https://issues.dlang.org/show_bug.cgi?id=20076
Simen Kjaeraas <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #2 from Simen Kjaeraas <[email protected]> --- Reduced example: struct S { int* ip; this(int* t1) { } alias ip this; } unittest { const S t3; // constructor S.this(int* t1) is not callable using argument types (const(int*)) S t4 = t3; } As you say, it has to do with the use of classes (or in the above example, pointers): const(T*) simply cannot be implicitly converted to T* without an explicit cast - and it shouldn't. In addition, you have a constructor that looks somewhat like the type of the alias this, so DMD tries that when a direct conversion fails. Removing the alias this in the above code results in the message 'cannot implicitly convert expression t3 of type const(S) to S', which may be more elucidating. It seems to me the correct behavior would be for DMD to print both error messages, probably with a hint that alias this is involved in one of the cases. In a way, alias this is like an overload, and the error messages should reflect this. --
