Constant get and invoke are never called.

lib/kernel_visitor.dart

Index: lib/kernel_visitor.dart
diff --git a/lib/kernel_visitor.dart b/lib/kernel_visitor.dart
index 2b6c00b13d79cc8680cdaa992821e291c6cbac1b..0634e7b3c674445ae0e829d74098e8a5f90bab11 100644
--- a/lib/kernel_visitor.dart
+++ b/lib/kernel_visitor.dart
@@ -1248,18 +1248,20 @@ class KernelVisitor extends Object
   }
 
   @override
-  ir.Throw visitConstantGet(Send node, ConstantExpression constant, _) {
-    return buildUnsupported(node, "ConstantGet");
+  visitConstantGet(Send node, ConstantExpression constant, _) {
+    // TODO(ahe): This method is never called. Is it a bug in semantic visitor?
+    return internalError(node, "ConstantGet");
   }
 
   @override
-  ir.Throw visitConstantInvoke(
+  visitConstantInvoke(
       Send node,
       ConstantExpression constant,
       NodeList arguments,
       CallStructure callStructure,
       _) {
-    return buildUnsupported(node, "ConstantInvoke");
+    // TODO(ahe): This method is never called. Is it a bug in semantic visitor?
+    return internalError(node, "ConstantInvoke");
   }
 
   @override