fix: accept tests on stable

tests-build/tests/fail/macros_type_mismatch.stderr

@@ -1,19 +1,19 @@
 error[E0308]: mismatched types
- --> tests/fail/macros_type_mismatch.rs:5:5
+ --> $DIR/macros_type_mismatch.rs:5:5
   |
 5 |     Ok(())
   |     ^^^^^^- help: consider using a semicolon here: `;`
   |     |
-  |     expected `()`, found `Result<(), _>`
+  |     expected `()`, found enum `Result`
   |
   = note: expected unit type `()`
                   found enum `Result<(), _>`
 
 error[E0308]: mismatched types
- --> tests/fail/macros_type_mismatch.rs:8:1
+ --> $DIR/macros_type_mismatch.rs:8:1
   |
 8 | #[tokio::main]
-  | ^^^^^^^^^^^^^^ expected `()`, found `Result<(), _>`
+  | ^^^^^^^^^^^^^^ expected `()`, found enum `Result`
 9 | async fn missing_return_type() {
   |                                - help: a return type might be missing here: `-> _`
   |
@@ -22,10 +22,10 @@ error[E0308]: mismatched types
   = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0308]: mismatched types
-  --> tests/fail/macros_type_mismatch.rs:14:31
+  --> $DIR/macros_type_mismatch.rs:14:31
    |
 14 | async fn extra_semicolon() -> Result<(), ()> {
-   |          ---------------      ^^^^^^^^^^^^^^ expected `Result<(), ()>`, found `()`
+   |          ---------------      ^^^^^^^^^^^^^^ expected enum `Result`, found `()`
    |          |
    |          implicitly returns `()` as its body has no tail or `return` expression
 ...
@@ -36,7 +36,7 @@ error[E0308]: mismatched types
            found unit type `()`
 
 error[E0308]: mismatched types
-  --> tests/fail/macros_type_mismatch.rs:29:1
+  --> $DIR/macros_type_mismatch.rs:29:1
    |
 29 | #[tokio::main]
    | ^^^^^^^^^^^^^^ expected `()`, found integer