An unmanaged constraint check causes a stack overflow in an error scenario

[AlekseyTs]

The following unit-test is fails due to a stack overflow:

        [Fact]
        public void UnmanagedExpandingTypeArgumentConstraintViolation_06()
        {
            var code = @"
public struct MyStruct<T>
{
    public string s;
    public event YourStruct<MyStruct<MyStruct<T>>> field;
}

public struct YourStruct<T> where T : unmanaged
{
    public T field;
}
";
            var compilation = CreateCompilation(code, options: TestOptions.UnsafeReleaseDll);
            compilation.VerifyDiagnostics(
                    // (4,52): error CS0066: 'MyStruct<T>.field': event must be of a delegate type
                    //     public event YourStruct<MyStruct<MyStruct<T>>> field;
                    Diagnostic(ErrorCode.ERR_EventNotDelegate, "field").WithArguments("MyStruct<T>.field").WithLocation(4, 52),
                    // (5,46): error CS0523: Struct member 'MyStruct<T>.field' of type 'YourStruct<MyStruct<MyStruct<T>>>' causes a cycle in the struct layout
                    //     public YourStruct<MyStruct<MyStruct<T>>> field;
                    Diagnostic(ErrorCode.ERR_StructLayoutCycle, "field").WithArguments("MyStruct<T>.field", "YourStruct<MyStruct<MyStruct<T>>>").WithLocation(5, 46),
                    // (5,46): error CS8377: The type 'MyStruct<MyStruct<T>>' must be a non-nullable value type, along with all fields at any level of nesting, in order to use it as parameter 'T' in the generic type or method 'YourStruct<T>'
                    //     public YourStruct<MyStruct<MyStruct<T>>> field;
                    Diagnostic(ErrorCode.ERR_UnmanagedConstraintNotSatisfied, "field").WithArguments("YourStruct<T>", "T", "MyStruct<MyStruct<T>>").WithLocation(5, 46));

            Assert.True(compilation.GetMember<NamedTypeSymbol>("MyStruct").IsManagedTypeNoUseSiteDiagnostics);
            Assert.False(compilation.GetMember<NamedTypeSymbol>("YourStruct").IsManagedTypeNoUseSiteDiagnostics);
        }