We can print futures with {integer} too

Author: compiler-errors

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -923,7 +923,7 @@ pub trait PrettyPrinter<'tcx>:
                         {
                             if let ty::Generator(_, substs, _) = substs.type_at(0).kind() {
                                 let return_ty = substs.as_generator().return_ty();
-                                if !return_ty.is_ty_infer() {
+                                if !return_ty.is_ty_var() {
                                     return_ty.into()
                                 } else {
                                     continue;

src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr

@@ -91,7 +91,7 @@ LL |   pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
    |                                             ------------------------------- the found opaque type
    |
    = note:   expected struct `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>`
-           found opaque type `impl Future`
+           found opaque type `impl Future<Output = {integer}>`
 help: you need to pin and box this expression
    |
 LL ~     Box::pin(async {