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feat: Improve "Generate Deref impl" assist #12276

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Merged
merged 1 commit into from
May 16, 2022
Merged

feat: Improve "Generate Deref impl" assist #12276

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211 changes: 165 additions & 46 deletions crates/ide-assists/src/handlers/generate_deref.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
use std::fmt::Display;

use hir::{ModPath, ModuleDef};
use ide_db::{famous_defs::FamousDefs, RootDatabase};
use syntax::{
ast::{self, HasName},
Expand All @@ -17,6 +18,7 @@ use crate::{
// Generate `Deref` impl using the given struct field.
//
// ```
// # //- minicore: deref, deref_mut
// struct A;
// struct B {
// $0a: A
Expand All @@ -29,7 +31,7 @@ use crate::{
// a: A
// }
//
// impl std::ops::Deref for B {
// impl core::ops::Deref for B {
// type Target = A;
//
// fn deref(&self) -> &Self::Target {
Expand All @@ -45,19 +47,36 @@ fn generate_record_deref(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
let field = ctx.find_node_at_offset::<ast::RecordField>()?;

if existing_deref_impl(&ctx.sema, &strukt).is_some() {
cov_mark::hit!(test_add_record_deref_impl_already_exists);
return None;
}
let deref_type_to_generate = match existing_deref_impl(&ctx.sema, &strukt) {
None => DerefType::Deref,
Some(DerefType::Deref) => DerefType::DerefMut,
Some(DerefType::DerefMut) => {
cov_mark::hit!(test_add_record_deref_impl_already_exists);
return None;
}
};

let module = ctx.sema.to_def(&strukt)?.module(ctx.db());
let trait_ = deref_type_to_generate.to_trait(&ctx.sema, module.krate())?;
let trait_path = module.find_use_path(ctx.db(), ModuleDef::Trait(trait_))?;

let field_type = field.ty()?;
let field_name = field.name()?;
let target = field.syntax().text_range();
acc.add(
AssistId("generate_deref", AssistKind::Generate),
format!("Generate `Deref` impl using `{}`", field_name),
format!("Generate `{:?}` impl using `{}`", deref_type_to_generate, field_name),
target,
|edit| generate_edit(edit, strukt, field_type.syntax(), field_name.syntax()),
|edit| {
generate_edit(
edit,
strukt,
field_type.syntax(),
field_name.syntax(),
deref_type_to_generate,
trait_path,
)
},
)
}

Expand All @@ -68,18 +87,35 @@ fn generate_tuple_deref(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let field_list_index =
field_list.syntax().children().into_iter().position(|s| &s == field.syntax())?;

if existing_deref_impl(&ctx.sema, &strukt).is_some() {
cov_mark::hit!(test_add_field_deref_impl_already_exists);
return None;
}
let deref_type_to_generate = match existing_deref_impl(&ctx.sema, &strukt) {
None => DerefType::Deref,
Some(DerefType::Deref) => DerefType::DerefMut,
Some(DerefType::DerefMut) => {
cov_mark::hit!(test_add_field_deref_impl_already_exists);
return None;
}
};

let module = ctx.sema.to_def(&strukt)?.module(ctx.db());
let trait_ = deref_type_to_generate.to_trait(&ctx.sema, module.krate())?;
let trait_path = module.find_use_path(ctx.db(), ModuleDef::Trait(trait_))?;

let field_type = field.ty()?;
let target = field.syntax().text_range();
acc.add(
AssistId("generate_deref", AssistKind::Generate),
format!("Generate `Deref` impl using `{}`", field.syntax()),
format!("Generate `{:?}` impl using `{}`", deref_type_to_generate, field.syntax()),
target,
|edit| generate_edit(edit, strukt, field_type.syntax(), field_list_index),
|edit| {
generate_edit(
edit,
strukt,
field_type.syntax(),
field_list_index,
deref_type_to_generate,
trait_path,
)
},
)
}

Expand All @@ -88,38 +124,72 @@ fn generate_edit(
strukt: ast::Struct,
field_type_syntax: &SyntaxNode,
field_name: impl Display,
deref_type: DerefType,
trait_path: ModPath,
) {
let start_offset = strukt.syntax().text_range().end();
let impl_code = format!(
r#" type Target = {0};
let impl_code = match deref_type {
DerefType::Deref => format!(
r#" type Target = {0};

fn deref(&self) -> &Self::Target {{
&self.{1}
}}"#,
field_type_syntax, field_name
);
field_type_syntax, field_name
),
DerefType::DerefMut => format!(
r#" fn deref_mut(&mut self) -> &mut Self::Target {{
&mut self.{}
}}"#,
field_name
),
};
let strukt_adt = ast::Adt::Struct(strukt);
let deref_impl = generate_trait_impl_text(&strukt_adt, "std::ops::Deref", &impl_code);
let deref_impl = generate_trait_impl_text(&strukt_adt, &trait_path.to_string(), &impl_code);
edit.insert(start_offset, deref_impl);
}

fn existing_deref_impl(
sema: &'_ hir::Semantics<'_, RootDatabase>,
sema: &hir::Semantics<'_, RootDatabase>,
strukt: &ast::Struct,
) -> Option<()> {
) -> Option<DerefType> {
let strukt = sema.to_def(strukt)?;
let krate = strukt.module(sema.db).krate();

let deref_trait = FamousDefs(sema, krate).core_ops_Deref()?;
let deref_mut_trait = FamousDefs(sema, krate).core_ops_DerefMut()?;
let strukt_type = strukt.ty(sema.db);

if strukt_type.impls_trait(sema.db, deref_trait, &[]) {
Some(())
if strukt_type.impls_trait(sema.db, deref_mut_trait, &[]) {
Some(DerefType::DerefMut)
} else {
Some(DerefType::Deref)
}
} else {
None
}
}

#[derive(Debug)]
enum DerefType {
Deref,
DerefMut,
}

impl DerefType {
fn to_trait(
&self,
sema: &hir::Semantics<'_, RootDatabase>,
krate: hir::Crate,
) -> Option<hir::Trait> {
match self {
DerefType::Deref => FamousDefs(sema, krate).core_ops_Deref(),
DerefType::DerefMut => FamousDefs(sema, krate).core_ops_DerefMut(),
}
}
}

#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
Expand All @@ -130,12 +200,39 @@ mod tests {
fn test_generate_record_deref() {
check_assist(
generate_deref,
r#"struct A { }
r#"
//- minicore: deref
struct A { }
struct B { $0a: A }"#,
r#"struct A { }
r#"
struct A { }
struct B { a: A }

impl std::ops::Deref for B {
impl core::ops::Deref for B {
type Target = A;

fn deref(&self) -> &Self::Target {
&self.a
}
}"#,
);
}

#[test]
fn test_generate_record_deref_short_path() {
check_assist(
generate_deref,
r#"
//- minicore: deref
use core::ops::Deref;
struct A { }
struct B { $0a: A }"#,
r#"
use core::ops::Deref;
struct A { }
struct B { a: A }

impl Deref for B {
type Target = A;

fn deref(&self) -> &Self::Target {
Expand All @@ -149,12 +246,15 @@ impl std::ops::Deref for B {
fn test_generate_field_deref_idx_0() {
check_assist(
generate_deref,
r#"struct A { }
r#"
//- minicore: deref
struct A { }
struct B($0A);"#,
r#"struct A { }
r#"
struct A { }
struct B(A);

impl std::ops::Deref for B {
impl core::ops::Deref for B {
type Target = A;

fn deref(&self) -> &Self::Target {
Expand All @@ -167,12 +267,15 @@ impl std::ops::Deref for B {
fn test_generate_field_deref_idx_1() {
check_assist(
generate_deref,
r#"struct A { }
r#"
//- minicore: deref
struct A { }
struct B(u8, $0A);"#,
r#"struct A { }
r#"
struct A { }
struct B(u8, A);

impl std::ops::Deref for B {
impl core::ops::Deref for B {
type Target = A;

fn deref(&self) -> &Self::Target {
Expand All @@ -182,23 +285,43 @@ impl std::ops::Deref for B {
);
}

#[test]
fn test_generates_derefmut_when_deref_present() {
check_assist(
generate_deref,
r#"
//- minicore: deref, deref_mut
struct B { $0a: u8 }

impl core::ops::Deref for B {}
"#,
r#"
struct B { a: u8 }

impl core::ops::DerefMut for B {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.a
}
}

impl core::ops::Deref for B {}
"#,
);
}

#[test]
fn test_generate_record_deref_not_applicable_if_already_impl() {
cov_mark::check!(test_add_record_deref_impl_already_exists);
check_assist_not_applicable(
generate_deref,
r#"
//- minicore: deref
//- minicore: deref, deref_mut
struct A { }
struct B { $0a: A }

impl core::ops::Deref for B {
type Target = A;

fn deref(&self) -> &Self::Target {
&self.a
}
}"#,
impl core::ops::Deref for B {}
impl core::ops::DerefMut for B {}
"#,
)
}

Expand All @@ -208,17 +331,13 @@ impl core::ops::Deref for B {
check_assist_not_applicable(
generate_deref,
r#"
//- minicore: deref
//- minicore: deref, deref_mut
struct A { }
struct B($0A)

impl core::ops::Deref for B {
type Target = A;

fn deref(&self) -> &Self::Target {
&self.0
}
}"#,
impl core::ops::Deref for B {}
impl core::ops::DerefMut for B {}
"#,
)
}
}
1 change: 0 additions & 1 deletion crates/ide-assists/src/tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -226,7 +226,6 @@ fn assist_order_field_struct() {
assert_eq!(assists.next().expect("expected assist").label, "Generate a getter method");
assert_eq!(assists.next().expect("expected assist").label, "Generate a mut getter method");
assert_eq!(assists.next().expect("expected assist").label, "Generate a setter method");
assert_eq!(assists.next().expect("expected assist").label, "Generate `Deref` impl using `bar`");
assert_eq!(assists.next().expect("expected assist").label, "Add `#[derive]`");
}

Expand Down
3 changes: 2 additions & 1 deletion crates/ide-assists/src/tests/generated.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -799,6 +799,7 @@ fn doctest_generate_deref() {
check_doc_test(
"generate_deref",
r#####"
//- minicore: deref, deref_mut
struct A;
struct B {
$0a: A
Expand All @@ -810,7 +811,7 @@ struct B {
a: A
}

impl std::ops::Deref for B {
impl core::ops::Deref for B {
type Target = A;

fn deref(&self) -> &Self::Target {
Expand Down
4 changes: 4 additions & 0 deletions crates/ide-db/src/famous_defs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,10 @@ impl FamousDefs<'_, '_> {
self.find_trait("core:ops:Deref")
}

pub fn core_ops_DerefMut(&self) -> Option<Trait> {
self.find_trait("core:ops:DerefMut")
}

pub fn core_convert_AsRef(&self) -> Option<Trait> {
self.find_trait("core:convert:AsRef")
}
Expand Down