diff --git a/lib/erl/include/thrift_protocol.hrl b/lib/erl/include/thrift_protocol.hrl
index 201bade..f85f455 100644
--- a/lib/erl/include/thrift_protocol.hrl
+++ b/lib/erl/include/thrift_protocol.hrl
@@ -57,6 +57,10 @@
                         | double
                         | string
                         .
+-type tprot_cont_tag() :: {list, _Type}
+                        | {map, _KType, _VType}
+                        | {set, _Type}
+                        .
 
 
 -endif.
diff --git a/lib/erl/include/thrift_protocol_impl.hrl b/lib/erl/include/thrift_protocol_impl.hrl
index fe9d20d..92f3a00 100644
--- a/lib/erl/include/thrift_protocol_impl.hrl
+++ b/lib/erl/include/thrift_protocol_impl.hrl
@@ -27,6 +27,7 @@
 
 -spec write(state(), term()) -> ok | {error, _Reason}.
 
+%% NOTE: Keep this in sync with thrift_protocol:read.
 -spec read
         (state(), tprot_empty_tag()) ->   ok                | {error, _Reason};
         (state(), tprot_header_tag()) -> tprot_header_val() | {error, _Reason};