Auto merge of #50760 - petrochenkov:legimp, r=nikomatsakis

Turn deprecation lint `legacy_imports` into a hard error

Closes https://github.com/rust-lang/rust/issues/38260

The lint was introduced in Dec 2016, then made deny-by-default in Jun 2017 when crater run found 0 regressions caused by it.

This lint requires some not entirely trivial amount of import resolution logic that (surprisingly or not) interacts with `feature(use_extern_macros)` (https://github.com/rust-lang/rust/issues/35896), so it would be desirable to remove it before stabilizing `use_extern_macros`.
In particular, this PR fixes the failing example in https://github.com/rust-lang/rust/issues/50725 (but not the whole issue, `use std::panic::{self}` still can cause other undesirable errors when `use_extern_macros` is enabled).

1 files changed, 0 insertions, 37 deletions

diff --git a/src/doc/rustc/src/lints/listing/deny-by-default.md b/src/doc/rustc/src/lints/listing/deny-by-default.md
index ef76295f04d..3a85a40fd1f 100644
--- a/src/doc/rustc/src/lints/listing/deny-by-default.md
+++ b/src/doc/rustc/src/lints/listing/deny-by-default.md
@@ -91,43 +91,6 @@ The legacy_directory_ownership warning is issued when
 The warning can be fixed by renaming the parent module to "mod.rs" and moving
 it into its own directory if appropriate.
 
-## legacy-imports
-
-This lint detects names that resolve to ambiguous glob imports. Some example
-code that triggers this lint:
-
-```rust,ignore
-pub struct Foo;
-
-mod bar {
-    struct Foo;
-
-    mod baz {
-        use *;
-        use bar::*;
-        fn f(_: Foo) {}
-    }
-}
-```
-
-This will produce:
-
-```text
-error: `Foo` is ambiguous
- --> src/main.rs:9:17
-  |
-7 |         use *;
-  |             - `Foo` could refer to the name imported here
-8 |         use bar::*;
-  |             ------ `Foo` could also refer to the name imported here
-9 |         fn f(_: Foo) {}
-  |                 ^^^
-  |
-  = note: #[deny(legacy_imports)] on by default
-  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-  = note: for more information, see issue #38260 <https://github.com/rust-lang/rust/issues/38260>
-```
-
 
 ## missing-fragment-specifier