[Issue 18216] New: struct no size because of forward reference

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18216

          Issue ID: 18216
           Summary: struct no size because of forward reference
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: blocker
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: changlon at gmail.com

==================
struct Node {
        mixin Type!() ;
        Pointer left;
}

mixin template Type() {
        alias Base      = typeof(this) ;

        static struct Proxy {
                struct Node {
                        Base m_payload ;
                }
                static immutable default_value = Base.init ; // just remove
this will work
        }

        alias pNode     = shared(Proxy.Node)* ;

        static struct Pointer {
                Base*   _ptr ;
                auto ptr() {
                        return cast(pNode) _ptr ;
                }

                void opAssign(ref Pointer other) {} // just remove this will
work

                alias getThis this; // just remove this will work
                ref auto getThis() return {
                        return ptr.m_payload;
                }
        }
}
===============================
Error: struct test.Node no size because of forward reference
test.d(28): Error: function type 'pure nothrow @nogc return @safe _error_()'
has 'return' but does not return any indirections
test.d(3): Error: mixin test.Node.Type!() error instantiating



If I remove "void opAssign(ref Pointer other)", or "static immutable
default_value = Base.init", or "alias getThis this" (just remove any one of the
three), the code will working.

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