Module codes 

Diagnostic code registry — the single source of truth for every diagnostic the compiler can emit.

Identity and severity are deliberately separate axes:

• A DiagnosticCode answers “which rule fired?” It is an opaque, namespaced, severity-free identifier rendered as MOS0010. The number has no semantic meaning — it does not encode severity, owner crate, category, or lint group. Numbers are globally unique and stable; new codes get the next free integer regardless of what they describe.
• A DiagnosticDef pairs that code with its slug, default severity, category, owning crate, and a one-line summary. The catalog groups by DiagnosticCategory, not by numeric range — so a rule that moves phases (parser → eval, fonts → text shaping) keeps its stable ID and just updates its category.

Both DiagnosticCode and DiagnosticDef have crate-private fields and crate-private constructors, so the only place a code or def can be minted is the define_codes! invocation below. Outside crates reference the pub static defs (&codes::MOS0010) and can neither forge new ones nor disagree with a code’s registered severity.

Structs

DiagnosticCode

Stable, severity-free diagnostic identifier (manifest §16).

DiagnosticDef

Registry entry: one code, its slug, default severity, category, owner, summary.

Enums

DiagnosticCategory

What kind of thing a diagnostic describes.

Statics

ALL

Every registered diagnostic definition, in declaration order.

MOS0010

#set not followed by an identifier.

MOS0011

Unknown #set target (only page, text, document, image).

MOS0012

Image file cannot be read from disk.

MOS0013

Missing ( after #set NAME, #image, or #figure.

MOS0014

PDF backend I/O failure (cannot create dir or write bytes).

MOS0015

Unknown keyword argument for #set TARGET, #image, or #figure.

MOS0016

Unterminated #NAME(...) or #NAME[[...]] block.

MOS0017

Unknown paper size in #set page(paper: ...).

MOS0018

Unknown font family; falling back to bundled Noto Sans.

MOS0019

Unexpected trailing content after a directive on the same line.

MOS0020

Argument type mismatch or non-positive length.

MOS0021

Internal: missing embedded font plan for a shaped run.

MOS0022

Malformed directive argument value (bad escape, unknown unit, unterminated string, lone -, malformed number/length).

MOS0023

Well-typed #set value breaks page geometry; previous value kept.

MOS0024

#set rejecting a positional argument where named is required.

MOS0025

Argument-list shape error (missing :, missing ,/), positional where named expected).

MOS0026

Font subsetting failure for an embedded face.

MOS0027

#set value passes typing but trips a sanity floor; still applied.

MOS0028

Unterminated **strong** run; treated as literal text.

MOS0029

Image file cannot be decoded (unsupported or corrupt).

MOS0030

Label declared more than once; first declaration wins.

MOS0031

Unterminated *emphasis* run; treated as literal text.

MOS0032

Base-14 /Differences glyph budget exhausted for a face.

MOS0033

@label reference to a label that does not exist.

MOS0034

Unterminated `code` run; treated as literal text.

MOS0035

Image reached layout without decoded pixels; skipped on the page.

MOS0036

Stray @ not followed by a label identifier; treated as text.

MOS0037

#image(...)/#figure(...) missing a path argument.

MOS0038

Lone trailing \ at end of input; treated as literal text.

MOS0039

Malformed citation group; treated as literal text.

MOS0040

#bibliography(...) missing a path argument.

MOS0041

Declared #bibliography(...) source file is not on disk.

MOS0042

#bibliography(...) path declared more than once; first wins.

MOS0043

BibTeX database could not be parsed (mos-bib).

MOS0044

CSL style could not be parsed (mos-csl).