Test case:

---
void main()
{
    import std.traits: ParameterDefaults;
    
    struct S
    {
        this(ref S) {}
    }
    
    pragma(msg, ParameterDefaults!(S.__ctor));
}
---

2.068.2 to 2.085.1: Success with output: (void)
Since      2.086.0: Failure with output:
-----
/path/to/dmd.linux/dmd2/linux/bin64/../../src/phobos/std/traits.d-mixin-1489(1497): Error: cannot access frame pointer of `onlineapp.main.S`
/path/to/dmd.linux/dmd2/linux/bin64/../../src/phobos/std/traits.d-mixin-1489(1500): Error: cannot access frame pointer of `onlineapp.main.S`
/path/to/dmd.linux/dmd2/linux/bin64/../../src/phobos/std/traits.d(1524): Error: template instance `std.traits.ParameterDefaults!(__ctor).Get!0LU` error instantiating
/path/to/dmd.linux/dmd2/linux/bin64/../../src/phobos/std/traits.d(1527):        instantiated from here: `Impl!0LU`
onlineapp.d(10):        instantiated from here: `ParameterDefaults!(__ctor)`
onlineapp.d(10):        while evaluating `pragma(msg, ParameterDefaults!(__ctor))`
-----