diff --git a/src/ast/rewriter/seq_range_collapse.cpp b/src/ast/rewriter/seq_range_collapse.cpp
index 0c739e0c07..988603af9e 100644
--- a/src/ast/rewriter/seq_range_collapse.cpp
+++ b/src/ast/rewriter/seq_range_collapse.cpp
@@ -130,8 +130,8 @@ namespace seq {
         // range bounds.  This matches the shape used elsewhere in
         // seq_rewriter and avoids creating duplicate AST nodes with
         // different ids for semantically identical ranges.
-        expr_ref slo(u.str.mk_unit(u.str.mk_char(lo)), m);
-        expr_ref shi(u.str.mk_unit(u.str.mk_char(hi)), m);
+        expr_ref slo(u.str.mk_string(zstring(lo)), m);
+        expr_ref shi(u.str.mk_string(zstring(hi)), m);
         return expr_ref(u.re.mk_range(slo, shi), m);
     }
 
diff --git a/src/ast/seq_decl_plugin.cpp b/src/ast/seq_decl_plugin.cpp
index 29949a151b..3cb049b457 100644
--- a/src/ast/seq_decl_plugin.cpp
+++ b/src/ast/seq_decl_plugin.cpp
@@ -422,7 +422,7 @@ func_decl* seq_decl_plugin::mk_func_decl(decl_kind k, unsigned num_parameters, p
     case OP_STRING_LE:
     case OP_STRING_IS_DIGIT:
     case OP_STRING_TO_CODE:
-    case OP_STRING_FROM_CODE:
+    case OP_STRING_FROM_CODE:        
         match(*m_sigs[k], arity, domain, range, rng);
         return m.mk_func_decl(m_sigs[k]->m_name, arity, domain, rng, func_decl_info(m_family_id, k));