diff --git a/parsers/src/bind.rs b/parsers/src/bind.rs
index f4f2bdf..982cbca 100644
--- a/parsers/src/bind.rs
+++ b/parsers/src/bind.rs
@@ -150,7 +150,7 @@ mod tests {
     #[test]
     fn test_size() {
         assert_size!(BindQuery, 24);
-        assert_size!(BindResponse, 72);
+        assert_size!(BindResponse, 32);
     }
 
     #[test]
diff --git a/parsers/src/bookmarks.rs b/parsers/src/bookmarks.rs
index 182c696..cbaea94 100644
--- a/parsers/src/bookmarks.rs
+++ b/parsers/src/bookmarks.rs
@@ -84,7 +84,7 @@ mod tests {
     #[cfg(target_pointer_width = "64")]
     #[test]
     fn test_size() {
-        assert_size!(Conference, 128);
+        assert_size!(Conference, 112);
         assert_size!(Url, 48);
         assert_size!(Storage, 48);
     }
diff --git a/parsers/src/carbons.rs b/parsers/src/carbons.rs
index 5ebbd52..47b08da 100644
--- a/parsers/src/carbons.rs
+++ b/parsers/src/carbons.rs
@@ -82,8 +82,8 @@ mod tests {
         assert_size!(Enable, 0);
         assert_size!(Disable, 0);
         assert_size!(Private, 0);
-        assert_size!(Received, 408);
-        assert_size!(Sent, 408);
+        assert_size!(Received, 288);
+        assert_size!(Sent, 288);
     }
 
     #[test]
diff --git a/parsers/src/delay.rs b/parsers/src/delay.rs
index cf0012d..a0c5225 100644
--- a/parsers/src/delay.rs
+++ b/parsers/src/delay.rs
@@ -47,7 +47,7 @@ mod tests {
     #[cfg(target_pointer_width = "64")]
     #[test]
     fn test_size() {
-        assert_size!(Delay, 120);
+        assert_size!(Delay, 80);
     }
 
     #[test]
diff --git a/parsers/src/disco.rs b/parsers/src/disco.rs
index 6625141..5e4e071 100644
--- a/parsers/src/disco.rs
+++ b/parsers/src/disco.rs
@@ -254,10 +254,7 @@ mod tests {
         assert_size!(DiscoInfoQuery, 24);
         assert_size!(DiscoInfoResult, 96);
 
-        #[cfg(rustc_nightly)]
-        assert_size!(Item, 120);
-        #[cfg(not(rustc_nightly))]
-        assert_size!(Item, 128);
+        assert_size!(Item, 88);
         assert_size!(DiscoItemsQuery, 24);
         assert_size!(DiscoItemsResult, 48);
     }
diff --git a/parsers/src/forwarding.rs b/parsers/src/forwarding.rs
index c59e9d1..4590058 100644
--- a/parsers/src/forwarding.rs
+++ b/parsers/src/forwarding.rs
@@ -39,7 +39,7 @@ mod tests {
     #[cfg(target_pointer_width = "64")]
     #[test]
     fn test_size() {
-        assert_size!(Forwarded, 408);
+        assert_size!(Forwarded, 288);
     }
 
     #[test]
diff --git a/parsers/src/iq.rs b/parsers/src/iq.rs
index 74cf019..5239b39 100644
--- a/parsers/src/iq.rs
+++ b/parsers/src/iq.rs
@@ -240,8 +240,8 @@ mod tests {
     #[cfg(target_pointer_width = "64")]
     #[test]
     fn test_size() {
-        assert_size!(IqType, 232);
-        assert_size!(Iq, 416);
+        assert_size!(IqType, 192);
+        assert_size!(Iq, 296);
     }
 
     #[test]
diff --git a/parsers/src/jid_prep.rs b/parsers/src/jid_prep.rs
index d37f507..69c767e 100644
--- a/parsers/src/jid_prep.rs
+++ b/parsers/src/jid_prep.rs
@@ -55,10 +55,7 @@ mod tests {
     #[test]
     fn test_size() {
         assert_size!(JidPrepQuery, 24);
-        #[cfg(rustc_nightly)]
-        assert_size!(JidPrepResponse, 72);
-        #[cfg(not(rustc_nightly))]
-        assert_size!(JidPrepResponse, 80);
+        assert_size!(JidPrepResponse, 40);
     }
 
     #[test]
diff --git a/parsers/src/jingle.rs b/parsers/src/jingle.rs
index c1a0f88..0784f3c 100644
--- a/parsers/src/jingle.rs
+++ b/parsers/src/jingle.rs
@@ -712,7 +712,7 @@ mod tests {
         assert_size!(Reason, 1);
         assert_size!(ReasonElement, 32);
         assert_size!(SessionId, 24);
-        assert_size!(Jingle, 304);
+        assert_size!(Jingle, 224);
     }
 
     #[test]
diff --git a/parsers/src/jingle_s5b.rs b/parsers/src/jingle_s5b.rs
index bbc845b..1e1a8e4 100644
--- a/parsers/src/jingle_s5b.rs
+++ b/parsers/src/jingle_s5b.rs
@@ -297,10 +297,7 @@ mod tests {
         assert_size!(Mode, 1);
         assert_size!(CandidateId, 24);
         assert_size!(StreamId, 24);
-        #[cfg(rustc_nightly)]
-        assert_size!(Candidate, 128);
-        #[cfg(not(rustc_nightly))]
-        assert_size!(Candidate, 136);
+        assert_size!(Candidate, 96);
         assert_size!(TransportPayload, 32);
         assert_size!(Transport, 88);
     }
diff --git a/parsers/src/mam.rs b/parsers/src/mam.rs
index e36f215..a8a0551 100644
--- a/parsers/src/mam.rs
+++ b/parsers/src/mam.rs
@@ -109,7 +109,7 @@ mod tests {
     fn test_size() {
         assert_size!(QueryId, 24);
         assert_size!(Query, 232);
-        assert_size!(Result_, 456);
+        assert_size!(Result_, 336);
         assert_size!(Complete, 1);
         assert_size!(Fin, 88);
     }
diff --git a/parsers/src/message.rs b/parsers/src/message.rs
index a8f9cac..1c86094 100644
--- a/parsers/src/message.rs
+++ b/parsers/src/message.rs
@@ -318,7 +318,7 @@ mod tests {
         assert_size!(Body, 24);
         assert_size!(Subject, 24);
         assert_size!(Thread, 24);
-        assert_size!(Message, 288);
+        assert_size!(Message, 208);
     }
 
     #[test]
diff --git a/parsers/src/presence.rs b/parsers/src/presence.rs
index bb8ee87..5bc3cc7 100644
--- a/parsers/src/presence.rs
+++ b/parsers/src/presence.rs
@@ -393,7 +393,7 @@ mod tests {
     fn test_size() {
         assert_size!(Show, 1);
         assert_size!(Type, 1);
-        assert_size!(Presence, 240);
+        assert_size!(Presence, 160);
     }
 
     #[test]
diff --git a/parsers/src/roster.rs b/parsers/src/roster.rs
index c6e0266..445a8bf 100644
--- a/parsers/src/roster.rs
+++ b/parsers/src/roster.rs
@@ -112,7 +112,7 @@ mod tests {
         assert_size!(Group, 24);
         assert_size!(Subscription, 1);
         assert_size!(Ask, 1);
-        assert_size!(Item, 104);
+        assert_size!(Item, 88);
         assert_size!(Roster, 48);
     }
 
diff --git a/parsers/src/stanza_error.rs b/parsers/src/stanza_error.rs
index b4d81ea..03dd103 100644
--- a/parsers/src/stanza_error.rs
+++ b/parsers/src/stanza_error.rs
@@ -326,7 +326,7 @@ mod tests {
     fn test_size() {
         assert_size!(ErrorType, 1);
         assert_size!(DefinedCondition, 1);
-        assert_size!(StanzaError, 232);
+        assert_size!(StanzaError, 192);
     }
 
     #[test]
diff --git a/parsers/src/stanza_id.rs b/parsers/src/stanza_id.rs
index eeb5d17..fadd5e8 100644
--- a/parsers/src/stanza_id.rs
+++ b/parsers/src/stanza_id.rs
@@ -52,10 +52,7 @@ mod tests {
     #[cfg(target_pointer_width = "64")]
     #[test]
     fn test_size() {
-        #[cfg(rustc_nightly)]
-        assert_size!(StanzaId, 96);
-        #[cfg(not(rustc_nightly))]
-        assert_size!(StanzaId, 104);
+        assert_size!(StanzaId, 64);
         assert_size!(OriginId, 24);
     }
 
diff --git a/parsers/src/stream.rs b/parsers/src/stream.rs
index 48eae77..21dcab5 100644
--- a/parsers/src/stream.rs
+++ b/parsers/src/stream.rs
@@ -85,7 +85,7 @@ mod tests {
     #[cfg(target_pointer_width = "64")]
     #[test]
     fn test_size() {
-        assert_size!(Stream, 168);
+        assert_size!(Stream, 136);
     }
 
     #[test]
diff --git a/parsers/src/websocket.rs b/parsers/src/websocket.rs
index fbc1fb2..ecd065d 100644
--- a/parsers/src/websocket.rs
+++ b/parsers/src/websocket.rs
@@ -84,7 +84,7 @@ mod tests {
     #[cfg(target_pointer_width = "64")]
     #[test]
     fn test_size() {
-        assert_size!(Open, 168);
+        assert_size!(Open, 136);
     }
 
     #[test]