On Wednesday, 14 July 2021 at 03:06:06 UTC, someone wrote:
...
I've ran into this rarely. At a guess, it seems something
triggers the compiler to either evaluate something in non-lexical
order; doesn't realise it needs to error out at the static assert
instead of doing it later, or maybe it somehow ends up gagging
the more relevant static assert error.
The fix usually involves changing the code in a way to make the
compiler evaluate things differently.
For your example:
```d
import std.stdio;
struct MyType(T) {
template ResultTypeT()
{
static if (is (T == float)) {
alias ResultTypeT = double;
} else static if (is (T == double)) {
alias ResultTypeT = real;
} else {
static assert(false, T.stringof ~ " is not
supported");
}
}
alias ResultType = ResultTypeT!();
ResultType doWork() {
writefln("The return type for %s is %s.",
T.stringof, ResultType.stringof);
ResultType result;
// ...
return result;
}
}
void main() {
auto f = MyType!float();
f.doWork();
auto d = MyType!double();
d.doWork();
auto g = MyType!string();
g.doWork();
}
```
