Diagnostics Guide

Diagnostics mirror DTCS style.

Implemented Rust types in src/diagnostics/:

pub enum Severity {
    Error,
    Warning,
    Information,
}

pub enum DiagnosticStage {
    Parse,
    CanonicalObjectModel,
    Validation,
    Analysis,
    Planning,
    Compilation,
    Runtime,
}

pub enum DiagnosticCategory {
    Syntax,
    Structure,
    Type,
    Reference,
    Semantic,
    Compatibility,
    Capability,
    Runtime,
    Extension,
}

pub struct Diagnostic {
    pub id: String,
    pub severity: Severity,
    pub stage: DiagnosticStage,
    pub category: DiagnosticCategory,
    pub message: String,
    pub object_ref: Option<String>,
    pub remediation: Option<String>,
    pub validation_phase: Option<ValidationPhase>, // JSON: validationPhase
}

Validation-stage diagnostics are built with validation_error(phase, id, category, message), which sets stage: Validation and validation_phase: Some(phase). Parse-stage diagnostics omit validationPhase.

Standard diagnostic identifiers live in src/diagnostics/codes.rs.

Diagnostics are stable enough for tests and CLI output. The Rust and Python CLIs include object_ref and remediation in text output when present.