Merge #9097

9097: feat: Implement per-edition preludes r=jonas-schievink a=jonas-schievink

Part of https://github.com/rust-analyzer/rust-analyzer/issues/9056

Our previous implementation was incorrect (presumably because of the misleading comment in libstd [here](https://github.com/rust-lang/rust/blob/a7890c7952bdc9445eb6c63dc671fa7a1ab0260d/library/std/src/lib.rs#L339-L343)). `#[prelude_import]` does not define the prelude, it can only override the implicit prelude for the current crate.

This PR fixes that, which also makes the prelude imports in `rustc_span` work. Closes https://github.com/rust-analyzer/rust-analyzer/issues/8815.

bors r+

Co-authored-by: Jonas Schievink <[email protected]>

1 files changed, 7 insertions, 7 deletions

diff --git a/crates/hir_ty/src/tests/method_resolution.rs b/crates/hir_ty/src/tests/method_resolution.rs
index a4c132bc5..058eb9129 100644
--- a/crates/hir_ty/src/tests/method_resolution.rs
+++ b/crates/hir_ty/src/tests/method_resolution.rs
@@ -796,7 +796,7 @@ fn test() {
 fn method_resolution_trait_from_prelude() {
     check_types(
         r#"
-//- /main.rs crate:main deps:other_crate
+//- /main.rs crate:main deps:core
 struct S;
 impl Clone for S {}
 
@@ -805,12 +805,12 @@ fn test() {
           //^ S
 }
 
-//- /lib.rs crate:other_crate
-#[prelude_import] use foo::*;
-
-mod foo {
-    trait Clone {
-        fn clone(&self) -> Self;
+//- /lib.rs crate:core
+pub mod prelude {
+    pub mod rust_2018 {
+        pub trait Clone {
+            fn clone(&self) -> Self;
+        }
     }
 }
 "#,