From 64ca55cfe0c187ec026e0ec5230d8b8ac54cdf8a Mon Sep 17 00:00:00 2001
From: Daniel Tschinder <daniel.tschinder@researchgate.net>
Date: Sun, 3 Jul 2016 12:13:36 +0200
Subject: [PATCH] Fixes Syntax error position with flow optional type

---
 src/parser/expression.js                      |   2 +-
 src/parser/util.js                            |   6 +-
 test/fixtures/flow/optional-type/4/actual.js  |   1 +
 .../flow/optional-type/4/expected.json        | 153 ++++++++++++++++++
 test/fixtures/flow/optional-type/5/actual.js  |   1 +
 .../flow/optional-type/5/options.json         |   3 +
 6 files changed, 162 insertions(+), 4 deletions(-)
 create mode 100644 test/fixtures/flow/optional-type/4/actual.js
 create mode 100644 test/fixtures/flow/optional-type/4/expected.json
 create mode 100644 test/fixtures/flow/optional-type/5/actual.js
 create mode 100644 test/fixtures/flow/optional-type/5/options.json

diff --git a/src/parser/expression.js b/src/parser/expression.js
index 16e297147b..f45f0550cb 100644
--- a/src/parser/expression.js
+++ b/src/parser/expression.js
@@ -558,7 +558,7 @@ pp.parseParenAndDistinguishExpression = function (startPos, startLoc, canBeArrow
     if (first) {
       first = false;
     } else {
-      this.expect(tt.comma);
+      this.expect(tt.comma, refNeedsArrowPos.start || null);
       if (this.match(tt.parenR) && this.hasPlugin("trailingFunctionCommas")) {
         optionalCommaStart = this.state.start;
         break;
diff --git a/src/parser/util.js b/src/parser/util.js
index c8cdeda9f1..7ab9c7a766 100644
--- a/src/parser/util.js
+++ b/src/parser/util.js
@@ -71,10 +71,10 @@ pp.semicolon = function () {
 };
 
 // Expect a token of a given type. If found, consume it, otherwise,
-// raise an unexpected token error.
+// raise an unexpected token error at given pos.
 
-pp.expect = function (type) {
-  return this.eat(type) || this.unexpected();
+pp.expect = function (type, pos) {
+  return this.eat(type) || this.unexpected(pos);
 };
 
 // Raise an unexpected token error.
diff --git a/test/fixtures/flow/optional-type/4/actual.js b/test/fixtures/flow/optional-type/4/actual.js
new file mode 100644
index 0000000000..32edff9f50
--- /dev/null
+++ b/test/fixtures/flow/optional-type/4/actual.js
@@ -0,0 +1 @@
+const f = (...x?) => {}
diff --git a/test/fixtures/flow/optional-type/4/expected.json b/test/fixtures/flow/optional-type/4/expected.json
new file mode 100644
index 0000000000..a570eafd13
--- /dev/null
+++ b/test/fixtures/flow/optional-type/4/expected.json
@@ -0,0 +1,153 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 23,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 23
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 23,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 23
+      }
+    },
+    "sourceType": "module",
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 23,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 23
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 6,
+            "end": 23,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 6
+              },
+              "end": {
+                "line": 1,
+                "column": 23
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 6,
+              "end": 7,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 6
+                },
+                "end": {
+                  "line": 1,
+                  "column": 7
+                }
+              },
+              "name": "f"
+            },
+            "init": {
+              "type": "ArrowFunctionExpression",
+              "start": 10,
+              "end": 23,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 10
+                },
+                "end": {
+                  "line": 1,
+                  "column": 23
+                }
+              },
+              "id": null,
+              "generator": false,
+              "expression": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "RestElement",
+                  "start": 11,
+                  "end": 15,
+                  "loc": {
+                    "start": {
+                      "line": 1,
+                      "column": 11
+                    },
+                    "end": {
+                      "line": 1,
+                      "column": 15
+                    }
+                  },
+                  "argument": {
+                    "type": "Identifier",
+                    "start": 14,
+                    "end": 15,
+                    "loc": {
+                      "start": {
+                        "line": 1,
+                        "column": 14
+                      },
+                      "end": {
+                        "line": 1,
+                        "column": 15
+                      }
+                    },
+                    "name": "x"
+                  },
+                  "optional": true
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start": 21,
+                "end": 23,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 21
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 23
+                  }
+                },
+                "body": [],
+                "directives": []
+              }
+            }
+          }
+        ],
+        "kind": "const"
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/test/fixtures/flow/optional-type/5/actual.js b/test/fixtures/flow/optional-type/5/actual.js
new file mode 100644
index 0000000000..7ea08edfc0
--- /dev/null
+++ b/test/fixtures/flow/optional-type/5/actual.js
@@ -0,0 +1 @@
+a ? b : c ? d : e ? f : g ? h : i ? j : k ? l : m ? n : (o ? p : =);
diff --git a/test/fixtures/flow/optional-type/5/options.json b/test/fixtures/flow/optional-type/5/options.json
new file mode 100644
index 0000000000..157ebff900
--- /dev/null
+++ b/test/fixtures/flow/optional-type/5/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token (1:65)"
+}