[Issue 20684] New: "Error: unknown" with some bad nested struct/template declarations

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20684

          Issue ID: 20684
           Summary: "Error: unknown" with some bad nested struct/template
                    declarations
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: ice
          Severity: normal
          Priority: P4
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: dlang-bugzilla at thecybershadow.net

/////////////// test.d ///////////////
struct RD
{
    struct BB
    {
        R!RD r;
    }

    Undeclared undeclared;

    struct VV
    {
        vector!int v;
    }

    struct VVV
    {
        vector!VV vv;
    }
}

struct R(T)
{
    static if (is(typeof(*p = *p)))
    {
    }

    T* p;
}


struct vector(T)
{
    Array!T array;
}

struct Array(T)
{
    struct Payload
    {
        T[] _payload;
    }

    ~this()
    {
        foreach (e; _data._payload) {}
    }

    Payload _data;

    this()()
    {
    }
}
//////////////////////////////////////

Compiler says:

$ dmd test.d 
Error: unknown, please file report on issues.dlang.org
test.d(17): Error: template instance test.vector!(VV) error instantiating

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