aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_ide/src/completion.rs
blob: 7b96902fbb878a80c936b1d2eaac8bb2dd52b3ce (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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
mod completion_config;
mod completion_item;
mod completion_context;
mod presentation;
mod patterns;
#[cfg(test)]
mod test_utils;

mod complete_attribute;
mod complete_dot;
mod complete_record;
mod complete_pattern;
mod complete_fn_param;
mod complete_keyword;
mod complete_snippet;
mod complete_qualified_path;
mod complete_unqualified_path;
mod complete_postfix;
mod complete_macro_in_item_position;
mod complete_trait_impl;
mod unstable_feature_descriptor;
use ra_ide_db::RootDatabase;

use crate::{
    completion::{
        completion_context::CompletionContext,
        completion_item::{CompletionKind, Completions},

        //TODO: rework 
        unstable_feature_descriptor::UNSTABLE_FEATURE_DESCRIPTOR,
        complete_attribute::LintCompletion,
    },
    FilePosition,
};

pub use crate::completion::{
    completion_config::CompletionConfig,
    completion_item::{CompletionItem, CompletionItemKind, CompletionScore, InsertTextFormat},
};

//FIXME: split the following feature into fine-grained features.

// Feature: Magic Completions
//
// In addition to usual reference completion, rust-analyzer provides some ✨magic✨
// completions as well:
//
// Keywords like `if`, `else` `while`, `loop` are completed with braces, and cursor
// is placed at the appropriate position. Even though `if` is easy to type, you
// still want to complete it, to get ` { }` for free! `return` is inserted with a
// space or `;` depending on the return type of the function.
//
// When completing a function call, `()` are automatically inserted. If a function
// takes arguments, the cursor is positioned inside the parenthesis.
//
// There are postfix completions, which can be triggered by typing something like
// `foo().if`. The word after `.` determines postfix completion. Possible variants are:
//
// - `expr.if` -> `if expr {}` or `if let ... {}` for `Option` or `Result`
// - `expr.match` -> `match expr {}`
// - `expr.while` -> `while expr {}` or `while let ... {}` for `Option` or `Result`
// - `expr.ref` -> `&expr`
// - `expr.refm` -> `&mut expr`
// - `expr.not` -> `!expr`
// - `expr.dbg` -> `dbg!(expr)`
//
// There also snippet completions:
//
// .Expressions
// - `pd` -> `eprintln!(" = {:?}", );`
// - `ppd` -> `eprintln!(" = {:#?}", );`
//
// .Items
// - `tfn` -> `#[test] fn feature(){}`
// - `tmod` ->
// ```rust
// #[cfg(test)]
// mod tests {
//     use super::*;
//
//     #[test]
//     fn test_name() {}
// }
// ```

/// Main entry point for completion. We run completion as a two-phase process.
///
/// First, we look at the position and collect a so-called `CompletionContext.
/// This is a somewhat messy process, because, during completion, syntax tree is
/// incomplete and can look really weird.
///
/// Once the context is collected, we run a series of completion routines which
/// look at the context and produce completion items. One subtlety about this
/// phase is that completion engine should not filter by the substring which is
/// already present, it should give all possible variants for the identifier at
/// the caret. In other words, for
///
/// ```no-run
/// fn f() {
///     let foo = 92;
///     let _ = bar<|>
/// }
/// ```
///
/// `foo` *should* be present among the completion variants. Filtering by
/// identifier prefix/fuzzy match should be done higher in the stack, together
/// with ordering of completions (currently this is done by the client).
pub(crate) fn completions(
    db: &RootDatabase,
    config: &CompletionConfig,
    position: FilePosition,
) -> Option<Completions> {
    let ctx = CompletionContext::new(db, position, config)?;

    let mut acc = Completions::default();
    complete_attribute::complete_attribute(&mut acc, &ctx);
    complete_fn_param::complete_fn_param(&mut acc, &ctx);
    complete_keyword::complete_expr_keyword(&mut acc, &ctx);
    complete_keyword::complete_use_tree_keyword(&mut acc, &ctx);
    complete_snippet::complete_expr_snippet(&mut acc, &ctx);
    complete_snippet::complete_item_snippet(&mut acc, &ctx);
    complete_qualified_path::complete_qualified_path(&mut acc, &ctx);
    complete_unqualified_path::complete_unqualified_path(&mut acc, &ctx);
    complete_dot::complete_dot(&mut acc, &ctx);
    complete_record::complete_record(&mut acc, &ctx);
    complete_pattern::complete_pattern(&mut acc, &ctx);
    complete_postfix::complete_postfix(&mut acc, &ctx);
    complete_macro_in_item_position::complete_macro_in_item_position(&mut acc, &ctx);
    complete_trait_impl::complete_trait_impl(&mut acc, &ctx);

    Some(acc)
}

#[cfg(test)]
mod tests {
    use crate::completion::completion_config::CompletionConfig;
    use crate::mock_analysis::analysis_and_position;

    struct DetailAndDocumentation<'a> {
        detail: &'a str,
        documentation: &'a str,
    }

    fn check_detail_and_documentation(ra_fixture: &str, expected: DetailAndDocumentation) {
        let (analysis, position) = analysis_and_position(ra_fixture);
        let config = CompletionConfig::default();
        let completions = analysis.completions(&config, position).unwrap().unwrap();
        for item in completions {
            if item.detail() == Some(expected.detail) {
                let opt = item.documentation();
                let doc = opt.as_ref().map(|it| it.as_str());
                assert_eq!(doc, Some(expected.documentation));
                return;
            }
        }
        panic!("completion detail not found: {}", expected.detail)
    }

    #[test]
    fn test_completion_detail_from_macro_generated_struct_fn_doc_attr() {
        check_detail_and_documentation(
            r#"
            //- /lib.rs
            macro_rules! bar {
                () => {
                    struct Bar;
                    impl Bar {
                        #[doc = "Do the foo"]
                        fn foo(&self) {}
                    }
                }
            }

            bar!();

            fn foo() {
                let bar = Bar;
                bar.fo<|>;
            }
            "#,
            DetailAndDocumentation { detail: "fn foo(&self)", documentation: "Do the foo" },
        );
    }

    #[test]
    fn test_completion_detail_from_macro_generated_struct_fn_doc_comment() {
        check_detail_and_documentation(
            r#"
            //- /lib.rs
            macro_rules! bar {
                () => {
                    struct Bar;
                    impl Bar {
                        /// Do the foo
                        fn foo(&self) {}
                    }
                }
            }

            bar!();

            fn foo() {
                let bar = Bar;
                bar.fo<|>;
            }
            "#,
            DetailAndDocumentation { detail: "fn foo(&self)", documentation: " Do the foo" },
        );
    }
}