2 use itertools::Itertools;
4 ast::{self, edit::IndentLevel, AstNode, GenericParamsOwner, NameOwner},
8 use crate::{AssistContext, AssistId, AssistKind, Assists};
10 // Assist: extract_type_alias
12 // Extracts the selected type as a type alias.
16 // field: $0(u8, u8, u8)$0,
21 // type $0Type = (u8, u8, u8);
27 pub(crate) fn extract_type_alias(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
28 if ctx.frange.range.is_empty() {
32 let ty = ctx.find_node_at_range::<ast::Type>()?;
33 let item = ty.syntax().ancestors().find_map(ast::Item::cast)?;
34 let assoc_owner = item.syntax().ancestors().nth(2).and_then(|it| {
37 ast::Trait(tr) => Some(Either::Left(tr)),
38 ast::Impl(impl_) => Some(Either::Right(impl_)),
43 let node = assoc_owner.as_ref().map_or_else(
45 |impl_| impl_.as_ref().either(AstNode::syntax, AstNode::syntax),
47 let insert_pos = node.text_range().start();
48 let target = ty.syntax().text_range();
51 AssistId("extract_type_alias", AssistKind::RefactorExtract),
52 "Extract type as type alias",
55 let mut known_generics = match item.generic_param_list() {
56 Some(it) => it.generic_params().collect(),
59 if let Some(it) = assoc_owner.as_ref().and_then(|it| match it {
60 Either::Left(it) => it.generic_param_list(),
61 Either::Right(it) => it.generic_param_list(),
63 known_generics.extend(it.generic_params());
65 let generics = collect_used_generics(&ty, &known_generics);
67 let replacement = if !generics.is_empty() {
70 generics.iter().format_with(", ", |generic, f| {
72 ast::GenericParam::ConstParam(cp) => f(&cp.name().unwrap()),
73 ast::GenericParam::LifetimeParam(lp) => f(&lp.lifetime().unwrap()),
74 ast::GenericParam::TypeParam(tp) => f(&tp.name().unwrap()),
81 builder.replace(target, replacement);
83 let indent = IndentLevel::from_node(node);
84 let generics = if !generics.is_empty() {
85 format!("<{}>", generics.iter().format(", "))
89 match ctx.config.snippet_cap {
91 builder.insert_snippet(
94 format!("type $0Type{} = {};\n\n{}", generics, ty, indent),
100 format!("type Type{} = {};\n\n{}", generics, ty, indent),
108 fn collect_used_generics<'gp>(
110 known_generics: &'gp [ast::GenericParam],
111 ) -> Vec<&'gp ast::GenericParam> {
112 // can't use a closure -> closure here cause lifetime inference fails for that
113 fn find_lifetime(text: &str) -> impl Fn(&&ast::GenericParam) -> bool + '_ {
114 move |gp: &&ast::GenericParam| match gp {
115 ast::GenericParam::LifetimeParam(lp) => {
116 lp.lifetime().map_or(false, |lt| lt.text() == text)
122 let mut generics = Vec::new();
123 ty.walk(&mut |ty| match ty {
124 ast::Type::PathType(ty) => {
125 if let Some(path) = ty.path() {
126 if let Some(name_ref) = path.as_single_name_ref() {
127 if let Some(param) = known_generics.iter().find(|gp| {
129 ast::GenericParam::ConstParam(cp) => cp.name(),
130 ast::GenericParam::TypeParam(tp) => tp.name(),
133 .map_or(false, |n| n.text() == name_ref.text())
135 generics.push(param);
140 .filter_map(|seg| seg.generic_arg_list())
141 .flat_map(|it| it.generic_args())
142 .filter_map(|it| match it {
143 ast::GenericArg::LifetimeArg(lt) => {
144 let lt = lt.lifetime()?;
145 known_generics.iter().find(find_lifetime(<.text()))
152 ast::Type::ImplTraitType(impl_ty) => {
153 if let Some(it) = impl_ty.type_bound_list() {
156 .filter_map(|it| it.lifetime())
157 .filter_map(|lt| known_generics.iter().find(find_lifetime(<.text()))),
161 ast::Type::DynTraitType(dyn_ty) => {
162 if let Some(it) = dyn_ty.type_bound_list() {
165 .filter_map(|it| it.lifetime())
166 .filter_map(|lt| known_generics.iter().find(find_lifetime(<.text()))),
170 ast::Type::RefType(ref_) => generics.extend(
171 ref_.lifetime().and_then(|lt| known_generics.iter().find(find_lifetime(<.text()))),
175 // stable resort to lifetime, type, const
176 generics.sort_by_key(|gp| match gp {
177 ast::GenericParam::ConstParam(_) => 2,
178 ast::GenericParam::LifetimeParam(_) => 0,
179 ast::GenericParam::TypeParam(_) => 1,
186 use crate::tests::{check_assist, check_assist_not_applicable};
191 fn test_not_applicable_without_selection() {
192 check_assist_not_applicable(
196 field: $0(u8, u8, u8),
203 fn test_simple_types() {
222 fn test_generic_type_arg() {
245 fn test_inner_type_arg() {
251 v: Vec<Vec<$0Vec<u8>$0>>,
256 type $0Type = Vec<u8>;
266 fn test_extract_inner_type() {
285 fn extract_from_impl_or_trait() {
286 // When invoked in an impl/trait, extracted type alias should be placed next to the
287 // impl/trait, not inside.
292 fn f() -> $0(u8, u8)$0 {}
296 type $0Type = (u8, u8);
307 fn f() -> $0(u8, u8)$0 {}
311 type $0Type = (u8, u8);
344 struct Struct<const C: usize>;
345 impl<'outer, Outer, const OUTER: usize> () {
346 fn func<'inner, Inner, const INNER: usize>(_: $0&(Struct<INNER>, Struct<OUTER>, Outer, &'inner (), Inner, &'outer ())$0) {}
350 struct Struct<const C: usize>;
351 type $0Type<'inner, 'outer, Outer, Inner, const INNER: usize, const OUTER: usize> = &(Struct<INNER>, Struct<OUTER>, Outer, &'inner (), Inner, &'outer ());
353 impl<'outer, Outer, const OUTER: usize> () {
354 fn func<'inner, Inner, const INNER: usize>(_: Type<'inner, 'outer, Outer, Inner, INNER, OUTER>) {}