Fix Async Generic After Await Parsing Error (babel#11092)

* test: add test case * fix: reset awaitPos before parsing generic arrow fn * fix: maybeInArrowParameters reset to true
rajasekarm · Feb 17, 2020 · b700655 · b700655
1 parent e103fb2
commit b700655
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diff --git a/packages/babel-parser/src/plugins/typescript/index.js b/packages/babel-parser/src/plugins/typescript/index.js
@@ -1528,6 +1528,14 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       if (!this.isRelational("<")) {
         return undefined;
       }
+
+      const oldMaybeInArrowParameters = this.state.maybeInArrowParameters;
+      const oldYieldPos = this.state.yieldPos;
+      const oldAwaitPos = this.state.awaitPos;
+      this.state.maybeInArrowParameters = true;
+      this.state.yieldPos = -1;
+      this.state.awaitPos = -1;
+
       const res: ?N.ArrowFunctionExpression = this.tsTryParseAndCatch(() => {
         const node: N.ArrowFunctionExpression = this.startNodeAt(
           startPos,
@@ -1541,6 +1549,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         return node;
       });
 
+      this.state.maybeInArrowParameters = oldMaybeInArrowParameters;
+      this.state.yieldPos = oldYieldPos;
+      this.state.awaitPos = oldAwaitPos;
+
       if (!res) {
         return undefined;
       }

diff --git a/...s/babel-parser/test/fixtures/typescript/arrow-function/async-generic-after-await/input.ts b/...s/babel-parser/test/fixtures/typescript/arrow-function/async-generic-after-await/input.ts
@@ -0,0 +1,4 @@
+async () => {
+  await null;
+  async <T>() => null;
+};
diff --git a/...abel-parser/test/fixtures/typescript/arrow-function/async-generic-after-await/output.json b/...abel-parser/test/fixtures/typescript/arrow-function/async-generic-after-await/output.json
@@ -0,0 +1,214 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 53,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 4,
+      "column": 2
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 53,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 4,
+        "column": 2
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 53,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 4,
+            "column": 2
+          }
+        },
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start": 0,
+          "end": 52,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 4,
+              "column": 1
+            }
+          },
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [],
+          "body": {
+            "type": "BlockStatement",
+            "start": 12,
+            "end": 52,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 12
+              },
+              "end": {
+                "line": 4,
+                "column": 1
+              }
+            },
+            "body": [
+              {
+                "type": "ExpressionStatement",
+                "start": 16,
+                "end": 27,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 2
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 13
+                  }
+                },
+                "expression": {
+                  "type": "AwaitExpression",
+                  "start": 16,
+                  "end": 26,
+                  "loc": {
+                    "start": {
+                      "line": 2,
+                      "column": 2
+                    },
+                    "end": {
+                      "line": 2,
+                      "column": 12
+                    }
+                  },
+                  "argument": {
+                    "type": "NullLiteral",
+                    "start": 22,
+                    "end": 26,
+                    "loc": {
+                      "start": {
+                        "line": 2,
+                        "column": 8
+                      },
+                      "end": {
+                        "line": 2,
+                        "column": 12
+                      }
+                    }
+                  }
+                }
+              },
+              {
+                "type": "ExpressionStatement",
+                "start": 30,
+                "end": 50,
+                "loc": {
+                  "start": {
+                    "line": 3,
+                    "column": 2
+                  },
+                  "end": {
+                    "line": 3,
+                    "column": 22
+                  }
+                },
+                "expression": {
+                  "type": "ArrowFunctionExpression",
+                  "start": 30,
+                  "end": 49,
+                  "loc": {
+                    "start": {
+                      "line": 3,
+                      "column": 2
+                    },
+                    "end": {
+                      "line": 3,
+                      "column": 21
+                    }
+                  },
+                  "typeParameters": {
+                    "type": "TSTypeParameterDeclaration",
+                    "start": 36,
+                    "end": 39,
+                    "loc": {
+                      "start": {
+                        "line": 3,
+                        "column": 8
+                      },
+                      "end": {
+                        "line": 3,
+                        "column": 11
+                      }
+                    },
+                    "params": [
+                      {
+                        "type": "TSTypeParameter",
+                        "start": 37,
+                        "end": 38,
+                        "loc": {
+                          "start": {
+                            "line": 3,
+                            "column": 9
+                          },
+                          "end": {
+                            "line": 3,
+                            "column": 10
+                          }
+                        },
+                        "name": "T"
+                      }
+                    ]
+                  },
+                  "params": [],
+                  "id": null,
+                  "generator": false,
+                  "async": true,
+                  "body": {
+                    "type": "NullLiteral",
+                    "start": 45,
+                    "end": 49,
+                    "loc": {
+                      "start": {
+                        "line": 3,
+                        "column": 17
+                      },
+                      "end": {
+                        "line": 3,
+                        "column": 21
+                      }
+                    }
+                  }
+                }
+              }
+            ],
+            "directives": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}