Typecheck constructor initializers properly

test/dart_codegen/expect/core/errors.dart

Index: test/dart_codegen/expect/core/errors.dart
diff --git a/test/dart_codegen/expect/core/errors.dart b/test/dart_codegen/expect/core/errors.dart
index 3968a12593ec5d5ab5fd520d13415e5115ad784b..93e9cb77ab50cdf8504e924bc0df4e3ce912eadb 100644
--- a/test/dart_codegen/expect/core/errors.dart
+++ b/test/dart_codegen/expect/core/errors.dart
@@ -98,7 +98,7 @@ explanation = ": Only valid value is $start";
 }
  class IndexError extends ArgumentError implements RangeError {final indexable;
  final int length;
- IndexError(int invalidValue, indexable, [String name, String message, int length]) : this.indexable = indexable, this.length = (length != null) ? length : indexable.length, super.value(invalidValue, name, (message != null) ? message : "Index out of range");
+ IndexError(int invalidValue, indexable, [String name, String message, int length]) : this.indexable = indexable, this.length = ((__x3) => DDC$RT.cast(__x3, dynamic, int, "CastGeneral", """line 371, column 23 of dart:core/errors.dart: """, __x3 is int, true))((length != null) ? length : indexable.length), super.value(invalidValue, name, (message != null) ? message : "Index out of range");
  int get start => 0;
  int get end => length - 1;
  String toString() {