Support runtime check of function types.

sdk/lib/_internal/compiler/implementation/ssa/optimize.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart b/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
index c61ff480cedd1db45e39ae9102a30f002aef18db..c2ff2c48ed73c5a43b1d75105807cae5b6267b45 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
@@ -596,6 +596,10 @@ class SsaConstantFolder extends HBaseVisitor implements OptimizationPhase {
     if (type != null && (!type.isRaw || type.kind == TypeKind.TYPE_VARIABLE)) {
       return node;
     }
+    if (type != null && type.kind == TypeKind.FUNCTION) {

[karlklose, 2013/06/20 07:32:55]

Merge the conditions? Or have one if (type != null) around both?

[Johnni Winther, 2013/06/21 12:19:15]

Done.

+      // TODO(johnniwinther): Optimize function type conversions.
+      return node;
+    }
     HType convertedType = node.instructionType;
     if (convertedType.isUnknown()) return node;
     HType combinedType = value.instructionType.intersection(