dockerfile2llb/pipe: remove the useless assignment

Signed-off-by: Wei Fu <fuweid89@gmail.com>

frontend/dockerfile/dockerfile2llb/convert.go

@@ -250,7 +250,6 @@ func Dockerfile2LLB(ctx context.Context, dt []byte, opt ConvertOpt) (*llb.State,
 								}
 							}
 							d.stage.BaseName = ref.String()
-							_ = ref
 							if len(img.RootFS.DiffIDs) == 0 {
 								isScratch = true
 								// schema1 images can't return diffIDs so double check :(

solver/internal/pipe/pipe.go

@@ -89,7 +89,6 @@ func New(req Request) *Pipe {
 	roundTripCh := &channel{}
 	pw := &sender{
 		req:         req,
-		recvChannel: cancelCh,
 		sendChannel: roundTripCh,
 	}
 	pr := &receiver{
@@ -125,7 +124,6 @@ func New(req Request) *Pipe {
 type sender struct {
 	status      Status
 	req         Request
-	recvChannel *channel
 	sendChannel *channel
 	mu          sync.Mutex
 }