diff --git a/include/daScript/ast/ast.h b/include/daScript/ast/ast.h
index 529969629b..fe6c1e016d 100644
--- a/include/daScript/ast/ast.h
+++ b/include/daScript/ast/ast.h
@@ -1151,7 +1151,7 @@ namespace das
             if ( objModule->visibleEverywhere ) return true;
             return requireModule.find(objModule) != requireModule.end();
         }
-        bool compileBuiltinModule ( const string & name, unsigned char * str, unsigned int str_len );//will replace last symbol to 0
+        bool compileBuiltinModule ( const string & name, const unsigned char * const str, unsigned int str_len );//will replace last symbol to 0
         static Module * require ( const string & name );
         static Module * requireEx ( const string & name, bool allowPromoted );
         static void Initialize();
diff --git a/src/ast/ast_module.cpp b/src/ast/ast_module.cpp
index 1d78ea311e..a1a2de5e01 100644
--- a/src/ast/ast_module.cpp
+++ b/src/ast/ast_module.cpp
@@ -571,7 +571,7 @@ namespace das {
         return it != callThis.end() ? &it->second : nullptr;
     }
 
-    bool Module::compileBuiltinModule ( const string & modName, unsigned char * str, unsigned int str_len ) {
+    bool Module::compileBuiltinModule ( const string & modName, const unsigned char * const str, unsigned int str_len ) {
         TextWriter issues;
         auto access = make_smart<FileAccess>();
         auto fileInfo = make_unique<TextFileInfo>((char *) str, uint32_t(str_len), false);