Complain about incorrect this/super constructor initializers.

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

Index: pkg/front_end/lib/src/fasta/kernel/kernel_procedure_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_procedure_builder.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_procedure_builder.dart
index 850c3ad45eefef77e5fa8bd01c9313ebef306f4f..79df4f8ab61870f81cd66d277bf94abab504b006 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_procedure_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_procedure_builder.dart
@@ -55,6 +55,7 @@ import 'kernel_builder.dart'
         MetadataBuilder,
         ProcedureBuilder,
         TypeVariableBuilder,
+        isRedirectingGenerativeConstructorImplementation,
         memberError;
 
 abstract class KernelFunctionBuilder
@@ -247,6 +248,7 @@ class KernelProcedureBuilder extends KernelFunctionBuilder {
 // TODO(ahe): Move this to own file?
 class KernelConstructorBuilder extends KernelFunctionBuilder {
   final Constructor constructor;
+
   final int charOpenParenOffset;
 
   bool hasMovedSuperInitializer = false;
@@ -281,6 +283,10 @@ class KernelConstructorBuilder extends KernelFunctionBuilder {
 
   ProcedureKind get kind => null;
 
+  bool get isRedirectingGenerativeConstructor {
+    return isRedirectingGenerativeConstructorImplementation(constructor);
+  }
+
   Constructor build(LibraryBuilder library) {
     if (constructor.name == null) {
       constructor.function = buildFunction(library);