nothrow and std.exception.ifThrown

[novice2]

Thank you Imperatron, Ali
both variants
```d
   scope(failure) assert(0);
```
```d
   collectException
```
works!

Thank Meta
> The reason for this, apparently, is in the definition of 
> `ifThrown`

i tried to modify ifThrown adding nothrow,
but compiler dont understand, that second parameter cant throw,
it just expression.

i dont understand why (templates too dificult for me yet),
but if i comment "lazy" from T2,
then compiler allow add "nothrow" to "ifThrown"

```d
CommonType!(T1, T2) ifThrown(E : Throwable = Exception, T1, 
T2)(lazy scope T1 expression, /*lazy*/ scope T2 errorHandler) 
nothrow
```
https://run.dlang.io/is/KTdd3G