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Add AsRef and Borrow for generate_mut_trait_impl #19917

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114 changes: 96 additions & 18 deletions crates/ide-assists/src/handlers/generate_mut_trait_impl.rs
Original file line number Diff line number Diff line change
Expand Up @@ -48,36 +48,42 @@ pub(crate) fn generate_mut_trait_impl(acc: &mut Assists, ctx: &AssistContext<'_>
let impl_def = ctx.find_node_at_offset::<ast::Impl>()?.clone_for_update();
let indent = impl_def.indent_level();

let (apply_trait, new_apply_trait) = impl_def
.syntax()
.descendants()
.filter_map(ast::NameRef::cast)
.find_map(process_trait_name)?;

let trait_ = impl_def.trait_()?;
if let ast::Type::PathType(trait_path) = trait_ {
let trait_type = ctx.sema.resolve_trait(&trait_path.path()?)?;
let scope = ctx.sema.scope(trait_path.syntax())?;
if trait_type != FamousDefs(&ctx.sema, scope.krate()).core_convert_Index()? {
let famous_defs = FamousDefs(&ctx.sema, scope.krate());
if trait_type != get_famous(&apply_trait.text(), famous_defs)? {
return None;
}
}

// Index -> IndexMut
let index_trait = impl_def
.syntax()
.descendants()
.filter_map(ast::NameRef::cast)
.find(|it| it.text() == "Index")?;
ted::replace(
index_trait.syntax(),
make::path_segment(make::name_ref("IndexMut")).clone_for_update().syntax(),
apply_trait.syntax(),
make::path_segment(make::name_ref(new_apply_trait)).clone_for_update().syntax(),
);

// index -> index_mut
let trait_method_name = impl_def
let (trait_method_name, new_trait_method_name) = impl_def
.syntax()
.descendants()
.filter_map(ast::Name::cast)
.find(|it| it.text() == "index")?;
ted::replace(trait_method_name.syntax(), make::name("index_mut").clone_for_update().syntax());
.find_map(process_method_name)?;
ted::replace(
trait_method_name.syntax(),
make::name(new_trait_method_name).clone_for_update().syntax(),
);

let type_alias = impl_def.syntax().descendants().find_map(ast::TypeAlias::cast)?;
ted::remove(type_alias.syntax());
if let Some(type_alias) = impl_def.syntax().descendants().find_map(ast::TypeAlias::cast) {
ted::remove(type_alias.syntax());
}

// &self -> &mut self
let mut_self_param = make::mut_self_param();
Expand All @@ -87,10 +93,8 @@ pub(crate) fn generate_mut_trait_impl(acc: &mut Assists, ctx: &AssistContext<'_>

// &Self::Output -> &mut Self::Output
let ret_type = impl_def.syntax().descendants().find_map(ast::RetType::cast)?;
ted::replace(
ret_type.syntax(),
make::ret_type(make::ty("&mut Self::Output")).clone_for_update().syntax(),
);
let new_ret_type = process_ret_type(&ret_type)?;
ted::replace(ret_type.syntax(), make::ret_type(new_ret_type).clone_for_update().syntax());

let fn_ = impl_def.assoc_item_list()?.assoc_items().find_map(|it| match it {
ast::AssocItem::Fn(f) => Some(f),
Expand All @@ -104,14 +108,51 @@ pub(crate) fn generate_mut_trait_impl(acc: &mut Assists, ctx: &AssistContext<'_>
let target = impl_def.syntax().text_range();
acc.add(
AssistId::generate("generate_mut_trait_impl"),
"Generate `IndexMut` impl from this `Index` trait",
format!("Generate `{new_apply_trait}` impl from this `{apply_trait}` trait"),
target,
|edit| {
edit.insert(target.start(), format!("$0{impl_def}\n\n{indent}"));
},
)
}

fn get_famous(apply_trait: &str, famous: FamousDefs<'_, '_>) -> Option<hir::Trait> {
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I think this should be receive hir::Trait though it's currently using &str before this PR.
Like here:

let impl_ = ctx.find_node_at_offset::<ast::Impl>()?;
let src_type = impl_.self_ty()?;
let ast_trait = impl_.trait_()?;
let module = ctx.sema.scope(impl_.syntax())?.module();
let trait_ = resolve_target_trait(&ctx.sema, &impl_)?;
if trait_ != FamousDefs(&ctx.sema, module.krate()).core_convert_Into()? {
return None;
}

match apply_trait {
"Index" => famous.core_convert_Index(),
"AsRef" => famous.core_convert_AsRef(),
"Borrow" => famous.core_borrow_Borrow(),
_ => None,
}
}

fn process_trait_name(name: ast::NameRef) -> Option<(ast::NameRef, &'static str)> {
let new_name = match &*name.text() {
"Index" => "IndexMut",
"AsRef" => "AsMut",
"Borrow" => "BorrowMut",
_ => return None,
};
Some((name, new_name))
}

fn process_method_name(name: ast::Name) -> Option<(ast::Name, &'static str)> {
let new_name = match &*name.text() {
"index" => "index_mut",
"as_ref" => "as_mut",
"borrow" => "borrow_mut",
_ => return None,
};
Some((name, new_name))
}

fn process_ret_type(ref_ty: &ast::RetType) -> Option<ast::Type> {
let ty = ref_ty.ty()?;
let ast::Type::RefType(ref_type) = ty else {
return None;
};
Some(make::ty_ref(ref_type.ty()?, true))
}

#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
Expand Down Expand Up @@ -186,6 +227,35 @@ impl<T> core::ops::Index<Axis> for [T; 3] where T: Copy {
var_name
}
}
"#,
);

check_assist(
generate_mut_trait_impl,
r#"
//- minicore: as_ref
struct Foo(i32);

impl<T> core::convert::AsRef$0<i32> for Foo {
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Those tests have redundant type parameter T

fn as_ref(&self) -> &i32 {
&self.0
}
}
"#,
r#"
struct Foo(i32);

$0impl<T> core::convert::AsMut<i32> for Foo {
fn as_mut(&mut self) -> &mut i32 {
&self.0
}
}

impl<T> core::convert::AsRef<i32> for Foo {
fn as_ref(&self) -> &i32 {
&self.0
}
}
"#,
);
}
Expand Down Expand Up @@ -285,6 +355,14 @@ mod foo {
pub trait Index<Idx: ?Sized> {}

impl<T> Index$0<i32> for [T; 3] {}
"#,
);
check_assist_not_applicable(
generate_mut_trait_impl,
r#"
pub trait AsRef<T: ?Sized> {}

impl<T> AsRef$0<i32> for [T; 3] {}
"#,
);
}
Expand Down
4 changes: 4 additions & 0 deletions crates/ide-db/src/famous_defs.rs
Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,10 @@ impl FamousDefs<'_, '_> {
self.find_trait("core:ops:Index")
}

pub fn core_borrow_Borrow(&self) -> Option<Trait> {
self.find_trait("core:borrow:Borrow")
}

pub fn core_option_Option(&self) -> Option<Enum> {
self.find_enum("core:option:Option")
}
Expand Down