Bug 17733 – idup fails for structs/classes with member functions

Test case: void main() { struct S { void f() {} } [S()].idup; } Also, compilation fails only if struct is defined in same scope idup is called, so this code works just fine: struct S { void f() {} } void main() { [S()].idup; } I've tested it with latest dmd, gdc and ldc

This is because in the first case, S has a hidden context pointer to the stack frame of main(). If you mark it as a static struct, you will not have this problem. Note that the ultimate reason it fails is because any items that have indirections cannot be implicitly converted to immutable.