Disallow await before exponential (#12441)

* refactor: move unary exponential check to parseMaybeUnary

* fix: disallow await before exponential

* add test cases

packages/babel-parser/src/parser/expression.js

@@ -399,17 +399,6 @@ export default class ExpressionParser extends LValParser {
         const node = this.startNodeAt(leftStartPos, leftStartLoc);
         node.left = left;
         node.operator = this.state.value;
-        if (
-          op === tt.exponent &&
-          left.type === "UnaryExpression" &&
-          (this.options.createParenthesizedExpressions ||
-            !(left.extra && left.extra.parenthesized))
-        ) {
-          this.raise(
-            left.argument.start,
-            Errors.UnexpectedTokenUnaryExponentiation,
-          );
-        }
 
         const logical = op === tt.logicalOR || op === tt.logicalAND;
         const coalesce = op === tt.nullishCoalescing;
@@ -506,16 +495,30 @@ export default class ExpressionParser extends LValParser {
     );
   }
 
+  checkExponentialAfterUnary(node: N.AwaitExpression | N.UnaryExpression) {
+    if (this.match(tt.exponent)) {
+      this.raise(
+        node.argument.start,
+        Errors.UnexpectedTokenUnaryExponentiation,
+      );
+    }
+  }
+
   // Parse unary operators, both prefix and postfix.
   // https://tc39.es/ecma262/#prod-UnaryExpression
-  parseMaybeUnary(refExpressionErrors: ?ExpressionErrors): N.Expression {
+  parseMaybeUnary(
+    refExpressionErrors: ?ExpressionErrors,
+    sawUnary?: boolean,
+  ): N.Expression {
     const startPos = this.state.start;
     const startLoc = this.state.startLoc;
     const isAwait = this.isContextual("await");
 
     if (isAwait && this.isAwaitAllowed()) {
       this.next();
-      return this.parseAwait(startPos, startLoc);
+      const expr = this.parseAwait(startPos, startLoc);
+      if (!sawUnary) this.checkExponentialAfterUnary(expr);
+      return expr;
     }
     if (
       this.isContextual("module") &&
@@ -536,7 +539,7 @@ export default class ExpressionParser extends LValParser {
       const isDelete = this.match(tt._delete);
       this.next();
 
-      node.argument = this.parseMaybeUnary();
+      node.argument = this.parseMaybeUnary(null, true);
 
       this.checkExpressionErrors(refExpressionErrors, true);
 
@@ -551,6 +554,7 @@ export default class ExpressionParser extends LValParser {
       }
 
       if (!update) {
+        if (!sawUnary) this.checkExponentialAfterUnary(node);
         return this.finishNode(node, "UnaryExpression");
       }
     }
@@ -2412,7 +2416,7 @@ export default class ExpressionParser extends LValParser {
     }
 
     if (!this.state.soloAwait) {
-      node.argument = this.parseMaybeUnary();
+      node.argument = this.parseMaybeUnary(null, true);
     }
 
     return this.finishNode(node, "AwaitExpression");

packages/babel-parser/src/types.js

@@ -391,7 +391,7 @@ export type YieldExpression = NodeBase & {
 
 export type AwaitExpression = NodeBase & {
   type: "AwaitExpression",
-  argument: ?Expression,
+  argument: Expression,
 };
 
 export type ArrayExpression = NodeBase & {

packages/babel-parser/test/fixtures/core/create-parenthesized-expressions/valid-parenthesized-await-before-exponential/input.js

@@ -0,0 +1 @@
+async () => (await 5) ** 6;

packages/babel-parser/test/fixtures/core/create-parenthesized-expressions/valid-parenthesized-await-before-exponential/output.json

@@ -0,0 +1,56 @@
+{
+  "type": "File",
+  "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [],
+          "body": {
+            "type": "BinaryExpression",
+            "start":12,"end":26,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":26}},
+            "left": {
+              "type": "ParenthesizedExpression",
+              "start":12,"end":21,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":21}},
+              "expression": {
+                "type": "AwaitExpression",
+                "start":13,"end":20,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":20}},
+                "argument": {
+                  "type": "NumericLiteral",
+                  "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20}},
+                  "extra": {
+                    "rawValue": 5,
+                    "raw": "5"
+                  },
+                  "value": 5
+                }
+              }
+            },
+            "operator": "**",
+            "right": {
+              "type": "NumericLiteral",
+              "start":25,"end":26,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":26}},
+              "extra": {
+                "rawValue": 6,
+                "raw": "6"
+              },
+              "value": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/await-before-exponential/input.js

@@ -0,0 +1 @@
+async () => await 5 ** 6;

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/await-before-exponential/output.json

@@ -0,0 +1,55 @@
+{
+  "type": "File",
+  "start":0,"end":25,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":25}},
+  "errors": [
+    "SyntaxError: Illegal expression. Wrap left hand side or entire exponentiation in parentheses. (1:18)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":25,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":25}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":25,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":25}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [],
+          "body": {
+            "type": "BinaryExpression",
+            "start":12,"end":24,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":24}},
+            "left": {
+              "type": "AwaitExpression",
+              "start":12,"end":19,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":19}},
+              "argument": {
+                "type": "NumericLiteral",
+                "start":18,"end":19,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":19}},
+                "extra": {
+                  "rawValue": 5,
+                  "raw": "5"
+                },
+                "value": 5
+              }
+            },
+            "operator": "**",
+            "right": {
+              "type": "NumericLiteral",
+              "start":23,"end":24,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":24}},
+              "extra": {
+                "rawValue": 6,
+                "raw": "6"
+              },
+              "value": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/await-unary-before-exponential/input.js

@@ -0,0 +1 @@
+async () => await -5 ** 6;

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/await-unary-before-exponential/output.json

@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+  "errors": [
+    "SyntaxError: Illegal expression. Wrap left hand side or entire exponentiation in parentheses. (1:18)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":25,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":25}},
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [],
+          "body": {
+            "type": "BinaryExpression",
+            "start":12,"end":25,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":25}},
+            "left": {
+              "type": "AwaitExpression",
+              "start":12,"end":20,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":20}},
+              "argument": {
+                "type": "UnaryExpression",
+                "start":18,"end":20,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":20}},
+                "operator": "-",
+                "prefix": true,
+                "argument": {
+                  "type": "NumericLiteral",
+                  "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20}},
+                  "extra": {
+                    "rawValue": 5,
+                    "raw": "5"
+                  },
+                  "value": 5
+                }
+              }
+            },
+            "operator": "**",
+            "right": {
+              "type": "NumericLiteral",
+              "start":24,"end":25,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":25}},
+              "extra": {
+                "rawValue": 6,
+                "raw": "6"
+              },
+              "value": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/nested-unary-before-exponential/input.js

@@ -0,0 +1 @@
+(-+5 ** 6);

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/nested-unary-before-exponential/output.json

@@ -0,0 +1,59 @@
+{
+  "type": "File",
+  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "errors": [
+    "SyntaxError: Illegal expression. Wrap left hand side or entire exponentiation in parentheses. (1:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":1,"end":9,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":9}},
+          "extra": {
+            "parenthesized": true,
+            "parenStart": 0
+          },
+          "left": {
+            "type": "UnaryExpression",
+            "start":1,"end":4,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":4}},
+            "operator": "-",
+            "prefix": true,
+            "argument": {
+              "type": "UnaryExpression",
+              "start":2,"end":4,"loc":{"start":{"line":1,"column":2},"end":{"line":1,"column":4}},
+              "operator": "+",
+              "prefix": true,
+              "argument": {
+                "type": "NumericLiteral",
+                "start":3,"end":4,"loc":{"start":{"line":1,"column":3},"end":{"line":1,"column":4}},
+                "extra": {
+                  "rawValue": 5,
+                  "raw": "5"
+                },
+                "value": 5
+              }
+            }
+          },
+          "operator": "**",
+          "right": {
+            "type": "NumericLiteral",
+            "start":8,"end":9,"loc":{"start":{"line":1,"column":8},"end":{"line":1,"column":9}},
+            "extra": {
+              "rawValue": 6,
+              "raw": "6"
+            },
+            "value": 6
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/valid-parenthesized-await-before-exponential/input.js

@@ -0,0 +1 @@
+async () => (await 5) ** 6;

packages/babel-parser/test/fixtures/es2016/exponentiation-operator/valid-parenthesized-await-before-exponential/output.json

@@ -0,0 +1,56 @@
+{
+  "type": "File",
+  "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [],
+          "body": {
+            "type": "BinaryExpression",
+            "start":12,"end":26,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":26}},
+            "left": {
+              "type": "AwaitExpression",
+              "start":13,"end":20,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":20}},
+              "extra": {
+                "parenthesized": true,
+                "parenStart": 12
+              },
+              "argument": {
+                "type": "NumericLiteral",
+                "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20}},
+                "extra": {
+                  "rawValue": 5,
+                  "raw": "5"
+                },
+                "value": 5
+              }
+            },
+            "operator": "**",
+            "right": {
+              "type": "NumericLiteral",
+              "start":25,"end":26,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":26}},
+              "extra": {
+                "rawValue": 6,
+                "raw": "6"
+              },
+              "value": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/typescript/exponentiation/await-non-null-before-exponential/input.ts

@@ -0,0 +1 @@
+async (a) => await a! ** 6;

packages/babel-parser/test/fixtures/typescript/exponentiation/await-non-null-before-exponential/output.json

@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+  "errors": [
+    "SyntaxError: Illegal expression. Wrap left hand side or entire exponentiation in parentheses. (1:19)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":27,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":27}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [
+            {
+              "type": "Identifier",
+              "start":7,"end":8,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":8},"identifierName":"a"},
+              "name": "a"
+            }
+          ],
+          "body": {
+            "type": "BinaryExpression",
+            "start":13,"end":26,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":26}},
+            "left": {
+              "type": "AwaitExpression",
+              "start":13,"end":21,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":21}},
+              "argument": {
+                "type": "TSNonNullExpression",
+                "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}},
+                "expression": {
+                  "type": "Identifier",
+                  "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"a"},
+                  "name": "a"
+                }
+              }
+            },
+            "operator": "**",
+            "right": {
+              "type": "NumericLiteral",
+              "start":25,"end":26,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":26}},
+              "extra": {
+                "rawValue": 6,
+                "raw": "6"
+              },
+              "value": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/typescript/exponentiation/unary-non-null-before-exponential/input.ts

@@ -0,0 +1 @@
+(a) => +a! ** 6;

packages/babel-parser/test/fixtures/typescript/exponentiation/unary-non-null-before-exponential/output.json

@@ -0,0 +1,63 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "errors": [
+    "SyntaxError: Illegal expression. Wrap left hand side or entire exponentiation in parentheses. (1:8)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "id": null,
+          "generator": false,
+          "async": false,
+          "params": [
+            {
+              "type": "Identifier",
+              "start":1,"end":2,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":2},"identifierName":"a"},
+              "name": "a"
+            }
+          ],
+          "body": {
+            "type": "BinaryExpression",
+            "start":7,"end":15,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "UnaryExpression",
+              "start":7,"end":10,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":10}},
+              "operator": "+",
+              "prefix": true,
+              "argument": {
+                "type": "TSNonNullExpression",
+                "start":8,"end":10,"loc":{"start":{"line":1,"column":8},"end":{"line":1,"column":10}},
+                "expression": {
+                  "type": "Identifier",
+                  "start":8,"end":9,"loc":{"start":{"line":1,"column":8},"end":{"line":1,"column":9},"identifierName":"a"},
+                  "name": "a"
+                }
+              }
+            },
+            "operator": "**",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 6,
+                "raw": "6"
+              },
+              "value": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/typescript/exponentiation/valid-parenthesized-await-non-null-before-exponential/input.ts

@@ -0,0 +1 @@
+async (a) => (await a!) ** 6;

packages/babel-parser/test/fixtures/typescript/exponentiation/valid-parenthesized-await-non-null-before-exponential/output.json

@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [
+            {
+              "type": "Identifier",
+              "start":7,"end":8,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":8},"identifierName":"a"},
+              "name": "a"
+            }
+          ],
+          "body": {
+            "type": "BinaryExpression",
+            "start":13,"end":28,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":28}},
+            "left": {
+              "type": "AwaitExpression",
+              "start":14,"end":22,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":22}},
+              "extra": {
+                "parenthesized": true,
+                "parenStart": 13
+              },
+              "argument": {
+                "type": "TSNonNullExpression",
+                "start":20,"end":22,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":22}},
+                "expression": {
+                  "type": "Identifier",
+                  "start":20,"end":21,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":21},"identifierName":"a"},
+                  "name": "a"
+                }
+              }
+            },
+            "operator": "**",
+            "right": {
+              "type": "NumericLiteral",
+              "start":27,"end":28,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":28}},
+              "extra": {
+                "rawValue": 6,
+                "raw": "6"
+              },
+              "value": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}