summaryrefslogtreecommitdiffstats
path: root/src/tools/rust-analyzer/crates/ide/src/inlay_hints/binding_mode.rs
blob: a0166d0048ab051c4fd67c656685d633a2180ae0 (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
//! Implementation of "binding mode" inlay hints:
//! ```no_run
//! let /* & */ (/* ref */ x,) = &(0,);
//! ```
use hir::{Mutability, Semantics};
use ide_db::RootDatabase;

use syntax::ast::{self, AstNode};

use crate::{InlayHint, InlayHintsConfig, InlayKind, InlayTooltip};

pub(super) fn hints(
    acc: &mut Vec<InlayHint>,
    sema: &Semantics<'_, RootDatabase>,
    config: &InlayHintsConfig,
    pat: &ast::Pat,
) -> Option<()> {
    if !config.binding_mode_hints {
        return None;
    }

    let outer_paren_pat = pat
        .syntax()
        .ancestors()
        .skip(1)
        .map_while(ast::Pat::cast)
        .map_while(|pat| match pat {
            ast::Pat::ParenPat(pat) => Some(pat),
            _ => None,
        })
        .last();
    let range =
        outer_paren_pat.as_ref().map_or_else(|| pat.syntax(), |it| it.syntax()).text_range();
    let pattern_adjustments = sema.pattern_adjustments(pat);
    pattern_adjustments.iter().for_each(|ty| {
        let reference = ty.is_reference();
        let mut_reference = ty.is_mutable_reference();
        let r = match (reference, mut_reference) {
            (true, true) => "&mut",
            (true, false) => "&",
            _ => return,
        };
        acc.push(InlayHint {
            range,
            kind: InlayKind::BindingModeHint,
            label: r.to_string().into(),
            tooltip: Some(InlayTooltip::String("Inferred binding mode".into())),
        });
    });
    match pat {
        ast::Pat::IdentPat(pat) if pat.ref_token().is_none() && pat.mut_token().is_none() => {
            let bm = sema.binding_mode_of_pat(pat)?;
            let bm = match bm {
                hir::BindingMode::Move => return None,
                hir::BindingMode::Ref(Mutability::Mut) => "ref mut",
                hir::BindingMode::Ref(Mutability::Shared) => "ref",
            };
            acc.push(InlayHint {
                range: pat.syntax().text_range(),
                kind: InlayKind::BindingModeHint,
                label: bm.to_string().into(),
                tooltip: Some(InlayTooltip::String("Inferred binding mode".into())),
            });
        }
        ast::Pat::OrPat(pat) if !pattern_adjustments.is_empty() && outer_paren_pat.is_none() => {
            acc.push(InlayHint {
                range: pat.syntax().text_range(),
                kind: InlayKind::OpeningParenthesis,
                label: "(".into(),
                tooltip: None,
            });
            acc.push(InlayHint {
                range: pat.syntax().text_range(),
                kind: InlayKind::ClosingParenthesis,
                label: ")".into(),
                tooltip: None,
            });
        }
        _ => (),
    }

    Some(())
}

#[cfg(test)]
mod tests {
    use crate::{
        inlay_hints::tests::{check_with_config, DISABLED_CONFIG},
        InlayHintsConfig,
    };

    #[test]
    fn hints_binding_modes() {
        check_with_config(
            InlayHintsConfig { binding_mode_hints: true, ..DISABLED_CONFIG },
            r#"
fn __(
    (x,): (u32,),
    (x,): &(u32,),
  //^^^^&
   //^ ref
    (x,): &mut (u32,)
  //^^^^&mut
   //^ ref mut
) {
    let (x,) = (0,);
    let (x,) = &(0,);
      //^^^^ &
       //^ ref
    let (x,) = &mut (0,);
      //^^^^ &mut
       //^ ref mut
    let &mut (x,) = &mut (0,);
    let (ref mut x,) = &mut (0,);
      //^^^^^^^^^^^^ &mut
    let &mut (ref mut x,) = &mut (0,);
    let (mut x,) = &mut (0,);
      //^^^^^^^^ &mut
    match (0,) {
        (x,) => ()
    }
    match &(0,) {
        (x,) | (x,) => (),
      //^^^^^^^^^^^&
       //^ ref
              //^ ref
      //^^^^^^^^^^^(
      //^^^^^^^^^^^)
        ((x,) | (x,)) => (),
      //^^^^^^^^^^^^^&
        //^ ref
               //^ ref
    }
    match &mut (0,) {
        (x,) => ()
      //^^^^ &mut
       //^ ref mut
    }
}"#,
        );
    }
}