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authorChetan Khilosiya <[email protected]>2021-02-22 18:47:48 +0000
committerChetan Khilosiya <[email protected]>2021-02-22 19:29:16 +0000
commite4756cb4f6e66097638b9d101589358976be2ba8 (patch)
treeb6ca0ae6b45b57834476ae0f9985cec3a6bd9090 /crates/assists/src/handlers/merge_match_arms.rs
parent8687053b118f47ce1a4962d0baa19b22d40d2758 (diff)
7526: Rename crate assists to ide_assists.
Diffstat (limited to 'crates/assists/src/handlers/merge_match_arms.rs')
-rw-r--r--crates/assists/src/handlers/merge_match_arms.rs248
1 files changed, 0 insertions, 248 deletions
diff --git a/crates/assists/src/handlers/merge_match_arms.rs b/crates/assists/src/handlers/merge_match_arms.rs
deleted file mode 100644
index 9bf076cb9..000000000
--- a/crates/assists/src/handlers/merge_match_arms.rs
+++ /dev/null
@@ -1,248 +0,0 @@
1use std::iter::successors;
2
3use syntax::{
4 algo::neighbor,
5 ast::{self, AstNode},
6 Direction,
7};
8
9use crate::{AssistContext, AssistId, AssistKind, Assists, TextRange};
10
11// Assist: merge_match_arms
12//
13// Merges identical match arms.
14//
15// ```
16// enum Action { Move { distance: u32 }, Stop }
17//
18// fn handle(action: Action) {
19// match action {
20// $0Action::Move(..) => foo(),
21// Action::Stop => foo(),
22// }
23// }
24// ```
25// ->
26// ```
27// enum Action { Move { distance: u32 }, Stop }
28//
29// fn handle(action: Action) {
30// match action {
31// Action::Move(..) | Action::Stop => foo(),
32// }
33// }
34// ```
35pub(crate) fn merge_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
36 let current_arm = ctx.find_node_at_offset::<ast::MatchArm>()?;
37 // Don't try to handle arms with guards for now - can add support for this later
38 if current_arm.guard().is_some() {
39 return None;
40 }
41 let current_expr = current_arm.expr()?;
42 let current_text_range = current_arm.syntax().text_range();
43
44 // We check if the following match arms match this one. We could, but don't,
45 // compare to the previous match arm as well.
46 let arms_to_merge = successors(Some(current_arm), |it| neighbor(it, Direction::Next))
47 .take_while(|arm| {
48 if arm.guard().is_some() {
49 return false;
50 }
51 match arm.expr() {
52 Some(expr) => expr.syntax().text() == current_expr.syntax().text(),
53 None => false,
54 }
55 })
56 .collect::<Vec<_>>();
57
58 if arms_to_merge.len() <= 1 {
59 return None;
60 }
61
62 acc.add(
63 AssistId("merge_match_arms", AssistKind::RefactorRewrite),
64 "Merge match arms",
65 current_text_range,
66 |edit| {
67 let pats = if arms_to_merge.iter().any(contains_placeholder) {
68 "_".into()
69 } else {
70 arms_to_merge
71 .iter()
72 .filter_map(ast::MatchArm::pat)
73 .map(|x| x.syntax().to_string())
74 .collect::<Vec<String>>()
75 .join(" | ")
76 };
77
78 let arm = format!("{} => {}", pats, current_expr.syntax().text());
79
80 let start = arms_to_merge.first().unwrap().syntax().text_range().start();
81 let end = arms_to_merge.last().unwrap().syntax().text_range().end();
82
83 edit.replace(TextRange::new(start, end), arm);
84 },
85 )
86}
87
88fn contains_placeholder(a: &ast::MatchArm) -> bool {
89 matches!(a.pat(), Some(ast::Pat::WildcardPat(..)))
90}
91
92#[cfg(test)]
93mod tests {
94 use crate::tests::{check_assist, check_assist_not_applicable};
95
96 use super::*;
97
98 #[test]
99 fn merge_match_arms_single_patterns() {
100 check_assist(
101 merge_match_arms,
102 r#"
103 #[derive(Debug)]
104 enum X { A, B, C }
105
106 fn main() {
107 let x = X::A;
108 let y = match x {
109 X::A => { 1i32$0 }
110 X::B => { 1i32 }
111 X::C => { 2i32 }
112 }
113 }
114 "#,
115 r#"
116 #[derive(Debug)]
117 enum X { A, B, C }
118
119 fn main() {
120 let x = X::A;
121 let y = match x {
122 X::A | X::B => { 1i32 }
123 X::C => { 2i32 }
124 }
125 }
126 "#,
127 );
128 }
129
130 #[test]
131 fn merge_match_arms_multiple_patterns() {
132 check_assist(
133 merge_match_arms,
134 r#"
135 #[derive(Debug)]
136 enum X { A, B, C, D, E }
137
138 fn main() {
139 let x = X::A;
140 let y = match x {
141 X::A | X::B => {$0 1i32 },
142 X::C | X::D => { 1i32 },
143 X::E => { 2i32 },
144 }
145 }
146 "#,
147 r#"
148 #[derive(Debug)]
149 enum X { A, B, C, D, E }
150
151 fn main() {
152 let x = X::A;
153 let y = match x {
154 X::A | X::B | X::C | X::D => { 1i32 },
155 X::E => { 2i32 },
156 }
157 }
158 "#,
159 );
160 }
161
162 #[test]
163 fn merge_match_arms_placeholder_pattern() {
164 check_assist(
165 merge_match_arms,
166 r#"
167 #[derive(Debug)]
168 enum X { A, B, C, D, E }
169
170 fn main() {
171 let x = X::A;
172 let y = match x {
173 X::A => { 1i32 },
174 X::B => { 2i$032 },
175 _ => { 2i32 }
176 }
177 }
178 "#,
179 r#"
180 #[derive(Debug)]
181 enum X { A, B, C, D, E }
182
183 fn main() {
184 let x = X::A;
185 let y = match x {
186 X::A => { 1i32 },
187 _ => { 2i32 }
188 }
189 }
190 "#,
191 );
192 }
193
194 #[test]
195 fn merges_all_subsequent_arms() {
196 check_assist(
197 merge_match_arms,
198 r#"
199 enum X { A, B, C, D, E }
200
201 fn main() {
202 match X::A {
203 X::A$0 => 92,
204 X::B => 92,
205 X::C => 92,
206 X::D => 62,
207 _ => panic!(),
208 }
209 }
210 "#,
211 r#"
212 enum X { A, B, C, D, E }
213
214 fn main() {
215 match X::A {
216 X::A | X::B | X::C => 92,
217 X::D => 62,
218 _ => panic!(),
219 }
220 }
221 "#,
222 )
223 }
224
225 #[test]
226 fn merge_match_arms_rejects_guards() {
227 check_assist_not_applicable(
228 merge_match_arms,
229 r#"
230 #[derive(Debug)]
231 enum X {
232 A(i32),
233 B,
234 C
235 }
236
237 fn main() {
238 let x = X::A;
239 let y = match x {
240 X::A(a) if a > 5 => { $01i32 },
241 X::B => { 1i32 },
242 X::C => { 2i32 }
243 }
244 }
245 "#,
246 );
247 }
248}
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