Re: PR28943 Unusable error message when using a conditional-expression with multiple type arguments

["Manuel López-Ibáñez" <lopezibanez at gmail dot com>]

On 31 Jan 2007 04:15:12 -0600, Gabriel Dos Reis <gdr@cs.tamu.edu> wrote:
> "Manuel López-Ibáñez" <lopezibanez@gmail.com> writes:
>
> | :ADDPATCH c++:
> |
> | The error message for this code:
> |
> | void debug (const char * string)
> | {
> |   return;
> | }
> |
> | int f()
> | {
> |   ( true == false ? 0 : debug ("Some string"));
> |   return 0;
> | }
> |
> | is:
> |
> | error: debug(((const char*)"Some string")) has type void and is not a
> | throw-expression
> |
> | The following patch changes the message to:
> |
> | error: 'debug(((const char*)"Some string"))' of type 'void' is
> | incompatible with '0' of type 'int'
>
> "incompatible" tends to have a precise meaning, especially when types
> are involded.
>
> The rule is: if one the operand is of type void, then the other
> operand must be of type void or a throw expression -- but both cannot
> be a throw-expression.
>
>
>
> I would prefer the "improved" diagnostic to say something like
>
>    third operand to the conditional operator is of type 'void', but
>    the second operand is neither a throw-expression nor of type 'void'
>
> and swap second/third the other around to cover the symmetric case.

Don't you think it is helpful to mention the type of the second
operand or either of the operands? Just asking, I quite like the
message but I think it could be more informative. Although showing the
operands may take a lot of space for some expressions.

Let me know your opinion and I will implement that.

Cheers,

Manuel.