DMD Regression as of version 2.084, ever since version 2.075.0

To reproduce the bug: $ dmd -c foo.d thud.d(4): Error: function void thud.Dap!int.Dap.thunk() does not override any function, did you mean to override void foo.Foo.thunk()? thud.d(7): Error: template instance thud.Dap!int error instantiating

Works with version 2.074.1 .