1 use syntax::{
2 ast::{self, AstNode, HasAttrs},
3 SyntaxKind::{COMMENT, WHITESPACE},
4 TextSize,
5 };
6
7 use crate::{AssistContext, AssistId, AssistKind, Assists};
8
9 // Assist: generate_derive
10 //
11 // Adds a new `#[derive()]` clause to a struct or enum.
12 //
13 // ```
14 // struct Point {
15 // x: u32,
16 // y: u32,$0
17 // }
18 // ```
19 // ->
20 // ```
21 // #[derive($0)]
22 // struct Point {
23 // x: u32,
24 // y: u32,
25 // }
26 // ```
generate_derive(acc: &mut Assists, ctx: &AssistContext) -> Option<()>27 pub(crate) fn generate_derive(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
28 let cap = ctx.config.snippet_cap?;
29 let nominal = ctx.find_node_at_offset::<ast::Adt>()?;
30 let node_start = derive_insertion_offset(&nominal)?;
31 let target = nominal.syntax().text_range();
32 acc.add(
33 AssistId("generate_derive", AssistKind::Generate),
34 "Add `#[derive]`",
35 target,
36 |builder| {
37 let derive_attr = nominal
38 .attrs()
39 .filter_map(|x| x.as_simple_call())
40 .filter(|(name, _arg)| name == "derive")
41 .map(|(_name, arg)| arg)
42 .next();
43 match derive_attr {
44 None => {
45 builder.insert_snippet(cap, node_start, "#[derive($0)]\n");
46 }
47 Some(tt) => {
48 // Just move the cursor.
49 builder.insert_snippet(
50 cap,
51 tt.syntax().text_range().end() - TextSize::of(')'),
52 "$0",
53 )
54 }
55 };
56 },
57 )
58 }
59
60 // Insert `derive` after doc comments.
derive_insertion_offset(nominal: &ast::Adt) -> Option<TextSize>61 fn derive_insertion_offset(nominal: &ast::Adt) -> Option<TextSize> {
62 let non_ws_child = nominal
63 .syntax()
64 .children_with_tokens()
65 .find(|it| it.kind() != COMMENT && it.kind() != WHITESPACE)?;
66 Some(non_ws_child.text_range().start())
67 }
68
69 #[cfg(test)]
70 mod tests {
71 use crate::tests::{check_assist, check_assist_target};
72
73 use super::*;
74
75 #[test]
add_derive_new()76 fn add_derive_new() {
77 check_assist(
78 generate_derive,
79 "struct Foo { a: i32, $0}",
80 "#[derive($0)]\nstruct Foo { a: i32, }",
81 );
82 check_assist(
83 generate_derive,
84 "struct Foo { $0 a: i32, }",
85 "#[derive($0)]\nstruct Foo { a: i32, }",
86 );
87 }
88
89 #[test]
add_derive_existing()90 fn add_derive_existing() {
91 check_assist(
92 generate_derive,
93 "#[derive(Clone)]\nstruct Foo { a: i32$0, }",
94 "#[derive(Clone$0)]\nstruct Foo { a: i32, }",
95 );
96 }
97
98 #[test]
add_derive_new_with_doc_comment()99 fn add_derive_new_with_doc_comment() {
100 check_assist(
101 generate_derive,
102 "
103 /// `Foo` is a pretty important struct.
104 /// It does stuff.
105 struct Foo { a: i32$0, }
106 ",
107 "
108 /// `Foo` is a pretty important struct.
109 /// It does stuff.
110 #[derive($0)]
111 struct Foo { a: i32, }
112 ",
113 );
114 }
115
116 #[test]
add_derive_target()117 fn add_derive_target() {
118 check_assist_target(
119 generate_derive,
120 "
121 struct SomeThingIrrelevant;
122 /// `Foo` is a pretty important struct.
123 /// It does stuff.
124 struct Foo { a: i32$0, }
125 struct EvenMoreIrrelevant;
126 ",
127 "/// `Foo` is a pretty important struct.
128 /// It does stuff.
129 struct Foo { a: i32, }",
130 );
131 }
132 }
133