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bynk_syntax/
error.rs

1//! Compiler diagnostics.
2//!
3//! Every error has a category (a dotted namespace string like
4//! `bynk.parse.expected_token`), a primary span, a primary message, and
5//! optionally some secondary labels and notes. Rendering goes through
6//! [`ariadne`] for source-pointing colour output.
7
8use ariadne::{Color, Config, Label, Report, ReportKind};
9
10use crate::span::Span;
11
12/// A compile error.
13#[derive(Debug, Clone)]
14pub struct CompileError {
15    pub category: &'static str,
16    pub span: Span,
17    pub message: String,
18    pub labels: Vec<(Span, String)>,
19    pub notes: Vec<String>,
20    /// v0.26 (ADR 0054): machine-applicable fixes, authored at the diagnosis
21    /// site — the only place the exact spans and replacement are known.
22    /// Consumed by the LSP (`codeAction`) and, later, a CLI `--fix`.
23    pub suggestions: Vec<Suggestion>,
24}
25
26/// A structured fix for the error it is attached to (v0.26, ADR 0054).
27///
28/// `edits` are span → replacement: an empty replacement deletes the span; an
29/// empty span inserts at its position. Spans are offsets into the same source
30/// text as the error's own span.
31#[derive(Debug, Clone)]
32pub struct Suggestion {
33    /// Human-facing action title, e.g. "remove `Clock` from the `given` clause".
34    pub message: String,
35    pub edits: Vec<(Span, String)>,
36    pub applicability: Applicability,
37}
38
39/// Whether a [`Suggestion`] can be applied without review (mirrors rustc;
40/// gates a future CLI `--fix` and the LSP's one-click apply).
41#[derive(Debug, Clone, Copy, PartialEq, Eq)]
42pub enum Applicability {
43    /// The fix is exactly right — safe to apply mechanically.
44    MachineApplicable,
45    /// The fix contains placeholder text a human must complete; never
46    /// auto-applied.
47    HasPlaceholders,
48}
49
50/// Severity classification for a [`CompileError`]. Mirrors LSP severity levels
51/// so the LSP server can map diagnostics to the protocol without reinterpreting
52/// error categories. Lives in the syntax leaf beside `CompileError` (it
53/// classifies one): shared by the IDE diagnose path (`bynk-ide`) and the
54/// `short`/`json` renderers, without either depending on the other.
55#[derive(Debug, Clone, Copy, PartialEq, Eq)]
56pub enum Severity {
57    Error,
58    Warning,
59}
60
61impl Severity {
62    /// Classify a [`CompileError`] by its category prefix.
63    ///
64    /// Categories starting with `bynk.parse.orphan_doc_block` or
65    /// `bynk.given.unused_capability` are warnings; everything else is an
66    /// error. Future categories can be added as the diagnostic surface grows.
67    pub fn for_error(err: &CompileError) -> Severity {
68        match err.category {
69            "bynk.parse.orphan_doc_block" | "bynk.given.unused_capability" => Severity::Warning,
70            _ => Severity::Error,
71        }
72    }
73}
74
75impl CompileError {
76    pub fn new(category: &'static str, span: Span, message: impl Into<String>) -> Self {
77        Self {
78            category,
79            span,
80            message: message.into(),
81            labels: Vec::new(),
82            notes: Vec::new(),
83            suggestions: Vec::new(),
84        }
85    }
86
87    pub fn with_label(mut self, span: Span, label: impl Into<String>) -> Self {
88        self.labels.push((span, label.into()));
89        self
90    }
91
92    pub fn with_note(mut self, note: impl Into<String>) -> Self {
93        self.notes.push(note.into());
94        self
95    }
96
97    /// Attach a machine-applicable fix (v0.26). Mirrors [`Self::with_note`];
98    /// the suggestion is authored where the diagnostic is raised.
99    pub fn with_suggestion(
100        mut self,
101        message: impl Into<String>,
102        edits: Vec<(Span, String)>,
103        applicability: Applicability,
104    ) -> Self {
105        self.suggestions.push(Suggestion {
106            message: message.into(),
107            edits,
108            applicability,
109        });
110        self
111    }
112
113    /// Build an [`ariadne::Report`] for this error, anchored to the given
114    /// filename. Colour is on (for the CLI and human-facing test output).
115    pub fn report<'a>(
116        &'a self,
117        filename: &'a str,
118    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
119        self.report_with_config(filename, Config::default())
120    }
121
122    /// Build a colourless [`ariadne::Report`], for transcripts committed to the
123    /// repo — no ANSI escape codes, so the output is byte-stable across machines.
124    pub fn report_plain<'a>(
125        &'a self,
126        filename: &'a str,
127    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
128        self.report_with_config(filename, Config::default().with_color(false))
129    }
130
131    fn report_with_config<'a>(
132        &'a self,
133        filename: &'a str,
134        config: Config,
135    ) -> Report<'a, (&'a str, std::ops::Range<usize>)> {
136        let primary_span = (filename, self.span.range());
137        let mut builder = Report::build(ReportKind::Error, primary_span.clone())
138            .with_config(config)
139            .with_code(self.category)
140            .with_message(&self.message)
141            .with_label(
142                Label::new(primary_span)
143                    .with_message(&self.message)
144                    .with_color(Color::Red),
145            );
146
147        for (span, label) in &self.labels {
148            builder = builder.with_label(
149                Label::new((filename, span.range()))
150                    .with_message(label)
151                    .with_color(Color::Yellow),
152            );
153        }
154
155        for note in &self.notes {
156            builder = builder.with_note(note);
157        }
158
159        builder.finish()
160    }
161}