Improve error message for opaque captures

15 files changed, 43 insertions, 31 deletions

diff --git a/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs b/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs
index 06c3d9ad434..a9ea657f10e 100644
--- a/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs
+++ b/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs
@@ -2,19 +2,19 @@
 use std::fmt::Debug;
 
 fn a() -> impl Fn(&u8) -> (impl Debug + '_) {
-    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
     //~^ ERROR lifetime may not live long enough
 }
 
 fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
-    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
     //~^ ERROR lifetime may not live long enough
 }
 
 fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
-    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
     //~^ ERROR lifetime may not live long enough
 }
diff --git a/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr b/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr
index 959d6577d9a..bdb099619b7 100644
--- a/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr
+++ b/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr
@@ -10,7 +10,7 @@ help: consider using the `'static` lifetime, but this is uncommon unless you're
 LL | fn d() -> impl Fn() -> (impl Debug + 'static) {
    |                                      ~~~~~~~
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/impl-fn-hrtb-bounds.rs:4:41
    |
 LL | fn a() -> impl Fn(&u8) -> (impl Debug + '_) {
@@ -31,7 +31,7 @@ LL |     |x| x
    |      |return type of closure is impl Debug + '2
    |      has type `&'1 u8`
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/impl-fn-hrtb-bounds.rs:10:52
    |
 LL | fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
@@ -52,7 +52,7 @@ LL |     |x| x
    |      |return type of closure is impl Debug + '2
    |      has type `&'1 u8`
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/impl-fn-hrtb-bounds.rs:16:52
    |
 LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
@@ -75,4 +75,5 @@ LL |     |x| x
 
 error: aborting due to 7 previous errors
 
-For more information about this error, try `rustc --explain E0106`.
+Some errors have detailed explanations: E0106, E0657.
+For more information about an error, try `rustc --explain E0106`.
diff --git a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs
index a4a1f1dcee1..ef9d8733509 100644
--- a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs
+++ b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs
@@ -3,7 +3,7 @@ use std::fmt::Debug;
 
 fn a() -> impl Fn(&u8) -> impl Debug + '_ {
     //~^ ERROR ambiguous `+` in a type
-    //~| ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~| ERROR cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
     //~^ ERROR lifetime may not live long enough
 }
diff --git a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr
index e18e89700b4..3881b37a0cb 100644
--- a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr
+++ b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr
@@ -10,7 +10,7 @@ error: ambiguous `+` in a type
 LL | fn b() -> impl Fn() -> impl Debug + Send {
    |                        ^^^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(impl Debug + Send)`
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/impl-fn-parsing-ambiguities.rs:4:40
    |
 LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
@@ -33,3 +33,4 @@ LL |     |x| x
 
 error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0657`.
diff --git a/tests/ui/impl-trait/implicit-capture-late.stderr b/tests/ui/impl-trait/implicit-capture-late.stderr
index 2fb5ebb6541..080750f8497 100644
--- a/tests/ui/impl-trait/implicit-capture-late.stderr
+++ b/tests/ui/impl-trait/implicit-capture-late.stderr
@@ -1,4 +1,10 @@
-error[E0657]: `impl Trait` can only capture lifetimes bound at the fn or impl level
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from `dyn` type
+  --> $DIR/implicit-capture-late.rs:10:55
+   |
+LL | fn foo(x: Vec<i32>) -> Box<dyn for<'a> Deref<Target = impl ?Sized>> {
+   |                                                       ^^^^^^^^^^^ `impl Trait` implicitly captures all lifetimes in scope
+   |
+note: lifetime declared here
   --> $DIR/implicit-capture-late.rs:10:36
    |
 LL | fn foo(x: Vec<i32>) -> Box<dyn for<'a> Deref<Target = impl ?Sized>> {
diff --git a/tests/ui/impl-trait/issues/issue-54895.rs b/tests/ui/impl-trait/issues/issue-54895.rs
index 8d7a1d56f83..13c0038ce43 100644
--- a/tests/ui/impl-trait/issues/issue-54895.rs
+++ b/tests/ui/impl-trait/issues/issue-54895.rs
@@ -13,7 +13,7 @@ impl<'a> Trait<'a> for X {
 }
 
 fn f() -> impl for<'a> Trait<'a, Out = impl Sized + 'a> {
-    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     X(())
 }
 
diff --git a/tests/ui/impl-trait/issues/issue-54895.stderr b/tests/ui/impl-trait/issues/issue-54895.stderr
index 999ffd52141..64b425328e3 100644
--- a/tests/ui/impl-trait/issues/issue-54895.stderr
+++ b/tests/ui/impl-trait/issues/issue-54895.stderr
@@ -1,4 +1,4 @@
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/issue-54895.rs:15:53
    |
 LL | fn f() -> impl for<'a> Trait<'a, Out = impl Sized + 'a> {
@@ -12,3 +12,4 @@ LL | fn f() -> impl for<'a> Trait<'a, Out = impl Sized + 'a> {
 
 error: aborting due to 1 previous error
 
+For more information about this error, try `rustc --explain E0657`.
diff --git a/tests/ui/impl-trait/issues/issue-67830.rs b/tests/ui/impl-trait/issues/issue-67830.rs
index 6dc8935c777..939eca82a8f 100644
--- a/tests/ui/impl-trait/issues/issue-67830.rs
+++ b/tests/ui/impl-trait/issues/issue-67830.rs
@@ -19,7 +19,7 @@ where
 
 struct A;
 fn test() -> impl for<'a> MyFn<&'a A, Output=impl Iterator + 'a> {
-    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     Wrap(|a| Some(a).into_iter())
     //~^ ERROR implementation of `FnOnce` is not general enough
     //~| ERROR implementation of `FnOnce` is not general enough
diff --git a/tests/ui/impl-trait/issues/issue-67830.stderr b/tests/ui/impl-trait/issues/issue-67830.stderr
index 546198b8a10..ef513a40cf3 100644
--- a/tests/ui/impl-trait/issues/issue-67830.stderr
+++ b/tests/ui/impl-trait/issues/issue-67830.stderr
@@ -1,4 +1,4 @@
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/issue-67830.rs:21:62
    |
 LL | fn test() -> impl for<'a> MyFn<&'a A, Output=impl Iterator + 'a> {
@@ -31,3 +31,4 @@ LL |     Wrap(|a| Some(a).into_iter())
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0657`.
diff --git a/tests/ui/impl-trait/issues/issue-88236-2.rs b/tests/ui/impl-trait/issues/issue-88236-2.rs
index f4354d1b2ae..7ff08d8174f 100644
--- a/tests/ui/impl-trait/issues/issue-88236-2.rs
+++ b/tests/ui/impl-trait/issues/issue-88236-2.rs
@@ -13,17 +13,17 @@ impl<'a> Hrtb<'a> for &'a () {
 }
 
 fn make_impl() -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {}
-//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
 
 fn make_weird_impl<'b>(x: &'b ()) -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {
-    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     &()
     //~^ ERROR implementation of `Hrtb` is not general enough
     //~| ERROR implementation of `Hrtb` is not general enough
 }
 
 fn make_bad_impl<'b>(x: &'b ()) -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {
-    //~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+    //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     x
     //~^ ERROR implementation of `Hrtb` is not general enough
     //~| ERROR implementation of `Hrtb` is not general enough
diff --git a/tests/ui/impl-trait/issues/issue-88236-2.stderr b/tests/ui/impl-trait/issues/issue-88236-2.stderr
index 1f5029f9d9f..09fd58056a5 100644
--- a/tests/ui/impl-trait/issues/issue-88236-2.stderr
+++ b/tests/ui/impl-trait/issues/issue-88236-2.stderr
@@ -1,4 +1,4 @@
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/issue-88236-2.rs:15:61
    |
 LL | fn make_impl() -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {}
@@ -10,7 +10,7 @@ note: lifetime declared here
 LL | fn make_impl() -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {}
    |                            ^^
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/issue-88236-2.rs:18:80
    |
 LL | fn make_weird_impl<'b>(x: &'b ()) -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {
@@ -40,7 +40,7 @@ LL |     &()
    = note: `Hrtb<'a>` would have to be implemented for the type `&()`
    = note: ...but `Hrtb<'0>` is actually implemented for the type `&'0 ()`, for some specific lifetime `'0`
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/issue-88236-2.rs:25:78
    |
 LL | fn make_bad_impl<'b>(x: &'b ()) -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {
@@ -90,3 +90,4 @@ LL |     x
 
 error: aborting due to 8 previous errors
 
+For more information about this error, try `rustc --explain E0657`.
diff --git a/tests/ui/impl-trait/issues/issue-88236.rs b/tests/ui/impl-trait/issues/issue-88236.rs
index 36d12417354..e782a876573 100644
--- a/tests/ui/impl-trait/issues/issue-88236.rs
+++ b/tests/ui/impl-trait/issues/issue-88236.rs
@@ -13,6 +13,6 @@ impl<'a> Hrtb<'a> for &'a () {
 }
 
 fn make_impl() -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {}
-//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
 
 fn main() {}
diff --git a/tests/ui/impl-trait/issues/issue-88236.stderr b/tests/ui/impl-trait/issues/issue-88236.stderr
index 6cf1a42d6a9..5dee5f88c89 100644
--- a/tests/ui/impl-trait/issues/issue-88236.stderr
+++ b/tests/ui/impl-trait/issues/issue-88236.stderr
@@ -1,4 +1,4 @@
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/issue-88236.rs:15:61
    |
 LL | fn make_impl() -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {}
@@ -12,3 +12,4 @@ LL | fn make_impl() -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {}
 
 error: aborting due to 1 previous error
 
+For more information about this error, try `rustc --explain E0657`.
diff --git a/tests/ui/impl-trait/nested-rpit-hrtb.rs b/tests/ui/impl-trait/nested-rpit-hrtb.rs
index a3eca741daa..c10bfbfe4dc 100644
--- a/tests/ui/impl-trait/nested-rpit-hrtb.rs
+++ b/tests/ui/impl-trait/nested-rpit-hrtb.rs
@@ -23,18 +23,18 @@ impl Qux<'_> for () {}
 
 // This is not supported.
 fn one_hrtb_outlives() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'a> {}
-//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
 
 // This is not supported.
 fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {}
-//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
 
 fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {}
-//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
 //~| ERROR implementation of `Bar` is not general enough
 
 fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
-//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
 //~| ERROR: the trait bound `for<'a> &'a (): Qux<'_>` is not satisfied
 
 // This should resolve.
diff --git a/tests/ui/impl-trait/nested-rpit-hrtb.stderr b/tests/ui/impl-trait/nested-rpit-hrtb.stderr
index 4fc22712de6..2779694a517 100644
--- a/tests/ui/impl-trait/nested-rpit-hrtb.stderr
+++ b/tests/ui/impl-trait/nested-rpit-hrtb.stderr
@@ -29,7 +29,7 @@ help: consider introducing lifetime `'b` here
 LL | fn two_htrb_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {}
    |                          ++++
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/nested-rpit-hrtb.rs:25:69
    |
 LL | fn one_hrtb_outlives() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'a> {}
@@ -41,7 +41,7 @@ note: lifetime declared here
 LL | fn one_hrtb_outlives() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'a> {}
    |                                    ^^
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/nested-rpit-hrtb.rs:29:68
    |
 LL | fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {}
@@ -53,7 +53,7 @@ note: lifetime declared here
 LL | fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {}
    |                                       ^^
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/nested-rpit-hrtb.rs:32:74
    |
 LL | fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {}
@@ -74,7 +74,7 @@ LL | fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a
    = note: `()` must implement `Bar<'a>`
    = note: ...but it actually implements `Bar<'0>`, for some specific lifetime `'0`
 
-error: higher kinded lifetime bounds on nested opaque types are not supported yet
+error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
   --> $DIR/nested-rpit-hrtb.rs:36:73
    |
 LL | fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
@@ -133,5 +133,5 @@ LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Si
 
 error: aborting due to 12 previous errors
 
-Some errors have detailed explanations: E0261, E0277.
+Some errors have detailed explanations: E0261, E0277, E0657.
 For more information about an error, try `rustc --explain E0261`.