/// <summary>
/// Called when a <see cref="ReturnBlock"/> block is read.
/// Verifies the structure of the return and calls the corresponding functions that
/// handle the return expression.
/// Called by <see cref="INSTRUCTION"/>.
/// </summary>
void RETURN()
{
Expect(52); // "return"
SUPER_EXP();
try { QuadrupleManager.ReturnEnd(); }
catch (Exception e) { SemErr(e.Message); }
}