[parser] Report escapes in kws only if they won't be used as i… (#10455)

We can do it by tokenizing escaped keywords as normal identifiers, so that they won't be accidentally used as real keywords.
babel · Sep 17, 2019 · cb881e6 · cb881e6
1 parent 45a484f
commit cb881e6
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Showing 9 changed files with 172 additions and 447 deletions.
diff --git a/packages/babel-parser/src/parser/expression.js b/packages/babel-parser/src/parser/expression.js
@@ -2066,6 +2066,11 @@ export default class ExpressionParser extends LValParser {
 
     if (this.match(tt.name)) {
       name = this.state.value;
+
+      // An escaped identifier whose value is the same as a keyword
+      if (!liberal && this.state.containsEsc && isKeyword(name)) {
+        this.raise(this.state.pos, `Escape sequence in keyword ${name}`);
+      }
     } else if (this.state.type.keyword) {
       name = this.state.type.keyword;
 

diff --git a/packages/babel-parser/src/tokenizer/index.js b/packages/babel-parser/src/tokenizer/index.js
@@ -1326,11 +1326,7 @@ export default class Tokenizer extends LocationParser {
 
   readWord(): void {
     const word = this.readWord1();
-    const type = keywordTypes.get(word) || tt.name;
-
-    if (type.keyword && this.state.containsEsc) {
-      this.raise(this.state.pos, `Escape sequence in keyword ${word}`);
-    }
+    const type = (!this.state.containsEsc && keywordTypes.get(word)) || tt.name;
 
     // Allow @@iterator and @@asyncIterator as a identifier only inside type
     if (

diff --git a/...fixtures/core/valid-escape/async/input.js → ...xtures/core/escape-keyword/async/input.js b/...fixtures/core/valid-escape/async/input.js → ...xtures/core/escape-keyword/async/input.js
diff --git a/...tures/core/valid-escape/async/output.json → ...res/core/escape-keyword/async/output.json b/...tures/core/valid-escape/async/output.json → ...res/core/escape-keyword/async/output.json
diff --git a/packages/babel-parser/test/fixtures/core/escape-keyword/invalid/input.js b/packages/babel-parser/test/fixtures/core/escape-keyword/invalid/input.js
@@ -0,0 +1,3 @@
+var a = {
+  br\u{65}ak
+};
diff --git a/packages/babel-parser/test/fixtures/core/escape-keyword/invalid/options.json b/packages/babel-parser/test/fixtures/core/escape-keyword/invalid/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected keyword 'break' (2:2)"
+}
diff --git a/packages/babel-parser/test/fixtures/core/escape-keyword/used-as-property/input.js b/packages/babel-parser/test/fixtures/core/escape-keyword/used-as-property/input.js
@@ -0,0 +1,3 @@
+var a = {
+  br\u{65}ak: 2
+};
diff --git a/packages/babel-parser/test/fixtures/core/escape-keyword/used-as-property/output.json b/packages/babel-parser/test/fixtures/core/escape-keyword/used-as-property/output.json
@@ -0,0 +1,157 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 28,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 3,
+      "column": 2
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 28,
+    "loc": {
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+        "column": 2
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 28,
+        "loc": {
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+            "column": 0
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+          }
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+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 27,
+            "loc": {
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+                "line": 1,
+                "column": 4
+              },
+              "end": {
+                "line": 3,
+                "column": 1
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 4,
+              "end": 5,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 4
+                },
+                "end": {
+                  "line": 1,
+                  "column": 5
+                },
+                "identifierName": "a"
+              },
+              "name": "a"
+            },
+            "init": {
+              "type": "ObjectExpression",
+              "start": 8,
+              "end": 27,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 8
+                },
+                "end": {
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+              },
+              "properties": [
+                {
+                  "type": "ObjectProperty",
+                  "start": 12,
+                  "end": 25,
+                  "loc": {
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+                      "line": 2,
+                      "column": 2
+                    },
+                    "end": {
+                      "line": 2,
+                      "column": 15
+                    }
+                  },
+                  "method": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start": 12,
+                    "end": 22,
+                    "loc": {
+                      "start": {
+                        "line": 2,
+                        "column": 2
+                      },
+                      "end": {
+                        "line": 2,
+                        "column": 12
+                      },
+                      "identifierName": "break"
+                    },
+                    "name": "break"
+                  },
+                  "computed": false,
+                  "shorthand": false,
+                  "value": {
+                    "type": "NumericLiteral",
+                    "start": 24,
+                    "end": 25,
+                    "loc": {
+                      "start": {
+                        "line": 2,
+                        "column": 14
+                      },
+                      "end": {
+                        "line": 2,
+                        "column": 15
+                      }
+                    },
+                    "extra": {
+                      "rawValue": 2,
+                      "raw": "2"
+                    },
+                    "value": 2
+                  }
+                }
+              ]
+            }
+          }
+        ],
+        "kind": "var"
+      }
+    ],
+    "directives": []
+  }
+}