ran go mod vendor on the whole project

vendor/github.com/gogo/protobuf/proto/table_merge.go

@@ -530,25 +530,6 @@ func (mi *mergeInfo) computeMergeInfo() {
 			}
 		case reflect.Struct:
 			switch {
-			case isSlice && !isPointer: // E.g. []pb.T
-				mergeInfo := getMergeInfo(tf)
-				zero := reflect.Zero(tf)
-				mfi.merge = func(dst, src pointer) {
-					// TODO: Make this faster?
-					dstsp := dst.asPointerTo(f.Type)
-					dsts := dstsp.Elem()
-					srcs := src.asPointerTo(f.Type).Elem()
-					for i := 0; i < srcs.Len(); i++ {
-						dsts = reflect.Append(dsts, zero)
-						srcElement := srcs.Index(i).Addr()
-						dstElement := dsts.Index(dsts.Len() - 1).Addr()
-						mergeInfo.merge(valToPointer(dstElement), valToPointer(srcElement))
-					}
-					if dsts.IsNil() {
-						dsts = reflect.MakeSlice(f.Type, 0, 0)
-					}
-					dstsp.Elem().Set(dsts)
-				}
 			case !isPointer:
 				mergeInfo := getMergeInfo(tf)
 				mfi.merge = func(dst, src pointer) {