Allow to invoke fields as if they were methods.

frog/leg/ssa/builder.dart

Index: frog/leg/ssa/builder.dart
diff --git a/frog/leg/ssa/builder.dart b/frog/leg/ssa/builder.dart
index dc05a8c86a8c45995ec71e4bfa40ac92a1ae1a74..3231580c95c00b3e0a8c38978f5fcc14388959dd 100644
--- a/frog/leg/ssa/builder.dart
+++ b/frog/leg/ssa/builder.dart
@@ -1587,18 +1587,23 @@ class SsaBuilder implements Visitor {
   visitStaticSend(Send node) {
     Selector selector = elements.getSelector(node);
     Element element = elements[node];
-    if (element.kind != ElementKind.FUNCTION &&
-        element.kind != ElementKind.GENERATIVE_CONSTRUCTOR) {
-      compiler.unimplemented(
-          "SsaBuilder.visitStaticSend static field invocation",
-          node: node);
-    }
-    HStatic target = new HStatic(element);
+    HInstruction target = new HStatic(element);
     add(target);
     var inputs = <HInstruction>[];
     inputs.add(target);
-    addStaticSendArgumentsToList(node, element, inputs);
-    push(new HInvokeStatic(selector, inputs));
+    if (element.kind == ElementKind.FUNCTION ||
+        element.kind == ElementKind.GENERATIVE_CONSTRUCTOR) {
+      addStaticSendArgumentsToList(node, element, inputs);
+      push(new HInvokeStatic(selector, inputs));
+    } else {
+      if (element.kind == ElementKind.GETTER) {
+        target = new HInvokeStatic(Selector.GETTER, inputs);
+        add(target);
+        inputs = <HInstruction>[target];
+      }
+      addDynamicSendArgumentsToList(node, inputs);
+      push(new HInvokeClosure(selector, inputs));
+    }
   }
 
   visitSend(Send node) {