Add a test

crates/ide/src/inlay_hints.rs

@@ -228,6 +228,8 @@ fn hint_iterator(
             _ => None,
         })?;
         if let Some(ty) = ty.normalize_trait_assoc_type(db, iter_trait, &[], assoc_type_item) {
+            // TODO kb also check for the iterator impls for this ty
+            dbg!(ty.display(db).to_string());
             const LABEL_START: &str = "impl Iterator<Item = ";
             const LABEL_END: &str = ">";
 
@@ -1002,18 +1004,6 @@ fn main() {
 
     println!("Unit expr");
 }
-
-//- /alloc.rs crate:alloc deps:core
-mod collections {
-    struct Vec<T> {}
-    impl<T> Vec<T> {
-        fn new() -> Self { Vec {} }
-        fn push(&mut self, t: T) { }
-    }
-    impl<T> IntoIterator for Vec<T> {
-        type Item=T;
-    }
-}
 "#,
         );
     }
@@ -1043,17 +1033,6 @@ fn main() {
         //^ &str
     }
 }
-//- /alloc.rs crate:alloc deps:core
-mod collections {
-    struct Vec<T> {}
-    impl<T> Vec<T> {
-        fn new() -> Self { Vec {} }
-        fn push(&mut self, t: T) { }
-    }
-    impl<T> IntoIterator for Vec<T> {
-        type Item=T;
-    }
-}
 "#,
         );
     }
@@ -1183,4 +1162,41 @@ fn main() {
             "#]],
         );
     }
+
+    #[test]
+    fn shorten_iterators_in_associated_params() {
+        check_with_config(
+            InlayHintsConfig {
+                parameter_hints: false,
+                type_hints: true,
+                chaining_hints: true,
+                max_length: None,
+            },
+            r#"
+use core::iter;
+
+pub struct SomeIter<T> {}
+
+impl<T> SomeIter<T> {
+    pub fn new() -> Self { SomeIter {} }
+    pub fn push(&mut self, t: T) {}
+}
+
+impl<T> Iterator for SomeIter<T> {
+    type Item = T;
+    fn next(&mut self) -> Option<Self::Item> {
+        None
+    }
+}
+
+fn main() {
+    let mut some_iter = SomeIter::new();
+      //^^^^^^^^^^^^^ SomeIter<Take<Repeat<i32>>>
+      some_iter.push(iter::repeat(2).take(2));
+    let zz = some_iter.take(2);
+      //^^ impl Iterator<Item = Take<Repeat<i32>>>
+}
+"#,
+        );
+    }
 }