Allow Symbols in switch and maps

runtime/vm/parser.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/parser.h"
 
 #include "lib/invocation_mirror.h"
 #include "platform/utils.h"
 #include "vm/ast_transformer.h"
 #include "vm/bootstrap.h"
@@ skipping 7232 matching lines @@
         ReportError(val_pos, "expected case expression of type String");
       }
       continue;
     }
     if (val.IsDouble()) {
       ReportError(val_pos, "case expression may not be of type double");
     }
     if (val.clazz() != first_value.clazz()) {
       ReportError(val_pos, "all case expressions must be of same type");
     }
+    if (val.clazz() == I->object_store()->symbol_class()) {
+      continue;
+    }
     if (i == 0) {
       // The value is of some type other than int, String or double.
       // Check that the type class does not override the == operator.
       // Check this only in the first loop iteration since all values
       // are of the same type, which we check above.
       if (ImplementsEqualOperator(val)) {
         ReportError(val_pos,
                     "type class of case expression must not "
                     "implement operator ==");
       }
@@ skipping 3749 matching lines @@
           key_pos, key, key_type, Symbols::ListLiteralElement());
     }
     if (is_const) {
       ASSERT(key->IsLiteralNode());
       const Instance& key_value = key->AsLiteralNode()->literal();
       if (key_value.IsDouble()) {
         ReportError(key_pos, "key value must not be of type double");
       }
       if (!key_value.IsInteger() &&
           !key_value.IsString() &&
+          (key_value.clazz() != I->object_store()->symbol_class()) &&
           ImplementsEqualOperator(key_value)) {
         ReportError(key_pos, "key value must not implement operator ==");
       }
     }
     ExpectToken(Token::kCOLON);
     const intptr_t value_pos = TokenPos();
     AstNode* value = ParseExpr(is_const, kConsumeCascades);
     SetAllowFunctionLiterals(saved_mode);
     if (FLAG_enable_type_checks &&
         !is_const &&
@@ skipping 174 matching lines @@
       ConsumeToken();
       symbol = String::Concat(symbol,
                               *ExpectIdentifier("identifier expected"));
     }
   } else if (Token::CanBeOverloaded(CurrentToken())) {
     symbol = String::New(Token::Str(CurrentToken()));
     ConsumeToken();
   } else {
     ReportError("illegal symbol literal");
   }
-  // Lookup class Symbol from internal library and call the
-  // constructor to create a symbol instance.
-  const Library& lib = Library::Handle(I, Library::InternalLibrary());
-  const Class& symbol_class = Class::Handle(I,
-                                            lib.LookupClass(Symbols::Symbol()));
+
+  // Call Symbol class constructor to create a symbol instance.
+  const Class& symbol_class = Class::Handle(I->object_store()->symbol_class());
   ASSERT(!symbol_class.IsNull());
   ArgumentListNode* constr_args = new(I) ArgumentListNode(symbol_pos);
   constr_args->Add(new(I) LiteralNode(
       symbol_pos, String::ZoneHandle(I, Symbols::New(symbol))));
   const Function& constr = Function::ZoneHandle(I,
       symbol_class.LookupConstructor(Symbols::SymbolCtor()));
   ASSERT(!constr.IsNull());
   const Object& result = Object::Handle(I,
       EvaluateConstConstructorCall(symbol_class,
                                    TypeArguments::Handle(I),
@@ skipping 970 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart