aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_assists/src/handlers/replace_unwrap_with_match.rs
blob: 62d4ea5220259f070d026aefdf6f04c13272a1f2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
use std::iter;

use ra_syntax::{
    ast::{self, edit::IndentLevel, make},
    AstNode,
};

use crate::{utils::TryEnum, Assist, AssistCtx, AssistId};

// Assist: replace_unwrap_with_match
//
// Replaces `unwrap` a `match` expression. Works for Result and Option.
//
// ```
// enum Result<T, E> { Ok(T), Err(E) }
// fn main() {
//     let x: Result<i32, i32> = Result::Ok(92);
//     let y = x.<|>unwrap();
// }
// ```
// ->
// ```
// enum Result<T, E> { Ok(T), Err(E) }
// fn main() {
//     let x: Result<i32, i32> = Result::Ok(92);
//     let y = match x {
//         Ok(a) => a,
//         _ => unreachable!(),
//     };
// }
// ```
pub(crate) fn replace_unwrap_with_match(ctx: AssistCtx) -> Option<Assist> {
    let method_call: ast::MethodCallExpr = ctx.find_node_at_offset()?;
    let name = method_call.name_ref()?;
    if name.text() != "unwrap" {
        return None;
    }
    let caller = method_call.expr()?;
    let ty = ctx.sema.type_of_expr(&caller)?;
    let happy_variant = TryEnum::from_ty(ctx.sema, &ty)?.happy_case();

    ctx.add_assist(AssistId("replace_unwrap_with_match"), "Replace unwrap with match", |edit| {
        let ok_path = make::path_unqualified(make::path_segment(make::name_ref(happy_variant)));
        let it = make::bind_pat(make::name("a")).into();
        let ok_tuple = make::tuple_struct_pat(ok_path, iter::once(it)).into();

        let bind_path = make::path_unqualified(make::path_segment(make::name_ref("a")));
        let ok_arm = make::match_arm(iter::once(ok_tuple), make::expr_path(bind_path));

        let unreachable_call = make::unreachable_macro_call().into();
        let err_arm = make::match_arm(iter::once(make::placeholder_pat().into()), unreachable_call);

        let match_arm_list = make::match_arm_list(vec![ok_arm, err_arm]);
        let match_expr = make::expr_match(caller.clone(), match_arm_list);
        let match_expr = IndentLevel::from_node(method_call.syntax()).increase_indent(match_expr);

        edit.target(method_call.syntax().text_range());
        edit.set_cursor(caller.syntax().text_range().start());
        edit.replace_ast::<ast::Expr>(method_call.into(), match_expr);
    })
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::helpers::{check_assist, check_assist_target};

    #[test]
    fn test_replace_result_unwrap_with_match() {
        check_assist(
            replace_unwrap_with_match,
            r"
enum Result<T, E> { Ok(T), Err(E) }
fn i<T>(a: T) -> T { a }
fn main() {
    let x: Result<i32, i32> = Result::Ok(92);
    let y = i(x).<|>unwrap();
}
            ",
            r"
enum Result<T, E> { Ok(T), Err(E) }
fn i<T>(a: T) -> T { a }
fn main() {
    let x: Result<i32, i32> = Result::Ok(92);
    let y = <|>match i(x) {
        Ok(a) => a,
        _ => unreachable!(),
    };
}
            ",
        )
    }

    #[test]
    fn test_replace_option_unwrap_with_match() {
        check_assist(
            replace_unwrap_with_match,
            r"
enum Option<T> { Some(T), None }
fn i<T>(a: T) -> T { a }
fn main() {
    let x = Option::Some(92);
    let y = i(x).<|>unwrap();
}
            ",
            r"
enum Option<T> { Some(T), None }
fn i<T>(a: T) -> T { a }
fn main() {
    let x = Option::Some(92);
    let y = <|>match i(x) {
        Some(a) => a,
        _ => unreachable!(),
    };
}
            ",
        );
    }

    #[test]
    fn test_replace_result_unwrap_with_match_chaining() {
        check_assist(
            replace_unwrap_with_match,
            r"
enum Result<T, E> { Ok(T), Err(E) }
fn i<T>(a: T) -> T { a }
fn main() {
    let x: Result<i32, i32> = Result::Ok(92);
    let y = i(x).<|>unwrap().count_zeroes();
}
            ",
            r"
enum Result<T, E> { Ok(T), Err(E) }
fn i<T>(a: T) -> T { a }
fn main() {
    let x: Result<i32, i32> = Result::Ok(92);
    let y = <|>match i(x) {
        Ok(a) => a,
        _ => unreachable!(),
    }.count_zeroes();
}
            ",
        )
    }

    #[test]
    fn replace_unwrap_with_match_target() {
        check_assist_target(
            replace_unwrap_with_match,
            r"
enum Option<T> { Some(T), None }
fn i<T>(a: T) -> T { a }
fn main() {
    let x = Option::Some(92);
    let y = i(x).<|>unwrap();
}
            ",
            r"i(x).unwrap()",
        );
    }
}