On Tuesday, 31 May 2022 at 08:51:45 UTC, realhet wrote:
Hi,
In my framework I just found a dozen of compile time error
handling like:
...else static assert("Invalid type");
This compiles without error. And it was useless for detecting
errors because I forgot the first "false" or "0" parameter.
I think it is because of the weird case of "every string casted
to bool is true".
There is an example in Phobos also:
https://github.com/dlang/phobos/blob/master/std/uni/package.d
at line 8847: static assert("Unknown normalization form "~norm);
It is easy to make this mistake, but does static assert(string)
has any meaningful use cases?
I was going to suggest to do something like:
```d
import std;
string compileError(string msg) {
import std.format;
return format("static assert(0,%(%s%));",[msg]);
}
auto doGreatThings(T)(T x)
{
static if(is(T==int))
{
return "great things!";
}
else mixin(compileError("Invalid type."));
}
void main()
{
doGreatThings!int(123).writeln;
doGreatThings!string("oh dear").writeln;
}
```
But (a) why should you need to and (b) this makes the message
more obscure.
onlineapp.d-mixin-14(14): Error: static assert: "Invalid type."
onlineapp.d(20): instantiated from here:
`doGreatThings!string`
