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author | bors[bot] <26634292+bors[bot]@users.noreply.github.com> | 2019-09-25 12:35:50 +0100 |
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committer | GitHub <[email protected]> | 2019-09-25 12:35:50 +0100 |
commit | 8f92309dbc00a0f88563030921706f205c01f452 (patch) | |
tree | 3e3f08ada8011f300faae3966cbe61a4a7dd7377 /crates/ra_assists/src/assists/merge_match_arms.rs | |
parent | d9b4835625ac96c7628e2ef66ef6e26cc48d231f (diff) | |
parent | 69689625ce4465f2d008d6543553d0d91d53dca4 (diff) |
Merge #1909
1909: move ast builder to a separate file r=matklad a=matklad
Co-authored-by: Aleksey Kladov <[email protected]>
Diffstat (limited to 'crates/ra_assists/src/assists/merge_match_arms.rs')
-rw-r--r-- | crates/ra_assists/src/assists/merge_match_arms.rs | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/crates/ra_assists/src/assists/merge_match_arms.rs b/crates/ra_assists/src/assists/merge_match_arms.rs new file mode 100644 index 000000000..3b6a99895 --- /dev/null +++ b/crates/ra_assists/src/assists/merge_match_arms.rs | |||
@@ -0,0 +1,188 @@ | |||
1 | use crate::{Assist, AssistCtx, AssistId, TextRange, TextUnit}; | ||
2 | use hir::db::HirDatabase; | ||
3 | use ra_syntax::ast::{AstNode, MatchArm}; | ||
4 | |||
5 | pub(crate) fn merge_match_arms(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> { | ||
6 | let current_arm = ctx.node_at_offset::<MatchArm>()?; | ||
7 | |||
8 | // We check if the following match arm matches this one. We could, but don't, | ||
9 | // compare to the previous match arm as well. | ||
10 | let next = current_arm.syntax().next_sibling(); | ||
11 | let next_arm = MatchArm::cast(next?)?; | ||
12 | |||
13 | // Don't try to handle arms with guards for now - can add support for this later | ||
14 | if current_arm.guard().is_some() || next_arm.guard().is_some() { | ||
15 | return None; | ||
16 | } | ||
17 | |||
18 | let current_expr = current_arm.expr()?; | ||
19 | let next_expr = next_arm.expr()?; | ||
20 | |||
21 | // Check for match arm equality by comparing lengths and then string contents | ||
22 | if current_expr.syntax().text_range().len() != next_expr.syntax().text_range().len() { | ||
23 | return None; | ||
24 | } | ||
25 | if current_expr.syntax().text() != next_expr.syntax().text() { | ||
26 | return None; | ||
27 | } | ||
28 | |||
29 | let cursor_to_end = current_arm.syntax().text_range().end() - ctx.frange.range.start(); | ||
30 | |||
31 | ctx.add_action(AssistId("merge_match_arms"), "merge match arms", |edit| { | ||
32 | fn contains_placeholder(a: &MatchArm) -> bool { | ||
33 | a.pats().any(|x| match x { | ||
34 | ra_syntax::ast::Pat::PlaceholderPat(..) => true, | ||
35 | _ => false, | ||
36 | }) | ||
37 | } | ||
38 | |||
39 | let pats = if contains_placeholder(¤t_arm) || contains_placeholder(&next_arm) { | ||
40 | "_".into() | ||
41 | } else { | ||
42 | let ps: Vec<String> = current_arm | ||
43 | .pats() | ||
44 | .map(|x| x.syntax().to_string()) | ||
45 | .chain(next_arm.pats().map(|x| x.syntax().to_string())) | ||
46 | .collect(); | ||
47 | ps.join(" | ") | ||
48 | }; | ||
49 | |||
50 | let arm = format!("{} => {}", pats, current_expr.syntax().text()); | ||
51 | let offset = TextUnit::from_usize(arm.len()) - cursor_to_end; | ||
52 | |||
53 | let start = current_arm.syntax().text_range().start(); | ||
54 | let end = next_arm.syntax().text_range().end(); | ||
55 | |||
56 | edit.target(current_arm.syntax().text_range()); | ||
57 | edit.replace(TextRange::from_to(start, end), arm); | ||
58 | edit.set_cursor(start + offset); | ||
59 | }); | ||
60 | |||
61 | ctx.build() | ||
62 | } | ||
63 | |||
64 | #[cfg(test)] | ||
65 | mod tests { | ||
66 | use super::merge_match_arms; | ||
67 | use crate::helpers::{check_assist, check_assist_not_applicable}; | ||
68 | |||
69 | #[test] | ||
70 | fn merge_match_arms_single_patterns() { | ||
71 | check_assist( | ||
72 | merge_match_arms, | ||
73 | r#" | ||
74 | #[derive(Debug)] | ||
75 | enum X { A, B, C } | ||
76 | |||
77 | fn main() { | ||
78 | let x = X::A; | ||
79 | let y = match x { | ||
80 | X::A => { 1i32<|> } | ||
81 | X::B => { 1i32 } | ||
82 | X::C => { 2i32 } | ||
83 | } | ||
84 | } | ||
85 | "#, | ||
86 | r#" | ||
87 | #[derive(Debug)] | ||
88 | enum X { A, B, C } | ||
89 | |||
90 | fn main() { | ||
91 | let x = X::A; | ||
92 | let y = match x { | ||
93 | X::A | X::B => { 1i32<|> } | ||
94 | X::C => { 2i32 } | ||
95 | } | ||
96 | } | ||
97 | "#, | ||
98 | ); | ||
99 | } | ||
100 | |||
101 | #[test] | ||
102 | fn merge_match_arms_multiple_patterns() { | ||
103 | check_assist( | ||
104 | merge_match_arms, | ||
105 | r#" | ||
106 | #[derive(Debug)] | ||
107 | enum X { A, B, C, D, E } | ||
108 | |||
109 | fn main() { | ||
110 | let x = X::A; | ||
111 | let y = match x { | ||
112 | X::A | X::B => {<|> 1i32 }, | ||
113 | X::C | X::D => { 1i32 }, | ||
114 | X::E => { 2i32 }, | ||
115 | } | ||
116 | } | ||
117 | "#, | ||
118 | r#" | ||
119 | #[derive(Debug)] | ||
120 | enum X { A, B, C, D, E } | ||
121 | |||
122 | fn main() { | ||
123 | let x = X::A; | ||
124 | let y = match x { | ||
125 | X::A | X::B | X::C | X::D => {<|> 1i32 }, | ||
126 | X::E => { 2i32 }, | ||
127 | } | ||
128 | } | ||
129 | "#, | ||
130 | ); | ||
131 | } | ||
132 | |||
133 | #[test] | ||
134 | fn merge_match_arms_placeholder_pattern() { | ||
135 | check_assist( | ||
136 | merge_match_arms, | ||
137 | r#" | ||
138 | #[derive(Debug)] | ||
139 | enum X { A, B, C, D, E } | ||
140 | |||
141 | fn main() { | ||
142 | let x = X::A; | ||
143 | let y = match x { | ||
144 | X::A => { 1i32 }, | ||
145 | X::B => { 2i<|>32 }, | ||
146 | _ => { 2i32 } | ||
147 | } | ||
148 | } | ||
149 | "#, | ||
150 | r#" | ||
151 | #[derive(Debug)] | ||
152 | enum X { A, B, C, D, E } | ||
153 | |||
154 | fn main() { | ||
155 | let x = X::A; | ||
156 | let y = match x { | ||
157 | X::A => { 1i32 }, | ||
158 | _ => { 2i<|>32 } | ||
159 | } | ||
160 | } | ||
161 | "#, | ||
162 | ); | ||
163 | } | ||
164 | |||
165 | #[test] | ||
166 | fn merge_match_arms_rejects_guards() { | ||
167 | check_assist_not_applicable( | ||
168 | merge_match_arms, | ||
169 | r#" | ||
170 | #[derive(Debug)] | ||
171 | enum X { | ||
172 | A(i32), | ||
173 | B, | ||
174 | C | ||
175 | } | ||
176 | |||
177 | fn main() { | ||
178 | let x = X::A; | ||
179 | let y = match x { | ||
180 | X::A(a) if a > 5 => { <|>1i32 }, | ||
181 | X::B => { 1i32 }, | ||
182 | X::C => { 2i32 } | ||
183 | } | ||
184 | } | ||
185 | "#, | ||
186 | ); | ||
187 | } | ||
188 | } | ||