rust-analyzer - Unnamed repository; edit this file 'description' to name the repository.


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

use hir::{db::ExpandDatabase, HirDisplay};
use ide_db::{
    assists::{Assist, AssistId, AssistKind},
    base_db::FileRange,
    label::Label,
    source_change::SourceChange,
};
use syntax::{ast, AstNode, TextRange};
use text_edit::TextEdit;

use crate::{Diagnostic, DiagnosticsContext};

// Diagnostic: unresolved-method
//
// This diagnostic is triggered if a method does not exist on a given type.
pub(crate) fn unresolved_method(
    ctx: &DiagnosticsContext<'_>,
    d: &hir::UnresolvedMethodCall,
) -> Diagnostic {
    let field_suffix = if d.field_with_same_name.is_some() {
        ", but a field with a similar name exists"
    } else {
        ""
    };
    Diagnostic::new(
        "unresolved-method",
        format!(
            "no method `{}` on type `{}`{field_suffix}",
            d.name.display(ctx.sema.db),
            d.receiver.display(ctx.sema.db)
        ),
        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
    )
    .with_fixes(fixes(ctx, d))
    .experimental()
}

fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::UnresolvedMethodCall) -> Option<Vec<Assist>> {
    if let Some(ty) = &d.field_with_same_name {
        field_fix(ctx, d, ty)
    } else {
        // FIXME: add quickfix
        None
    }
}

fn field_fix(
    ctx: &DiagnosticsContext<'_>,
    d: &hir::UnresolvedMethodCall,
    ty: &hir::Type,
) -> Option<Vec<Assist>> {
    if !ty.impls_fnonce(ctx.sema.db) {
        return None;
    }
    let expr_ptr = &d.expr;
    let root = ctx.sema.db.parse_or_expand(expr_ptr.file_id);
    let expr = expr_ptr.value.to_node(&root);
    let (file_id, range) = match expr {
        ast::Expr::MethodCallExpr(mcall) => {
            let FileRange { range, file_id } =
                ctx.sema.original_range_opt(mcall.receiver()?.syntax())?;
            let FileRange { range: range2, file_id: file_id2 } =
                ctx.sema.original_range_opt(mcall.name_ref()?.syntax())?;
            if file_id != file_id2 {
                return None;
            }
            (file_id, TextRange::new(range.start(), range2.end()))
        }
        _ => return None,
    };
    Some(vec![Assist {
        id: AssistId("expected-method-found-field-fix", AssistKind::QuickFix),
        label: Label::new("Use parentheses to call the value of the field".to_string()),
        group: None,
        target: range,
        source_change: Some(SourceChange::from_iter([
            (file_id, TextEdit::insert(range.start(), "(".to_owned())),
            (file_id, TextEdit::insert(range.end(), ")".to_owned())),
        ])),
        trigger_signature_help: false,
    }])
}

#[cfg(test)]
mod tests {
    use crate::tests::{check_diagnostics, check_fix};

    #[test]
    fn smoke_test() {
        check_diagnostics(
            r#"
fn main() {
    ().foo();
 // ^^^^^^^^ error: no method `foo` on type `()`
}
"#,
        );
    }

    #[test]
    fn field() {
        check_diagnostics(
            r#"
struct Foo { bar: i32 }
fn foo() {
    Foo { bar: i32 }.bar();
 // ^^^^^^^^^^^^^^^^^^^^^^ error: no method `bar` on type `Foo`, but a field with a similar name exists
}
"#,
        );
    }

    #[test]
    fn callable_field() {
        check_fix(
            r#"
//- minicore: fn
struct Foo { bar: fn() }
fn foo() {
    Foo { bar: foo }.b$0ar();
}
"#,
            r#"
struct Foo { bar: fn() }
fn foo() {
    (Foo { bar: foo }.bar)();
}
"#,
        );
    }
}