Add CustomEvent

test/codegen/expect/collection/src/wrappers.txt

Index: test/codegen/expect/collection/src/wrappers.txt
diff --git a/test/codegen/expect/collection/src/wrappers.txt b/test/codegen/expect/collection/src/wrappers.txt
index 7435e0048a99e302b0ea0a16c864277a68557e76..3be4c77ea9481701a4f23bff698739a7d8323396 100644
--- a/test/codegen/expect/collection/src/wrappers.txt
+++ b/test/codegen/expect/collection/src/wrappers.txt
@@ -1,17 +1,17 @@
 // Messages from compiling wrappers.dart
 severe: [INVALID_METHOD_OVERRIDE] Invalid override. The type of _DelegatingIterableBase.expand (((E) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<E>.expand (<T>((E) → Iterable<T>) → Iterable<T>). (package:collection/src/wrappers.dart, line 27, col 3)
 severe: [INVALID_METHOD_OVERRIDE] Invalid override. The type of _DelegatingIterableBase.map (((E) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<E>.map (<T>((E) → T) → Iterable<T>). (package:collection/src/wrappers.dart, line 54, col 3)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/src/wrappers.dart, line 97, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/src/wrappers.dart, line 97, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((E) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<E>.expand (<T>((E) → Iterable<T>) → Iterable<T>). (package:collection/src/wrappers.dart, line 97, col 25)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((E) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<E>.map (<T>((E) → T) → Iterable<T>). (package:collection/src/wrappers.dart, line 97, col 25)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/src/wrappers.dart, line 194, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/src/wrappers.dart, line 194, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((E) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<E>.expand (<T>((E) → Iterable<T>) → Iterable<T>). (package:collection/src/wrappers.dart, line 194, col 24)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((E) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<E>.map (<T>((E) → T) → Iterable<T>). (package:collection/src/wrappers.dart, line 194, col 24)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/src/wrappers.dart, line 245, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/src/wrappers.dart, line 245, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((E) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<E>.expand (<T>((E) → Iterable<T>) → Iterable<T>). (package:collection/src/wrappers.dart, line 245, col 26)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((E) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<E>.map (<T>((E) → T) → Iterable<T>). (package:collection/src/wrappers.dart, line 245, col 26)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/src/wrappers.dart, line 339, col 7)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/src/wrappers.dart, line 414, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/src/wrappers.dart, line 339, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/src/wrappers.dart, line 414, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((V) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<V>.expand (<T>((V) → Iterable<T>) → Iterable<T>). (package:collection/src/wrappers.dart, line 414, col 25)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((V) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<V>.map (<T>((V) → T) → Iterable<T>). (package:collection/src/wrappers.dart, line 414, col 25)
 warning: [DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to T (package:collection/src/wrappers.dart, line 35, col 7)