Method alias

lib/checkunusedvar.cpp:190–230

* Alias the 2 given variables. Either replace the existing aliases if * they exist or merge them. You would replace an existing alias when this * assignment is in the same scope as the previous assignment. You might * merge the aliases when this assignment is in a different scope from the * previous assignment depending on the relationship of the 2 scopes. */

 * previous assignment depending on the relationship of the 2 scopes.
 */
void Variables::alias(nonneg int varid1, nonneg int varid2, bool replace)
{
    VariableUsage *var1 = find(varid1);
    VariableUsage *var2 = find(varid2);

    if (!var1 || !var2)
        return;

    // alias to self
    if (varid1 == varid2) {
        var1->use();
        return;
    }

    if (replace) {
        // remove var1 from all aliases
        for (auto i = var1->_aliases.cbegin(); i != var1->_aliases.cend(); ++i) {
            VariableUsage *temp = find(*i);

            if (temp)
                temp->_aliases.erase(var1->_var->declarationId());
        }

        // remove all aliases from var1
        var1->_aliases.clear();
    }

    // var1 gets all var2s aliases
    for (auto i = var2->_aliases.cbegin(); i != var2->_aliases.cend(); ++i) {
        if (*i != varid1)
            var1->_aliases.insert(*i);
    }

    // var2 is an alias of var1
    var2->_aliases.insert(varid1);
    var1->_aliases.insert(varid2);

    if (var2->mType == Variables::pointer) {
        var2->_read = true;
    }
}

void Variables::clearAliases(nonneg int varid)
{