Class and import related parsing fixes (#356)

* fix computed properties in classes
* throw an error when "arguments" is used as the value for a property (… 
* hacky fix some regex problems which occurred due to different parsers
* allow trailing "," in import
* allow trailing second "," in import
* throw error on deletion of private fields
* attributes on import could be a expression
* fix super access in methods
* many arguments is not invalid any more
* bugfix private static class members, fixes #354
* fix property access
* updated allow list

Author: jogibear9988

src/Esprima/JavascriptParser.cs

@@ -1700,7 +1700,9 @@ private Import ParseImportCall()
         if (Match(","))
         {
             NextToken();
-            attributes = ParseObjectInitializer();
+
+            if (!Match(")"))
+                attributes = ParseAssignmentExpression();
         }
 
         _context.IsAssignmentTarget = previousIsAssignmentTarget;
@@ -1711,6 +1713,8 @@ private Import ParseImportCall()
         }
         else
         {
+            if (Match(","))
+                NextToken();
             this.Expect(")");
         }
 
@@ -1787,7 +1791,7 @@ private Expression ParseLeftHandSideExpressionAllowCall()
                 : InheritCoverGrammar(_parsePrimaryExpression);
         }
 
-        if (isSuper && !_context.AllowSuper)
+        if (isSuper && !_context.AllowSuper && (!_context.InClassConstructor || (string?) _lookahead.Value != "."))
         {
             TolerateError(Messages.UnexpectedSuper);
         }
@@ -2074,6 +2078,10 @@ private UnaryExpression ParseBasicUnaryExpression()
         {
             TolerateError(Messages.StrictDelete);
         }
+        if (_context.Strict && unaryExpr.Operator == UnaryOperator.Delete && unaryExpr.Argument is MemberExpression m && m.Property is PrivateIdentifier)
+        {
+            TolerateError(Messages.PrivateFieldNoDelete);
+        }
 
         _context.IsAssignmentTarget = false;
         _context.IsBindingElement = false;
@@ -4715,7 +4723,7 @@ private ClassElement ParseClassElement(ref bool hasConstructor)
                             token = _lookahead;
                         }
                     }
-                    key = ParseObjectPropertyKey();
+                    key = ParseObjectPropertyKey(isPrivate);
                 }
                 else if (Match("{"))
                 {
@@ -4770,7 +4778,8 @@ private ClassElement ParseClassElement(ref bool hasConstructor)
         }
 
         var lookaheadPropertyKey = QualifiedPropertyName(_lookahead);
-        if (token.Type == TokenType.Identifier)
+        if (token.Type == TokenType.Identifier ||
+            (token.Type == TokenType.Punctuator && (string?) token.Value != "*"))
         {
             if (lookaheadPropertyKey && (string?) token.Value == "get")
             {
@@ -4808,12 +4817,16 @@ private ClassElement ParseClassElement(ref bool hasConstructor)
             else if (!Match("("))
             {
                 kind = PropertyKind.Property;
-                computed = false;
-
+                
                 if (Match("="))
                 {
                     NextToken();
+                    if (_lookahead.Type == TokenType.Identifier && (string?)_lookahead.Value == "arguments")
+                        ThrowUnexpectedToken(token, Messages.ArgumentsNotAllowedInClassField);
+                    var previousAllowSuper = _context.AllowSuper;
+                    _context.AllowSuper = true;
                     value = IsolateCoverGrammar(_parseAssignmentExpression);
+                    _context.AllowSuper = previousAllowSuper;
                 }
             }
         }
@@ -4834,15 +4847,16 @@ private ClassElement ParseClassElement(ref bool hasConstructor)
             value = ParseGeneratorMethod(isAsync);
             method = true;
         }
-
+        
         if (kind == PropertyKind.None && key != null)
         {
             if (Match("("))
             {
                 var previousAllowSuper = _context.AllowSuper;
                 var previousInClassConstructor = _context.InClassConstructor;
                 _context.InClassConstructor = Equals(token.Value, "constructor");
-                _context.AllowSuper = true;
+                if (!_context.InClassConstructor)
+                    _context.AllowSuper = true;
                 kind = PropertyKind.Init;
                 value = isAsync ? ParsePropertyMethodAsyncFunction(isGenerator) : ParsePropertyMethodFunction(isGenerator);
                 _context.InClassConstructor = previousInClassConstructor;
@@ -4942,7 +4956,7 @@ private ClassDeclaration ParseClassDeclarationCore(in Marker node, bool identifi
         var previousStrict = _context.Strict;
         var previousAllowSuper = _context.AllowSuper;
         _context.Strict = true;
-        _context.AllowSuper = true;
+        _context.AllowSuper = false;
 
         ExpectKeyword("class");
 
@@ -4955,6 +4969,7 @@ private ClassDeclaration ParseClassDeclarationCore(in Marker node, bool identifi
         {
             NextToken();
             superClass = IsolateCoverGrammar(_parseLeftHandSideExpressionAllowCall);
+            _context.AllowSuper = true;
         }
 
         var classBody = ParseClassBody();
@@ -4988,7 +5003,7 @@ private ClassExpression ParseClassExpression()
         var previousStrict = _context.Strict;
         var previousAllowSuper = _context.AllowSuper;
         _context.Strict = true;
-        _context.AllowSuper = true;
+        _context.AllowSuper = false;
 
         ExpectKeyword("class");
         var id = _lookahead.Type == TokenType.Identifier
@@ -5000,6 +5015,7 @@ private ClassExpression ParseClassExpression()
         {
             NextToken();
             superClass = IsolateCoverGrammar(_parseLeftHandSideExpressionAllowCall);
+            _context.AllowSuper = true;
         }
 
         var classBody = ParseClassBody();

src/Esprima/Messages.cs

@@ -3,6 +3,7 @@
 // Error messages should be identical to V8.
 public static class Messages
 {
+    public const string ArgumentsNotAllowedInClassField = "'arguments' is not allowed in class field initializer or static initialization block";
     public const string AsyncFunctionInSingleStatementContext = "Async functions can only be declared at the top level or inside a block.";
     public const string BadGetterArity = "Getter must not have any formal parameters";
     public const string BadSetterArity = "Setter must have exactly one formal parameter";
@@ -48,6 +49,7 @@ public static class Messages
     public const string NumericSeparatorNotAllowedHere = "Numeric separator is not allowed here";
     public const string NumericSeparatorOneUnderscore = "Numeric separator must be exactly one underscore";
     public const string ParameterAfterRestParameter = "Rest parameter must be last formal parameter";
+    public const string PrivateFieldNoDelete = "Private fields can not be deleted";
     public const string PropertyAfterRestProperty = "Unexpected token";
     public const string Redeclaration = "{0} \"{1}\" has already been declared";
     public const string RegexIncompleteQuantifier = "Invalid regular expression: Incomplete quantifier";

src/Esprima/Scanner.cs

@@ -2361,6 +2361,17 @@ internal string EscapeFailingRegex(string pattern)
             pattern = pattern.Replace("[^]", @"[\s\S]");
         }
 
+        if (pattern.Contains("--"))
+        {
+            pattern = pattern.Replace("--[", "-[");
+            var r = new Regex("--([^\\[\\]]*)");
+            pattern = r.Replace(pattern, "-[$1]"); //it should only be replaced when inside of a "[", but for this we need a regex parser.
+        }
+
+        if (pattern.Contains("?<$"))
+        {
+            pattern = pattern.Replace("?<$", "?<a");
+        }
 
         // .NET doesn't support [] which should not match any characters (inverse of [^])
         if (pattern.Contains("[]"))