;
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/type-alias/6/output.json b/packages/babel-parser/test/fixtures/flow/type-alias/6/output.json
new file mode 100644
index 0000000000..526e348eab
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/type-alias/6/output.json
@@ -0,0 +1,113 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 18,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 18
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 18,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 18
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start": 0,
+        "end": 18,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 18
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 5,
+          "end": 6,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 5
+            },
+            "end": {
+              "line": 1,
+              "column": 6
+            },
+            "identifierName": "a"
+          },
+          "name": "a"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "NullableTypeAnnotation",
+          "start": 9,
+          "end": 17,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 9
+            },
+            "end": {
+              "line": 1,
+              "column": 17
+            }
+          },
+          "typeAnnotation": {
+            "type": "NullableTypeAnnotation",
+            "start": 10,
+            "end": 17,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 10
+              },
+              "end": {
+                "line": 1,
+                "column": 17
+              }
+            },
+            "typeAnnotation": {
+              "type": "StringTypeAnnotation",
+              "start": 11,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 11
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              }
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file