On Wednesday, 31 March 2021 at 04:49:50 UTC, novice3 wrote:
On Tuesday, 30 March 2021 at 21:53:34 UTC, Basile B. wrote:
struct Typedef(TBase)
{
TBase payload;
alias payload this;
}
alias Xobj = Typedef!(void*);
This is how std.typecons.Typedef made, IMHO.
The problem is this code generate struct with name
"Typedef!(void*)",
then compiler show this name (not "Xobj") in messages:
https://run.dlang.io/is/eEI2yC
void* bad;
foo(bad);
Error: function foo(Typedef!(void*) obj) is not callable using
argument types (void*)
cannot pass argument bad of type void* to parameter
Typedef!(void*) obj
yeah template instances are identified using the parameters
identifiers, then the alias is just a syntactic shortcut to that,
not producing a new symbol with a unique mangle... but the
message is correct assuming you want void* to be rejected.
That being said you can still use a string mixin if the messages
have to be correct
---
string genTypeDef(TBase)(string name)
{
return "struct " ~ name ~ "{" ~ TBase.stringof ~ " payload;
alias payload this;}";
}
mixin(genTypeDef!(void*)("Xobj"));
void foo (Xobj obj) {}
---
