f - add comment about minimal encoding of type id

Author: jkczyz

lightning/src/util/ser_macros.rs

@@ -236,8 +236,10 @@ macro_rules! decode_tlv_stream_range {
 					},
 					Err(e) => return Err(e),
 					Ok(t) => if $range.contains(&t.0) { t } else {
-						use $crate::util::ser::Writeable;
 						drop(tracking_reader);
+
+						// Assumes the type id is minimally encoded, which is enforced on read.
+						use $crate::util::ser::Writeable;
 						let bytes_read = t.serialized_length();
 						$rewind(stream_ref, bytes_read);
 						break 'tlv_read;