• rbscott (27/27) Dec 03 2019 Hello,
• mipri (12/24) Dec 03 2019 Unit tests are special functions, and their contents have
• MoonlightSentinel (3/9) Dec 03 2019 Not a forward reference error, local symbols are excluded from
• rbscott (10/21) Dec 04 2019 I see, thanks for the explanation about unittests being a special

rbscott <tjonsies818 yahoo.com> writes:

Hello,

I was using a unittest to test a mixin that creates a class 
inside of a struct and I ran into an unexpected error. I removed 
all of the templates and simplified it down to this case:

unittest {
   static struct SimpleStruct {
     static class NestedClass {
       private SimpleStruct value;
     }
   }
}

For some reason this generates a forward reference error, but if 
I take the exact same code and declare it outside of a unittest 
it goes away. If it runs in a version block instead of a unittest 
block it also works? I think declaring structs is OK in 
unittests? I tested this with:

unittest {
   static struct SimpleStruct {
     static class NestedClass {
       private int value;
     }
   }
}

And this works fine. Any ideas about why this doesn't work in a 
unittest?

Thanks!
rbscott

mipri <mipri minimaltype.com> writes:

On Tuesday, 3 December 2019 at 08:48:47 UTC, rbscott wrote:
 Hello,

 I was using a unittest to test a mixin that creates a class 
 inside of a struct and I ran into an unexpected error. I 
 removed all of the templates and simplified it down to this 
 case:

 unittest {
   static struct SimpleStruct {
     static class NestedClass {
       private SimpleStruct value;
     }
   }
 }

Unit tests are special functions, and their contents have
the same restrictions of functions, which seem to include
a ban on forward references (there's a reference in a comment
in https://dlang.org/spec/function.html#nested but I don't
have a better citation).

Likewise this fails, but would succeed if foo were moved
out of the unit test:

unittest {
     void foo(int x) { writeln(x); }

     42.foo;
}

MoonlightSentinel <moonlightsentinel disroot.org> writes:

On Tuesday, 3 December 2019 at 10:30:34 UTC, mipri wrote:

 Likewise this fails, but would succeed if foo were moved
 out of the unit test:

 unittest {
     void foo(int x) { writeln(x); }

     42.foo;
 }

Not a forward reference error, local symbols are excluded from 
UFCS (see https://dlang.org/spec/function.html#pseudo-member)

rbscott <tjonsies818 yahoo.com> writes:

On Tuesday, 3 December 2019 at 11:31:40 UTC, MoonlightSentinel 
wrote:
 On Tuesday, 3 December 2019 at 10:30:34 UTC, mipri wrote:

 Likewise this fails, but would succeed if foo were moved
 out of the unit test:

 unittest {
     void foo(int x) { writeln(x); }

     42.foo;
 }

 Not a forward reference error, local symbols are excluded from 
 UFCS (see https://dlang.org/spec/function.html#pseudo-member)

I see, thanks for the explanation about unittests being a special 
case of functions. That is really helpful context and makes sense 
since functions should evaluate sequentially. A little surprised 
the same restrictions apply to a static struct declared inside of 
the unittest, but that is easy to work around by moving the 
declarations to the version section.

cheers,
rbscott