JavaScript: Make parsing of decorators more restrictive.

Max Schaefer · Max Schaefer · commit 1ad4867f2a05 · 2019-02-24T20:45:41.000Z
As per [the proposal](https://tc39.github.io/proposal-decorators/#sec-new-syntax), decorators can only contain identifiers or parenthesised expressions, optionally followed by property accesses and arguments.
diff --git a/javascript/extractor/src/com/semmle/jcorn/ESNextParser.java b/javascript/extractor/src/com/semmle/jcorn/ESNextParser.java
@@ -257,7 +257,7 @@ protected MemberDefinition<?> parseClassMember(boolean hadConstructor) {
 		return member;
 	}
 
-	private List<Decorator> parseDecorators() {
+	public List<Decorator> parseDecorators() {
 		List<Decorator> result = new ArrayList<Decorator>();
 		while (this.type == at)
 			result.add(this.parseDecorator());
@@ -267,10 +267,23 @@ private List<Decorator> parseDecorators() {
 	private Decorator parseDecorator() {
 		Position start = startLoc;
 		this.next();
-		Decorator decorator = new Decorator(new SourceLocation(start), this.parseMaybeAssign(false, null, null));
+		Expression body = parseDecoratorBody();
+		Decorator decorator = new Decorator(new SourceLocation(start), body);
 		return this.finishNode(decorator);
 	}
 
+	protected Expression parseDecoratorBody() {
+		Expression base;
+		int startPos = this.start;
+		Position startLoc = this.startLoc;
+		if (this.type == TokenType.parenL) {
+			base = parseParenExpression();
+		} else {
+			base = parseIdent(true);
+		}
+		return parseSubscripts(base, startPos, startLoc, false);
+	}
+
 	/*
 	 * Support for proposed extensions to `export`
 	 * (http://leebyron.com/ecmascript-export-ns-from and http://leebyron.com/ecmascript-export-default-from)
