```d
auto bar(int i){
foo()
}
unittest{
bar(3);
}
```
Given any definition of foo, any compiler bugs, how would you
detect the `3` from `foo`?
___
My attempts at scanning the call stack didn't work but for anyone
attempting it, I believe this breakdown of control flow may be
part of the solution
```d
import std;
void bar(ubyte i){
(&i).writeln("arg");
//float f;
//bool b;
foo();
}
//---
//class badgoto:Throwable{
// this(string){}
// this(){}
//}
enum ubyte senty=117;
void foo(){
int[0] callstack;
static int call;
static void* start;
static void* start2;
static void* end;
static ubyte copy;
switch(call++){
case 0:
start=cast(void*)&callstack;
start2=cast(void*)&callstack;
try{bar(senty);}//1st
//catch(badgoto){}//3rd
catch(Error){}
copy=*cast(ubyte*)start2;
break;
case 1://2nd
end=cast(void*)&callstack;
start.writeln("start");
end.writeln("end");
while(start>end && *(cast(ubyte*)start)!=senty){
writeln(start,":",*(cast(ubyte*)start));
start--;
}
writeln(start,":",*(cast(ubyte*)start),"last");
"---".writeln;
start.writeln;
end.writeln;
start2=start2+(end-start);
start2.writeln;
throw new Error("");
break;
default:
copy.writeln;
}
}
unittest{
bar(3);
foo;
}
```
