diff --git a/crates/ide-assists/src/handlers/generate_delegate_trait.rs b/crates/ide-assists/src/handlers/generate_delegate_trait.rs
new file mode 100644
index 00000000000..ce8f4256c08
--- /dev/null
+++ b/crates/ide-assists/src/handlers/generate_delegate_trait.rs
@@ -0,0 +1,1064 @@
+use std::ops::Not;
+
+use crate::{
+ assist_context::{AssistContext, Assists},
+ utils::convert_param_list_to_arg_list,
+};
+use either::Either;
+use hir::{db::HirDatabase, HasVisibility};
+use ide_db::{
+ assists::{AssistId, GroupLabel},
+ path_transform::PathTransform,
+};
+use syntax::{
+ ast::{
+ self,
+ edit::{self, AstNodeEdit},
+ make, AssocItem, HasGenericParams, HasName, HasVisibility as astHasVisibility, Path,
+ },
+ ted::{self, Position},
+ AstNode, NodeOrToken, SyntaxKind,
+};
+
+// Assist: generate_delegate_trait
+//
+// Generate delegate trait implementation for `StructField`s.
+//
+// ```
+// trait SomeTrait {
+// type T;
+// fn fn_(arg: u32) -> u32;
+// fn method_(&mut self) -> bool;
+// }
+// struct A;
+// impl SomeTrait for A {
+// type T = u32;
+//
+// fn fn_(arg: u32) -> u32 {
+// 42
+// }
+//
+// fn method_(&mut self) -> bool {
+// false
+// }
+// }
+// struct B {
+// a$0: A,
+// }
+// ```
+// ->
+// ```
+// trait SomeTrait {
+// type T;
+// fn fn_(arg: u32) -> u32;
+// fn method_(&mut self) -> bool;
+// }
+// struct A;
+// impl SomeTrait for A {
+// type T = u32;
+//
+// fn fn_(arg: u32) -> u32 {
+// 42
+// }
+//
+// fn method_(&mut self) -> bool {
+// false
+// }
+// }
+// struct B {
+// a: A,
+// }
+//
+// impl SomeTrait for B {
+// type T = ::T;
+//
+// fn fn_(arg: u32) -> u32 {
+// ::fn_(arg)
+// }
+//
+// fn method_(&mut self) -> bool {
+// ::method_( &mut self.a )
+// }
+// }
+// ```
+pub(crate) fn generate_delegate_trait(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
+ let strukt = Struct::new(ctx.find_node_at_offset::()?)?;
+
+ let field: Field = match ctx.find_node_at_offset::() {
+ Some(field) => Field::new(&ctx, Either::Left(field))?,
+ None => {
+ let field = ctx.find_node_at_offset::()?;
+ let field_list = ctx.find_node_at_offset::()?;
+ Field::new(&ctx, either::Right((field, field_list)))?
+ }
+ };
+
+ strukt.delegate(field, acc, ctx);
+ Some(())
+}
+
+/// A utility object that represents a struct's field.
+struct Field {
+ name: String,
+ ty: ast::Type,
+ range: syntax::TextRange,
+ impls: Vec,
+}
+
+impl Field {
+ pub fn new(
+ ctx: &AssistContext<'_>,
+ f: Either,
+ ) -> Option {
+ let db = ctx.sema.db;
+ let name: String;
+ let range: syntax::TextRange;
+ let ty: ast::Type;
+
+ let module = ctx.sema.to_module_def(ctx.file_id())?;
+
+ match f {
+ Either::Left(f) => {
+ name = f.name()?.to_string();
+ ty = f.ty()?;
+ range = f.syntax().text_range();
+ }
+ Either::Right((f, l)) => {
+ name = l.fields().position(|it| it == f)?.to_string();
+ ty = f.ty()?;
+ range = f.syntax().text_range();
+ }
+ };
+
+ let hir_ty = ctx.sema.resolve_type(&ty)?;
+ let type_impls = hir::Impl::all_for_type(db, hir_ty.clone());
+ let mut impls = Vec::with_capacity(type_impls.len());
+ let type_param = hir_ty.as_type_param(db);
+
+ if let Some(tp) = type_param {
+ for tb in tp.trait_bounds(db) {
+ impls.push(Delegee::Bound(BoundCase { 0: tb }));
+ }
+ };
+
+ for imp in type_impls {
+ match imp.trait_(db) {
+ Some(tr) => {
+ if tr.is_visible_from(db, module) {
+ impls.push(Delegee::Impls(ImplCase { 0: tr, 1: imp }))
+ }
+ }
+ None => {
+ continue;
+ }
+ }
+ }
+
+ Some(Field { name, ty, range, impls })
+ }
+}
+
+/// A field that we want to delegate can offer the enclosing struct
+/// trait to implement in two ways. The first way is when the field
+/// actually implements the trait and the second way is when the field
+/// has a bound type parameter. We handle these cases in different ways
+/// hence the enum.
+enum Delegee {
+ Bound(BoundCase),
+ Impls(ImplCase),
+}
+
+struct BoundCase(hir::Trait);
+struct ImplCase(hir::Trait, hir::Impl);
+
+/// When we list traits we can implement for the enclosing struct
+/// we use the absolute path of a trait. This trait consists of a single
+/// method that produces this path.
+trait Signatured {
+ fn signature(&self, db: &dyn HirDatabase) -> String;
+}
+
+impl Signatured for Delegee {
+ fn signature(&self, db: &dyn HirDatabase) -> String {
+ let mut s = String::new();
+ let trait_: hir::Trait;
+
+ match self {
+ Delegee::Bound(b) => trait_ = b.0,
+ Delegee::Impls(i) => trait_ = i.0,
+ };
+
+ for m in trait_.module(db).path_to_root(db).iter().rev() {
+ if let Some(name) = m.name(db) {
+ s.push_str(&format!("{}::", name.to_smol_str()));
+ } else {
+ continue;
+ }
+ }
+
+ s.push_str(&trait_.name(db).to_smol_str());
+ s
+ }
+}
+
+/// A utility struct that is used for the enclosing struct.
+struct Struct {
+ strukt: ast::Struct,
+ name: ast::Name,
+}
+
+impl Struct {
+ pub fn new(s: ast::Struct) -> Option {
+ let name = s.name()?;
+ Some(Struct { name, strukt: s })
+ }
+
+ pub fn delegate(&self, field: Field, acc: &mut Assists, ctx: &AssistContext<'_>) {
+ let db = ctx.db();
+ for delegee in &field.impls {
+ // FIXME : We can omit already implemented impl_traits
+ // But we don't know what the &[hir::Type] argument should look like.
+
+ // let trait_ = match delegee {
+ // Delegee::Bound(b) => b.0,
+ // Delegee::Impls(i) => i.1,
+ // };
+
+ // if self.hir_ty.impls_trait(db, trait_, &[]) {
+ // continue;
+ // }
+ let signature = delegee.signature(db);
+ let delegate = generate_impl(ctx, self, &field.ty, &field.name, delegee);
+
+ acc.add_group(
+ &GroupLabel("Generate delegate traits...".to_owned()),
+ AssistId("generate_delegate_trait", ide_db::assists::AssistKind::Generate),
+ format!("Generate delegate impl `{}` for `{}`", signature, field.name),
+ field.range,
+ |builder| {
+ builder.insert(
+ self.strukt.syntax().text_range().end(),
+ format!("\n\n{}", delegate.syntax()),
+ );
+ },
+ );
+ }
+ }
+}
+
+fn generate_impl(
+ ctx: &AssistContext<'_>,
+ strukt: &Struct,
+ field_ty: &ast::Type,
+ field_name: &String,
+ delegee: &Delegee,
+) -> ast::Impl {
+ let delegate: ast::Impl;
+ let source: ast::Impl;
+ let genpar: Option;
+ let db = ctx.db();
+ let base_path = make::path_from_text(&field_ty.to_string().as_str());
+ let s_path = make::ext::ident_path(&strukt.name.to_string());
+
+ match delegee {
+ Delegee::Bound(delegee) => {
+ let in_file = ctx.sema.source(delegee.0.to_owned()).unwrap();
+ let source: ast::Trait = in_file.value;
+
+ delegate = make::impl_trait(
+ delegee.0.is_unsafe(db),
+ None,
+ None,
+ strukt.strukt.generic_param_list(),
+ None,
+ delegee.0.is_auto(db),
+ make::ty(&delegee.0.name(db).to_smol_str()),
+ make::ty_path(s_path),
+ source.where_clause(),
+ strukt.strukt.where_clause(),
+ None,
+ )
+ .clone_for_update();
+
+ genpar = source.generic_param_list();
+ let delegate_assoc_items = delegate.get_or_create_assoc_item_list();
+ let gen_args: String =
+ genpar.map_or_else(String::new, |params| params.to_generic_args().to_string());
+
+ // Goto link : https://doc.rust-lang.org/reference/paths.html#qualified-paths
+ let qualified_path_type = make::path_from_text(&format!(
+ "<{} as {}{}>",
+ base_path.to_string(),
+ delegee.0.name(db).to_smol_str(),
+ gen_args.to_string()
+ ));
+
+ match source.assoc_item_list() {
+ Some(ai) => {
+ ai.assoc_items()
+ .filter(|item| matches!(item, AssocItem::MacroCall(_)).not())
+ .for_each(|item| {
+ let assoc =
+ process_assoc_item(item, qualified_path_type.clone(), &field_name);
+ if let Some(assoc) = assoc {
+ delegate_assoc_items.add_item(assoc);
+ }
+ });
+ }
+ None => {}
+ };
+
+ let target = ctx.sema.scope(strukt.strukt.syntax()).unwrap();
+ let source = ctx.sema.scope_for_def(delegee.0);
+
+ let transform =
+ PathTransform::trait_impl(&target, &source, delegee.0, delegate.clone());
+ transform.apply(&delegate.syntax());
+ }
+ Delegee::Impls(delegee) => {
+ let in_file = ctx.sema.source(delegee.1.to_owned()).unwrap();
+ source = in_file.value;
+ delegate = make::impl_trait(
+ delegee.0.is_unsafe(db),
+ source.generic_param_list(),
+ None,
+ None,
+ None,
+ delegee.0.is_auto(db),
+ make::ty(&delegee.0.name(db).to_smol_str()),
+ make::ty_path(s_path),
+ source.where_clause(),
+ strukt.strukt.where_clause(),
+ None,
+ )
+ .clone_for_update();
+ genpar = source.generic_param_list();
+ let delegate_assoc_items = delegate.get_or_create_assoc_item_list();
+ let gen_args: String =
+ genpar.map_or_else(String::new, |params| params.to_generic_args().to_string());
+
+ // Goto link : https://doc.rust-lang.org/reference/paths.html#qualified-paths
+ let qualified_path_type = make::path_from_text(&format!(
+ "<{} as {}{}>",
+ base_path.to_string().as_str(),
+ delegee.0.name(db).to_smol_str(),
+ gen_args.to_string().as_str()
+ ));
+
+ source
+ .get_or_create_assoc_item_list()
+ .assoc_items()
+ .filter(|item| matches!(item, AssocItem::MacroCall(_)).not())
+ .for_each(|item| {
+ let assoc = process_assoc_item(item, qualified_path_type.clone(), &field_name);
+ if let Some(assoc) = assoc {
+ delegate_assoc_items.add_item(assoc);
+ }
+ });
+
+ let target = ctx.sema.scope(strukt.strukt.syntax()).unwrap();
+ let source = ctx.sema.scope_for_def(delegee.0);
+
+ let transform =
+ PathTransform::trait_impl(&target, &source, delegee.0, delegate.clone());
+ transform.apply(&delegate.syntax());
+ }
+ }
+
+ delegate
+}
+
+fn process_assoc_item(
+ item: syntax::ast::AssocItem,
+ qual_path_ty: ast::Path,
+ base_name: &str,
+) -> Option {
+ match item {
+ AssocItem::Const(c) => Some(const_assoc_item(c, qual_path_ty)),
+ AssocItem::Fn(f) => Some(func_assoc_item(f, qual_path_ty, base_name)),
+ AssocItem::MacroCall(_) => {
+ // FIXME : Handle MacroCall case.
+ // return Some(macro_assoc_item(mac, qual_path_ty));
+ None
+ }
+ AssocItem::TypeAlias(ta) => Some(ty_assoc_item(ta, qual_path_ty)),
+ }
+}
+
+fn const_assoc_item(item: syntax::ast::Const, qual_path_ty: ast::Path) -> AssocItem {
+ let path_expr_segment = make::path_from_text(item.name().unwrap().to_string().as_str());
+
+ // We want rhs of the const assignment to be a qualified path
+ // The general case for const assigment can be found [here](`https://doc.rust-lang.org/reference/items/constant-items.html`)
+ // The qualified will have the following generic syntax :
+ // >::ConstName;
+ // FIXME : We can't rely on `make::path_qualified` for now but it would be nice to replace the following with it.
+ // make::path_qualified(qual_path_ty, path_expr_segment.as_single_segment().unwrap());
+ let qualpath = qualpath(qual_path_ty, path_expr_segment);
+ let inner = make::item_const(
+ item.visibility(),
+ item.name().unwrap(),
+ item.ty().unwrap(),
+ make::expr_path(qualpath),
+ )
+ .clone_for_update();
+
+ AssocItem::Const(inner)
+}
+
+fn func_assoc_item(item: syntax::ast::Fn, qual_path_ty: Path, base_name: &str) -> AssocItem {
+ let path_expr_segment = make::path_from_text(item.name().unwrap().to_string().as_str());
+ let qualpath = qualpath(qual_path_ty, path_expr_segment);
+
+ let call = match item.param_list() {
+ // Methods and funcs should be handled separately.
+ // We ask if the func has a `self` param.
+ Some(l) => match l.self_param() {
+ Some(slf) => {
+ let mut self_kw = make::expr_path(make::path_from_text("self"));
+ self_kw = make::expr_field(self_kw, base_name);
+
+ let tail_expr_self = match slf.kind() {
+ ast::SelfParamKind::Owned => self_kw,
+ ast::SelfParamKind::Ref => make::expr_ref(self_kw, false),
+ ast::SelfParamKind::MutRef => make::expr_ref(self_kw, true),
+ };
+
+ let param_count = l.params().count();
+ let args = convert_param_list_to_arg_list(l).clone_for_update();
+
+ if param_count > 0 {
+ // Add SelfParam and a TOKEN::COMMA
+ ted::insert_all(
+ Position::after(args.l_paren_token().unwrap()),
+ vec![
+ NodeOrToken::Node(tail_expr_self.syntax().clone_for_update()),
+ NodeOrToken::Token(make::token(SyntaxKind::WHITESPACE)),
+ NodeOrToken::Token(make::token(SyntaxKind::COMMA)),
+ ],
+ );
+ } else {
+ // Add SelfParam only
+ ted::insert(
+ Position::after(args.l_paren_token().unwrap()),
+ NodeOrToken::Node(tail_expr_self.syntax().clone_for_update()),
+ );
+ }
+
+ make::expr_call(make::expr_path(qualpath), args)
+ }
+ None => make::expr_call(make::expr_path(qualpath), convert_param_list_to_arg_list(l)),
+ },
+ None => make::expr_call(
+ make::expr_path(qualpath),
+ convert_param_list_to_arg_list(make::param_list(None, Vec::new())),
+ ),
+ }
+ .clone_for_update();
+
+ let body = make::block_expr(vec![], Some(call)).clone_for_update();
+ let func = make::fn_(
+ item.visibility(),
+ item.name().unwrap(),
+ item.generic_param_list(),
+ item.where_clause(),
+ item.param_list().unwrap(),
+ body,
+ item.ret_type(),
+ item.async_token().is_some(),
+ item.const_token().is_some(),
+ item.unsafe_token().is_some(),
+ )
+ .clone_for_update();
+
+ AssocItem::Fn(func.indent(edit::IndentLevel(1)).clone_for_update())
+}
+
+fn ty_assoc_item(item: syntax::ast::TypeAlias, qual_path_ty: Path) -> AssocItem {
+ let path_expr_segment = make::path_from_text(item.name().unwrap().to_string().as_str());
+ let qualpath = qualpath(qual_path_ty, path_expr_segment);
+ let ty = make::ty_path(qualpath);
+ let ident = item.name().unwrap().to_string();
+
+ let alias = make::ty_alias(
+ ident.as_str(),
+ item.generic_param_list(),
+ None,
+ item.where_clause(),
+ Some((ty, None)),
+ )
+ .clone_for_update();
+
+ AssocItem::TypeAlias(alias)
+}
+
+fn qualpath(qual_path_ty: ast::Path, path_expr_seg: ast::Path) -> ast::Path {
+ make::path_from_text(&format!("{}::{}", qual_path_ty.to_string(), path_expr_seg.to_string()))
+}
+
+#[cfg(test)]
+mod test {
+
+ use super::*;
+ use crate::tests::{check_assist, check_assist_not_applicable};
+
+ #[test]
+ fn test_tuple_struct_basic() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+struct Base;
+struct S(B$0ase);
+trait Trait {}
+impl Trait for Base {}
+"#,
+ r#"
+struct Base;
+struct S(Base);
+
+impl Trait for S {}
+trait Trait {}
+impl Trait for Base {}
+"#,
+ );
+ }
+
+ #[test]
+ fn test_struct_struct_basic() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+struct Base;
+struct S {
+ ba$0se : Base
+}
+trait Trait {}
+impl Trait for Base {}
+"#,
+ r#"
+struct Base;
+struct S {
+ base : Base
+}
+
+impl Trait for S {}
+trait Trait {}
+impl Trait for Base {}
+"#,
+ )
+ }
+
+ // Structs need to be by def populated with fields
+ // However user can invoke this assist while still editing
+ // We therefore assert its non-applicability
+ #[test]
+ fn test_yet_empty_struct() {
+ check_assist_not_applicable(
+ generate_delegate_trait,
+ r#"
+struct Base;
+struct S {
+ $0
+}
+
+impl Trait for S {}
+trait Trait {}
+impl Trait for Base {}
+"#,
+ )
+ }
+
+ #[test]
+ fn test_yet_unspecified_field_type() {
+ check_assist_not_applicable(
+ generate_delegate_trait,
+ r#"
+struct Base;
+struct S {
+ ab$0c
+}
+
+impl Trait for S {}
+trait Trait {}
+impl Trait for Base {}
+"#,
+ );
+ }
+
+ #[test]
+ fn test_unsafe_trait() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+struct Base;
+struct S {
+ ba$0se : Base
+}
+unsafe trait Trait {}
+unsafe impl Trait for Base {}
+"#,
+ r#"
+struct Base;
+struct S {
+ base : Base
+}
+
+unsafe impl Trait for S {}
+unsafe trait Trait {}
+unsafe impl Trait for Base {}
+"#,
+ );
+ }
+
+ #[test]
+ fn test_unsafe_trait_with_unsafe_fn() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+struct Base;
+struct S {
+ ba$0se: Base,
+}
+
+unsafe trait Trait {
+ unsafe fn a_func();
+ unsafe fn a_method(&self);
+}
+unsafe impl Trait for Base {
+ unsafe fn a_func() {}
+ unsafe fn a_method(&self) {}
+}
+"#,
+ r#"
+struct Base;
+struct S {
+ base: Base,
+}
+
+unsafe impl Trait for S {
+ unsafe fn a_func() {
+ ::a_func()
+ }
+
+ unsafe fn a_method(&self) {
+ ::a_method( &self.base )
+ }
+}
+
+unsafe trait Trait {
+ unsafe fn a_func();
+ unsafe fn a_method(&self);
+}
+unsafe impl Trait for Base {
+ unsafe fn a_func() {}
+ unsafe fn a_method(&self) {}
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn test_struct_with_where_clause() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+trait AnotherTrait {}
+struct S
+where
+ T: AnotherTrait,
+{
+ b$0 : T,
+}"#,
+ r#"
+trait AnotherTrait {}
+struct S
+where
+ T: AnotherTrait,
+{
+ b : T,
+}
+
+impl AnotherTrait for S
+where
+ T: AnotherTrait,
+{}"#,
+ );
+ }
+
+ #[test]
+ fn test_complex_without_where() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+trait Trait<'a, T, const C: usize> {
+ type AssocType;
+ const AssocConst: usize;
+ fn assoc_fn(p: ());
+ fn assoc_method(&self, p: ());
+}
+
+struct Base;
+struct S {
+ field$0: Base
+}
+
+impl<'a, T, const C: usize> Trait<'a, T, C> for Base {
+ type AssocType = ();
+ const AssocConst: usize = 0;
+ fn assoc_fn(p: ()) {}
+ fn assoc_method(&self, p: ()) {}
+}
+"#,
+ r#"
+trait Trait<'a, T, const C: usize> {
+ type AssocType;
+ const AssocConst: usize;
+ fn assoc_fn(p: ());
+ fn assoc_method(&self, p: ());
+}
+
+struct Base;
+struct S {
+ field: Base
+}
+
+impl<'a, T, const C: usize> Trait<'a, T, C> for S {
+ type AssocType = >::AssocType;
+
+ const AssocConst: usize = >::AssocConst;
+
+ fn assoc_fn(p: ()) {
+ >::assoc_fn(p)
+ }
+
+ fn assoc_method(&self, p: ()) {
+ >::assoc_method( &self.field , p)
+ }
+}
+
+impl<'a, T, const C: usize> Trait<'a, T, C> for Base {
+ type AssocType = ();
+ const AssocConst: usize = 0;
+ fn assoc_fn(p: ()) {}
+ fn assoc_method(&self, p: ()) {}
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn test_complex_two() {
+ check_assist(
+ generate_delegate_trait,
+ r"
+trait AnotherTrait {}
+
+trait Trait<'a, T, const C: usize> {
+ type AssocType;
+ const AssocConst: usize;
+ fn assoc_fn(p: ());
+ fn assoc_method(&self, p: ());
+}
+
+struct Base;
+struct S {
+ fi$0eld: Base,
+}
+
+impl<'b, C, const D: usize> Trait<'b, C, D> for Base
+where
+ C: AnotherTrait,
+{
+ type AssocType = ();
+ const AssocConst: usize = 0;
+ fn assoc_fn(p: ()) {}
+ fn assoc_method(&self, p: ()) {}
+}",
+ r#"
+trait AnotherTrait {}
+
+trait Trait<'a, T, const C: usize> {
+ type AssocType;
+ const AssocConst: usize;
+ fn assoc_fn(p: ());
+ fn assoc_method(&self, p: ());
+}
+
+struct Base;
+struct S {
+ field: Base,
+}
+
+impl<'b, C, const D: usize> Trait<'b, C, D> for S
+where
+ C: AnotherTrait,
+{
+ type AssocType = >::AssocType;
+
+ const AssocConst: usize = >::AssocConst;
+
+ fn assoc_fn(p: ()) {
+ >::assoc_fn(p)
+ }
+
+ fn assoc_method(&self, p: ()) {
+ >::assoc_method( &self.field , p)
+ }
+}
+
+impl<'b, C, const D: usize> Trait<'b, C, D> for Base
+where
+ C: AnotherTrait,
+{
+ type AssocType = ();
+ const AssocConst: usize = 0;
+ fn assoc_fn(p: ()) {}
+ fn assoc_method(&self, p: ()) {}
+}"#,
+ )
+ }
+
+ #[test]
+ fn test_complex_three() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+trait AnotherTrait {}
+trait YetAnotherTrait {}
+
+struct StructImplsAll();
+impl AnotherTrait for StructImplsAll {}
+impl YetAnotherTrait for StructImplsAll {}
+
+trait Trait<'a, T, const C: usize> {
+ type A;
+ const ASSOC_CONST: usize = C;
+ fn assoc_fn(p: ());
+ fn assoc_method(&self, p: ());
+}
+
+struct Base;
+struct S {
+ fi$0eld: Base,
+}
+
+impl<'b, A: AnotherTrait + YetAnotherTrait, const B: usize> Trait<'b, A, B> for Base
+where
+ A: AnotherTrait,
+{
+ type A = i32;
+
+ const ASSOC_CONST: usize = B;
+
+ fn assoc_fn(p: ()) {}
+
+ fn assoc_method(&self, p: ()) {}
+}
+"#,
+ r#"
+trait AnotherTrait {}
+trait YetAnotherTrait {}
+
+struct StructImplsAll();
+impl AnotherTrait for StructImplsAll {}
+impl YetAnotherTrait for StructImplsAll {}
+
+trait Trait<'a, T, const C: usize> {
+ type A;
+ const ASSOC_CONST: usize = C;
+ fn assoc_fn(p: ());
+ fn assoc_method(&self, p: ());
+}
+
+struct Base;
+struct S {
+ field: Base,
+}
+
+impl<'b, A: AnotherTrait + YetAnotherTrait, const B: usize> Trait<'b, A, B> for S
+where
+ A: AnotherTrait,
+{
+ type A = >::A;
+
+ const ASSOC_CONST: usize = >::ASSOC_CONST;
+
+ fn assoc_fn(p: ()) {
+ >::assoc_fn(p)
+ }
+
+ fn assoc_method(&self, p: ()) {
+ >::assoc_method( &self.field , p)
+ }
+}
+
+impl<'b, A: AnotherTrait + YetAnotherTrait, const B: usize> Trait<'b, A, B> for Base
+where
+ A: AnotherTrait,
+{
+ type A = i32;
+
+ const ASSOC_CONST: usize = B;
+
+ fn assoc_fn(p: ()) {}
+
+ fn assoc_method(&self, p: ()) {}
+}
+"#,
+ )
+ }
+
+ #[test]
+ fn test_type_bound() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+trait AnotherTrait {}
+struct S
+where
+ T: AnotherTrait,
+{
+ b$0: T,
+}"#,
+ r#"
+trait AnotherTrait {}
+struct S
+where
+ T: AnotherTrait,
+{
+ b: T,
+}
+
+impl AnotherTrait for S
+where
+ T: AnotherTrait,
+{}"#,
+ );
+ }
+
+ #[test]
+ fn test_docstring_example() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+trait SomeTrait {
+ type T;
+ fn fn_(arg: u32) -> u32;
+ fn method_(&mut self) -> bool;
+}
+struct A;
+impl SomeTrait for A {
+ type T = u32;
+ fn fn_(arg: u32) -> u32 {
+ 42
+ }
+ fn method_(&mut self) -> bool {
+ false
+ }
+}
+struct B {
+ a$0: A,
+}
+"#,
+ r#"
+trait SomeTrait {
+ type T;
+ fn fn_(arg: u32) -> u32;
+ fn method_(&mut self) -> bool;
+}
+struct A;
+impl SomeTrait for A {
+ type T = u32;
+ fn fn_(arg: u32) -> u32 {
+ 42
+ }
+ fn method_(&mut self) -> bool {
+ false
+ }
+}
+struct B {
+ a: A,
+}
+
+impl SomeTrait for B {
+ type T = ::T;
+
+ fn fn_(arg: u32) -> u32 {
+ ::fn_(arg)
+ }
+
+ fn method_(&mut self) -> bool {
+ ::method_( &mut self.a )
+ }
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn import_from_other_mod() {
+ check_assist(
+ generate_delegate_trait,
+ r#"
+mod some_module {
+ pub trait SomeTrait {
+ type T;
+ fn fn_(arg: u32) -> u32;
+ fn method_(&mut self) -> bool;
+ }
+ pub struct A;
+ impl SomeTrait for A {
+ type T = u32;
+
+ fn fn_(arg: u32) -> u32 {
+ 42
+ }
+
+ fn method_(&mut self) -> bool {
+ false
+ }
+ }
+}
+
+struct B {
+ a$0: some_module::A,
+}"#,
+ r#"
+mod some_module {
+ pub trait SomeTrait {
+ type T;
+ fn fn_(arg: u32) -> u32;
+ fn method_(&mut self) -> bool;
+ }
+ pub struct A;
+ impl SomeTrait for A {
+ type T = u32;
+
+ fn fn_(arg: u32) -> u32 {
+ 42
+ }
+
+ fn method_(&mut self) -> bool {
+ false
+ }
+ }
+}
+
+struct B {
+ a: some_module::A,
+}
+
+impl some_module::SomeTrait for B {
+ type T = ::T;
+
+ fn fn_(arg: u32) -> u32 {
+ ::fn_(arg)
+ }
+
+ fn method_(&mut self) -> bool {
+ ::method_( &mut self.a )
+ }
+}"#,
+ )
+ }
+}
diff --git a/crates/ide-assists/src/lib.rs b/crates/ide-assists/src/lib.rs
index 111753bf309..dc0a69971ef 100644
--- a/crates/ide-assists/src/lib.rs
+++ b/crates/ide-assists/src/lib.rs
@@ -145,6 +145,7 @@ mod handlers {
mod generate_constant;
mod generate_default_from_enum_variant;
mod generate_default_from_new;
+ mod generate_delegate_trait;
mod generate_deref;
mod generate_derive;
mod generate_documentation_template;
@@ -251,6 +252,7 @@ mod handlers {
generate_constant::generate_constant,
generate_default_from_enum_variant::generate_default_from_enum_variant,
generate_default_from_new::generate_default_from_new,
+ generate_delegate_trait::generate_delegate_trait,
generate_derive::generate_derive,
generate_documentation_template::generate_documentation_template,
generate_documentation_template::generate_doc_example,
diff --git a/crates/ide-assists/src/tests/generated.rs b/crates/ide-assists/src/tests/generated.rs
index c097e073980..c6c70cc64a6 100644
--- a/crates/ide-assists/src/tests/generated.rs
+++ b/crates/ide-assists/src/tests/generated.rs
@@ -1015,6 +1015,69 @@ impl Person {
)
}
+#[test]
+fn doctest_generate_delegate_trait() {
+ check_doc_test(
+ "generate_delegate_trait",
+ r#####"
+trait SomeTrait {
+ type T;
+ fn fn_(arg: u32) -> u32;
+ fn method_(&mut self) -> bool;
+}
+struct A;
+impl SomeTrait for A {
+ type T = u32;
+
+ fn fn_(arg: u32) -> u32 {
+ 42
+ }
+
+ fn method_(&mut self) -> bool {
+ false
+ }
+}
+struct B {
+ a$0: A,
+}
+"#####,
+ r#####"
+trait SomeTrait {
+ type T;
+ fn fn_(arg: u32) -> u32;
+ fn method_(&mut self) -> bool;
+}
+struct A;
+impl SomeTrait for A {
+ type T = u32;
+
+ fn fn_(arg: u32) -> u32 {
+ 42
+ }
+
+ fn method_(&mut self) -> bool {
+ false
+ }
+}
+struct B {
+ a: A,
+}
+
+impl SomeTrait for B {
+ type T = ::T;
+
+ fn fn_(arg: u32) -> u32 {
+ ::fn_(arg)
+ }
+
+ fn method_(&mut self) -> bool {
+ ::method_( &mut self.a )
+ }
+}
+"#####,
+ )
+}
+
#[test]
fn doctest_generate_deref() {
check_doc_test(