Fix EnumCount with disabled variants (#268)

Do not include disabled variants in the count with EnumCount. Fixes #267

strum_macros/src/macros/enum_count.rs

@@ -2,11 +2,18 @@ use proc_macro2::TokenStream;
 use quote::quote;
 use syn::{Data, DeriveInput};
 
+use crate::helpers::variant_props::HasStrumVariantProperties;
 use crate::helpers::{non_enum_error, HasTypeProperties};
 
 pub(crate) fn enum_count_inner(ast: &DeriveInput) -> syn::Result<TokenStream> {
     let n = match &ast.data {
-        Data::Enum(v) => v.variants.len(),
+        Data::Enum(v) => v.variants.iter().try_fold(0usize, |acc, v| {
+            if v.get_variant_properties()?.disabled.is_none() {
+                Ok::<usize, syn::Error>(acc + 1usize)
+            } else {
+                Ok::<usize, syn::Error>(acc)
+            }
+        })?,
         _ => return Err(non_enum_error()),
     };
     let type_properties = ast.get_type_properties()?;

strum_tests/tests/enum_count.rs

@@ -11,12 +11,29 @@ enum Week {
     Saturday,
 }
 
+#[allow(dead_code)]
+#[derive(Debug, EnumCount, EnumIter)]
+enum Pets {
+    Dog,
+    Cat,
+    Fish,
+    Bird,
+    #[strum(disabled)]
+    Hamster,
+}
+
 #[test]
 fn simple_test() {
     assert_eq!(7, Week::COUNT);
     assert_eq!(Week::iter().count(), Week::COUNT);
 }
 
+#[test]
+fn disabled_test() {
+    assert_eq!(4, Pets::COUNT);
+    assert_eq!(Pets::iter().count(), Pets::COUNT);
+}
+
 #[test]
 fn crate_module_path_test() {
     pub mod nested {