manual_let_else: Add test with expanded macros

Author: dswij

tests/ui/manual_let_else.rs

@@ -234,4 +234,18 @@ fn not_fire() {
     // If a type annotation is present, don't lint as
     // expressing the type might be too hard
     let v: () = if let Some(v_some) = g() { v_some } else { panic!() };
+
+    // Issue 9940
+    // Suggestion should not expand macros
+    macro_rules! macro_call {
+        () => {
+            return ()
+        };
+    }
+
+    let ff = Some(1);
+    let _ = match ff {
+        Some(value) => value,
+        _ => macro_call!(),
+    };
 }

tests/ui/manual_let_else.stderr

@@ -259,5 +259,14 @@ LL |     create_binding_if_some!(w, g());
    |
    = note: this error originates in the macro `create_binding_if_some` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 17 previous errors
+error: this could be rewritten as `let...else`
+  --> $DIR/manual_let_else.rs:247:5
+   |
+LL | /     let _ = match ff {
+LL | |         Some(value) => value,
+LL | |         _ => macro_call!(),
+LL | |     };
+   | |______^ help: consider writing: `let Some(value) = ff else { macro_call!() };`
+
+error: aborting due to 18 previous errors