Use JavaScript runtime semantics when constant folding.

lib/compiler/implementation/compiler.dart

Index: lib/compiler/implementation/compiler.dart
diff --git a/lib/compiler/implementation/compiler.dart b/lib/compiler/implementation/compiler.dart
index f22184e30d276639fb1c1936d6f9042114e7f6fe..14e0d17dca88c7dd831b690b122f1997eb3d87e9 100644
--- a/lib/compiler/implementation/compiler.dart
+++ b/lib/compiler/implementation/compiler.dart
@@ -182,14 +182,16 @@ class Compiler implements DiagnosticListener {
             this.enableTypeAssertions = false,
             this.enableUserAssertions = false,
             this.enableMinification = false,
-            bool emitJavascript = true,
+            bool emitJavaScript = true,
             bool generateSourceMap = true,
             bool cutDeclarationTypes = false])
       : libraries = new Map<String, LibraryElement>(),
         world = new World(),
         progress = new Stopwatch.start() {
     namer = new Namer(this);
-    constantHandler = new ConstantHandler(this);
+    ConstantSystem constantSystem =
+        emitJavaScript ? JAVA_SCRIPT_CONSTANT_SYSTEM : DART_CONSTANT_SYSTEM;

[ngeoffray, 2012/09/05 11:20:36]

Should that be part of the backend then?

[floitsch, 2012/09/05 16:12:01]

Done.

+    constantHandler = new ConstantHandler(this, constantSystem);
     scanner = new ScannerTask(this);
     dietParser = new DietParserTask(this);
     parser = new ParserTask(this);
@@ -199,7 +201,7 @@ class Compiler implements DiagnosticListener {
     closureToClassMapper = new closureMapping.ClosureTask(this);
     checker = new TypeCheckerTask(this);
     typesTask = new ti.TypesTask(this);
-    backend = emitJavascript ?
+    backend = emitJavaScript ?
         new js_backend.JavaScriptBackend(this, generateSourceMap) :
         new dart_backend.DartBackend(this, cutDeclarationTypes);
     enqueuer = new EnqueueTask(this);