Fix some incorrect typeof parsing in flow

packages/babel-parser/src/plugins/flow.js

@@ -22,12 +22,15 @@ import {
   SCOPE_OTHER,
 } from "../util/scopeflags";
 
-const reservedTypes = [
+const reservedTypes = new Set([
+  "_",
   "any",
   "bool",
   "boolean",
   "empty",
+  "extends",
   "false",
+  "interface",
   "mixed",
   "null",
   "number",
@@ -36,10 +39,7 @@ const reservedTypes = [
   "true",
   "typeof",
   "void",
-  "interface",
-  "extends",
-  "_",
-];
+]);
 
 function isEsModuleType(bodyElement: N.Node): boolean {
   return (
@@ -483,7 +483,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       node: N.FlowDeclare,
       isClass?: boolean = false,
     ): void {
-      node.id = this.flowParseRestrictedIdentifier(/*liberal*/ !isClass);
+      node.id = this.flowParseRestrictedIdentifier(
+        /* liberal */ !isClass,
+        /* declaration */ true,
+      );
 
       this.scope.declareName(
         node.id.name,
@@ -557,21 +560,32 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
-    checkReservedType(word: string, startLoc: number) {
-      if (reservedTypes.indexOf(word) > -1) {
+    checkReservedType(word: string, startLoc: number, declaration?: boolean) {
+      if (!reservedTypes.has(word)) return;
+
+      if (declaration) {
         this.raise(startLoc, `Cannot overwrite reserved type ${word}`);
+        return;
       }
+
+      this.raise(startLoc, `Unexpected reserved type ${word}`);
     }
 
-    flowParseRestrictedIdentifier(liberal?: boolean): N.Identifier {
-      this.checkReservedType(this.state.value, this.state.start);
+    flowParseRestrictedIdentifier(
+      liberal?: boolean,
+      declaration?: boolean,
+    ): N.Identifier {
+      this.checkReservedType(this.state.value, this.state.start, declaration);
       return this.parseIdentifier(liberal);
     }
 
     // Type aliases
 
     flowParseTypeAlias(node: N.FlowTypeAlias): N.FlowTypeAlias {
-      node.id = this.flowParseRestrictedIdentifier();
+      node.id = this.flowParseRestrictedIdentifier(
+        /* liberal */ false,
+        /* declaration */ true,
+      );
       this.scope.declareName(node.id.name, BIND_LEXICAL, node.id.start);
 
       if (this.isRelational("<")) {
@@ -591,7 +605,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       declare: boolean,
     ): N.FlowOpaqueType {
       this.expectContextual("type");
-      node.id = this.flowParseRestrictedIdentifier(/*liberal*/ true);
+      node.id = this.flowParseRestrictedIdentifier(
+        /* liberal */ true,
+        /* declaration */ true,
+      );
       this.scope.declareName(node.id.name, BIND_LEXICAL, node.id.start);
 
       if (this.isRelational("<")) {
@@ -1134,12 +1151,12 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     ): N.FlowQualifiedTypeIdentifier {
       startPos = startPos || this.state.start;
       startLoc = startLoc || this.state.startLoc;
-      let node = id || this.parseIdentifier();
+      let node = id || this.parseIdentifier(true);
 
       while (this.eat(tt.dot)) {
         const node2 = this.startNodeAt(startPos, startLoc);
         node2.qualification = node;
-        node2.id = this.parseIdentifier();
+        node2.id = this.flowParseRestrictedIdentifier(true);
         node = this.finishNode(node2, "QualifiedTypeIdentifier");
       }
 
@@ -2352,7 +2369,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       contextDescription: string,
     ): void {
       specifier.local = hasTypeImportKind(node)
-        ? this.flowParseRestrictedIdentifier(true)
+        ? this.flowParseRestrictedIdentifier(
+            /* liberal */ true,
+            /* declaration */ true,
+          )
         : this.parseIdentifier();
 
       this.checkLVal(
@@ -2458,7 +2478,11 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
 
       if (nodeIsTypeImport || specifierIsTypeImport) {
-        this.checkReservedType(specifier.local.name, specifier.local.start);
+        this.checkReservedType(
+          specifier.local.name,
+          specifier.local.start,
+          /* declaration */ true,
+        );
       }
 
       if (isBinding && !nodeIsTypeImport && !specifierIsTypeImport) {

packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/implements-reserved-type-invalid-2/input.js

@@ -0,0 +1 @@
+class Foo implements Bar, string {}

packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/implements-reserved-type-invalid-2/output.json

@@ -0,0 +1,155 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 35,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 35
+    }
+  },
+  "errors": [
+    "SyntaxError: Unexpected reserved type string (1:26)"
+  ],
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 35,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 35
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 35,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 35
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 6,
+          "end": 9,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 6
+            },
+            "end": {
+              "line": 1,
+              "column": 9
+            },
+            "identifierName": "Foo"
+          },
+          "name": "Foo"
+        },
+        "superClass": null,
+        "implements": [
+          {
+            "type": "ClassImplements",
+            "start": 21,
+            "end": 24,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 21
+              },
+              "end": {
+                "line": 1,
+                "column": 24
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 21,
+              "end": 24,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 21
+                },
+                "end": {
+                  "line": 1,
+                  "column": 24
+                },
+                "identifierName": "Bar"
+              },
+              "name": "Bar"
+            },
+            "typeParameters": null
+          },
+          {
+            "type": "ClassImplements",
+            "start": 26,
+            "end": 32,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 26
+              },
+              "end": {
+                "line": 1,
+                "column": 32
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 26,
+              "end": 32,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 26
+                },
+                "end": {
+                  "line": 1,
+                  "column": 32
+                },
+                "identifierName": "string"
+              },
+              "name": "string"
+            },
+            "typeParameters": null
+          }
+        ],
+        "body": {
+          "type": "ClassBody",
+          "start": 33,
+          "end": 35,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 33
+            },
+            "end": {
+              "line": 1,
+              "column": 35
+            }
+          },
+          "body": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/implements-reserved-type-invalid/output.json

@@ -13,7 +13,7 @@
     }
   },
   "errors": [
-    "SyntaxError: Cannot overwrite reserved type string (1:21)"
+    "SyntaxError: Unexpected reserved type string (1:21)"
   ],
   "program": {
     "type": "Program",

packages/babel-parser/test/fixtures/flow/type-annotations/132/output.json

@@ -13,7 +13,7 @@
     }
   },
   "errors": [
-    "SyntaxError: Cannot overwrite reserved type number (1:9)"
+    "SyntaxError: Unexpected reserved type number (1:9)"
   ],
   "program": {
     "type": "Program",

packages/babel-parser/test/fixtures/flow/type-annotations/133/output.json

@@ -13,7 +13,7 @@
     }
   },
   "errors": [
-    "SyntaxError: Cannot overwrite reserved type string (1:11)"
+    "SyntaxError: Unexpected reserved type string (1:11)"
   ],
   "program": {
     "type": "Program",

packages/babel-parser/test/fixtures/flow/type-annotations/typeof-reserved-invalid-1/input.js

@@ -0,0 +1,2 @@
+// @flow
+const x: typeof interface = "hi";

packages/babel-parser/test/fixtures/flow/type-annotations/typeof-reserved-invalid-1/options.json

@@ -0,0 +1,8 @@
+{
+  "sourceType": "module",
+  "plugins": [
+    "jsx",
+    "flow"
+  ],
+  "throws": "Unexpected token, expected \"{\" (2:26)"
+}

packages/babel-parser/test/fixtures/flow/type-annotations/typeof-reserved-invalid-2/input.js

@@ -0,0 +1,2 @@
+// @flow
+const x: typeof type.interface = "hi";