What version of Go are you using (go version)?

$ go version
go version devel +6d620fc42e Wed Nov 14 00:22:40 2018 +0000 linux/amd64

Does this issue reproduce with the latest release?

No, only go master branch.

What operating system and processor architecture are you using (go env)?

$ go env

What did you do?

My code:

// MarshalXML allows type H to be used with xml.Marshal.
func (h H) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	start.Name = xml.Name{
		Space: "",
		Local: "map",
	}
	if err := e.EncodeToken(start); err != nil {
		return err
	}
	for key, value := range h {
		elem := xml.StartElement{
			Name: xml.Name{Space: "", Local: key},
			Attr: []xml.Attr{},
		}
		if err := e.EncodeElement(value, elem); err != nil {
			return err
		}
	}

	return e.EncodeToken(xml.EndElement{Name: start.Name})
}

What did you expect to see?

correctly run on go master.

What did you see instead?

15.41s$ make vet
go vet github.com/gin-gonic/gin github.com/gin-gonic/gin/binding github.com/gin-gonic/gin/ginS github.com/gin-gonic/gin/internal/json github.com/gin-gonic/gin/render
# github.com/gin-gonic/gin
./utils.go:56: method MarshalXML(e *encoding/xml.Encoder, start encoding/xml.StartElement) error should have signature MarshalXML(*xml.Encoder, xml.StartElement) error
# github.com/gin-gonic/gin/render
render/render_test.go:221: method MarshalXML(e *encoding/xml.Encoder, start encoding/xml.StartElement) error should have signature MarshalXML(*xml.Encoder, xml.StartElement) error
make: *** [vet] Error 2
The command "make vet" exited with 2.