Use correct types on cloned constructors in mixin applications.

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 2427f3de0797a5b404fce5efa3eba1d1930173f7..d3c0b5bddde81eda78566a84fa8b340c1ca80cc7 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -169,6 +169,13 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
   @override
   Expression toValue(Object node) {
     if (node is UnresolvedIdentifier) {
+      if (isDartLibrary &&
+          node.name.name == "main" &&
+          library.uri.path == "_builtin" &&
+          member?.name == "_getMainClosure") {
+        // TODO(ahe): https://github.com/dart-lang/sdk/issues/28989
+        return new NullLiteral()..fileOffset = node.fileOffset;
+      }
       return throwNoSuchMethodError(
           node.name.name, new Arguments.empty(), node.fileOffset,
           isGetter: true);