1 use ide_db::helpers::FamousDefs;
2 use ide_db::RootDatabase;
3 use syntax::ast::{self, AstNode, NameOwner};
6 use crate::{utils::generate_trait_impl_text, AssistContext, AssistId, AssistKind, Assists};
8 // Assist: generate_from_impl_for_enum
10 // Adds a From impl for an enum variant with one tuple field.
13 // enum A { $0One(u32) }
17 // enum A { One(u32) }
19 // impl From<u32> for A {
20 // fn from(v: u32) -> Self {
25 pub(crate) fn generate_from_impl_for_enum(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
26 let variant = ctx.find_node_at_offset::<ast::Variant>()?;
27 let variant_name = variant.name()?;
28 let enum_ = ast::Adt::Enum(variant.parent_enum());
29 let (field_name, field_type) = match variant.kind() {
30 ast::StructKind::Tuple(field_list) => {
31 if field_list.fields().count() != 1 {
34 (None, field_list.fields().next()?.ty()?)
36 ast::StructKind::Record(field_list) => {
37 if field_list.fields().count() != 1 {
40 let field = field_list.fields().next()?;
41 (Some(field.name()?), field.ty()?)
43 ast::StructKind::Unit => return None,
46 if existing_from_impl(&ctx.sema, &variant).is_some() {
47 mark::hit!(test_add_from_impl_already_exists);
51 let target = variant.syntax().text_range();
53 AssistId("generate_from_impl_for_enum", AssistKind::Generate),
54 "Generate `From` impl for this enum variant",
57 let start_offset = variant.parent_enum().syntax().text_range().end();
58 let from_trait = format!("From<{}>", field_type.syntax());
59 let impl_code = if let Some(name) = field_name {
61 r#" fn from({0}: {1}) -> Self {{
70 r#" fn from(v: {}) -> Self {{
77 let from_impl = generate_trait_impl_text(&enum_, &from_trait, &impl_code);
78 edit.insert(start_offset, from_impl);
83 fn existing_from_impl(
84 sema: &'_ hir::Semantics<'_, RootDatabase>,
85 variant: &ast::Variant,
87 let variant = sema.to_def(variant)?;
88 let enum_ = variant.parent_enum(sema.db);
89 let krate = enum_.module(sema.db).krate();
91 let from_trait = FamousDefs(sema, Some(krate)).core_convert_From()?;
93 let enum_type = enum_.ty(sema.db);
95 let wrapped_type = variant.fields(sema.db).get(0)?.signature_ty(sema.db);
97 if enum_type.impls_trait(sema.db, from_trait, &[wrapped_type]) {
106 use test_utils::mark;
108 use crate::tests::{check_assist, check_assist_not_applicable};
113 fn test_generate_from_impl_for_enum() {
115 generate_from_impl_for_enum,
116 "enum A { $0One(u32) }",
117 r#"enum A { One(u32) }
119 impl From<u32> for A {
120 fn from(v: u32) -> Self {
128 fn test_generate_from_impl_for_enum_complicated_path() {
130 generate_from_impl_for_enum,
131 r#"enum A { $0One(foo::bar::baz::Boo) }"#,
132 r#"enum A { One(foo::bar::baz::Boo) }
134 impl From<foo::bar::baz::Boo> for A {
135 fn from(v: foo::bar::baz::Boo) -> Self {
142 fn check_not_applicable(ra_fixture: &str) {
144 format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
145 check_assist_not_applicable(generate_from_impl_for_enum, &fixture)
149 fn test_add_from_impl_no_element() {
150 check_not_applicable("enum A { $0One }");
154 fn test_add_from_impl_more_than_one_element_in_tuple() {
155 check_not_applicable("enum A { $0One(u32, String) }");
159 fn test_add_from_impl_struct_variant() {
161 generate_from_impl_for_enum,
162 "enum A { $0One { x: u32 } }",
163 r#"enum A { One { x: u32 } }
165 impl From<u32> for A {
166 fn from(x: u32) -> Self {
174 fn test_add_from_impl_already_exists() {
175 mark::check!(test_add_from_impl_already_exists);
176 check_not_applicable(
178 enum A { $0One(u32), }
180 impl From<u32> for A {
181 fn from(v: u32) -> Self {
190 fn test_add_from_impl_different_variant_impl_exists() {
192 generate_from_impl_for_enum,
193 r#"enum A { $0One(u32), Two(String), }
195 impl From<String> for A {
196 fn from(v: String) -> Self {
204 r#"enum A { One(u32), Two(String), }
206 impl From<u32> for A {
207 fn from(v: u32) -> Self {
212 impl From<String> for A {
213 fn from(v: String) -> Self {
225 fn test_add_from_impl_static_str() {
227 generate_from_impl_for_enum,
228 "enum A { $0One(&'static str) }",
229 r#"enum A { One(&'static str) }
231 impl From<&'static str> for A {
232 fn from(v: &'static str) -> Self {
240 fn test_add_from_impl_generic_enum() {
242 generate_from_impl_for_enum,
243 "enum Generic<T, U: Clone> { $0One(T), Two(U) }",
244 r#"enum Generic<T, U: Clone> { One(T), Two(U) }
246 impl<T, U: Clone> From<T> for Generic<T, U> {
247 fn from(v: T) -> Self {
255 fn test_add_from_impl_with_lifetime() {
257 generate_from_impl_for_enum,
258 "enum Generic<'a> { $0One(&'a i32) }",
259 r#"enum Generic<'a> { One(&'a i32) }
261 impl<'a> From<&'a i32> for Generic<'a> {
262 fn from(v: &'a i32) -> Self {