error: unexpected `required`
  --> testdata/parser/type/ok.proto:22:5
   |
22 |     required M x3 = 3;
   |     ^^^^^^^^ expected type name, `optional`, or `repeated`
   |
  help: delete it
   |
22 | -     required M x3 = 3;
22 | +     M x3 = 3;
   |
   |
   = help: required fields are only permitted in proto2; even then, their use is
           strongly discouraged

encountered 1 error
