rescan gt/lt token after TsAsExpression is parsed (#11912)

* refactor: move inType checks to flow plugin * polish: replace hardcoded char codes * fix: rescan greater/less token after asExpression is parsed
2020-08-04 17:00:21 -04:00 · 2020-08-04 17:00:21 -04:00 · a1eabb84ea
commit a1eabb84ea
parent c29138fd72
5 changed files with 136 additions and 30 deletions
--- a/packages/babel-parser/src/plugins/flow.js
+++ b/packages/babel-parser/src/plugins/flow.js
@ -2135,6 +2135,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
        (code === charCodes.greaterThan || code === charCodes.lessThan)
      ) {
        return this.finishOp(tt.relational, 1);
+      } else if (this.state.inType && code === charCodes.questionMark) {
+        // allow double nullable types in Flow: ??string
+        return this.finishOp(tt.question, 1);
      } else if (isIteratorStart(code, next)) {
        this.state.isIterator = true;
        return super.readWord();
--- a/packages/babel-parser/src/plugins/typescript/index.js
+++ b/packages/babel-parser/src/plugins/typescript/index.js
@ -1884,6 +1884,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
          node.typeAnnotation = this.tsNextThenParseType();
        }
        this.finishNode(node, "TSAsExpression");
+        // rescan `<`, `>` because they were scanned when this.state.inType was true
+        this.reScan_lt_gt();
        return this.parseExprOp(
          node,
          leftStartPos,
@ -2628,13 +2630,27 @@ export default (superClass: Class<Parser>): Class<Parser> =>

    // ensure that inside types, we bypass the jsx parser plugin
    getTokenFromCode(code: number): void {
-      if (this.state.inType && (code === 62 || code === 60)) {
+      if (
+        this.state.inType &&
+        (code === charCodes.greaterThan || code === charCodes.lessThan)
+      ) {
        return this.finishOp(tt.relational, 1);
      } else {
        return super.getTokenFromCode(code);
      }
    }

+    // used after we have finished parsing types
+    reScan_lt_gt() {
+      if (this.match(tt.relational)) {
+        const code = this.input.charCodeAt(this.state.start);
+        if (code === charCodes.lessThan || code === charCodes.greaterThan) {
+          this.state.pos -= 1;
+          this.readToken_lt_gt(code);
+        }
+      }
+    }
+
    toAssignableList(exprList: N.Expression[]): $ReadOnlyArray<N.Pattern> {
      for (let i = 0; i < exprList.length; i++) {
        const expr = exprList[i];
--- a/packages/babel-parser/src/tokenizer/index.js
+++ b/packages/babel-parser/src/tokenizer/index.js
@ -693,7 +693,7 @@ export default class Tokenizer extends ParserErrors {
    // '?'
    const next = this.input.charCodeAt(this.state.pos + 1);
    const next2 = this.input.charCodeAt(this.state.pos + 2);
-    if (next === charCodes.questionMark && !this.state.inType) {
+    if (next === charCodes.questionMark) {
      if (next2 === charCodes.equalsTo) {
        // '??='
        this.finishOp(tt.assign, 3);
--- a/packages/babel-parser/test/fixtures/typescript/cast/as/input.ts
+++ b/packages/babel-parser/test/fixtures/typescript/cast/as/input.ts
@ -1,4 +1,6 @@
 x as T;
 x < y as boolean; // (x < y) as boolean;
+x as boolean <= y; // (x as boolean) <= y;
 x === 1 as number; // x === (1 as number);
 x as any as T;
+x as boolean ?? y; // (x as boolean) ?? y;
--- a/packages/babel-parser/test/fixtures/typescript/cast/as/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/cast/as/output.json
@ -1,9 +1,9 @@
 {
  "type": "File",
-  "start":0,"end":106,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":14}},
+  "start":0,"end":192,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":42}},
  "program": {
    "type": "Program",
-    "start":0,"end":106,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":14}},
+    "start":0,"end":192,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":42}},
    "sourceType": "module",
    "interpreter": null,
    "body": [
@ -70,27 +70,23 @@
          "type": "BinaryExpression",
          "start":49,"end":66,"loc":{"start":{"line":3,"column":0},"end":{"line":3,"column":17}},
          "left": {
+            "type": "TSAsExpression",
+            "start":49,"end":61,"loc":{"start":{"line":3,"column":0},"end":{"line":3,"column":12}},
+            "expression": {
              "type": "Identifier",
              "start":49,"end":50,"loc":{"start":{"line":3,"column":0},"end":{"line":3,"column":1},"identifierName":"x"},
              "name": "x"
            },
-          "operator": "===",
-          "right": {
-            "type": "TSAsExpression",
-            "start":55,"end":66,"loc":{"start":{"line":3,"column":6},"end":{"line":3,"column":17}},
-            "expression": {
-              "type": "NumericLiteral",
-              "start":55,"end":56,"loc":{"start":{"line":3,"column":6},"end":{"line":3,"column":7}},
-              "extra": {
-                "rawValue": 1,
-                "raw": "1"
-              },
-              "value": 1
-            },
            "typeAnnotation": {
-              "type": "TSNumberKeyword",
-              "start":60,"end":66,"loc":{"start":{"line":3,"column":11},"end":{"line":3,"column":17}}
+              "type": "TSBooleanKeyword",
+              "start":54,"end":61,"loc":{"start":{"line":3,"column":5},"end":{"line":3,"column":12}}
            }
+          },
+          "operator": "<=",
+          "right": {
+            "type": "Identifier",
+            "start":65,"end":66,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":17},"identifierName":"y"},
+            "name": "y"
          }
        },
        "leadingComments": [
@ -103,36 +99,81 @@
        "trailingComments": [
          {
            "type": "CommentLine",
-            "value": " x === (1 as number);",
+            "value": " (x as boolean) <= y;",
            "start":68,"end":91,"loc":{"start":{"line":3,"column":19},"end":{"line":3,"column":42}}
          }
        ]
      },
      {
        "type": "ExpressionStatement",
-        "start":92,"end":106,"loc":{"start":{"line":4,"column":0},"end":{"line":4,"column":14}},
-        "expression": {
-          "type": "TSAsExpression",
-          "start":92,"end":105,"loc":{"start":{"line":4,"column":0},"end":{"line":4,"column":13}},
-          "expression": {
-            "type": "TSAsExpression",
-            "start":92,"end":100,"loc":{"start":{"line":4,"column":0},"end":{"line":4,"column":8}},
+        "start":92,"end":110,"loc":{"start":{"line":4,"column":0},"end":{"line":4,"column":18}},
        "expression": {
+          "type": "BinaryExpression",
+          "start":92,"end":109,"loc":{"start":{"line":4,"column":0},"end":{"line":4,"column":17}},
+          "left": {
            "type": "Identifier",
            "start":92,"end":93,"loc":{"start":{"line":4,"column":0},"end":{"line":4,"column":1},"identifierName":"x"},
            "name": "x"
          },
+          "operator": "===",
+          "right": {
+            "type": "TSAsExpression",
+            "start":98,"end":109,"loc":{"start":{"line":4,"column":6},"end":{"line":4,"column":17}},
+            "expression": {
+              "type": "NumericLiteral",
+              "start":98,"end":99,"loc":{"start":{"line":4,"column":6},"end":{"line":4,"column":7}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            },
+            "typeAnnotation": {
+              "type": "TSNumberKeyword",
+              "start":103,"end":109,"loc":{"start":{"line":4,"column":11},"end":{"line":4,"column":17}}
+            }
+          }
+        },
+        "leadingComments": [
+          {
+            "type": "CommentLine",
+            "value": " (x as boolean) <= y;",
+            "start":68,"end":91,"loc":{"start":{"line":3,"column":19},"end":{"line":3,"column":42}}
+          }
+        ],
+        "trailingComments": [
+          {
+            "type": "CommentLine",
+            "value": " x === (1 as number);",
+            "start":111,"end":134,"loc":{"start":{"line":4,"column":19},"end":{"line":4,"column":42}}
+          }
+        ]
+      },
+      {
+        "type": "ExpressionStatement",
+        "start":135,"end":149,"loc":{"start":{"line":5,"column":0},"end":{"line":5,"column":14}},
+        "expression": {
+          "type": "TSAsExpression",
+          "start":135,"end":148,"loc":{"start":{"line":5,"column":0},"end":{"line":5,"column":13}},
+          "expression": {
+            "type": "TSAsExpression",
+            "start":135,"end":143,"loc":{"start":{"line":5,"column":0},"end":{"line":5,"column":8}},
+            "expression": {
+              "type": "Identifier",
+              "start":135,"end":136,"loc":{"start":{"line":5,"column":0},"end":{"line":5,"column":1},"identifierName":"x"},
+              "name": "x"
+            },
            "typeAnnotation": {
              "type": "TSAnyKeyword",
-              "start":97,"end":100,"loc":{"start":{"line":4,"column":5},"end":{"line":4,"column":8}}
+              "start":140,"end":143,"loc":{"start":{"line":5,"column":5},"end":{"line":5,"column":8}}
            }
          },
          "typeAnnotation": {
            "type": "TSTypeReference",
-            "start":104,"end":105,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":13}},
+            "start":147,"end":148,"loc":{"start":{"line":5,"column":12},"end":{"line":5,"column":13}},
            "typeName": {
              "type": "Identifier",
-              "start":104,"end":105,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":13},"identifierName":"T"},
+              "start":147,"end":148,"loc":{"start":{"line":5,"column":12},"end":{"line":5,"column":13},"identifierName":"T"},
              "name": "T"
            }
          }
@ -141,7 +182,41 @@
          {
            "type": "CommentLine",
            "value": " x === (1 as number);",
-            "start":68,"end":91,"loc":{"start":{"line":3,"column":19},"end":{"line":3,"column":42}}
+            "start":111,"end":134,"loc":{"start":{"line":4,"column":19},"end":{"line":4,"column":42}}
+          }
+        ]
+      },
+      {
+        "type": "ExpressionStatement",
+        "start":150,"end":168,"loc":{"start":{"line":6,"column":0},"end":{"line":6,"column":18}},
+        "expression": {
+          "type": "LogicalExpression",
+          "start":150,"end":167,"loc":{"start":{"line":6,"column":0},"end":{"line":6,"column":17}},
+          "left": {
+            "type": "TSAsExpression",
+            "start":150,"end":162,"loc":{"start":{"line":6,"column":0},"end":{"line":6,"column":12}},
+            "expression": {
+              "type": "Identifier",
+              "start":150,"end":151,"loc":{"start":{"line":6,"column":0},"end":{"line":6,"column":1},"identifierName":"x"},
+              "name": "x"
+            },
+            "typeAnnotation": {
+              "type": "TSBooleanKeyword",
+              "start":155,"end":162,"loc":{"start":{"line":6,"column":5},"end":{"line":6,"column":12}}
+            }
+          },
+          "operator": "??",
+          "right": {
+            "type": "Identifier",
+            "start":166,"end":167,"loc":{"start":{"line":6,"column":16},"end":{"line":6,"column":17},"identifierName":"y"},
+            "name": "y"
+          }
+        },
+        "trailingComments": [
+          {
+            "type": "CommentLine",
+            "value": " (x as boolean) ?? y;",
+            "start":169,"end":192,"loc":{"start":{"line":6,"column":19},"end":{"line":6,"column":42}}
          }
        ]
      }
@ -156,8 +231,18 @@
    },
    {
      "type": "CommentLine",
-      "value": " x === (1 as number);",
+      "value": " (x as boolean) <= y;",
      "start":68,"end":91,"loc":{"start":{"line":3,"column":19},"end":{"line":3,"column":42}}
+    },
+    {
+      "type": "CommentLine",
+      "value": " x === (1 as number);",
+      "start":111,"end":134,"loc":{"start":{"line":4,"column":19},"end":{"line":4,"column":42}}
+    },
+    {
+      "type": "CommentLine",
+      "value": " (x as boolean) ?? y;",
+      "start":169,"end":192,"loc":{"start":{"line":6,"column":19},"end":{"line":6,"column":42}}
    }
  ]
 }