Merge pull request #589 from Qantas94Heavy/fix-private-fields

Add delete check and fix nested class parsing for private fields

src/parser/expression.js

@@ -252,8 +252,16 @@ export default class ExpressionParser extends LValParser {
 
       if (update) {
         this.checkLVal(node.argument, undefined, undefined, "prefix operation");
-      } else if (this.state.strict && node.operator === "delete" && node.argument.type === "Identifier") {
-        this.raise(node.start, "Deleting local variable in strict mode");
+      } else if (this.state.strict && node.operator === "delete") {
+        const arg = node.argument;
+
+        if (arg.type === "Identifier") {
+          this.raise(node.start, "Deleting local variable in strict mode");
+        } else if (this.hasPlugin("classPrivateProperties")) {
+          if (arg.type === "PrivateName" || (arg.type === "MemberExpression" && arg.property.type === "PrivateName")) {
+            this.raise(node.start, "Deleting a private field is not allowed");
+          }
+        }
       }
 
       return this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression");

src/parser/statement.js

@@ -684,7 +684,7 @@ export default class StatementParser extends ExpressionParser {
     // class bodies are implicitly strict
     const oldStrict = this.state.strict;
     this.state.strict = true;
-    this.state.inClass = true;
+    this.state.classLevel++;
 
     const state = { hadConstructor: false };
     let decorators = [];
@@ -731,7 +731,7 @@ export default class StatementParser extends ExpressionParser {
 
     node.body = this.finishNode(classBody, "ClassBody");
 
-    this.state.inClass = false;
+    this.state.classLevel--;
     this.state.strict = oldStrict;
   }
 

src/tokenizer/index.js

@@ -444,7 +444,7 @@ export default class Tokenizer extends LocationParser {
     switch (code) {
 
       case 35: // '#'
-        if (this.hasPlugin("classPrivateProperties") && this.state.inClass) {
+        if (this.hasPlugin("classPrivateProperties") && this.state.classLevel > 0) {
           ++this.state.pos; return this.finishToken(tt.hash);
         } else {
           this.raise(this.state.pos, `Unexpected character '${codePointToString(code)}'`);

src/tokenizer/state.js

@@ -24,11 +24,12 @@ export default class State {
       this.inAsync =
       this.inPropertyName =
       this.inType =
-      this.inClass =
       this.inClassProperty =
       this.noAnonFunctionType =
         false;
 
+    this.classLevel = 0;
+
     this.labels = [];
 
     this.decorators = [];
@@ -84,7 +85,9 @@ export default class State {
   noAnonFunctionType: boolean;
   inPropertyName: boolean;
   inClassProperty: boolean;
-  inClass: boolean;
+
+  // Check whether we are in a (nested) class or not.
+  classLevel: number;
 
   // Labels in scope.
   labels: Array<{ kind: ?("loop" | "switch"), statementStart?: number }>;