diff --git a/src/smt/theory_seq.cpp b/src/smt/theory_seq.cpp
index 4125e9cc1..dca1bbce2 100644
--- a/src/smt/theory_seq.cpp
+++ b/src/smt/theory_seq.cpp
@@ -1640,7 +1640,6 @@ bool theory_seq::enforce_length(expr_ref_vector const& es, vector<rational> & le
             len.push_back(rational(s.length()));
         }
         else if (get_length(e, val)) {
-			SASSERT(!val.is_neg());
             len.push_back(val);
         }
         else {
diff --git a/src/util/buffer.h b/src/util/buffer.h
index 13a5ca00b..cd8c1d4ac 100644
--- a/src/util/buffer.h
+++ b/src/util/buffer.h
@@ -13,6 +13,7 @@ Abstract:
 Author:
 
     Leonardo de Moura (leonardo) 2006-10-16.
+    Daniel Schemmel 2019-2-23
 
 Revision History:
 
diff --git a/src/util/vector.h b/src/util/vector.h
index f94fda4f0..5dfb199a4 100644
--- a/src/util/vector.h
+++ b/src/util/vector.h
@@ -17,10 +17,10 @@ Abstract:
 Author:
 
     Leonardo de Moura (leonardo) 2006-09-11.
+    Daniel Schemmel 2019-2-23
 
 Revision History:
 
-   2019-2-23 Renamed from vector to vector to provide new implementation
 
 --*/
 #ifndef VECTOR_H_