Error: @nogc function run cannot call non-@nogc destructor TcpServer.~this

[Newbie2019 via Digitalmars-d-learn]

this is very hard to made a minimal example, and the projects 
only build with ldc.

There is a struct TcpServer has no destructor, and all method is 
@nogc nothrow.

but some how when I use it on function run @nogc nothrow, ldc 
report : @nogc function run cannot call non-@nogc destructor 
TcpServer.~this


this problem only exists for this TcpServer struct, all other 
struct without ~this() is ok.

And the code run fun before we add copyConstructor, but this one 
has no copyConstructor.