macros: fix span of body variable (#5244)

tokio-macros/src/entry.rs

@@ -383,14 +383,15 @@ fn parse_knobs(mut input: syn::ItemFn, is_test: bool, config: FinalConfig) -> To
 
     let body = &input.block;
     let brace_token = input.block.brace_token;
+    let body_ident = quote! { body };
     let block_expr = quote_spanned! {last_stmt_end_span=>
         #[allow(clippy::expect_used, clippy::diverging_sub_expression)]
         {
             return #rt
                 .enable_all()
                 .build()
                 .expect("Failed building the Runtime")
-                .block_on(body);
+                .block_on(#body_ident);
         }
     };
 
@@ -479,7 +480,7 @@ pub(crate) fn test(args: TokenStream, item: TokenStream, rt_multi_thread: bool)
     };
     let config = if let Some(attr) = input.attrs.iter().find(|attr| attr.path.is_ident("test")) {
         let msg = "second test attribute is supplied";
-        Err(syn::Error::new_spanned(&attr, msg))
+        Err(syn::Error::new_spanned(attr, msg))
     } else {
         AttributeArgs::parse_terminated
             .parse(args)

tokio/tests/macros_test.rs

@@ -71,3 +71,18 @@ pub mod clippy_semicolon_if_nothing_returned {
         // To trigger clippy::semicolon_if_nothing_returned lint, the block needs to contain newline.
     }
 }
+
+// https://github.com/tokio-rs/tokio/issues/5243
+pub mod issue_5243 {
+    macro_rules! mac {
+        (async fn $name:ident() $b:block) => {
+            #[::tokio::test]
+            async fn $name() {
+                $b
+            }
+        };
+    }
+    mac!(
+        async fn foo() {}
+    );
+}