ban varargs

Author: workingjubilee

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -471,6 +471,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             replace: fn_ptr,
                         });
                     }
+                    // generics? in C variadic? naaah
+                    ty::Adt(_def, gen_args) if gen_args.len() > 0 => {
+                        bug!("what the ferris are you doing")
+                    }
                     _ => {}
                 }
             }