Comments inside field options break parser

[adamhosier]

For example:

syntax = "proto3";

message Foo {
  string bar = 1 [
    // comment 
    deprecated=true
  ];
}

this file compiles with protoc, but fails parsing with

2019/07/12 14:27:53 visit proto file:/tmp/proto/foo.proto:5:5: found "// comment " but expected [option identifier]

[emicklei]

thank you for reporting this. will fix it soon

[emicklei]

the current fix does not preserve the comment.