Artificial AST

[sls1005]

What will happen if the AST generated by a macro is obviously artificial or 
unnatural (that will never come from the code parser)?

For example,
    
    
    Infix
      Ident "*"
      Infix
        Ident "+"
        IntLit 1
        IntLit 2
      IntLit 3
    
    
    Run

Is it still vaild?