diff --git a/.gitignore b/.gitignore
index 4bda837..44483a9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,4 +45,4 @@ Testing/
 .DS_Store
 compile_commands.json
 .cache/
-
+out/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6d15525..c8f6078 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,7 +33,7 @@ option(ENABLE_Z3 "Enables the download and compilation of the expr::z3_driver dr
 # library dependencies
 CPMAddPackage("gh:yalibs/yaoverload@1.0.0")
 CPMAddPackage("gh:yalibs/yahashcombine@1.0.0")
-CPMAddPackage("gh:yalibs/yatree@1.2.1")
+CPMAddPackage("gh:yalibs/yatree@1.2.2")
 CPMAddPackage("gh:yalibs/yauuid@1.0.1")
 # demo dependencies
 CPMAddPackage("gh:yalibs/yatimer@1.0.0")
diff --git a/src/symbol/symbol_table.cpp b/src/symbol/symbol_table.cpp
index 26dea7e..56a2ca3 100644
--- a/src/symbol/symbol_table.cpp
+++ b/src/symbol/symbol_table.cpp
@@ -24,6 +24,7 @@
 #include "extensions.h"
 #include <overload>
 #include <stdexcept>
+#include <algorithm>
 
 namespace expr {
     auto symbol_table_t::operator+=(const symbol_table_t &other) -> symbol_table_t& {