wrappers.proto in grpc-tools-1.20.0.pre1

- old
+ new

@@ -30,9 +30,14 @@
 
 // Wrappers for primitive (non-message) types. These types are useful
 // for embedding primitives in the `google.protobuf.Any` type and for places
 // where we need to distinguish between the absence of a primitive
 // typed field and its default value.
+//
+// These wrappers have no meaningful use within repeated fields as they lack
+// the ability to detect presence on individual elements.
+// These wrappers have no meaningful use within a map or a oneof since
+// individual entries of a map or fields of a oneof can already detect presence.
 
 syntax = "proto3";
 
 package google.protobuf;
 