Wrap dyn type with parentheses in suggestion

tests/ui/suggestions/impl-trait-with-missing-trait-bounds-in-arg.fixed

@@ -12,7 +12,18 @@ impl Foo for S {}
 impl Bar for S {}
 
 fn test(foo: impl Foo + Bar) {
-    foo.hello(); //~ ERROR E0599
+    foo.hello(); //~ ERROR no method named `hello` found
+}
+
+trait Trait {
+    fn method(&self) {}
+}
+
+impl Trait for fn() {}
+
+#[allow(dead_code)]
+fn test2(f: impl Fn() -> (dyn std::fmt::Debug) + Trait) {
+    f.method(); //~ ERROR no method named `method` found
 }
 
 fn main() {

tests/ui/suggestions/impl-trait-with-missing-trait-bounds-in-arg.rs

@@ -12,7 +12,18 @@ impl Foo for S {}
 impl Bar for S {}
 
 fn test(foo: impl Foo) {
-    foo.hello(); //~ ERROR E0599
+    foo.hello(); //~ ERROR no method named `hello` found
+}
+
+trait Trait {
+    fn method(&self) {}
+}
+
+impl Trait for fn() {}
+
+#[allow(dead_code)]
+fn test2(f: impl Fn() -> dyn std::fmt::Debug) {
+    f.method(); //~ ERROR no method named `method` found
 }
 
 fn main() {

tests/ui/suggestions/impl-trait-with-missing-trait-bounds-in-arg.stderr

@@ -12,6 +12,20 @@ help: the following trait defines an item `hello`, perhaps you need to restrict
 LL | fn test(foo: impl Foo + Bar) {
    |                       +++++
 
-error: aborting due to 1 previous error
+error[E0599]: no method named `method` found for type parameter `impl Fn() -> dyn std::fmt::Debug` in the current scope
+  --> $DIR/impl-trait-with-missing-trait-bounds-in-arg.rs:26:7
+   |
+LL | fn test2(f: impl Fn() -> dyn std::fmt::Debug) {
+   |             -------------------------------- method `method` not found for this type parameter
+LL |     f.method();
+   |       ^^^^^^ method not found in `impl Fn() -> dyn std::fmt::Debug`
+   |
+   = help: items from traits can only be used if the type parameter is bounded by the trait
+help: the following trait defines an item `method`, perhaps you need to restrict type parameter `impl Fn() -> dyn std::fmt::Debug` with it:
+   |
+LL | fn test2(f: impl Fn() -> (dyn std::fmt::Debug) + Trait) {
+   |                          +                   +++++++++
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0599`.

tests/ui/suggestions/wrap-dyn-in-suggestion-issue-120223.rs

@@ -0,0 +1,35 @@
+#![feature(dyn_star)] //~ WARNING the feature `dyn_star` is incomplete
+
+use std::future::Future;
+
+pub fn dyn_func<T>(
+    executor: impl FnOnce(T) -> dyn Future<Output = ()>,
+) -> Box<dyn FnOnce(T) -> dyn Future<Output = ()>> {
+    Box::new(executor) //~ ERROR may not live long enough
+}
+
+pub fn dyn_star_func<T>(
+    executor: impl FnOnce(T) -> dyn* Future<Output = ()>,
+) -> Box<dyn FnOnce(T) -> dyn* Future<Output = ()>> {
+    Box::new(executor) //~ ERROR may not live long enough
+}
+
+trait Trait {
+    fn method(&self) {}
+}
+
+impl Trait for fn() {}
+
+pub fn in_ty_param<T: Fn() -> dyn std::fmt::Debug> (t: T) {
+    t.method();
+    //~^ ERROR no method named `method` found for type parameter `T`
+}
+
+fn with_sized<T: Fn() -> &'static (dyn std::fmt::Debug) + ?Sized>() {
+    without_sized::<T>();
+    //~^ ERROR the size for values of type `T` cannot be known at compilation time
+}
+
+fn without_sized<T: Fn() -> &'static dyn std::fmt::Debug>() {}
+
+fn main() {}

tests/ui/suggestions/wrap-dyn-in-suggestion-issue-120223.stderr

@@ -0,0 +1,78 @@
+warning: the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/wrap-dyn-in-suggestion-issue-120223.rs:1:12
+   |
+LL | #![feature(dyn_star)]
+   |            ^^^^^^^^
+   |
+   = note: see issue #102425 <https://github.com/rust-lang/rust/issues/102425> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0599]: no method named `method` found for type parameter `T` in the current scope
+  --> $DIR/wrap-dyn-in-suggestion-issue-120223.rs:24:7
+   |
+LL | pub fn in_ty_param<T: Fn() -> dyn std::fmt::Debug> (t: T) {
+   |                    - method `method` not found for this type parameter
+LL |     t.method();
+   |       ^^^^^^ method not found in `T`
+   |
+   = help: items from traits can only be used if the type parameter is bounded by the trait
+help: the following trait defines an item `method`, perhaps you need to restrict type parameter `T` with it:
+   |
+LL | pub fn in_ty_param<T: Fn() -> (dyn std::fmt::Debug) + Trait> (t: T) {
+   |                               +                   +++++++++
+
+error[E0277]: the size for values of type `T` cannot be known at compilation time
+  --> $DIR/wrap-dyn-in-suggestion-issue-120223.rs:29:21
+   |
+LL | fn with_sized<T: Fn() -> &'static (dyn std::fmt::Debug) + ?Sized>() {
+   |               - this type parameter needs to be `Sized`
+LL |     without_sized::<T>();
+   |                     ^ doesn't have a size known at compile-time
+   |
+note: required by an implicit `Sized` bound in `without_sized`
+  --> $DIR/wrap-dyn-in-suggestion-issue-120223.rs:33:18
+   |
+LL | fn without_sized<T: Fn() -> &'static dyn std::fmt::Debug>() {}
+   |                  ^ required by the implicit `Sized` requirement on this type parameter in `without_sized`
+help: consider removing the `?Sized` bound to make the type parameter `Sized`
+   |
+LL - fn with_sized<T: Fn() -> &'static (dyn std::fmt::Debug) + ?Sized>() {
+LL + fn with_sized<T: Fn() -> &'static (dyn std::fmt::Debug)>() {
+   |
+help: consider relaxing the implicit `Sized` restriction
+   |
+LL | fn without_sized<T: Fn() -> &'static (dyn std::fmt::Debug) + ?Sized>() {}
+   |                                      +                   ++++++++++
+
+error[E0310]: the parameter type `impl FnOnce(T) -> dyn Future<Output = ()>` may not live long enough
+  --> $DIR/wrap-dyn-in-suggestion-issue-120223.rs:8:5
+   |
+LL |     Box::new(executor)
+   |     ^^^^^^^^^^^^^^^^^^
+   |     |
+   |     the parameter type `impl FnOnce(T) -> dyn Future<Output = ()>` must be valid for the static lifetime...
+   |     ...so that the type `impl FnOnce(T) -> dyn Future<Output = ()>` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound
+   |
+LL |     executor: impl FnOnce(T) -> (dyn Future<Output = ()>) + 'static,
+   |                                 +                       +++++++++++
+
+error[E0310]: the parameter type `impl FnOnce(T) -> Future<Output = ()>` may not live long enough
+  --> $DIR/wrap-dyn-in-suggestion-issue-120223.rs:14:5
+   |
+LL |     Box::new(executor)
+   |     ^^^^^^^^^^^^^^^^^^
+   |     |
+   |     the parameter type `impl FnOnce(T) -> Future<Output = ()>` must be valid for the static lifetime...
+   |     ...so that the type `impl FnOnce(T) -> Future<Output = ()>` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound
+   |
+LL |     executor: impl FnOnce(T) -> (dyn* Future<Output = ()>) + 'static,
+   |                                 +                        +++++++++++
+
+error: aborting due to 4 previous errors; 1 warning emitted
+
+Some errors have detailed explanations: E0277, E0310, E0599.
+For more information about an error, try `rustc --explain E0277`.