ref and auto ref variable breaks escape analysis within typeof

[Bolpat]

void main()
{
    int x;

    ref typeof(x) r0 = x; // good
    auto ref typeof(x) r1 = 0; // good

    typeof(function{ return 0; }()) v0 = x; // good
    typeof(function{ return 0; }()) v1 = 0; // good

    ref typeof(function{ return 0; }()) r2 = x;
    // Error: cannot `ref` return constant `0`
    // Error: type `int` cannot be assigned to `ref _error_ r2`
    
    auto ref typeof(function{ return 0; }()) r3 = x;
    // Error: cannot `ref` return constant `0`

    auto ref typeof(function{ return 0; }()) r4 = 0;
    // Error: cannot `ref` return constant `0`


    typeof(function ref{ return x; }) fp0; // infers `ref int function() pure nothrow @nogc @safe` (`ref` needed)
    /*auto*/ ref typeof(function{ return x; }) fp = fp0; // Note: no `ref` after `function`
    static assert(__traits(isRef, fp)); // `fp` is a reference variable: as intended
    static assert(is(typeof(&fp()))); // `fp` returns by reference: makes no sense
    // With`auto ref` instead of `ref`: No change in behavior
}

It seems the presence of ref or auto ref on the variable makes the function literal within typeof have a ref return. If within the literal, return 0; is replaced by returning a local variable,