From eae29031504d62769b94dffca4aba3d78a6fafae Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume.gomez@huawei.com>
Date: Sun, 27 Mar 2022 13:58:06 +0200
Subject: [PATCH 1/2] Add long error explanation for E0667
---
compiler/rustc_error_codes/src/error_codes.rs | 2 +-
.../rustc_error_codes/src/error_codes/E0667.md | 18 ++++++++++++++++++
2 files changed, 19 insertions(+), 1 deletion(-)
create mode 100644 compiler/rustc_error_codes/src/error_codes/E0667.md
diff --git a/compiler/rustc_error_codes/src/error_codes.rs b/compiler/rustc_error_codes/src/error_codes.rs
index a185902123d8a..61a177f291ba0 100644
--- a/compiler/rustc_error_codes/src/error_codes.rs
+++ b/compiler/rustc_error_codes/src/error_codes.rs
@@ -394,6 +394,7 @@ E0663: include_str!("./error_codes/E0663.md"),
E0664: include_str!("./error_codes/E0664.md"),
E0665: include_str!("./error_codes/E0665.md"),
E0666: include_str!("./error_codes/E0666.md"),
+E0667: include_str!("./error_codes/E0667.md"),
E0668: include_str!("./error_codes/E0668.md"),
E0669: include_str!("./error_codes/E0669.md"),
E0670: include_str!("./error_codes/E0670.md"),
@@ -633,7 +634,6 @@ E0787: include_str!("./error_codes/E0787.md"),
// attribute
E0640, // infer outlives requirements
// E0645, // trait aliases not finished
- E0667, // `impl Trait` in projections
// E0694, // an unknown tool name found in scoped attributes
// E0702, // replaced with a generic attribute input check
// E0707, // multiple elided lifetimes used in arguments of `async fn`
diff --git a/compiler/rustc_error_codes/src/error_codes/E0667.md b/compiler/rustc_error_codes/src/error_codes/E0667.md
new file mode 100644
index 0000000000000..0709a24c43312
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0667.md
@@ -0,0 +1,18 @@
+`impl Trait` is not allowed in path parameters.
+
+Erroneous code example:
+
+```compile_fail,E0667
+fn some_fn(mut x: impl Iterator) -> <impl Iterator>::Item { // error!
+ x.next().unwrap()
+}
+```
+
+You cannot use `impl Trait` in path parameters. If you want something
+equivalent, you can do this instead:
+
+```
+fn some_fn<T: Iterator>(mut x: T) -> T::Item { // ok!
+ x.next().unwrap()
+}
+```
From 81f24c1f776c6546289d3c5936dfa3862f9b0c7e Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume.gomez@huawei.com>
Date: Sun, 27 Mar 2022 19:21:50 +0200
Subject: [PATCH 2/2] Update ui test output
---
src/test/ui/impl-trait/impl_trait_projections.stderr | 3 ++-
.../ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr | 1 +
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/test/ui/impl-trait/impl_trait_projections.stderr b/src/test/ui/impl-trait/impl_trait_projections.stderr
index e85ed0eda5215..82d2422c40779 100644
--- a/src/test/ui/impl-trait/impl_trait_projections.stderr
+++ b/src/test/ui/impl-trait/impl_trait_projections.stderr
@@ -30,4 +30,5 @@ LL | fn projection_is_disallowed(x: impl Iterator) -> <impl Iterator>::Item {
error: aborting due to 5 previous errors
-For more information about this error, try `rustc --explain E0223`.
+Some errors have detailed explanations: E0223, E0667.
+For more information about an error, try `rustc --explain E0223`.
diff --git a/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr b/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr
index f64545d83b8d6..e31393181d734 100644
--- a/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr
+++ b/src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr
@@ -6,3 +6,4 @@ LL | pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
error: aborting due to previous error
+For more information about this error, try `rustc --explain E0667`.