Perform type inference on constructor field initializer expressions.

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

Index: pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
index a70cede998894ca4420b9a606e2871708abb2e90..ef96e93926947b22f5d4636df3b3db5c49bbe6d1 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
@@ -690,6 +690,19 @@ class KernelField extends Field implements KernelMember {
   }
 }
 
+/// Concrete shadow object representing a field initializer in kernel form.
+class KernelFieldInitializer extends FieldInitializer
+    implements KernelInitializer {
+  KernelFieldInitializer(Field field, Expression value) : super(field, value);
+
+  @override
+  void _inferInitializer(KernelTypeInferrer inferrer) {
+    inferrer.listener.fieldInitializerEnter(this);
+    inferrer.inferExpression(value, field.type, false);
+    inferrer.listener.fieldInitializerExit(this);
+  }
+}
+
 /// Concrete shadow object representing a for-in loop in kernel form.
 class KernelForInStatement extends ForInStatement implements KernelStatement {
   final bool _declaresVariable;