Struct Explain 

pub struct Explain {
    pub code: &'static str,
    pub blurb: &'static str,
    pub example: &'static str,
    pub page: &'static str,
    pub anchor: &'static str,
}

A curated, offline-complete explanation of a diagnostic code (#853).

This is the compiler-owned code → { blurb, href } table (DECISION A): the blurb/example are the offline answer bynk explain prints, while page/anchor compose the hosted-Book href the LSP hangs off the code as a clickable codeDescription link (DECISION C). Only the highest-traffic, newcomer-facing codes are curated; every other code simply has no entry and falls back gracefully — no link, no error (DECISION B).

The mapping points at existing Book concept pages rather than duplicating their prose; the reference-page generator (render_markdown) links every explained code at its page/anchor as an in-site link, so astro build’s link checker fails if a page moves or an anchor is renamed — the doc-drift guard the rest of the site already relies on.

Fields

code: &'static str

The diagnostic code this explains. Must be a real REGISTRY code (enforced by tests/diagnostics_registry.rs).

blurb: &'static str

A longer-form paragraph: what the rule is and, crucially, why it exists. This is the offline-complete answer — useful without network.

example: &'static str

A minimal example of the violation and its fix.

page: &'static str

The target Book page as a site-root-relative path, no extension and no trailing slash, e.g. /book/reference/types. Used verbatim as an in-site link by render_markdown (so the site link checker guards it) and prefixed with BOOK_BASE_URL for the hosted codeDescription.

anchor: &'static str

The in-page heading anchor (slug), or "" for the page top.

Implementations

impl Explain

pub fn href(&self) -> String

The hosted-Book URL for this explanation: BOOK_BASE_URL + the page (Starlight serves pages with a trailing slash) + #anchor when set.

pub fn in_site_link(&self) -> String

The site-root-relative link used inside the generated reference page, e.g. /book/reference/types/#record-types. Same shape as href, sans the host, so the in-site link checker resolves it.