Improve Error Messages and Diagnostics

[Kinflou]

Improve Error Messages and Diagnostics

Priority

P2 (Medium) - Developer experience

Labels

• dx
• error-handling
• diagnostics
• P2

Estimated Effort

2 weeks

Description

Create rich, helpful compiler diagnostics using the ariadne crate. Good error messages are critical for developer experience.

Current State

Location: core/src/report.rs

Error reporting module exists but has todo!() placeholder and is underutilized throughout the codebase.

TODO References

• report.rs:53 - todo!()

Examples of Good Error Messages

Current (Bad)

Error: Failed to compile schema

Desired (Good)

error: undefined type `Uesr`
  ┌─ example.ids:5:12
  │
5 │     user: Uesr
  │            ^^^^ not found in this scope
  │
  = help: did you mean `User`?

Acceptance Criteria

• Source location tracking throughout compilation
• Beautiful error messages with ariadne for:
  • Parse errors
  • Semantic errors
  • Type errors
  • Import errors
• "Did you mean?" suggestions for typos
• Multiple errors shown (don't stop at first)
• Warning system for non-critical issues
• Documentation of common errors with solutions

Tasks

Infrastructure

• Add Span tracking to all AST nodes
• Thread source locations through compilation
• Create error types with location info
• Integrate ariadne for rendering

Error Categories

• Parse errors: syntax mistakes, invalid tokens
• Semantic errors: undefined symbols, duplicate names
• Type errors: type mismatches, invalid operations
• Import errors: missing files, circular imports
• Version errors: incompatible versions, breaking changes

Enhancements

• Add "did you mean?" for common typos (Levenshtein distance)
• Multi-error reporting (collect all errors, not just first)
• Warning levels (error, warning, note)
• Colored output (using ariadne's auto-color feature)
• JSON output mode for IDE integration

Documentation

• Document common errors with examples
• Create error code system (E001, E002, etc.)
• Add links to documentation in errors

Example Implementation

use ariadne::{Report, ReportKind, Label, Source};

Report::build(ReportKind::Error, source_id, span.start)
    .with_message("undefined type")
    .with_label(
        Label::new((source_id, span))
            .with_message("not found in this scope")
            .with_color(Color::Red)
    )
    .with_help("did you mean `User`?")
    .finish()
    .print((source_id, Source::from(source_code)))

Dependencies

• Consolidate and Complete IDL Parser #3 IR Compilation (errors occur during compilation)

Blocks

None