Consider for Constructor

impl/src/constructor.rs

@@ -26,6 +26,7 @@ pub fn expand(input: &DeriveInput, _: &str) -> TokenStream {
     let original_types = &get_field_types(&fields);
     quote! {
         #[allow(missing_docs)]
+        #[allow(unreachable_code)] // omit warnings for `!` and other unreachable types
         #[automatically_derived]
         impl #impl_generics #input_type #ty_generics #where_clause {
             #[inline]

tests/constructor.rs

@@ -1,4 +1,5 @@
 #![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(nightly, feature(never_type))]
 #![allow(dead_code)] // some code is tested for type checking only
 
 use derive_more::Constructor;
@@ -30,3 +31,21 @@ struct Point2D {
 }
 
 const POINT_2D: Point2D = Point2D::new(-4, 7);
+
+#[cfg(nightly)]
+mod never {
+    use super::*;
+
+    #[derive(Constructor)]
+    struct Tuple(!);
+
+    #[derive(Constructor)]
+    struct Struct { field: ! }
+
+    #[derive(Constructor)]
+    struct TupleMulti(i32, !);
+
+    #[derive(Constructor)]
+    struct StructMulti { field: !, other: i32 }
+}
+