const map<string, VariableDeclaration *> &prev_vars = stage->previous->content.variables;
for(map<string, VariableDeclaration *>::const_iterator i=prev_vars.begin(); i!=prev_vars.end(); ++i)
{
const map<string, VariableDeclaration *> &prev_vars = stage->previous->content.variables;
for(map<string, VariableDeclaration *>::const_iterator i=prev_vars.begin(); i!=prev_vars.end(); ++i)
{