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

use crate::Span;

/// An enum representing a diagnostic level.
#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
#[derive(Copy, Clone, Debug)]
#[non_exhaustive]
pub enum Level {
    /// An error.
    Error,
    /// A warning.
    Warning,
    /// A note.
    Note,
    /// A help message.
    Help,
}

/// Trait implemented by types that can be converted into a set of `Span`s.
#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
pub trait MultiSpan {
    /// Converts `self` into a `Vec<Span>`.
    fn into_spans(self) -> Vec<Span>;
}

#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
impl MultiSpan for Span {
    fn into_spans(self) -> Vec<Span> {
        vec![self]
    }
}

#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
impl MultiSpan for Vec<Span> {
    fn into_spans(self) -> Vec<Span> {
        self
    }
}

#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
impl<'a> MultiSpan for &'a [Span] {
    fn into_spans(self) -> Vec<Span> {
        self.to_vec()
    }
}

/// A structure representing a diagnostic message and associated children
/// messages.
#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
#[derive(Clone, Debug)]
pub struct Diagnostic {
    level: Level,
    message: String,
    spans: Vec<Span>,
    children: Vec<Diagnostic>,
}

macro_rules! diagnostic_child_methods {
    ($spanned:ident, $regular:ident, $level:expr) => {
        #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
        #[doc = concat!("Adds a new child diagnostics message to `self` with the [`",
                        stringify!($level), "`] level, and the given `spans` and `message`.")]
        pub fn $spanned<S, T>(mut self, spans: S, message: T) -> Diagnostic
        where
            S: MultiSpan,
            T: Into<String>,
        {
            self.children.push(Diagnostic::spanned(spans, $level, message));
            self
        }

        #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
        #[doc = concat!("Adds a new child diagnostic message to `self` with the [`",
                        stringify!($level), "`] level, and the given `message`.")]
        pub fn $regular<T: Into<String>>(mut self, message: T) -> Diagnostic {
            self.children.push(Diagnostic::new($level, message));
            self
        }
    };
}

/// Iterator over the children diagnostics of a `Diagnostic`.
#[derive(Debug, Clone)]
#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
pub struct Children<'a>(std::slice::Iter<'a, Diagnostic>);

#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
impl<'a> Iterator for Children<'a> {
    type Item = &'a Diagnostic;

    fn next(&mut self) -> Option<Self::Item> {
        self.0.next()
    }
}

#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
impl Diagnostic {
    /// Creates a new diagnostic with the given `level` and `message`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
        Diagnostic { level, message: message.into(), spans: vec![], children: vec![] }
    }

    /// Creates a new diagnostic with the given `level` and `message` pointing to
    /// the given set of `spans`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn spanned<S, T>(spans: S, level: Level, message: T) -> Diagnostic
    where
        S: MultiSpan,
        T: Into<String>,
    {
        Diagnostic { level, message: message.into(), spans: spans.into_spans(), children: vec![] }
    }

    diagnostic_child_methods!(span_error, error, Level::Error);
    diagnostic_child_methods!(span_warning, warning, Level::Warning);
    diagnostic_child_methods!(span_note, note, Level::Note);
    diagnostic_child_methods!(span_help, help, Level::Help);

    /// Returns the diagnostic `level` for `self`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn level(&self) -> Level {
        self.level
    }

    /// Sets the level in `self` to `level`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn set_level(&mut self, level: Level) {
        self.level = level;
    }

    /// Returns the message in `self`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn message(&self) -> &str {
        &self.message
    }

    /// Sets the message in `self` to `message`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn set_message<T: Into<String>>(&mut self, message: T) {
        self.message = message.into();
    }

    /// Returns the `Span`s in `self`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn spans(&self) -> &[Span] {
        &self.spans
    }

    /// Sets the `Span`s in `self` to `spans`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn set_spans<S: MultiSpan>(&mut self, spans: S) {
        self.spans = spans.into_spans();
    }

    /// Returns an iterator over the children diagnostics of `self`.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn children(&self) -> Children<'_> {
        Children(self.children.iter())
    }

    /// Emit the diagnostic.
    #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
    pub fn emit(self) {
        fn to_internal(spans: Vec<Span>) -> crate::bridge::client::MultiSpan {
            let mut multi_span = crate::bridge::client::MultiSpan::new();
            for span in spans {
                multi_span.push(span.0);
            }
            multi_span
        }

        let mut diag = crate::bridge::client::Diagnostic::new(
            self.level,
            &self.message[..],
            to_internal(self.spans),
        );
        for c in self.children {
            diag.sub(c.level, &c.message[..], to_internal(c.spans));
        }
        diag.emit();
    }
}