Rollup merge of #106167 - yanchen4791:issue-105544-fix, r=oli-obk

Fix invalid syntax and incomplete suggestion in impl Trait parameter type suggestions for E0311

Fixes #105544

The problems: The suggestion given for E0311 has invalid syntax when the synthetic type parameter is used for Trait type in function declaration:
```rust
fn foo(d: impl Sized) -> impl Sized
```
instead of explicitly specified like the following:
```rust
fn foo<T: Sized>(d: T) -> impl Sized
```
In addition to the syntax error, the suggestions given for E0311 are not complete when multiple elided lifetimes are involved in lifetime bounds, not all involved parameters are given the named lifetime in the suggestions. For the following test case:
```
fn foo(d: impl Sized, p: &mut ()) -> impl Sized + '_ {
    (d, p)
}
```
a good suggestion should add the lifetime 'a to both d and p, instead of d only:
```
fn foo<'a>(d: impl Sized + 'a, p: &'a mut ()) -> impl Sized + '_ {
    (d, p)
}
```

The Solution: Fix the syntax problem in the suggestions when synthetic type parameter is used, and also add lifetimes for all involved parameters.

14 files changed, 365 insertions, 39 deletions

diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index 66db1a2f928..9747f360eca 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -2144,18 +2144,21 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         // suggest adding an explicit lifetime bound to it.
         let generics = self.tcx.generics_of(generic_param_scope);
         // type_param_span is (span, has_bounds)
+        let mut is_synthetic = false;
+        let mut ast_generics = None;
         let type_param_span = match bound_kind {
             GenericKind::Param(ref param) => {
                 // Account for the case where `param` corresponds to `Self`,
                 // which doesn't have the expected type argument.
                 if !(generics.has_self && param.index == 0) {
                     let type_param = generics.type_param(param, self.tcx);
+                    is_synthetic = type_param.kind.is_synthetic();
                     type_param.def_id.as_local().map(|def_id| {
                         // Get the `hir::Param` to verify whether it already has any bounds.
                         // We do this to avoid suggesting code that ends up as `T: 'a'b`,
                         // instead we suggest `T: 'a + 'b` in that case.
                         let hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id);
-                        let ast_generics = self.tcx.hir().get_generics(hir_id.owner.def_id);
+                        ast_generics = self.tcx.hir().get_generics(hir_id.owner.def_id);
                         let bounds =
                             ast_generics.and_then(|g| g.bounds_span_for_suggestions(def_id));
                         // `sp` only covers `T`, change it so that it covers
@@ -2187,11 +2190,64 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 .unwrap_or("'lt".to_string())
         };
 
-        let add_lt_sugg = generics
-            .params
-            .first()
-            .and_then(|param| param.def_id.as_local())
-            .map(|def_id| (self.tcx.def_span(def_id).shrink_to_lo(), format!("{}, ", new_lt)));
+        let mut add_lt_suggs: Vec<Option<_>> = vec![];
+        if is_synthetic {
+            if let Some(ast_generics) = ast_generics {
+                let named_lifetime_param_exist = ast_generics.params.iter().any(|p| {
+                    matches!(
+                        p.kind,
+                        hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit }
+                    )
+                });
+                if named_lifetime_param_exist && let [param, ..] = ast_generics.params
+                {
+                    add_lt_suggs.push(Some((
+                        self.tcx.def_span(param.def_id).shrink_to_lo(),
+                        format!("{new_lt}, "),
+                    )));
+                } else {
+                    add_lt_suggs
+                        .push(Some((ast_generics.span.shrink_to_hi(), format!("<{new_lt}>"))));
+                }
+            }
+        } else {
+            if let [param, ..] = &generics.params[..] && let Some(def_id) = param.def_id.as_local()
+            {
+                add_lt_suggs
+                    .push(Some((self.tcx.def_span(def_id).shrink_to_lo(), format!("{new_lt}, "))));
+            }
+        }
+
+        if let Some(ast_generics) = ast_generics {
+            for p in ast_generics.params {
+                if p.is_elided_lifetime() {
+                    if self
+                        .tcx
+                        .sess
+                        .source_map()
+                        .span_to_prev_source(p.span.shrink_to_hi())
+                        .ok()
+                        .map_or(false, |s| *s.as_bytes().last().unwrap() == b'&')
+                    {
+                        add_lt_suggs
+                            .push(Some(
+                                (
+                                    p.span.shrink_to_hi(),
+                                    if let Ok(snip) = self.tcx.sess.source_map().span_to_next_source(p.span)
+                                        && snip.starts_with(' ')
+                                    {
+                                        format!("{new_lt}")
+                                    } else {
+                                        format!("{new_lt} ")
+                                    }
+                                )
+                            ));
+                    } else {
+                        add_lt_suggs.push(Some((p.span.shrink_to_hi(), format!("<{new_lt}>"))));
+                    }
+                }
+            }
+        }
 
         let labeled_user_string = match bound_kind {
             GenericKind::Param(ref p) => format!("the parameter type `{}`", p),
@@ -2215,20 +2271,22 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             );
         }
 
-        fn binding_suggestion<S: fmt::Display>(
+        fn binding_suggestion<'tcx, S: fmt::Display>(
             err: &mut Diagnostic,
             type_param_span: Option<(Span, bool)>,
-            bound_kind: GenericKind<'_>,
+            bound_kind: GenericKind<'tcx>,
             sub: S,
-            add_lt_sugg: Option<(Span, String)>,
+            add_lt_suggs: Vec<Option<(Span, String)>>,
         ) {
             let msg = "consider adding an explicit lifetime bound";
             if let Some((sp, has_lifetimes)) = type_param_span {
                 let suggestion =
                     if has_lifetimes { format!(" + {}", sub) } else { format!(": {}", sub) };
                 let mut suggestions = vec![(sp, suggestion)];
-                if let Some(add_lt_sugg) = add_lt_sugg {
-                    suggestions.push(add_lt_sugg);
+                for add_lt_sugg in add_lt_suggs {
+                    if let Some(add_lt_sugg) = add_lt_sugg {
+                        suggestions.push(add_lt_sugg);
+                    }
                 }
                 err.multipart_suggestion_verbose(
                     format!("{msg}..."),
@@ -2252,9 +2310,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     };
                     let mut sugg =
                         vec![(sp, suggestion), (span.shrink_to_hi(), format!(" + {}", new_lt))];
-                    if let Some(lt) = add_lt_sugg.clone() {
-                        sugg.push(lt);
-                        sugg.rotate_right(1);
+                    for add_lt_sugg in add_lt_suggs.clone() {
+                        if let Some(lt) = add_lt_sugg {
+                            sugg.push(lt);
+                            sugg.rotate_right(1);
+                        }
                     }
                     // `MaybeIncorrect` due to issue #41966.
                     err.multipart_suggestion(msg, sugg, Applicability::MaybeIncorrect);
@@ -2358,7 +2418,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 // for the bound is not suitable for suggestions when `-Zverbose` is set because it
                 // uses `Debug` output, so we handle it specially here so that suggestions are
                 // always correct.
-                binding_suggestion(&mut err, type_param_span, bound_kind, name, None);
+                binding_suggestion(&mut err, type_param_span, bound_kind, name, vec![]);
                 err
             }
 
@@ -2371,7 +2431,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     "{} may not live long enough",
                     labeled_user_string
                 );
-                binding_suggestion(&mut err, type_param_span, bound_kind, "'static", None);
+                binding_suggestion(&mut err, type_param_span, bound_kind, "'static", vec![]);
                 err
             }
 
@@ -2410,7 +2470,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                                 type_param_span,
                                 bound_kind,
                                 new_lt,
-                                add_lt_sugg,
+                                add_lt_suggs,
                             );
                         }
                     }
diff --git a/tests/ui/error-codes/E0311.fixed b/tests/ui/error-codes/E0311.fixed
new file mode 100644
index 00000000000..4410a4d707a
--- /dev/null
+++ b/tests/ui/error-codes/E0311.fixed
@@ -0,0 +1,13 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
+    with_restriction::<T>(x) //~ ERROR E0311
+}
+
+fn with_restriction<'a, T: 'a>(x: &'a ()) -> &'a () {
+    x
+}
+
+fn main() {}
diff --git a/tests/ui/error-codes/E0311.rs b/tests/ui/error-codes/E0311.rs
index 566b518b433..99e454f4d75 100644
--- a/tests/ui/error-codes/E0311.rs
+++ b/tests/ui/error-codes/E0311.rs
@@ -1,3 +1,7 @@
+// run-rustfix
+
+#![allow(warnings)]
+
 fn no_restriction<T>(x: &()) -> &() {
     with_restriction::<T>(x) //~ ERROR E0311
 }
diff --git a/tests/ui/error-codes/E0311.stderr b/tests/ui/error-codes/E0311.stderr
index 9873b5ae6ff..b0e6dd1e272 100644
--- a/tests/ui/error-codes/E0311.stderr
+++ b/tests/ui/error-codes/E0311.stderr
@@ -1,23 +1,23 @@
 error[E0311]: the parameter type `T` may not live long enough
-  --> $DIR/E0311.rs:2:5
+  --> $DIR/E0311.rs:6:5
    |
 LL |     with_restriction::<T>(x)
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
 note: the parameter type `T` must be valid for the anonymous lifetime defined here...
-  --> $DIR/E0311.rs:1:25
+  --> $DIR/E0311.rs:5:25
    |
 LL | fn no_restriction<T>(x: &()) -> &() {
    |                         ^^^
 note: ...so that the type `T` will meet its required lifetime bounds
-  --> $DIR/E0311.rs:2:5
+  --> $DIR/E0311.rs:6:5
    |
 LL |     with_restriction::<T>(x)
    |     ^^^^^^^^^^^^^^^^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn no_restriction<'a, T: 'a>(x: &()) -> &() {
-   |                   +++  ++++
+LL | fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
+   |                   +++  ++++      ++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed
new file mode 100644
index 00000000000..f977f0bd3a8
--- /dev/null
+++ b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed
@@ -0,0 +1,13 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
+    with_restriction::<T>(x) //~ ERROR the parameter type `T` may not live long enough
+}
+
+fn with_restriction<'b, T: 'b>(x: &'b ()) -> &'b () {
+    x
+}
+
+fn main() {}
diff --git a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs
index 645bc7db0dd..d6ce112ec93 100644
--- a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs
+++ b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs
@@ -1,3 +1,7 @@
+// run-rustfix
+
+#![allow(warnings)]
+
 fn no_restriction<T>(x: &()) -> &() {
     with_restriction::<T>(x) //~ ERROR the parameter type `T` may not live long enough
 }
diff --git a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
index 31fd8a4d633..2d58d3a02f3 100644
--- a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
+++ b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
@@ -1,23 +1,23 @@
 error[E0311]: the parameter type `T` may not live long enough
-  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:2:5
+  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:6:5
    |
 LL |     with_restriction::<T>(x)
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
 note: the parameter type `T` must be valid for the anonymous lifetime defined here...
-  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:1:25
+  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:5:25
    |
 LL | fn no_restriction<T>(x: &()) -> &() {
    |                         ^^^
 note: ...so that the type `T` will meet its required lifetime bounds
-  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:2:5
+  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:6:5
    |
 LL |     with_restriction::<T>(x)
    |     ^^^^^^^^^^^^^^^^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn no_restriction<'a, T: 'a>(x: &()) -> &() {
-   |                   +++  ++++
+LL | fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
+   |                   +++  ++++      ++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/suggestions/lifetimes/issue-105544.fixed b/tests/ui/suggestions/lifetimes/issue-105544.fixed
new file mode 100644
index 00000000000..47087eb4749
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/issue-105544.fixed
@@ -0,0 +1,45 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+fn foo<'a>(d: impl Sized + 'a, p: &'a mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `impl Sized` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `impl Sized` may not live long enough
+    //~| NOTE ...so that the type `impl Sized` will meet its required lifetime bounds
+}
+
+fn foo1<'b>(d: impl Sized + 'b, p: &'b mut ()) -> impl Sized + '_ {
+//~^ HELP consider adding an explicit lifetime bound...
+    (d, p) //~ NOTE ...so that the type `impl Sized` will meet its required lifetime bounds
+    //~^ ERROR the parameter type `impl Sized` may not live long enough
+}
+
+fn foo2<'b, 'a>(d: impl Sized + 'a + 'b, p: &'b mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `impl Sized + 'a` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `impl Sized + 'a` may not live long enough
+    //~| NOTE ...so that the type `impl Sized + 'a` will meet its required lifetime bounds
+}
+
+fn bar<'a, T : Sized + 'a>(d: T, p: &'a mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `T` may not live long enough
+    //~| NOTE ...so that the type `T` will meet its required lifetime bounds
+}
+
+fn bar1<'b, T : Sized + 'b>(d: T, p: &'b mut ()) -> impl Sized + '_ {
+//~^ HELP consider adding an explicit lifetime bound...
+    (d, p) //~ NOTE ...so that the type `T` will meet its required lifetime bounds
+    //~^ ERROR the parameter type `T` may not live long enough
+}
+
+fn bar2<'b, 'a, T : Sized + 'a + 'b>(d: T, p: &'b mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `T` may not live long enough
+    //~| NOTE ...so that the type `T` will meet its required lifetime bounds
+}
+
+fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/issue-105544.rs b/tests/ui/suggestions/lifetimes/issue-105544.rs
new file mode 100644
index 00000000000..bd3bc1ef9bd
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/issue-105544.rs
@@ -0,0 +1,45 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+fn foo(d: impl Sized, p: &mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `impl Sized` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `impl Sized` may not live long enough
+    //~| NOTE ...so that the type `impl Sized` will meet its required lifetime bounds
+}
+
+fn foo1<'b>(d: impl Sized, p: &'b mut ()) -> impl Sized + '_ {
+//~^ HELP consider adding an explicit lifetime bound...
+    (d, p) //~ NOTE ...so that the type `impl Sized` will meet its required lifetime bounds
+    //~^ ERROR the parameter type `impl Sized` may not live long enough
+}
+
+fn foo2<'a>(d: impl Sized + 'a, p: &mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `impl Sized + 'a` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `impl Sized + 'a` may not live long enough
+    //~| NOTE ...so that the type `impl Sized + 'a` will meet its required lifetime bounds
+}
+
+fn bar<T : Sized>(d: T, p: & mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `T` may not live long enough
+    //~| NOTE ...so that the type `T` will meet its required lifetime bounds
+}
+
+fn bar1<'b, T : Sized>(d: T, p: &'b mut ()) -> impl Sized + '_ {
+//~^ HELP consider adding an explicit lifetime bound...
+    (d, p) //~ NOTE ...so that the type `T` will meet its required lifetime bounds
+    //~^ ERROR the parameter type `T` may not live long enough
+}
+
+fn bar2<'a, T : Sized + 'a>(d: T, p: &mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
+//~^ HELP consider adding an explicit lifetime bound
+    (d, p)
+    //~^ ERROR the parameter type `T` may not live long enough
+    //~| NOTE ...so that the type `T` will meet its required lifetime bounds
+}
+
+fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/issue-105544.stderr b/tests/ui/suggestions/lifetimes/issue-105544.stderr
new file mode 100644
index 00000000000..08fe21b11b5
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/issue-105544.stderr
@@ -0,0 +1,110 @@
+error[E0311]: the parameter type `impl Sized` may not live long enough
+  --> $DIR/issue-105544.rs:7:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+   |
+note: the parameter type `impl Sized` must be valid for the anonymous lifetime defined here...
+  --> $DIR/issue-105544.rs:5:26
+   |
+LL | fn foo(d: impl Sized, p: &mut ()) -> impl Sized + '_ {
+   |                          ^^^^^^^
+note: ...so that the type `impl Sized` will meet its required lifetime bounds
+  --> $DIR/issue-105544.rs:7:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn foo<'a>(d: impl Sized + 'a, p: &'a mut ()) -> impl Sized + '_ {
+   |       ++++               ++++      ++
+
+error[E0309]: the parameter type `impl Sized` may not live long enough
+  --> $DIR/issue-105544.rs:14:5
+   |
+LL |     (d, p)
+   |     ^^^^^^ ...so that the type `impl Sized` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn foo1<'b>(d: impl Sized + 'b, p: &'b mut ()) -> impl Sized + '_ {
+   |                           ++++
+
+error[E0311]: the parameter type `impl Sized + 'a` may not live long enough
+  --> $DIR/issue-105544.rs:20:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+   |
+note: the parameter type `impl Sized + 'a` must be valid for the anonymous lifetime defined here...
+  --> $DIR/issue-105544.rs:18:36
+   |
+LL | fn foo2<'a>(d: impl Sized + 'a, p: &mut ()) -> impl Sized + '_ {
+   |                                    ^^^^^^^
+note: ...so that the type `impl Sized + 'a` will meet its required lifetime bounds
+  --> $DIR/issue-105544.rs:20:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn foo2<'b, 'a>(d: impl Sized + 'a + 'b, p: &'b mut ()) -> impl Sized + '_ {
+   |         +++                        ++++      ++
+
+error[E0311]: the parameter type `T` may not live long enough
+  --> $DIR/issue-105544.rs:27:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+   |
+note: the parameter type `T` must be valid for the anonymous lifetime defined here...
+  --> $DIR/issue-105544.rs:25:28
+   |
+LL | fn bar<T : Sized>(d: T, p: & mut ()) -> impl Sized + '_ {
+   |                            ^^^^^^^^
+note: ...so that the type `T` will meet its required lifetime bounds
+  --> $DIR/issue-105544.rs:27:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn bar<'a, T : Sized + 'a>(d: T, p: &'a mut ()) -> impl Sized + '_ {
+   |        +++           ++++            ++
+
+error[E0309]: the parameter type `T` may not live long enough
+  --> $DIR/issue-105544.rs:34:5
+   |
+LL |     (d, p)
+   |     ^^^^^^ ...so that the type `T` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn bar1<'b, T : Sized + 'b>(d: T, p: &'b mut ()) -> impl Sized + '_ {
+   |                       ++++
+
+error[E0311]: the parameter type `T` may not live long enough
+  --> $DIR/issue-105544.rs:40:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+   |
+note: the parameter type `T` must be valid for the anonymous lifetime defined here...
+  --> $DIR/issue-105544.rs:38:38
+   |
+LL | fn bar2<'a, T : Sized + 'a>(d: T, p: &mut ()) -> impl Sized + '_ {
+   |                                      ^^^^^^^
+note: ...so that the type `T` will meet its required lifetime bounds
+  --> $DIR/issue-105544.rs:40:5
+   |
+LL |     (d, p)
+   |     ^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn bar2<'b, 'a, T : Sized + 'a + 'b>(d: T, p: &'b mut ()) -> impl Sized + '_ {
+   |         +++                    ++++            ++
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0309, E0311.
+For more information about an error, try `rustc --explain E0309`.
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed
new file mode 100644
index 00000000000..4013d98c3cf
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed
@@ -0,0 +1,29 @@
+// Regression test for #81650
+// run-rustfix
+
+#![allow(warnings)]
+
+struct Foo<'a> {
+    x: &'a mut &'a i32,
+}
+
+impl<'a> Foo<'a> {
+    fn bar<F, T>(&self, f: F)
+    where
+        F: FnOnce(&Foo<'a>) -> T,
+        F: 'a,
+    {}
+}
+
+trait Test {
+    fn test(&self);
+}
+
+fn func<'a, T: Test + 'a>(foo: &'a Foo<'a>, t: T) {
+    foo.bar(move |_| {
+    //~^ ERROR the parameter type `T` may not live long enough
+        t.test();
+    });
+}
+
+fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs
index c6802ac6cc7..4096d95e5fd 100644
--- a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs
@@ -1,4 +1,7 @@
 // Regression test for #81650
+// run-rustfix
+
+#![allow(warnings)]
 
 struct Foo<'a> {
     x: &'a mut &'a i32,
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
index 872263fd731..936d87f7968 100644
--- a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
@@ -1,5 +1,5 @@
 error[E0311]: the parameter type `T` may not live long enough
-  --> $DIR/missing-lifetimes-in-signature-2.rs:20:5
+  --> $DIR/missing-lifetimes-in-signature-2.rs:23:5
    |
 LL | /     foo.bar(move |_| {
 LL | |
@@ -8,12 +8,12 @@ LL | |     });
    | |______^
    |
 note: the parameter type `T` must be valid for the anonymous lifetime defined here...
-  --> $DIR/missing-lifetimes-in-signature-2.rs:19:24
+  --> $DIR/missing-lifetimes-in-signature-2.rs:22:24
    |
 LL | fn func<T: Test>(foo: &Foo, t: T) {
    |                        ^^^
 note: ...so that the type `T` will meet its required lifetime bounds
-  --> $DIR/missing-lifetimes-in-signature-2.rs:20:5
+  --> $DIR/missing-lifetimes-in-signature-2.rs:23:5
    |
 LL | /     foo.bar(move |_| {
 LL | |
@@ -22,8 +22,8 @@ LL | |     });
    | |______^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn func<'a, T: Test + 'a>(foo: &Foo, t: T) {
-   |         +++         ++++
+LL | fn func<'a, T: Test + 'a>(foo: &'a Foo<'a>, t: T) {
+   |         +++         ++++        ++    ++++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
index fa758bf05df..c5c3f7b468c 100644
--- a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
@@ -47,7 +47,7 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL ~ fn bar<'a, G, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
+LL ~ fn bar<'a, G, T>(g: G, dest: &'a mut T) -> impl FnOnce() + '_
 LL | where
 LL ~     G: Get<T> + 'a,
    |
@@ -76,8 +76,8 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn qux<'b, 'a, G: 'a + 'b, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
-   |        +++           ++++
+LL | fn qux<'b, 'a, G: 'a + 'b, T>(g: G, dest: &'b mut T) -> impl FnOnce() + '_
+   |        +++           ++++                  ++
 
 error[E0311]: the parameter type `G` may not live long enough
   --> $DIR/missing-lifetimes-in-signature.rs:61:9
@@ -103,8 +103,8 @@ LL | |         }
    | |_________^
 help: consider adding an explicit lifetime bound...
    |
-LL |     fn qux<'c, 'b, G: Get<T> + 'b + 'c, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ {
-   |            +++                    ++++
+LL |     fn qux<'c, 'b, G: Get<T> + 'b + 'c, T>(g: G, dest: &'c mut T) -> impl FnOnce() + '_ {
+   |            +++                    ++++                  ++
 
 error[E0311]: the parameter type `G` may not live long enough
   --> $DIR/missing-lifetimes-in-signature.rs:73:5
@@ -132,8 +132,8 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn bat<'b, 'a, G: 'a + 'b, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
-   |        +++           ++++
+LL | fn bat<'b, 'a, G: 'a + 'b, T>(g: G, dest: &'b mut T) -> impl FnOnce() + '_ + 'a
+   |        +++           ++++                  ++
 
 error[E0621]: explicit lifetime required in the type of `dest`
   --> $DIR/missing-lifetimes-in-signature.rs:73:5