Bug 7808 – Nullable's alias this does not work with structs containing classes

This code compiled just fine with 2.058 import std.typecons; void main() { auto s = Nullable!S(S(new C)); func(s); } class C { } struct S { C c; this(C c) { this.c = c; } } void func(S s) { } But it fails to compile with the latest dmd, giving the error q.d(6): Error: function q.func (S s) is not callable using argument types (Nullable!(S)) q.d(6): Error: cannot implicitly convert expression (s) of type Nullable!(S) to S It works if the member variable is an int or string. It works if the member variable is a struct type which does _not_ have a class as a member variable. But if the struct has a member variable which is a class, or it has a member variable which is a struct which has a member variable which is a class, then it fails. Nullable!S' alias this should convert it to an S when passed to func, but it doesn't when S contains a member variable which is a class - either directly or indirectly.

Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/b90543ea6d93aec7963004261e8fa749b0bdbf35 Merge pull request #857 from 9rnsr/fix7808 Issue 7808 - Nullable's alias this does not work with structs containing classes