Bug 21073 – Rebindable does not work when class has alias this to inout property

import std.typecons; class Internal { } class Class { inout(Internal) internal() inout { return _internal; } alias internal this; Internal _internal; } void main(string[] args) { const c = new Class; auto r = c.rebindable; } When compiling with dmd (2.093.0) it reports the error: /usr/include/dmd/phobos/std/typecons.d(2173): Error: pure function std.typecons.Rebindable!(const(Class)).Rebindable.RebindableCommon!(const(Class), Class, Rebindable!(const(Class))).opAssign cannot call impure delegate std.typecons.Rebindable!(const(Class)).Rebindable.RebindableCommon!(const(Class), Class, Rebindable!(const(Class))).opAssign.__lambda2 /usr/include/dmd/phobos/std/typecons.d(2173): Error: @nogc function std.typecons.Rebindable!(const(Class)).Rebindable.RebindableCommon!(const(Class), Class, Rebindable!(const(Class))).opAssign cannot call non-@nogc delegate std.typecons.Rebindable!(const(Class)).Rebindable.RebindableCommon!(const(Class), Class, Rebindable!(const(Class))).opAssign.__lambda2 main.d(20): Error: template instance std.typecons.rebindable!(const(Class)) error instantiating This code was compilable on dmd 2.083. Current workaround is to add 'pure' attribute to 'internal' method.

This is indeed a regression, but a compiler one, not a standard library one. Test case for the ultimate cause: ```d class C { auto internal() const { return 5; } alias internal this; }; void main() pure { const c = new C; auto r = cast(C)c; } ``` This should compile (I think?), but does not (since 2.084). Using `cast()` instead of `cast(C)` still works.

@BorisCarvajal created dlang/dmd pull request #13291 "Fix Issue 21073 - Rebindable does not work when class has alias this to inout property" fixing this issue: - Fix Issue 21073 - Rebindable does not work when class has alias this to inout property The cast expression was trying an 'alias this' but without error gagging. https://github.com/dlang/dmd/pull/13291

dlang/dmd pull request #13291 "Fix Issue 21073 - Rebindable does not work when class has alias this to inout property" was merged into stable: - a7ce6929f6708debfae3e3854bed5f1c02cdf1a0 by Boris Carvajal: Fix Issue 21073 - Rebindable does not work when class has alias this to inout property The cast expression was trying an 'alias this' but without error gagging. https://github.com/dlang/dmd/pull/13291

dlang/dmd pull request #13421 "merge stable" was merged into master: - 2367744d505cf739c90b926480e880a29a29b9e8 by Boris Carvajal: Fix Issue 21073 - Rebindable does not work when class has alias this to inout property (#13291) The cast expression was trying an 'alias this' but without error gagging. https://github.com/dlang/dmd/pull/13421