Improve checking of patches.

sdk/lib/_internal/compiler/implementation/warnings.dart

Index: sdk/lib/_internal/compiler/implementation/warnings.dart
diff --git a/sdk/lib/_internal/compiler/implementation/warnings.dart b/sdk/lib/_internal/compiler/implementation/warnings.dart
index 78ed8274c83f58e78626775227630047f015bcbd..4f105498500af063d77aa41d5752fea47f976729 100644
--- a/sdk/lib/_internal/compiler/implementation/warnings.dart
+++ b/sdk/lib/_internal/compiler/implementation/warnings.dart
@@ -357,6 +357,51 @@ Length: #{3}''');
       "Patch method parameter '#{3}' doesn't match '#{2}' on origin method "
       "#{1}.");
 
+  static const PATCH_POINT_TO_FUNCTION = const MessageKind(
+      "Info: This is the function patch '#{1}'.");
+
+  static const PATCH_POINT_TO_CLASS = const MessageKind(
+      "Info: This is the class patch '#{1}'.");
+
+  static const PATCH_POINT_TO_GETTER = const MessageKind(
+      "Info: This is the getter patch '#{1}'.");
+
+  static const PATCH_POINT_TO_SETTER = const MessageKind(
+      "Info: This is the setter patch '#{1}'.");
+
+  static const PATCH_POINT_TO_CONSTRUCTOR = const MessageKind(
+      "Info: This is the constructor patch '#{1}'.");
+
+  static const PATCH_NON_EXISTING = const MessageKind(
+      "Error: Origin does not exist for patch '#{1}'.");
+
+  static const PATCH_NONPATCHABLE = const MessageKind(
+      "Error: Only classes and functions can be patched.");
+
+  static const PATCH_NON_EXTERNAL = const MessageKind(
+      "Error: Only external functions can be patched.");
+
+  static const PATCH_NON_CLASS = const MessageKind(
+      "Error: Patching non-class with class patch '#{1}'.");
+
+  static const PATCH_NON_GETTER = const MessageKind(
+      "Error: Cannot patch non-getter '#{1}' with getter patch.");
+
+  static const PATCH_NO_GETTER = const MessageKind(
+      "Error: No getter found for getter patch '#{1}'.");
+
+  static const PATCH_NON_SETTER = const MessageKind(
+      "Error: Cannot patch non-setter with setter patch '#{1}'.");
+
+  static const PATCH_NO_SETTER = const MessageKind(
+      "Error: No setter found for getter patch '#{1}'.");
+
+  static const PATCH_NON_CONSTRUCTOR = const MessageKind(
+      "Error: Cannot patch non-constructor with constructor patch '#{1}'.");
+
+  static const PATCH_NON_FUNCTION = const MessageKind(
+      "Error: Cannot patch non-function with function patch '#{1}'.");
+
   static const TOP_LEVEL_VARIABLE_DECLARED_STATIC = const MessageKind(
       "Top-level variable cannot be declared static.");