I feel like i need to fully re-learn and familiarize myself with
D now.

  This is an interesting error I'm coming across, it's not
pointing to anything in particular. I've used the -v verbose flag
and it seems to appear each time after a struct declaration.

code      subrecord
function  smartmerged.subrecord.Changes.__xopEquals
Error: type FlagStates is not an expression
Error: type FlagStates is not an expression

The struct is as follows:

   struct Changes {
     string fileFrom;  ///
     Flags state;      ///previous state, be it master/plugin, or
whatever
     ROMBuffer oldData;///the data in question
   }

aliases referenced from Changes:
   alias immutable(ubyte)[] ROMBuffer;
   alias HandleFlags!(FlagStates, int) Flags;

   enum FlagStates {
     def = 0x0,
     changed   = 1,
     readOnly  = 1 << 1,
     isOriginal= 1 << 2,
     invisible = 1 << 3,
     //other states, truncated for example
   }


   struct HandleFlags(E, I)
     if (is(E == enum) && isIntegral!(I) && isFloatingPoint!(I) ==
false) {
       // Yeah a lot of stuff in here.. binary flag handling
       // in my GitHub somewhere.
   }

  From what I can see, the default opEquals is breaking as it's
doing something. This used to compile and has needed some tweaks.
I'll see if I can compile enough to duplicate this simply.

  k here's the condensed test file. Seems related to an 'alias
this', in theory the HandleFlags bit/flag handling you should be
able to say 'state.def' and it would be the same as
'FlagStates.def' without actually having to name it.

[code]

import std.traits;

///
struct HandleFlags(E, I)
if (is(E == enum) && isIntegral!(I) && isFloatingPoint!(I) ==
false) {
   I state;	///Holds state.
   alias E Enum;
   alias Enum this;    //seems to be root cause of the problem...
}

enum FlagStates {def}

struct Changes {
   string fileFrom;    //goes away if commented out...?
   HandleFlags!(FlagStates, int) state;
}

[/code]

On Mon, Sep 02, 2013 at 06:21:18AM +0200, Era Scarecrow wrote:
>   k here's the condensed test file. Seems related to an 'alias
> this', in theory the HandleFlags bit/flag handling you should be
> able to say 'state.def' and it would be the same as
> 'FlagStates.def' without actually having to name it.
> 
> [code]
> 
> import std.traits;
> 
> ///
> struct HandleFlags(E, I)
> if (is(E == enum) && isIntegral!(I) && isFloatingPoint!(I) ==
> false) {
>    I state;	///Holds state.
>    alias E Enum;
>    alias Enum this;    //seems to be root cause of the problem...

You can't alias a type to this. You need to instantiate it first, then alias the instance to this (because 'this' is an object, not a type). For example:

	struct S {}
	struct T {
		//alias S this;  // NG: S is a type
		S s;
		alias s this;	// OK: s is an instance of S
	}


T

-- 
Three out of two people have difficulties with fractions. -- Dirk Eddelbuettel

On Monday, 2 September 2013 at 04:49:46 UTC, H. S. Teoh wrote:
> You can't alias a type to this. You need to instantiate it first, then alias the instance to this (because 'this' is an object, not a type). For example:
>
> 	struct S {}
> 	struct T {
> 		//alias S this;  // NG: S is a type
> 		S s;
> 		alias s this;	// OK: s is an instance of S
> 	}

  Curiously the earlier version (v2.60?) Allowed this, but it was
an Enum (not a struct) that was being aliased. If memory serves
me right, you can alias a function as 'this' as well.

 (Dern I'm tripping the spam filter.... a lot...)