Using `with()` on a struct that contains alias this only works within a single module.

[realhet]

Hi,

I developed a DB transaction class. It's a nested class, have 
some methods.
Later I decided to use it from with(){} blocks, so I wrapped it 
inside a struct and exposed its fields using `alias this = ...;`.
It worked fine up until I moved the testing into another module. 
 From that point, the with() was unable see the effect of `alias 
this=...`.

I've fixed it by delegating all the methods from  the Transaction 
class to the Wrapper struct. It is not nice, and redundant.

Is there a better way to do it?

I really need that scope wrapper struct, so the transaction 
object will be closed exactly when the CPU exits from the with() 
block.

```d
static struct ScopedTransaction
{
	private Transaction transaction_;
	@property Transaction transaction() => transaction_;
	
	/+
		//alias this = transaction_;
		This FAILS when using with() in another module.
	+/
	@property active() => transaction.active;
	void enforceActive() { transaction.enforceActive; }
	void commit() { transaction.commit; }
	void rollback() { transaction.rollback; }
	scope execute(Args...)(Args args) => 
transaction.execute!(Args)(args);
	scope 查(Args...)(LOCATION_t loc, Args args) => 
transaction.查!(Args)(loc, args);
	
	@disable this(this);
	this(Transaction transaction)
	{ transaction_ = transaction; }
	
	~this()
	{ freeTransaction(transaction_); }
}

scope transaction(bool modify = false)
=> ScopedTransaction(startTransaction(modify: modify));

```