Add test for the case span is unavailable

tests/ui/lint/static-mut-refs-interior-mutability-no-sugg.rs

@@ -0,0 +1,18 @@
+//@ edition:2024
+// Ensure that we don't make structured suggestions for interior mutability note
+// when span is not available.
+
+use std::sync::Mutex;
+
+macro_rules! declare_mutex {
+    () => {
+        static mut MACRO_MUTEX: Mutex<bool> = Mutex::new(false);
+    };
+}
+
+declare_mutex!();
+
+fn main() {
+    let _lock = unsafe { MACRO_MUTEX.lock().unwrap() };
+    //~^ ERROR creating a shared reference to mutable static [static_mut_refs]
+}

tests/ui/lint/static-mut-refs-interior-mutability-no-sugg.stderr

@@ -0,0 +1,13 @@
+error: creating a shared reference to mutable static
+  --> $DIR/static-mut-refs-interior-mutability-no-sugg.rs:16:26
+   |
+LL |     let _lock = unsafe { MACRO_MUTEX.lock().unwrap() };
+   |                          ^^^^^^^^^^^^^^^^^^ shared reference to mutable static
+   |
+   = note: shared references to mutable statics are dangerous; it's undefined behavior if the static is mutated or if a mutable reference is created for it while the shared reference lives
+   = help: use a type that relies on "interior mutability" instead; to read more on this, visit <https://doc.rust-lang.org/reference/interior-mutability.html>
+   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2024/static-mut-references.html>
+   = note: `#[deny(static_mut_refs)]` (part of `#[deny(rust_2024_compatibility)]`) on by default
+
+error: aborting due to 1 previous error
+