Pinq\Analysis\ExpressionAnalyser::visitVariable PHP Method

    public function visitVariable(O\VariableExpression $expression)
    {
        $nameExpression = $expression->getName();
        $this->walk($nameExpression);
        $type = $this->analysisContext->getExpressionType($expression);
        if ($type === null) {
            throw new TypeException('Invalid variable expression: \'%s\' type is unknown', $nameExpression->compileDebug());
        }
        $this->analysis[$expression] = $type;
    }