Rollup merge of #89734 - estebank:issue-72312, r=nikomatsakis

Point at capture points for non-`'static` reference crossing a `yield` point

```
error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
  --> $DIR/issue-72312.rs:10:24
   |
LL |     pub async fn start(&self) {
   |                        ^^^^^ this data with an anonymous lifetime `'_`...
...
LL |         require_static(async move {
   |         -------------- ...is required to live as long as `'static` here...
LL |             &self;
   |             ----- ...and is captured here
   |
note: `'static` lifetime requirement introduced by this trait bound
  --> $DIR/issue-72312.rs:2:22
   |
LL | fn require_static<T: 'static>(val: T) -> T {
   |                      ^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0759`.
```

Fix #72312.

28 files changed, 313 insertions, 50 deletions

diff --git a/src/test/ui/associated-types/cache/project-fn-ret-contravariant.transmute.stderr b/src/test/ui/associated-types/cache/project-fn-ret-contravariant.transmute.stderr
index 0be9b37263a..33f1e0f05b2 100644
--- a/src/test/ui/associated-types/cache/project-fn-ret-contravariant.transmute.stderr
+++ b/src/test/ui/associated-types/cache/project-fn-ret-contravariant.transmute.stderr
@@ -4,7 +4,7 @@ error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime
 LL | fn baz<'a,'b>(x: &'a u32) -> &'static u32 {
    |                  ------- this data with lifetime `'a`...
 LL |    bar(foo, x)
-   |    ----^^^---- ...is captured and required to live as long as `'static` here
+   |        ^^^  - ...is used and required to live as long as `'static` here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr b/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr
index 0a44864b249..609627aaa9e 100644
--- a/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr
+++ b/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr
@@ -5,7 +5,16 @@ LL | fn baz<'a, 'b>(x: Type<'a>) -> Type<'static> {
    |                   -------- this data with lifetime `'a`...
 ...
 LL |     bar(foo, x)
-   |     ----^^^---- ...is captured and required to live as long as `'static` here
+   |         ^^^  - ...is used and required to live as long as `'static` here
+   |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/project-fn-ret-invariant.rs:45:37
+   |
+LL | fn baz<'a, 'b>(x: Type<'a>) -> Type<'static> {
+   |                                     ^^^^^^^ `'static` requirement introduced here
+...
+LL |     bar(foo, x)
+   |     ----------- because of this returned expression
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/async-await/issues/issue-62097.stderr b/src/test/ui/async-await/issues/issue-62097.stderr
index 56a28d904b9..e23277543c6 100644
--- a/src/test/ui/async-await/issues/issue-62097.stderr
+++ b/src/test/ui/async-await/issues/issue-62097.stderr
@@ -2,12 +2,15 @@ error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'
   --> $DIR/issue-62097.rs:12:31
    |
 LL |     pub async fn run_dummy_fn(&self) {
-   |                               ^^^^^
-   |                               |
-   |                               this data with an anonymous lifetime `'_`...
-   |                               ...is captured here...
+   |                               ^^^^^ this data with an anonymous lifetime `'_`...
 LL |         foo(|| self.bar()).await;
-   |         --- ...and is required to live as long as `'static` here
+   |         --- ...is used and required to live as long as `'static` here
+   |
+note: `'static` lifetime requirement introduced by this bound
+  --> $DIR/issue-62097.rs:4:19
+   |
+LL |     F: FnOnce() + 'static
+   |                   ^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/async-await/issues/issue-72312.nll.stderr b/src/test/ui/async-await/issues/issue-72312.nll.stderr
new file mode 100644
index 00000000000..068d8c64d68
--- /dev/null
+++ b/src/test/ui/async-await/issues/issue-72312.nll.stderr
@@ -0,0 +1,21 @@
+error[E0521]: borrowed data escapes outside of associated function
+  --> $DIR/issue-72312.rs:13:24
+   |
+LL |       pub async fn start(&self) {
+   |                          -----
+   |                          |
+   |                          `self` is a reference that is only valid in the associated function body
+   |                          let's call the lifetime of this reference `'1`
+...
+LL |           require_static(async move {
+   |  ________________________^
+LL | |             &self;
+LL | |         });
+   | |         ^
+   | |         |
+   | |_________`self` escapes the associated function body here
+   |           argument requires that `'1` must outlive `'static`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/async-await/issues/issue-72312.rs b/src/test/ui/async-await/issues/issue-72312.rs
new file mode 100644
index 00000000000..eb7d12e290c
--- /dev/null
+++ b/src/test/ui/async-await/issues/issue-72312.rs
@@ -0,0 +1,19 @@
+// edition:2018
+fn require_static<T: 'static>(val: T) -> T {
+    //~^ NOTE 'static` lifetime requirement introduced by this bound
+    val
+}
+
+struct Problem;
+
+impl Problem {
+    pub async fn start(&self) { //~ ERROR E0759
+        //~^ NOTE this data with an anonymous lifetime `'_`
+        //~| NOTE in this expansion of desugaring of `async` block or function
+        require_static(async move { //~ NOTE ...and is required to live as long as `'static` here
+            &self; //~ NOTE ...is used here...
+        });
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/async-await/issues/issue-72312.stderr b/src/test/ui/async-await/issues/issue-72312.stderr
new file mode 100644
index 00000000000..798f755765c
--- /dev/null
+++ b/src/test/ui/async-await/issues/issue-72312.stderr
@@ -0,0 +1,23 @@
+error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
+  --> $DIR/issue-72312.rs:10:24
+   |
+LL |     pub async fn start(&self) {
+   |                        ^^^^^ this data with an anonymous lifetime `'_`...
+...
+LL |             &self;
+   |             ----- ...is used here...
+   |
+note: ...and is required to live as long as `'static` here
+  --> $DIR/issue-72312.rs:13:9
+   |
+LL |         require_static(async move {
+   |         ^^^^^^^^^^^^^^
+note: `'static` lifetime requirement introduced by this bound
+  --> $DIR/issue-72312.rs:2:22
+   |
+LL | fn require_static<T: 'static>(val: T) -> T {
+   |                      ^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/closures/closure-bounds-static-cant-capture-borrowed.stderr b/src/test/ui/closures/closure-bounds-static-cant-capture-borrowed.stderr
index d761abdfc6a..af1f908a808 100644
--- a/src/test/ui/closures/closure-bounds-static-cant-capture-borrowed.stderr
+++ b/src/test/ui/closures/closure-bounds-static-cant-capture-borrowed.stderr
@@ -8,13 +8,18 @@ LL |       bar(|| {
 LL | |
 LL | |         let _ = x;
 LL | |     })
-   | |_____^ ...is captured here...
+   | |_____^ ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/closure-bounds-static-cant-capture-borrowed.rs:5:5
    |
 LL |     bar(|| {
    |     ^^^
+note: `'static` lifetime requirement introduced by this bound
+  --> $DIR/closure-bounds-static-cant-capture-borrowed.rs:1:39
+   |
+LL | fn bar<F>(blk: F) where F: FnOnce() + 'static {
+   |                                       ^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generator/generator-region-requirements.stderr b/src/test/ui/generator/generator-region-requirements.stderr
index b6b9db22426..30d67050b90 100644
--- a/src/test/ui/generator/generator-region-requirements.stderr
+++ b/src/test/ui/generator/generator-region-requirements.stderr
@@ -5,7 +5,7 @@ LL | fn dangle(x: &mut i32) -> &'static mut i32 {
    |              -------- this data with an anonymous lifetime `'_`...
 ...
 LL |         x
-   |         ^ ...is captured here...
+   |         ^ ...is used here...
 ...
 LL |             GeneratorState::Complete(c) => return c,
    |                                                   - ...and is required to live as long as `'static` here
diff --git a/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr b/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr
index 1ffd205652f..32c5ccf1648 100644
--- a/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr
+++ b/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr
@@ -4,7 +4,9 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
 LL | fn f(x: &impl for<'a> X<Y<'a> = &'a ()>) -> &'static () {
    |         ------------------------------- this data with an anonymous lifetime `'_`...
 LL |     x.m()
-   |     --^-- ...is captured and required to live as long as `'static` here
+   |     - ^
+   |     |
+   |     ...is used and required to live as long as `'static` here
 
 error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
   --> $DIR/projection-type-lifetime-mismatch.rs:22:7
@@ -12,7 +14,9 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
 LL | fn g<T: for<'a> X<Y<'a> = &'a ()>>(x: &T) -> &'static () {
    |                                       -- this data with an anonymous lifetime `'_`...
 LL |     x.m()
-   |     --^-- ...is captured and required to live as long as `'static` here
+   |     - ^
+   |     |
+   |     ...is used and required to live as long as `'static` here
 
 error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
   --> $DIR/projection-type-lifetime-mismatch.rs:27:7
@@ -20,7 +24,9 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
 LL | fn h(x: &()) -> &'static () {
    |         --- this data with an anonymous lifetime `'_`...
 LL |     x.m()
-   |     --^-- ...is captured and required to live as long as `'static` here
+   |     - ^
+   |     |
+   |     ...is used and required to live as long as `'static` here
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/impl-header-lifetime-elision/dyn-trait.stderr b/src/test/ui/impl-header-lifetime-elision/dyn-trait.stderr
index b3bef677d19..2307572cc3f 100644
--- a/src/test/ui/impl-header-lifetime-elision/dyn-trait.stderr
+++ b/src/test/ui/impl-header-lifetime-elision/dyn-trait.stderr
@@ -4,7 +4,7 @@ error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime
 LL | fn with_dyn_debug_static<'a>(x: Box<dyn Debug + 'a>) {
    |                                 ------------------- this data with lifetime `'a`...
 LL |     static_val(x);
-   |                ^ ...is captured here...
+   |                ^ ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/dyn-trait.rs:20:5
diff --git a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr
index d65dea7adc9..de5d3b612c9 100644
--- a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr
+++ b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr
@@ -28,7 +28,7 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
   --> $DIR/must_outlive_least_region_or_bound.rs:9:46
    |
 LL | fn elided2(x: &i32) -> impl Copy + 'static { x }
-   |               ----                           ^ ...is captured here...
+   |               ----                           ^ ...is used here...
    |               |
    |               this data with an anonymous lifetime `'_`...
    |
@@ -50,7 +50,7 @@ error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime
   --> $DIR/must_outlive_least_region_or_bound.rs:11:55
    |
 LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x }
-   |                     -------                           ^ ...is captured here...
+   |                     -------                           ^ ...is used here...
    |                     |
    |                     this data with lifetime `'a`...
    |
@@ -80,7 +80,7 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
   --> $DIR/must_outlive_least_region_or_bound.rs:24:65
    |
 LL | fn elided5(x: &i32) -> (Box<dyn Debug>, impl Debug) { (Box::new(x), x) }
-   |               ---- this data with an anonymous lifetime `'_`... ^ ...is captured here, requiring it to live as long as `'static`
+   |               ---- this data with an anonymous lifetime `'_`... ^ ...is used and required to live as long as `'static` here
    |
 help: to declare that the trait object captures data from argument `x`, you can add an explicit `'_` lifetime bound
    |
@@ -95,7 +95,7 @@ error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime
   --> $DIR/must_outlive_least_region_or_bound.rs:29:69
    |
 LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
-   |                      ------- this data with lifetime `'a`...        ^ ...is captured here...
+   |                      ------- this data with lifetime `'a`...        ^ ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/must_outlive_least_region_or_bound.rs:29:34
@@ -136,10 +136,17 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
   --> $DIR/must_outlive_least_region_or_bound.rs:16:50
    |
 LL | fn elided3(x: &i32) -> Box<dyn Debug> { Box::new(x) }
-   |               ----                               ^ ...is captured here, requiring it to live as long as `'static`
+   |               ----                               ^ ...is used and required to live as long as `'static` here
    |               |
    |               this data with an anonymous lifetime `'_`...
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/must_outlive_least_region_or_bound.rs:16:28
+   |
+LL | fn elided3(x: &i32) -> Box<dyn Debug> { Box::new(x) }
+   |                            ^^^^^^^^^    ----------- because of this returned expression
+   |                            |
+   |                            `'static` requirement introduced here
 help: to declare that the trait object captures data from argument `x`, you can add an explicit `'_` lifetime bound
    |
 LL | fn elided3(x: &i32) -> Box<dyn Debug + '_> { Box::new(x) }
@@ -149,10 +156,17 @@ error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime
   --> $DIR/must_outlive_least_region_or_bound.rs:18:59
    |
 LL | fn explicit3<'a>(x: &'a i32) -> Box<dyn Debug> { Box::new(x) }
-   |                     -------                               ^ ...is captured here, requiring it to live as long as `'static`
+   |                     -------                               ^ ...is used and required to live as long as `'static` here
    |                     |
    |                     this data with lifetime `'a`...
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/must_outlive_least_region_or_bound.rs:18:37
+   |
+LL | fn explicit3<'a>(x: &'a i32) -> Box<dyn Debug> { Box::new(x) }
+   |                                     ^^^^^^^^^    ----------- because of this returned expression
+   |                                     |
+   |                                     `'static` requirement introduced here
 help: to declare that the trait object captures data from argument `x`, you can add an explicit `'a` lifetime bound
    |
 LL | fn explicit3<'a>(x: &'a i32) -> Box<dyn Debug + 'a> { Box::new(x) }
@@ -162,10 +176,17 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
   --> $DIR/must_outlive_least_region_or_bound.rs:20:60
    |
 LL | fn elided4(x: &i32) -> Box<dyn Debug + 'static> { Box::new(x) }
-   |               ----                                         ^ ...is captured here, requiring it to live as long as `'static`
+   |               ----                                         ^ ...is used and required to live as long as `'static` here
    |               |
    |               this data with an anonymous lifetime `'_`...
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/must_outlive_least_region_or_bound.rs:20:40
+   |
+LL | fn elided4(x: &i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+   |                                        ^^^^^^^    ----------- because of this returned expression
+   |                                        |
+   |                                        `'static` requirement introduced here
 help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x`
    |
 LL | fn elided4(x: &i32) -> Box<dyn Debug + '_> { Box::new(x) }
@@ -179,8 +200,15 @@ error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime
   --> $DIR/must_outlive_least_region_or_bound.rs:22:69
    |
 LL | fn explicit4<'a>(x: &'a i32) -> Box<dyn Debug + 'static> { Box::new(x) }
-   |                     ------- this data with lifetime `'a`...         ^ ...is captured here, requiring it to live as long as `'static`
+   |                     ------- this data with lifetime `'a`...         ^ ...is used and required to live as long as `'static` here
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/must_outlive_least_region_or_bound.rs:22:49
+   |
+LL | fn explicit4<'a>(x: &'a i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+   |                                                 ^^^^^^^    ----------- because of this returned expression
+   |                                                 |
+   |                                                 `'static` requirement introduced here
 help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x`
    |
 LL | fn explicit4<'a>(x: &'a i32) -> Box<dyn Debug + 'a> { Box::new(x) }
diff --git a/src/test/ui/issues/issue-16922.stderr b/src/test/ui/issues/issue-16922.stderr
index 8b09b7d5907..53405a660f8 100644
--- a/src/test/ui/issues/issue-16922.stderr
+++ b/src/test/ui/issues/issue-16922.stderr
@@ -4,7 +4,7 @@ error[E0759]: `value` has an anonymous lifetime `'_` but it needs to satisfy a `
 LL | fn foo<T: Any>(value: &T) -> Box<dyn Any> {
    |                       -- this data with an anonymous lifetime `'_`...
 LL |     Box::new(value) as Box<dyn Any>
-   |              ^^^^^ ...is captured here, requiring it to live as long as `'static`
+   |              ^^^^^ ...is used and required to live as long as `'static` here
    |
 help: to declare that the trait object captures data from argument `value`, you can add an explicit `'_` lifetime bound
    |
diff --git a/src/test/ui/issues/issue-46983.stderr b/src/test/ui/issues/issue-46983.stderr
index 77fb130f519..ed9f1884c42 100644
--- a/src/test/ui/issues/issue-46983.stderr
+++ b/src/test/ui/issues/issue-46983.stderr
@@ -4,7 +4,7 @@ error[E0759]: `x` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
 LL | fn foo(x: &u32) -> &'static u32 {
    |           ---- this data with an anonymous lifetime `'_`...
 LL |     &*x
-   |     ^^^ ...is captured and required to live as long as `'static` here
+   |     ^^^ ...is used and required to live as long as `'static` here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetimes/issue-90600-expected-return-static-indirect.stderr b/src/test/ui/lifetimes/issue-90600-expected-return-static-indirect.stderr
index 3f65d3af725..e06255e4ea3 100644
--- a/src/test/ui/lifetimes/issue-90600-expected-return-static-indirect.stderr
+++ b/src/test/ui/lifetimes/issue-90600-expected-return-static-indirect.stderr
@@ -4,7 +4,7 @@ error[E0759]: `foo` has an anonymous lifetime `'_` but it needs to satisfy a `'s
 LL | fn inner(mut foo: &[u8]) {
    |                   ----- this data with an anonymous lifetime `'_`...
 LL |     let refcell = RefCell::new(&mut foo);
-   |                                ^^^^^^^^ ...is captured here...
+   |                                ^^^^^^^^ ...is used here...
 ...
 LL |     read_thing(read);
    |                ---- ...and is required to live as long as `'static` here
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr
index 1931934a211..4a6378b84f1 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr
@@ -4,7 +4,7 @@ error[E0759]: `fn` parameter has lifetime `'a` but it needs to satisfy a `'stati
 LL | fn foo<'a>(_: &'a u32) -> &'static u32 {
    |               ------- this data with lifetime `'a`...
 LL |     <Foo<'a>>::C
-   |     ^^^^^^^^^^^^ ...is captured and required to live as long as `'static` here
+   |     ^^^^^^^^^^^^ ...is used and required to live as long as `'static` here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr b/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr
index e0a8534cd28..1708700f77a 100644
--- a/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr
+++ b/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr
@@ -5,8 +5,16 @@ LL | fn load(ss: &mut SomeStruct) -> Box<dyn SomeTrait> {
    |             --------------- this data with an anonymous lifetime `'_`...
 ...
 LL |     ss.r
-   |     ^^^^ ...is captured and required to live as long as `'static` here
+   |     ^^^^ ...is used and required to live as long as `'static` here
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/object-lifetime-default-from-box-error.rs:14:37
+   |
+LL | fn load(ss: &mut SomeStruct) -> Box<dyn SomeTrait> {
+   |                                     ^^^^^^^^^^^^^ `'static` requirement introduced here
+...
+LL |     ss.r
+   |     ---- because of this returned expression
 help: to declare that the trait object captures data from argument `ss`, you can add an explicit `'_` lifetime bound
    |
 LL | fn load(ss: &mut SomeStruct) -> Box<dyn SomeTrait + '_> {
diff --git a/src/test/ui/regions/region-object-lifetime-in-coercion.stderr b/src/test/ui/regions/region-object-lifetime-in-coercion.stderr
index 04d22e58a1d..d8932c067ac 100644
--- a/src/test/ui/regions/region-object-lifetime-in-coercion.stderr
+++ b/src/test/ui/regions/region-object-lifetime-in-coercion.stderr
@@ -4,7 +4,7 @@ error[E0759]: `v` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
 LL | fn a(v: &[u8]) -> Box<dyn Foo + 'static> {
    |         ----- this data with an anonymous lifetime `'_`...
 LL |     let x: Box<dyn Foo + 'static> = Box::new(v);
-   |                                              ^ ...is captured here, requiring it to live as long as `'static`
+   |                                              ^ ...is used and required to live as long as `'static` here
    |
 help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
    |
@@ -21,8 +21,15 @@ error[E0759]: `v` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
 LL | fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
    |         ----- this data with an anonymous lifetime `'_`...
 LL |     Box::new(v)
-   |              ^ ...is captured here, requiring it to live as long as `'static`
+   |              ^ ...is used and required to live as long as `'static` here
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/region-object-lifetime-in-coercion.rs:12:33
+   |
+LL | fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
+   |                                 ^^^^^^^ `'static` requirement introduced here
+LL |     Box::new(v)
+   |     ----------- because of this returned expression
 help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
    |
 LL | fn b(v: &[u8]) -> Box<dyn Foo + '_> {
@@ -39,8 +46,16 @@ LL | fn c(v: &[u8]) -> Box<dyn Foo> {
    |         ----- this data with an anonymous lifetime `'_`...
 ...
 LL |     Box::new(v)
-   |              ^ ...is captured here, requiring it to live as long as `'static`
+   |              ^ ...is used and required to live as long as `'static` here
+   |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/region-object-lifetime-in-coercion.rs:16:23
    |
+LL | fn c(v: &[u8]) -> Box<dyn Foo> {
+   |                       ^^^^^^^ `'static` requirement introduced here
+...
+LL |     Box::new(v)
+   |     ----------- because of this returned expression
 help: to declare that the trait object captures data from argument `v`, you can add an explicit `'_` lifetime bound
    |
 LL | fn c(v: &[u8]) -> Box<dyn Foo + '_> {
diff --git a/src/test/ui/regions/regions-addr-of-self.stderr b/src/test/ui/regions/regions-addr-of-self.stderr
index 738691fd695..3453c6458f1 100644
--- a/src/test/ui/regions/regions-addr-of-self.stderr
+++ b/src/test/ui/regions/regions-addr-of-self.stderr
@@ -4,7 +4,7 @@ error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'
 LL |     pub fn chase_cat(&mut self) {
    |                      --------- this data with an anonymous lifetime `'_`...
 LL |         let p: &'static mut usize = &mut self.cats_chased;
-   |                                     ^^^^^^^^^^^^^^^^^^^^^ ...is captured and required to live as long as `'static` here
+   |                                     ^^^^^^^^^^^^^^^^^^^^^ ...is used and required to live as long as `'static` here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/regions/regions-close-object-into-object-2.stderr b/src/test/ui/regions/regions-close-object-into-object-2.stderr
index 9a7df8c0188..4153f4f29bc 100644
--- a/src/test/ui/regions/regions-close-object-into-object-2.stderr
+++ b/src/test/ui/regions/regions-close-object-into-object-2.stderr
@@ -4,8 +4,15 @@ error[E0759]: `v` has lifetime `'a` but it needs to satisfy a `'static` lifetime
 LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'static> {
    |                         ------------------ this data with lifetime `'a`...
 LL |     Box::new(B(&*v)) as Box<dyn X>
-   |                ^^^ ...is captured here, requiring it to live as long as `'static`
+   |                ^^^ ...is used and required to live as long as `'static` here
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/regions-close-object-into-object-2.rs:8:60
+   |
+LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'static> {
+   |                                                            ^^^^^^^ `'static` requirement introduced here
+LL |     Box::new(B(&*v)) as Box<dyn X>
+   |     ------------------------------ because of this returned expression
 help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
    |
 LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'a> {
diff --git a/src/test/ui/regions/regions-close-object-into-object-4.stderr b/src/test/ui/regions/regions-close-object-into-object-4.stderr
index a7a9b16b080..2ea4b431b38 100644
--- a/src/test/ui/regions/regions-close-object-into-object-4.stderr
+++ b/src/test/ui/regions/regions-close-object-into-object-4.stderr
@@ -4,8 +4,15 @@ error[E0759]: `v` has lifetime `'a` but it needs to satisfy a `'static` lifetime
 LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'static> {
    |                   ---------------- this data with lifetime `'a`...
 LL |     Box::new(B(&*v)) as Box<dyn X>
-   |                ^^^ ...is captured here, requiring it to live as long as `'static`
+   |                ^^^ ...is used and required to live as long as `'static` here
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/regions-close-object-into-object-4.rs:8:52
+   |
+LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'static> {
+   |                                                    ^^^^^^^ `'static` requirement introduced here
+LL |     Box::new(B(&*v)) as Box<dyn X>
+   |     ------------------------------ because of this returned expression
 help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
    |
 LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'a> {
diff --git a/src/test/ui/regions/regions-proc-bound-capture.stderr b/src/test/ui/regions/regions-proc-bound-capture.stderr
index 50b3748bf40..2ebe874da93 100644
--- a/src/test/ui/regions/regions-proc-bound-capture.stderr
+++ b/src/test/ui/regions/regions-proc-bound-capture.stderr
@@ -5,8 +5,16 @@ LL | fn static_proc(x: &isize) -> Box<dyn FnMut() -> (isize) + 'static> {
    |                   ------ this data with an anonymous lifetime `'_`...
 LL |     // This is illegal, because the region bound on `proc` is 'static.
 LL |     Box::new(move || { *x })
-   |              ^^^^^^^^^^^^^^ ...is captured here, requiring it to live as long as `'static`
+   |              ^^^^^^^^^^^^^^ ...is used and required to live as long as `'static` here
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/regions-proc-bound-capture.rs:7:59
+   |
+LL | fn static_proc(x: &isize) -> Box<dyn FnMut() -> (isize) + 'static> {
+   |                                                           ^^^^^^^ `'static` requirement introduced here
+LL |     // This is illegal, because the region bound on `proc` is 'static.
+LL |     Box::new(move || { *x })
+   |     ------------------------ because of this returned expression
 help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x`
    |
 LL | fn static_proc(x: &isize) -> Box<dyn FnMut() -> (isize) + '_> {
diff --git a/src/test/ui/regions/regions-static-bound.stderr b/src/test/ui/regions/regions-static-bound.stderr
index 51fe16ca9da..b8e69e02609 100644
--- a/src/test/ui/regions/regions-static-bound.stderr
+++ b/src/test/ui/regions/regions-static-bound.stderr
@@ -17,7 +17,7 @@ error[E0759]: `u` has an anonymous lifetime `'_` but it needs to satisfy a `'sta
 LL | fn error(u: &(), v: &()) {
    |             --- this data with an anonymous lifetime `'_`...
 LL |     static_id(&u);
-   |     ^^^^^^^^^ -- ...is captured here...
+   |     ^^^^^^^^^ -- ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/regions-static-bound.rs:10:5
@@ -32,7 +32,7 @@ LL | fn error(u: &(), v: &()) {
    |                     --- this data with an anonymous lifetime `'_`...
 LL |     static_id(&u);
 LL |     static_id_indirect(&v);
-   |     ^^^^^^^^^^^^^^^^^^ -- ...is captured here...
+   |     ^^^^^^^^^^^^^^^^^^ -- ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/regions-static-bound.rs:11:5
diff --git a/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr b/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr
index 2961d8d7eac..63d291ed7cd 100644
--- a/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr
+++ b/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr
@@ -22,7 +22,7 @@ error[E0772]: `val` has lifetime `'a` but calling `use_self` introduces an impli
 LL |     fn use_it<'a>(val: Box<dyn ObjectTrait<Assoc = i32> + 'a>) -> &'a () {
    |                        -------------------------------------- this data with lifetime `'a`...
 LL |         val.use_self()
-   |             ^^^^^^^^ ...is captured and required to live as long as `'static` here
+   |             ^^^^^^^^ ...is used and required to live as long as `'static` here
    |
 note: the used `impl` has a `'static` requirement
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.rs:60:30
diff --git a/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.stderr b/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.stderr
index 6d9f0811b27..55a1bbf18ab 100644
--- a/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.stderr
+++ b/src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.stderr
@@ -4,7 +4,7 @@ error[E0759]: `val` has lifetime `'a` but it needs to satisfy a `'static` lifeti
 LL |     fn use_it<'a, T>(val: &'a dyn ObjectTrait<T>) -> impl OtherTrait<'a> + 'a {
    |                           ---------------------- this data with lifetime `'a`...
 LL |         val.use_self::<T>()
-   |             ^^^^^^^^ ...is captured and required to live as long as `'static` here
+   |             ^^^^^^^^ ...is used and required to live as long as `'static` here
    |
 note: the used `impl` has a `'static` requirement
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:14:32
@@ -24,7 +24,7 @@ error[E0772]: `val` has lifetime `'a` but calling `use_self` introduces an impli
 LL |     fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> + 'a {
    |                        ------------------- this data with lifetime `'a`...
 LL |         val.use_self()
-   |             ^^^^^^^^ ...is captured and required to live as long as `'static` here because of an implicit lifetime bound on the inherent `impl`
+   |             ^^^^^^^^ ...is used and required to live as long as `'static` here because of an implicit lifetime bound on the inherent `impl`
    |
 note: the used `impl` has a `'static` requirement
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:64:14
@@ -44,7 +44,7 @@ error[E0759]: `val` has lifetime `'a` but it needs to satisfy a `'static` lifeti
 LL |     fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> {
    |                        ------------------- this data with lifetime `'a`...
 LL |         val.use_self()
-   |             ^^^^^^^^ ...is captured and required to live as long as `'static` here
+   |             ^^^^^^^^ ...is used and required to live as long as `'static` here
    |
 note: the used `impl` has a `'static` requirement
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:85:26
@@ -69,7 +69,7 @@ error[E0759]: `val` has lifetime `'a` but it needs to satisfy a `'static` lifeti
 LL |     fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> + 'a {
    |                        ------------------- this data with lifetime `'a`...
 LL |         MyTrait::use_self(val)
-   |                           ^^^ ...is captured here...
+   |                           ^^^ ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:108:9
@@ -95,7 +95,7 @@ error[E0772]: `val` has lifetime `'a` but calling `use_self` introduces an impli
 LL |     fn use_it<'a>(val: &'a dyn ObjectTrait) -> &'a () {
    |                        ------------------- this data with lifetime `'a`...
 LL |         val.use_self()
-   |             ^^^^^^^^ ...is captured and required to live as long as `'static` here
+   |             ^^^^^^^^ ...is used and required to live as long as `'static` here
    |
 note: the used `impl` has a `'static` requirement
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:31:26
@@ -115,7 +115,7 @@ error[E0772]: `val` has lifetime `'a` but calling `use_self` introduces an impli
 LL |     fn use_it<'a>(val: &'a Box<dyn ObjectTrait + 'a>) -> &'a () {
    |                        ----------------------------- this data with lifetime `'a`...
 LL |         val.use_self()
-   |             ^^^^^^^^ ...is captured and required to live as long as `'static` here
+   |             ^^^^^^^^ ...is used and required to live as long as `'static` here
    |
 note: the used `impl` has a `'static` requirement
   --> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:48:30
diff --git a/src/test/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr b/src/test/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr
index 1ca22ebeef4..a5b50634c71 100644
--- a/src/test/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr
+++ b/src/test/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr
@@ -7,7 +7,7 @@ LL |     fn iter(&self) -> impl Iterator<Item = Box<dyn Foo>> {
 LL |             remaining: self.0.iter(),
    |                        ------ ^^^^
    |                        |
-   |                        ...is captured here...
+   |                        ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/trait-object-nested-in-impl-trait.rs:27:23
@@ -32,7 +32,7 @@ LL |     fn iter(&self) -> impl Iterator<Item = Box<dyn Foo>> + '_ {
 LL |             remaining: self.0.iter(),
    |                        ------ ^^^^
    |                        |
-   |                        ...is captured here...
+   |                        ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/trait-object-nested-in-impl-trait.rs:38:23
@@ -53,7 +53,7 @@ LL |     fn iter<'a>(&'a self) -> impl Iterator<Item = Box<dyn Foo>> + 'a {
 LL |             remaining: self.0.iter(),
    |                        ------ ^^^^
    |                        |
-   |                        ...is captured here...
+   |                        ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/trait-object-nested-in-impl-trait.rs:49:30
@@ -74,7 +74,7 @@ LL |     fn iter<'a>(&'a self) -> impl Iterator<Item = Box<dyn Foo>> {
 LL |             remaining: self.0.iter(),
    |                        ------ ^^^^
    |                        |
-   |                        ...is captured here...
+   |                        ...is used here...
    |
 note: ...and is required to live as long as `'static` here
   --> $DIR/trait-object-nested-in-impl-trait.rs:60:30
diff --git a/src/test/ui/traits/trait-upcasting/type-checking-test-4.rs b/src/test/ui/traits/trait-upcasting/type-checking-test-4.rs
index 9b27fd46f7a..95698fd1e1a 100644
--- a/src/test/ui/traits/trait-upcasting/type-checking-test-4.rs
+++ b/src/test/ui/traits/trait-upcasting/type-checking-test-4.rs
@@ -29,4 +29,22 @@ fn test_wrong3<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
     y.get_b() // ERROR
 }
 
+fn test_wrong4<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+    <_ as Bar>::get_b(x) // ERROR
+    //~^ ERROR `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime requirement
+}
+
+fn test_wrong5<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+    <_ as Bar<'_, '_>>::get_b(x) // ERROR
+    //~^ ERROR `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime requirement
+}
+
+fn test_wrong6<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+    let y = x as &dyn Bar<'_, '_>;
+    //~^ ERROR `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime requirement
+    y.get_b(); // ERROR
+    let z = y;
+    z.get_b() // ERROR
+}
+
 fn main() {}
diff --git a/src/test/ui/traits/trait-upcasting/type-checking-test-4.stderr b/src/test/ui/traits/trait-upcasting/type-checking-test-4.stderr
index 4967f3dc2c8..d4bb9350b0b 100644
--- a/src/test/ui/traits/trait-upcasting/type-checking-test-4.stderr
+++ b/src/test/ui/traits/trait-upcasting/type-checking-test-4.stderr
@@ -36,12 +36,88 @@ LL | fn test_wrong3<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
 LL |     let y = x as &dyn Bar<'_, '_>;
    |             -             ^^
    |             |
-   |             ...is captured here...
+   |             ...is used here...
 LL |
 LL |     y.get_b() // ERROR
-   |     --------- ...and is required to live as long as `'static` here
+   |     - ...is used here...
+   |
+note: ...and is required to live as long as `'static` here
+  --> $DIR/type-checking-test-4.rs:29:5
+   |
+LL |     y.get_b() // ERROR
+   |     ^^^^^^^^^
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/type-checking-test-4.rs:26:48
+   |
+LL | fn test_wrong3<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+   |                                                ^^^^^^^ `'static` requirement introduced here
+...
+LL |     y.get_b() // ERROR
+   |     --------- because of this returned expression
+
+error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime requirement
+  --> $DIR/type-checking-test-4.rs:33:5
+   |
+LL | fn test_wrong4<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+   |                       ------------ this data with lifetime `'a`...
+LL |     <_ as Bar>::get_b(x) // ERROR
+   |     ^^^^^^^^^^^^^^^^^ ...is used and required to live as long as `'static` here
+   |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/type-checking-test-4.rs:32:48
+   |
+LL | fn test_wrong4<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+   |                                                ^^^^^^^ `'static` requirement introduced here
+LL |     <_ as Bar>::get_b(x) // ERROR
+   |     -------------------- because of this returned expression
+
+error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime requirement
+  --> $DIR/type-checking-test-4.rs:38:15
+   |
+LL | fn test_wrong5<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+   |                       ------------ this data with lifetime `'a`...
+LL |     <_ as Bar<'_, '_>>::get_b(x) // ERROR
+   |     ----------^^------------- ...is used and required to live as long as `'static` here
+   |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/type-checking-test-4.rs:37:48
+   |
+LL | fn test_wrong5<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+   |                                                ^^^^^^^ `'static` requirement introduced here
+LL |     <_ as Bar<'_, '_>>::get_b(x) // ERROR
+   |     ---------------------------- because of this returned expression
+
+error[E0759]: `x` has lifetime `'a` but it needs to satisfy a `'static` lifetime requirement
+  --> $DIR/type-checking-test-4.rs:43:27
+   |
+LL | fn test_wrong6<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+   |                       ------------ this data with lifetime `'a`...
+LL |     let y = x as &dyn Bar<'_, '_>;
+   |             -             ^^
+   |             |
+   |             ...is used here...
+LL |
+LL |     y.get_b(); // ERROR
+   |     - ...is used here...
+LL |     let z = y;
+LL |     z.get_b() // ERROR
+   |     - ...is used here...
+   |
+note: ...and is required to live as long as `'static` here
+  --> $DIR/type-checking-test-4.rs:47:5
+   |
+LL |     z.get_b() // ERROR
+   |     ^^^^^^^^^
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/type-checking-test-4.rs:42:48
+   |
+LL | fn test_wrong6<'a>(x: &dyn Foo<'a>) -> Option<&'static u32> {
+   |                                                ^^^^^^^ `'static` requirement introduced here
+...
+LL |     z.get_b() // ERROR
+   |     --------- because of this returned expression
 
-error: aborting due to 3 previous errors
+error: aborting due to 6 previous errors
 
 Some errors have detailed explanations: E0308, E0759.
 For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr b/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr
index de3a6bbae17..f4285a0f98e 100644
--- a/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr
+++ b/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr
@@ -5,8 +5,18 @@ LL | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
    |                ---- this data with an anonymous lifetime `'_`...
 LL |     //                      ^^^^^^^^^^^^^^^^^^^^^ bound *here* defaults to `'static`
 LL |     Box::new(items.iter())
-   |     ---------------^^^^--- ...is captured and required to live as long as `'static` here
+   |              ----- ^^^^
+   |              |
+   |              ...is used and required to live as long as `'static` here
    |
+note: `'static` lifetime requirement introduced by the return type
+  --> $DIR/dyn-trait-underscore.rs:6:29
+   |
+LL | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
+   |                             ^^^^^^^^^^^^^^^^^^^^^ `'static` requirement introduced here
+LL |     //                      ^^^^^^^^^^^^^^^^^^^^^ bound *here* defaults to `'static`
+LL |     Box::new(items.iter())
+   |     ---------------------- because of this returned expression
 help: to declare that the trait object captures data from argument `items`, you can add an explicit `'_` lifetime bound
    |
 LL | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T> + '_> {