Add BitFlags::{EMPTY, ALL}

Author: meithecatte

enumflags_derive/src/lib.rs

@@ -233,6 +233,8 @@ fn gen_enumflags(ident: &Ident, item: &DeriveInput, data: &DataEnum)
             impl ::enumflags2::_internal::RawBitFlags for #ident {
                 type Type = #ty;
 
+                const EMPTY: Self::Type = 0;
+
                 const ALL_BITS: Self::Type =
                     0 #(| (#repeated_name::#variant_names as #ty))*;
 

src/lib.rs

@@ -167,6 +167,9 @@ pub mod _internal {
         /// The underlying integer type.
         type Type: BitFlagNum;
 
+        /// A value with no bits set.
+        const EMPTY: Self::Type;
+
         /// A value with all flag bits set.
         const ALL_BITS: Self::Type;
 
@@ -334,6 +337,18 @@ where
         unsafe { BitFlags::new(T::ALL_BITS) }
     }
 
+    /// An empty `BitFlags`. Equivalent to [`empty()`],
+    /// but works in a const context.
+    ///
+    /// [`empty()`]: #method.empty
+    pub const EMPTY: Self = BitFlags { val: T::EMPTY };
+
+    /// A `BitFlags` with all flags set. Equivalent to [`all()`],
+    /// but works in a const context.
+    ///
+    /// [`all()`]: #method.all
+    pub const ALL: Self = BitFlags { val: T::ALL_BITS };
+
     /// Returns true if all flags are set
     pub fn is_all(self) -> bool {
         self.val == T::ALL_BITS