From 9a84e66021c1e206e7b1b64ff6de81447ab122c2 Mon Sep 17 00:00:00 2001
From: A4-Tacks <wdsjxhno1001@163.com>
Date: Wed, 4 Feb 2026 12:22:42 +0800
Subject: [PATCH] fix: Fix loses associated bounds for
 replace_derive_with_manual_impl

Example
---
```rust
#[derive(Clo$0ne)]
struct Foo<T: core::ops::Deref>(T::Target);
```

**Before this PR**

```rust
struct Foo<T: core::ops::Deref>(T::Target);

impl<T: core::ops::Deref + Clone> Clone for Foo<T> {
    $0fn clone(&self) -> Self {
        Self(self.0.clone())
    }
}
```

**After this PR**

```rust
struct Foo<T: core::ops::Deref>(T::Target);

impl<T: core::ops::Deref + Clone> Clone for Foo<T>
where T::Target: Clone
{
    $0fn clone(&self) -> Self {
        Self(self.0.clone())
    }
}
```
---
 .../replace_derive_with_manual_impl.rs        | 23 ++++++++
 .../crates/ide-assists/src/utils.rs           | 53 ++++++++++++++++++-
 2 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
index 11b3fd22faa3..7c024263b4a8 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -1307,6 +1307,29 @@ impl<T: Clone> Clone for Foo<T> {
         )
     }
 
+    #[test]
+    fn add_custom_impl_clone_generic_tuple_struct_with_associated() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: clone, derive, deref
+#[derive(Clo$0ne)]
+struct Foo<T: core::ops::Deref>(T::Target);
+"#,
+            r#"
+struct Foo<T: core::ops::Deref>(T::Target);
+
+impl<T: core::ops::Deref + Clone> Clone for Foo<T>
+where T::Target: Clone
+{
+    $0fn clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+}
+"#,
+        )
+    }
+
     #[test]
     fn test_ignore_derive_macro_without_input() {
         check_assist_not_applicable(
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs b/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs
index 4b8c19305793..1732d8c2018e 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs
@@ -15,6 +15,7 @@ use ide_db::{
     path_transform::PathTransform,
     syntax_helpers::{node_ext::preorder_expr, prettify_macro_expansion},
 };
+use itertools::Itertools;
 use stdx::format_to;
 use syntax::{
     AstNode, AstToken, Direction, NodeOrToken, SourceFile,
@@ -766,6 +767,11 @@ fn generate_impl_inner(
     });
     let generic_args =
         generic_params.as_ref().map(|params| params.to_generic_args().clone_for_update());
+    let trait_where_clause = trait_
+        .as_ref()
+        .zip(generic_params.as_ref())
+        .and_then(|(trait_, params)| generic_param_associated_bounds(adt, trait_, params));
+
     let ty = make::ty_path(make::ext::ident_path(&adt.name().unwrap().text()));
 
     let cfg_attrs =
@@ -781,7 +787,7 @@ fn generate_impl_inner(
             false,
             trait_,
             ty,
-            None,
+            trait_where_clause,
             adt.where_clause(),
             body,
         ),
@@ -790,6 +796,51 @@ fn generate_impl_inner(
     .clone_for_update()
 }
 
+fn generic_param_associated_bounds(
+    adt: &ast::Adt,
+    trait_: &ast::Type,
+    generic_params: &ast::GenericParamList,
+) -> Option<ast::WhereClause> {
+    let in_type_params = |name: &ast::NameRef| {
+        generic_params
+            .generic_params()
+            .filter_map(|param| match param {
+                ast::GenericParam::TypeParam(type_param) => type_param.name(),
+                _ => None,
+            })
+            .any(|param| param.text() == name.text())
+    };
+    let adt_body = match adt {
+        ast::Adt::Enum(e) => e.variant_list().map(|it| it.syntax().clone()),
+        ast::Adt::Struct(s) => s.field_list().map(|it| it.syntax().clone()),
+        ast::Adt::Union(u) => u.record_field_list().map(|it| it.syntax().clone()),
+    };
+    let mut trait_where_clause = adt_body
+        .into_iter()
+        .flat_map(|it| it.descendants())
+        .filter_map(ast::Path::cast)
+        .filter_map(|path| {
+            let qualifier = path.qualifier()?.as_single_segment()?;
+            let qualifier = qualifier
+                .name_ref()
+                .or_else(|| match qualifier.type_anchor()?.ty()? {
+                    ast::Type::PathType(path_type) => path_type.path()?.as_single_name_ref(),
+                    _ => None,
+                })
+                .filter(in_type_params)?;
+            Some((qualifier, path.segment()?.name_ref()?))
+        })
+        .map(|(qualifier, assoc_name)| {
+            let segments = [qualifier, assoc_name].map(make::path_segment);
+            let path = make::path_from_segments(segments, false);
+            let bounds = Some(make::type_bound(trait_.clone()));
+            make::where_pred(either::Either::Right(make::ty_path(path)), bounds)
+        })
+        .unique_by(|it| it.syntax().to_string())
+        .peekable();
+    trait_where_clause.peek().is_some().then(|| make::where_clause(trait_where_clause))
+}
+
 pub(crate) fn add_method_to_adt(
     builder: &mut SourceChangeBuilder,
     adt: &ast::Adt,