error: expected message type, found scalar type `string`
  --> testdata/options/validate/groups.proto:20:5
   |
20 |     string x1 = 1 [features.message_encoding = DELIMITED];
   |     ^^^^^^         ------------------------- `message_encoding` set here
   |
   = help: `message_encoding` can only be set on message-typed fields

error: expected message type, found map entry type `buf.test.M.X4Entry`
  --> testdata/options/validate/groups.proto:23:5
   |
23 |     map<int32, M> x4 = 4 [features.message_encoding = DELIMITED];
   |     ^^^^^^^^^^^^^         -------------------------
   |                            |
   |                            `message_encoding` set here
   |
   = help: `message_encoding` can only be set on message-typed fields
   = help: even though map fields count as repeated message-typed fields,
           `message_encoding` cannot be set on them

encountered 2 errors
