Define the property function in the original scope.

This is to support adding regression test in the same scope calling the property function.

PiperOrigin-RevId: 982093389

rust/fuzztest_macro/src/lib.rs

diff --git a/rust/fuzztest_macro/src/lib.rs b/rust/fuzztest_macro/src/lib.rs
index 12f164e..d51935a 100644
--- a/rust/fuzztest_macro/src/lib.rs
+++ b/rust/fuzztest_macro/src/lib.rs
@@ -64,7 +64,7 @@
 pub fn fuzztest(args: TokenStream, input: TokenStream) -> TokenStream {
     let item = parse_macro_input!(input as Item);
 
-    let syn::Item::Fn(mut test_fn) = item else {
+    let syn::Item::Fn(test_fn) = item else {
         return syn::Error::new_spanned(item, "not a function").into_compile_error().into();
     };
 
@@ -102,18 +102,21 @@
         Err(e) => return e.into_compile_error().into(),
     };
 
-    test_fn.sig.ident = fuzztest_registration_context.prop_fn_ident().clone();
+    let prop_fn_ident = fuzztest_registration_context.prop_fn_ident().clone();
 
     let fuzztest_mod_name = quote::format_ident!("__fuzztest_mod__{}", original_ident);
 
     // TODO(mathuxny-73): Extract the current module path from the invocation of the macro
     //   (ie: from `item.attrs`)
     let tokens = quote! {
+
+        #test_fn
+
         #[allow(non_snake_case)]
         mod #fuzztest_mod_name {
             use super::*;
 
-            #test_fn
+            use super::#original_ident as #prop_fn_ident;
 
             #fuzztest_object_tokenstream
 

rust/tests/macro_compiles.rs

diff --git a/rust/tests/macro_compiles.rs b/rust/tests/macro_compiles.rs
index 5eee104..04c245e 100644
--- a/rust/tests/macro_compiles.rs
+++ b/rust/tests/macro_compiles.rs
@@ -26,4 +26,8 @@
 #[fuzztest(_a = VecOf::new(Arbitrary::<i32>::default()).with_max_len(10))]
 fn fuzztest_macro_compiles_with_vec(_a: Vec<i32>) {}
 
-fn main() {}
+fn main() {
+    // The property function is defined in the scope where the macro is
+    // invoked, so it can be called directly, e.g. from a regression test.
+    fuzztest_macro_compiles(0);
+}