diff --git a/src/ast/rewriter/seq_rewriter.cpp b/src/ast/rewriter/seq_rewriter.cpp index abc5eba67..a811e4d8d 100644 --- a/src/ast/rewriter/seq_rewriter.cpp +++ b/src/ast/rewriter/seq_rewriter.cpp @@ -2471,6 +2471,10 @@ br_status seq_rewriter::mk_str_lt(expr* a, expr* b, expr_ref& result) { result = m().mk_false(); return BR_DONE; } + if (str().is_empty(a)) { + result = m().mk_not(m().mk_eq(a, b)); + return BR_DONE; + } if (str().is_string(a, as) && str().is_string(b, bs)) { unsigned sz = std::min(as.length(), bs.length()); for (unsigned i = 0; i < sz; ++i) {