aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_ide_api/src/hover.rs
blob: ef3b5df292a3154493326e79fca74488547b1c8c (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
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
use ra_db::SourceDatabase;
use ra_syntax::{
    AstNode, SyntaxNode, TreeArc, ast::{self, NameOwner, VisibilityOwner},
    algo::{find_covering_node, find_node_at_offset, find_leaf_at_offset, visit::{visitor, Visitor}},
};

use crate::{db::RootDatabase, RangeInfo, FilePosition, FileRange, NavigationTarget};

/// Contains the results when hovering over an item
#[derive(Debug, Clone)]
pub struct HoverResult {
    results: Vec<String>,
    exact: bool,
}

impl HoverResult {
    pub fn new() -> HoverResult {
        HoverResult {
            results: Vec::new(),
            // We assume exact by default
            exact: true,
        }
    }

    pub fn extend(&mut self, item: Option<String>) {
        self.results.extend(item);
    }

    pub fn is_exact(&self) -> bool {
        self.exact
    }

    pub fn is_empty(&self) -> bool {
        self.results.is_empty()
    }

    pub fn len(&self) -> usize {
        self.results.len()
    }

    pub fn first(&self) -> Option<&str> {
        self.results.first().map(String::as_str)
    }

    pub fn results(&self) -> &[String] {
        &self.results
    }

    /// Returns the results converted into markup
    /// for displaying in a UI
    pub fn to_markup(&self) -> String {
        let mut markup = if !self.exact {
            let mut msg = String::from("Failed to exactly resolve the symbol. This is probably because rust_analyzer does not yet support glob imports or traits.");
            if !self.results.is_empty() {
                msg.push_str("  \nThese items were found instead:");
            }
            msg.push_str("\n\n---\n");
            msg
        } else {
            String::new()
        };

        markup.push_str(&self.results.join("\n\n---\n"));

        markup
    }
}

pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeInfo<HoverResult>> {
    let file = db.parse(position.file_id);
    let mut res = HoverResult::new();

    let mut range = None;
    if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(file.syntax(), position.offset) {
        use crate::goto_definition::{ReferenceResult::*, reference_definition};
        let ref_result = reference_definition(db, position.file_id, name_ref);
        match ref_result {
            Exact(nav) => res.extend(doc_text_for(db, nav)),
            Approximate(navs) => {
                // We are no longer exact
                res.exact = false;

                for nav in navs {
                    res.extend(doc_text_for(db, nav))
                }
            }
        }
        if !res.is_empty() {
            range = Some(name_ref.syntax().range())
        }
    } else if let Some(name) = find_node_at_offset::<ast::Name>(file.syntax(), position.offset) {
        let navs = crate::goto_definition::name_definition(db, position.file_id, name);

        if let Some(navs) = navs {
            for nav in navs {
                res.extend(doc_text_for(db, nav))
            }
        }

        if !res.is_empty() && range.is_none() {
            range = Some(name.syntax().range());
        }
    }

    if range.is_none() {
        let node = find_leaf_at_offset(file.syntax(), position.offset).find_map(|leaf| {
            leaf.ancestors().find(|n| ast::Expr::cast(*n).is_some() || ast::Pat::cast(*n).is_some())
        })?;
        let frange = FileRange { file_id: position.file_id, range: node.range() };
        res.extend(type_of(db, frange).map(Into::into));
        range = Some(node.range());
    }

    let range = range?;
    if res.is_empty() {
        return None;
    }
    let res = RangeInfo::new(range, res);
    Some(res)
}

pub(crate) fn type_of(db: &RootDatabase, frange: FileRange) -> Option<String> {
    let file = db.parse(frange.file_id);
    let syntax = file.syntax();
    let leaf_node = find_covering_node(syntax, frange.range);
    // if we picked identifier, expand to pattern/expression
    let node = leaf_node
        .ancestors()
        .take_while(|it| it.range() == leaf_node.range())
        .find(|&it| ast::Expr::cast(it).is_some() || ast::Pat::cast(it).is_some())
        .unwrap_or(leaf_node);
    let parent_fn = node.ancestors().find_map(ast::FnDef::cast)?;
    let function = hir::source_binder::function_from_source(db, frange.file_id, parent_fn)?;
    let infer = function.infer(db);
    let syntax_mapping = function.body_syntax_mapping(db);
    if let Some(expr) = ast::Expr::cast(node).and_then(|e| syntax_mapping.node_expr(e)) {
        Some(infer[expr].to_string())
    } else if let Some(pat) = ast::Pat::cast(node).and_then(|p| syntax_mapping.node_pat(p)) {
        Some(infer[pat].to_string())
    } else {
        None
    }
}

// FIXME: this should not really use navigation target. Rather, approximately
// resolved symbol should return a `DefId`.
fn doc_text_for(db: &RootDatabase, nav: NavigationTarget) -> Option<String> {
    match (nav.description(db), nav.docs(db)) {
        (Some(desc), Some(docs)) => Some("```rust\n".to_string() + &*desc + "\n```\n\n" + &*docs),
        (Some(desc), None) => Some("```rust\n".to_string() + &*desc + "\n```"),
        (None, Some(docs)) => Some(docs),
        _ => None,
    }
}

impl NavigationTarget {
    fn node(&self, db: &RootDatabase) -> Option<TreeArc<SyntaxNode>> {
        let source_file = db.parse(self.file_id());
        let source_file = source_file.syntax();
        let node = source_file
            .descendants()
            .find(|node| node.kind() == self.kind() && node.range() == self.full_range())?
            .to_owned();
        Some(node)
    }

    fn docs(&self, db: &RootDatabase) -> Option<String> {
        let node = self.node(db)?;
        fn doc_comments<N: ast::DocCommentsOwner>(node: &N) -> Option<String> {
            node.doc_comment_text()
        }

        visitor()
            .visit(doc_comments::<ast::FnDef>)
            .visit(doc_comments::<ast::StructDef>)
            .visit(doc_comments::<ast::EnumDef>)
            .visit(doc_comments::<ast::TraitDef>)
            .visit(doc_comments::<ast::Module>)
            .visit(doc_comments::<ast::TypeAliasDef>)
            .visit(doc_comments::<ast::ConstDef>)
            .visit(doc_comments::<ast::StaticDef>)
            .accept(&node)?
    }

    /// Get a description of this node.
    ///
    /// e.g. `struct Name`, `enum Name`, `fn Name`
    fn description(&self, db: &RootDatabase) -> Option<String> {
        // TODO: After type inference is done, add type information to improve the output
        let node = self.node(db)?;

        fn visit_node<T>(node: &T, label: &str) -> Option<String>
        where
            T: NameOwner + VisibilityOwner,
        {
            let mut string =
                node.visibility().map(|v| format!("{} ", v.syntax().text())).unwrap_or_default();
            string.push_str(label);
            node.name()?.syntax().text().push_to(&mut string);
            Some(string)
        }

        visitor()
            .visit(crate::completion::function_label)
            .visit(|node: &ast::StructDef| visit_node(node, "struct "))
            .visit(|node: &ast::EnumDef| visit_node(node, "enum "))
            .visit(|node: &ast::TraitDef| visit_node(node, "trait "))
            .visit(|node: &ast::Module| visit_node(node, "mod "))
            .visit(|node: &ast::TypeAliasDef| visit_node(node, "type "))
            .visit(|node: &ast::ConstDef| visit_node(node, "const "))
            .visit(|node: &ast::StaticDef| visit_node(node, "static "))
            .accept(&node)?
    }
}

#[cfg(test)]
mod tests {
    use ra_syntax::TextRange;
    use crate::mock_analysis::{single_file_with_position, single_file_with_range, analysis_and_position};

    fn trim_markup(s: &str) -> &str {
        s.trim_start_matches("```rust\n").trim_end_matches("\n```")
    }

    fn check_hover_result(fixture: &str, expected: &[&str]) {
        let (analysis, position) = analysis_and_position(fixture);
        let hover = analysis.hover(position).unwrap().unwrap();

        for (markup, expected) in
            hover.info.results().iter().zip(expected.iter().chain(std::iter::repeat(&"<missing>")))
        {
            assert_eq!(trim_markup(&markup), *expected);
        }

        assert_eq!(hover.info.len(), expected.len());
    }

    #[test]
    fn hover_shows_type_of_an_expression() {
        let (analysis, position) = single_file_with_position(
            "
            pub fn foo() -> u32 { 1 }

            fn main() {
                let foo_test = foo()<|>;
            }
            ",
        );
        let hover = analysis.hover(position).unwrap().unwrap();
        assert_eq!(hover.range, TextRange::from_to(95.into(), 100.into()));
        assert_eq!(hover.info.first(), Some("u32"));
    }

    #[test]
    fn hover_shows_fn_signature() {
        // Single file with result
        check_hover_result(
            r#"
            //- /main.rs
            pub fn foo() -> u32 { 1 }

            fn main() {
                let foo_test = fo<|>o();
            }
        "#,
            &["pub fn foo() -> u32"],
        );

        // Multiple results
        check_hover_result(
            r#"
            //- /a.rs
            pub fn foo() -> u32 { 1 }

            //- /b.rs
            pub fn foo() -> &str { "" }

            //- /c.rs
            pub fn foo(a: u32, b: u32) {}

            //- /main.rs
            mod a;
            mod b;
            mod c;

            fn main() {
                let foo_test = fo<|>o();
            }
        "#,
            &["pub fn foo() -> &str", "pub fn foo() -> u32", "pub fn foo(a: u32, b: u32)"],
        );
    }

    #[test]
    fn hover_shows_fn_signature_with_type_params() {
        check_hover_result(
            r#"
            //- /main.rs
            pub fn foo<'a, T: AsRef<str>>(b: &'a T) -> &'a str { }

            fn main() {
                let foo_test = fo<|>o();
            }
        "#,
            &["pub fn foo<'a, T: AsRef<str>>(b: &'a T) -> &'a str"],
        );
    }

    #[test]
    fn hover_shows_fn_signature_on_fn_name() {
        check_hover_result(
            r#"
            //- /main.rs
            pub fn foo<|>(a: u32, b: u32) -> u32 {}

            fn main() {
            }
        "#,
            &["pub fn foo(a: u32, b: u32) -> u32"],
        );
    }

    #[test]
    fn hover_some() {
        let (analysis, position) = single_file_with_position(
            "
            enum Option<T> { Some(T) }
            use Option::Some;

            fn main() {
                So<|>me(12);
            }
            ",
        );
        let hover = analysis.hover(position).unwrap().unwrap();
        // not the nicest way to show it currently
        assert_eq!(hover.info.first(), Some("Some<i32>(T) -> Option<T>"));
    }

    #[test]
    fn hover_for_local_variable() {
        let (analysis, position) = single_file_with_position("fn func(foo: i32) { fo<|>o; }");
        let hover = analysis.hover(position).unwrap().unwrap();
        assert_eq!(hover.info.first(), Some("i32"));
    }

    #[test]
    fn hover_for_local_variable_pat() {
        let (analysis, position) = single_file_with_position("fn func(fo<|>o: i32) {}");
        let hover = analysis.hover(position).unwrap().unwrap();
        assert_eq!(hover.info.first(), Some("i32"));
    }

    #[test]
    fn test_type_of_for_function() {
        let (analysis, range) = single_file_with_range(
            "
            pub fn foo() -> u32 { 1 };

            fn main() {
                let foo_test = <|>foo()<|>;
            }
            ",
        );

        let type_name = analysis.type_of(range).unwrap().unwrap();
        assert_eq!("u32", &type_name);
    }

    // FIXME: improve type_of to make this work
    #[test]
    fn test_type_of_for_expr_1() {
        let (analysis, range) = single_file_with_range(
            "
            fn main() {
                let foo = <|>1 + foo_test<|>;
            }
            ",
        );

        let type_name = analysis.type_of(range).unwrap().unwrap();
        assert_eq!("[unknown]", &type_name);
    }

    #[test]
    fn test_type_of_for_expr_2() {
        let (analysis, range) = single_file_with_range(
            "
            fn main() {
                let foo: usize = 1;
                let bar = <|>1 + foo<|>;
            }
            ",
        );

        let type_name = analysis.type_of(range).unwrap().unwrap();
        assert_eq!("usize", &type_name);
    }

    #[test]
    fn test_hover_infer_associated_method_result() {
        let (analysis, position) = single_file_with_position(
            "
            struct Thing { x: u32 };

            impl Thing {
                fn new() -> Thing {
                    Thing { x: 0 }
                }
            }

            fn main() {
                let foo_<|>test = Thing::new();
            }
            ",
        );
        let hover = analysis.hover(position).unwrap().unwrap();
        assert_eq!(hover.info.first(), Some("Thing"));
    }
}