Add test case for different impl Futures

Author: estebank

src/test/ui/suggestions/match-prev-arm-needing-semi.rs

@@ -15,6 +15,7 @@ fn extra_semicolon() {
 
 async fn async_dummy() {} //~ NOTE the `Output` of this `async fn`'s found opaque type
 async fn async_dummy2() {} //~ NOTE the `Output` of this `async fn`'s found opaque type
+//~^ NOTE the `Output` of this `async fn`'s found opaque type
 
 async fn async_extra_semicolon_same() {
     let _ = match true { //~ NOTE `match` arms have incompatible types
@@ -42,4 +43,14 @@ async fn async_extra_semicolon_different() {
     };
 }
 
+async fn async_different_futures() {
+    let _ = match true { //~ NOTE `match` arms have incompatible types
+        true => async_dummy(), //~ NOTE this is found to be
+        false => async_dummy2(), //~ ERROR `match` arms have incompatible types
+        //~^ NOTE expected opaque type, found a different opaque type
+        //~| NOTE expected type `impl Future`
+        //~| NOTE distinct uses of `impl Trait` result in different opaque types
+    };
+}
+
 fn main() {}

src/test/ui/suggestions/match-prev-arm-needing-semi.stderr

@@ -1,5 +1,5 @@
 error[E0308]: `match` arms have incompatible types
-  --> $DIR/match-prev-arm-needing-semi.rs:25:18
+  --> $DIR/match-prev-arm-needing-semi.rs:26:18
    |
 LL |   async fn async_dummy() {}
    |                          - the `Output` of this `async fn`'s found opaque type
@@ -30,7 +30,7 @@ LL |         false => async_dummy().await,
    |                               ^^^^^^
 
 error[E0308]: `match` arms have incompatible types
-  --> $DIR/match-prev-arm-needing-semi.rs:38:18
+  --> $DIR/match-prev-arm-needing-semi.rs:39:18
    |
 LL |   async fn async_dummy2() {}
    |                           - the `Output` of this `async fn`'s found opaque type
@@ -60,6 +60,28 @@ help: consider `await`ing on the `Future`
 LL |         false => async_dummy2().await,
    |                                ^^^^^^
 
+error[E0308]: `match` arms have incompatible types
+  --> $DIR/match-prev-arm-needing-semi.rs:49:18
+   |
+LL |   async fn async_dummy2() {}
+   |                           - the `Output` of this `async fn`'s found opaque type
+...
+LL |       let _ = match true {
+   |  _____________-
+LL | |         true => async_dummy(),
+   | |                 ------------- this is found to be of type `impl Future`
+LL | |         false => async_dummy2(),
+   | |                  ^^^^^^^^^^^^^^ expected opaque type, found a different opaque type
+LL | |
+LL | |
+LL | |
+LL | |     };
+   | |_____- `match` arms have incompatible types
+   |
+   = note:     expected type `impl Future` (opaque type at <$DIR/match-prev-arm-needing-semi.rs:16:24>)
+           found opaque type `impl Future` (opaque type at <$DIR/match-prev-arm-needing-semi.rs:17:25>)
+   = note: distinct uses of `impl Trait` result in different opaque types
+
 error[E0308]: `match` arms have incompatible types
   --> $DIR/match-prev-arm-needing-semi.rs:11:18
    |
@@ -79,6 +101,6 @@ LL | |
 LL | |     };
    | |_____- `match` arms have incompatible types
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0308`.