````
import std.stdio;
import std.traits;

void foo(int b);
void foo(int a);

void foo(int a) {
    writeln(a);
}

pragma(msg, ParameterIdentifierTuple!foo); // prints "b"

void main() {
 	foo(5);
}
```

Ambigious parameter names should trigger an error, as per spec they _are_ part of the public API.
Also if you imagine foo beeing declared in two seperate modules i suspect import oder would change the behaviour of ParameterIdentifierTuple.
If D gets named parameters this will probably also matter.