[Issue 19098] Improve error for non-assignable struct

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=19098

--- Comment #1 from RazvanN <razvan.nitu1...@gmail.com> ---
PR: https://github.com/dlang/dmd/pull/8506

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