What does the compiler generated opAssign for a struct look like?
Let's say I have a struct, which has at least one
this(int some_a, int some_b)
a = some_a;
b = some_b;
const int b;
If I then try to assign to it, the compiler complains that struct instances with const members cannot be be modified.
auto s = S(1, 2);
s = S(3, 4);
Full example here: https://run.dlang.io/is/ssT12m
This makes sense to me if I understand the compiler to be generating a member-by-member assignment operator like in C++, but the description in Programming in D states that in D (Assignment Operator section here) the compiler generated function will create a temporary copy of the right-hand-side, and then replace the left-hand-side with that temporary copy. To me that description implies that const members should be ok when it comes to assigning to the entire object.
In my specific encounter with this scenario, I'm dealing with
core.stdcpp.string_view so I can't modify the definition to remove the const member. Also with an old version of ldc I have on my linux machine this seems to work, though I'm not able to replicate that with the "all dmd versions" option on run.dlang.io (where they all fail to compile).