4 files changed, 80 insertions, 70 deletions

diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index 9cd33d0e4..335d57a0d 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -434,7 +434,6 @@ fn get_callable(
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
-    use ide_db::helpers::FamousDefs;
     use test_utils::extract_annotations;
 
     use crate::{fixture, inlay_hints::InlayHintsConfig};
@@ -487,8 +486,6 @@ mod tests {
     }
 
     fn check_with_config(config: InlayHintsConfig, ra_fixture: &str) {
-        let ra_fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
         let (analysis, file_id) = fixture::file(&ra_fixture);
         let expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
         let inlay_hints = analysis.inlay_hints(file_id, &config).unwrap();
@@ -498,8 +495,6 @@ mod tests {
     }
 
     fn check_expect(config: InlayHintsConfig, ra_fixture: &str, expect: Expect) {
-        let ra_fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
         let (analysis, file_id) = fixture::file(&ra_fixture);
         let inlay_hints = analysis.inlay_hints(file_id, &config).unwrap();
         expect.assert_debug_eq(&inlay_hints)
@@ -823,6 +818,7 @@ fn main() {
     fn shorten_iterators_in_associated_params() {
         check_types(
             r#"
+//- minicore: iterators
 use core::iter;
 
 pub struct SomeIter<T> {}
@@ -875,7 +871,7 @@ fn main() {
     fn fn_hints() {
         check_types(
             r#"
-trait Sized {}
+//- minicore: fn, sized
 
 fn foo() -> impl Fn() { loop {} }
 fn foo1() -> impl Fn(f64) { loop {} }
@@ -1073,6 +1069,7 @@ fn main() {
     fn complete_for_hint() {
         check_types(
             r#"
+//- minicore: iterator
 pub struct Vec<T> {}
 
 impl<T> Vec<T> {
@@ -1129,6 +1126,7 @@ fn main() {
     fn shorten_iterator_hints() {
         check_types(
             r#"
+//- minicore: iterators
 use core::iter;
 
 struct MyIter;
@@ -1230,12 +1228,12 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 148..173,
+                        range: 147..172,
                         kind: ChainingHint,
                         label: "B",
                     },
                     InlayHint {
-                        range: 148..155,
+                        range: 147..154,
                         kind: ChainingHint,
                         label: "A",
                     },
@@ -1290,12 +1288,12 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 144..191,
+                        range: 143..190,
                         kind: ChainingHint,
                         label: "C",
                     },
                     InlayHint {
-                        range: 144..180,
+                        range: 143..179,
                         kind: ChainingHint,
                         label: "B",
                     },
@@ -1335,12 +1333,12 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 247..284,
+                        range: 246..283,
                         kind: ChainingHint,
                         label: "B<X<i32, bool>>",
                     },
                     InlayHint {
-                        range: 247..266,
+                        range: 246..265,
                         kind: ChainingHint,
                         label: "A<X<i32, bool>>",
                     },
@@ -1359,6 +1357,7 @@ fn main() {
                 max_length: None,
             },
             r#"
+//- minicore: iterators
 use core::iter;
 
 struct MyIter;
@@ -1381,22 +1380,22 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 175..242,
+                        range: 174..241,
                         kind: ChainingHint,
                         label: "impl Iterator<Item = ()>",
                     },
                     InlayHint {
-                        range: 175..225,
+                        range: 174..224,
                         kind: ChainingHint,
                         label: "impl Iterator<Item = ()>",
                     },
                     InlayHint {
-                        range: 175..207,
+                        range: 174..206,
                         kind: ChainingHint,
                         label: "impl Iterator<Item = ()>",
                     },
                     InlayHint {
-                        range: 175..190,
+                        range: 174..189,
                         kind: ChainingHint,
                         label: "&mut MyIter",
                     },
diff --git a/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs b/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs
index 8e571723d..5f2aa016f 100644
--- a/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs
+++ b/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs
@@ -186,18 +186,14 @@ fn main() {
     fn test_for_borrowed() {
         check_assist(
             replace_for_loop_with_for_each,
-            r"
-//- minicore: iterator
-struct Iter;
-impl Iterator for Iter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
+            r#"
+//- minicore: iterators
+use core::iter::{Repeat, repeat};
 
 struct S;
 impl S {
-    fn iter(&self) -> Iter { Iter }
-    fn iter_mut(&mut self) -> Iter { Iter }
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
 }
 
 fn main() {
@@ -206,18 +202,14 @@ fn main() {
         let a = v * 2;
     }
 }
-",
-            r"
-struct Iter;
-impl Iterator for Iter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
+"#,
+            r#"
+use core::iter::{Repeat, repeat};
 
 struct S;
 impl S {
-    fn iter(&self) -> Iter { Iter }
-    fn iter_mut(&mut self) -> Iter { Iter }
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
 }
 
 fn main() {
@@ -226,7 +218,7 @@ fn main() {
         let a = v * 2;
     });
 }
-",
+"#,
         )
     }
 
@@ -259,18 +251,14 @@ fn main() {
     fn test_for_borrowed_mut() {
         check_assist(
             replace_for_loop_with_for_each,
-            r"
-//- minicore: iterator
-struct Iter;
-impl Iterator for Iter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
+            r#"
+//- minicore: iterators
+use core::iter::{Repeat, repeat};
 
 struct S;
 impl S {
-    fn iter(&self) -> Iter { Iter }
-    fn iter_mut(&mut self) -> Iter { Iter }
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
 }
 
 fn main() {
@@ -279,18 +267,14 @@ fn main() {
         let a = v * 2;
     }
 }
-",
-            r"
-struct Iter;
-impl Iterator for Iter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
+"#,
+            r#"
+use core::iter::{Repeat, repeat};
 
 struct S;
 impl S {
-    fn iter(&self) -> Iter { Iter }
-    fn iter_mut(&mut self) -> Iter { Iter }
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
 }
 
 fn main() {
@@ -299,7 +283,7 @@ fn main() {
         let a = v * 2;
     });
 }
-",
+"#,
         )
     }
 
@@ -332,28 +316,16 @@ fn main() {
         check_assist(
             replace_for_loop_with_for_each,
             r#"
-//- minicore: iterator
-struct Iter;
-impl Iterator for Iter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
-
+//- minicore: iterators
 fn main() {
-    for$0 a in Iter.take(1) {
+    for$0 a in core::iter::repeat(92).take(1) {
         println!("{}", a);
     }
 }
 "#,
             r#"
-struct Iter;
-impl Iterator for Iter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
-
 fn main() {
-    Iter.take(1).for_each(|a| {
+    core::iter::repeat(92).take(1).for_each(|a| {
         println!("{}", a);
     });
 }
diff --git a/crates/test_utils/src/fixture.rs b/crates/test_utils/src/fixture.rs
index 005a5c092..8d8f3b560 100644
--- a/crates/test_utils/src/fixture.rs
+++ b/crates/test_utils/src/fixture.rs
@@ -154,7 +154,7 @@ impl Fixture {
         let components = meta.split_ascii_whitespace().collect::<Vec<_>>();
 
         let path = components[0].to_string();
-        assert!(path.starts_with('/'));
+        assert!(path.starts_with('/'), "fixture path does not start with `/`: {:?}", path);
 
         let mut krate = None;
         let mut deps = Vec::new();
diff --git a/crates/test_utils/src/minicore.rs b/crates/test_utils/src/minicore.rs
index 2f0da7fe5..e6d2301c7 100644
--- a/crates/test_utils/src/minicore.rs
+++ b/crates/test_utils/src/minicore.rs
@@ -21,6 +21,7 @@
 //!     option:
 //!     result:
 //!     iterator: option
+//!     iterators: iterator
 
 pub mod marker {
     // region:sized
@@ -209,6 +210,7 @@ pub mod task {
 
 // region:iterator
 pub mod iter {
+    // region:iterators
     mod adapters {
         pub struct Take<I> {
             iter: I,
@@ -228,6 +230,29 @@ pub mod iter {
     }
     pub use self::adapters::Take;
 
+    mod sources {
+        mod repeat {
+            pub fn repeat<T>(elt: T) -> Repeat<T> {
+                loop {}
+            }
+
+            pub struct Repeat<A> {
+                element: A,
+            }
+
+            impl<A> Iterator for Repeat<A> {
+                type Item = A;
+
+                fn next(&mut self) -> Option<A> {
+                    loop {}
+                }
+            }
+        }
+        pub use self::repeat::{repeat, Repeat};
+    }
+    pub use self::sources::{repeat, Repeat};
+    // endregion:iterators
+
     mod traits {
         mod iterator {
             use super::super::Take;
@@ -239,9 +264,23 @@ pub mod iter {
                 fn nth(&mut self, n: usize) -> Option<Self::Item> {
                     loop {}
                 }
+                fn by_ref(&mut self) -> &mut Self
+                where
+                    Self: Sized,
+                {
+                    self
+                }
+                // region:iterators
                 fn take(self, n: usize) -> crate::iter::Take<Self> {
                     loop {}
                 }
+                // endregion:iterators
+            }
+            impl<I: Iterator + ?Sized> Iterator for &mut I {
+                type Item = I::Item;
+                fn next(&mut self) -> Option<I::Item> {
+                    (**self).next()
+                }
             }
         }
         pub use self::iterator::Iterator;