​

import core.stdc.stdio;

​

__gshared int gi = 0;

struct A; struct B;

​

struct Node {

    @disable this();

    @nogc nothrow:

    int i;

​

    this(int i) {

        this.i  = i;

    }

​

    this(ref Node o) {

        gi++;

        i = o.i;

    }

    ref auto getList() return scope {

        if( i ) return NodeList(null); // remove this line will fix this error

        A* a;

        B* b;

        auto list = NodeList(a, b);

        return list;

    }

}

​

struct NodeList {

    @nogc nothrow:    @disable this();    @disable this(this);

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    this(A* a, B* b) { }

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    this(A* a) { }

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    ref auto one() return {

        return node(1) ;

    }

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    private ref auto node(int i) return {

        return Node(i);

    }

}

​

​

extern(C) void main() @nogc nothrow {

    NodeList list = NodeList(null);

    auto one = list.one;

    printf("gi=%d\n", gi);

}

​