Mixin/static if issue

[DLearner via Digitalmars-d-learn]

Please see below:
```
void main() {
   import std.stdio;

   uint TestVar = 5;

   string mxnWrite_Size_t(string VarName) {

      static if (typeof(VarName).stringof == "uint") {

         return `write("` ~ VarName ~ `");`;
      } else {

         return `writeln("Apparently TestVar not a uint");`;  
          }
   }

   mixin(mxnWrite_Size_t("TestVar"));
}
```
What I expected was the string "TestVar".
What I got was the "Apparently..." error message.
Please, why is this?