Made it so an error occurs when an unsupported attribute is specified…

… for enum variants. (fix #12)

src/arbitrary.rs

@@ -105,12 +105,21 @@ fn expr_for_enum(input: &DeriveInput, data: &DataEnum, bounds: &mut Bounds) -> R
         let args: ArbitraryArgsForFieldOrVariant = parse_from_attrs(&variant.attrs, "arbitrary")?;
         let mut weight = None;
         for attr in &variant.attrs {
-            if attr.path().is_ident("weight") {
+            let Some(ident) = attr.path().get_ident() else {
+                continue;
+            };
+            if ident == "weight" {
                 if weight.is_some() {
                     bail!(attr.span(), "`#[weight]` can specify only once.");
                 }
                 weight = Some(attr.parse_args::<WeightArg>()?);
             }
+            if ident == "any" || ident == "strategy" || ident == "map" || ident == "by_ref" {
+                bail!(
+                    attr.span(),
+                    "`#[{ident}]` cannot be specified for a variant. Consider specifying it for a field instead."
+                );
+            }
         }
         let weight = if let Some(arg) = weight {
             if arg.is_zero() {

src/syn_utils.rs

@@ -20,14 +20,14 @@ use syn::{
 };
 
 macro_rules! bail {
-    ($span:expr, $message:literal $(,)?) => {
-        return std::result::Result::Err(syn::Error::new($span, $message))
+    (_, $($arg:tt)*) => {
+        bail!(::proc_macro2::Span::call_site(), $($arg)*)
     };
-    ($span:expr, $err:expr $(,)?) => {
-        return std::result::Result::Err(syn::Error::new($span, $err))
+    ($span:expr, $fmt:literal $(,)?) => {
+        return ::std::result::Result::Err(::syn::Error::new($span, ::std::format!($fmt)))
     };
-    ($span:expr, $fmt:expr, $($arg:tt)*) => {
-        return std::result::Result::Err(syn::Error::new($span, std::format!($fmt, $($arg)*)))
+    ($span:expr, $fmt:literal, $($arg:tt)*) => {
+        return ::std::result::Result::Err(::syn::Error::new($span, ::std::format!($fmt, $($arg)*)))
     };
 }
 

tests/compile_fail/variant_any_attr.rs

@@ -0,0 +1,8 @@
+use test_strategy::Arbitrary;
+#[derive(Arbitrary, Debug)]
+enum X {
+    #[any]
+    A,
+}
+
+fn main() {}

tests/compile_fail/variant_any_attr.stderr

@@ -0,0 +1,5 @@
+error: `#[any]` cannot be specified for a variant. Consider specifying it for a field instead.
+ --> tests/compile_fail/variant_any_attr.rs:4:5
+  |
+4 |     #[any]
+  |     ^

tests/compile_fail/variant_strategy_attr.rs

@@ -0,0 +1,8 @@
+use test_strategy::Arbitrary;
+#[derive(Arbitrary, Debug)]
+enum X {
+    #[strategy(0..10usize)]
+    A(usize),
+}
+
+fn main() {}

tests/compile_fail/variant_strategy_attr.stderr

@@ -0,0 +1,5 @@
+error: `#[strategy]` cannot be specified for a variant. Consider specifying it for a field instead.
+ --> tests/compile_fail/variant_strategy_attr.rs:4:5
+  |
+4 |     #[strategy(0..10usize)]
+  |     ^