🚀 go-pugleaf

In article <4ja3rl$pa9@solutions.solon.com> jcoffin@rmii.com (Jerry Coffin) writes:
>
>This is also a constraint violation, so a conforming implementation must 
>"issue a diagnostic" which is generally taken to mean an error message rather 
>than a warning.  Warnings can (and generally are) given for code that's legal 
>but may do unintended things, where errors are given for code that's actually 
>illegal.  

Actually, not all compilers follow the above.  Ours have several levels
of diagnostics.

Fatal_errors:  The code is illegal, and so badly screwed up that
       the compiler abandons further source analysis.
Errors: The compiler detected something illegal and will not continue
        other passes.  No usable object deck (loader input) will
        be produced.  The compiler does try to analyse for other
        errors.
Warning: The code is illegal, but the compiler thinks it can generate
        code to do what the programmer wanted.  (The duplicate
        qualifier probably gets this.)  A usable object deck is
        produced.

There are also some other diagnostics for legal but questionable
constructs.  (E.g. variables declared but not used) These get
"notes" and "unusual" type headers.