brink_ir/hir/

diagnostics.rs

//! Diagnostic codes, severities, and the [`Diagnostic`] record.
//!
//! Split out of [`super::types`] (issue #652). The stable [`DiagnosticCode`]
//! catalogue and its lookup tables are touched by every diagnostic-adding
//! change, while the HIR node definitions next door are touched by every
//! language-feature change; keeping the two in separate files keeps those
//! streams of work from colliding.
//!
//! Everything here is re-exported through `hir::*`, so consumers keep
//! importing these names from `brink_ir::hir` exactly as before.

use rowan::TextRange;

use super::types::FileId;

/// A diagnostic produced during HIR lowering or cross-file analysis.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Diagnostic {
    /// Which file this diagnostic belongs to.
    pub file: FileId,
    /// The source span this diagnostic points at.
    pub range: TextRange,
    /// Human-readable message describing the problem.
    pub message: String,
    /// Structured error code for documentation and tooling.
    pub code: DiagnosticCode,
}

/// How seriously a diagnostic should be treated by a consumer (CLI renderer,
/// LSP client, editor diagnostics panel).
///
/// Until issue #1674, no `DiagnosticCode`'s *default* severity
/// ([`DiagnosticCode::severity`]) was ever `Info` or `Hint` — the two
/// advisory tiers existed only so a project's `[lints]` table
/// (`brink-project-config`'s `LintLevel::Info`/`LintLevel::Hint`, resolved
/// through `brink_analyzer::effective_severity`) could opt a `Warning`-default
/// code down to one when a squiggle is too loud (issue #1162). Moving any
/// *existing* code's default into one of these tiers is a separate decision,
/// deliberately not made by the issue that introduced the tiers.
/// [`DiagnosticCode::E157`] (issue #1674) is the first code to default here
/// directly — RULED "off or info by default" for a narrow, precision-tuned
/// lint that must not nag a single-shot project.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum Severity {
    /// Blocks compilation / is surfaced as a hard failure.
    Error,
    /// Non-fatal; the default tier for advisory diagnostics until a
    /// `[lints]` override says otherwise.
    Warning,
    /// Advisory, LSP `DiagnosticSeverity::INFORMATION` — worth telling the
    /// author about, but not something they need to act on.
    Info,
    /// Advisory and quiet, LSP `DiagnosticSeverity::HINT` — the tier IDEs use
    /// for things like unused-symbol dimming, where even an info-level
    /// squiggle is too loud.
    Hint,
}

/// Stable error codes for brink diagnostics.
///
/// Codes are never reused once assigned. Each code has a corresponding
/// explanation file at `docs/diagnostics/Exxx.md`.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum DiagnosticCode {
    // ── Containers ──────────────────────────────────────────────
    /// Knot definition is missing a name.
    E001,
    /// Stitch definition is missing a name.
    E002,
    /// Knot or stitch parameter is missing a name.
    E003,

    // ── Declarations ────────────────────────────────────────────
    /// `VAR` declaration is missing a name.
    E004,
    /// `VAR` declaration is missing an initializer.
    E005,
    /// `CONST` declaration is missing a name.
    E006,
    /// `CONST` declaration is missing an initializer.
    E007,
    /// `LIST` declaration is missing a name.
    E008,
    /// `LIST` member is missing a name.
    E009,
    /// `EXTERNAL` declaration is missing a name.
    E010,
    /// RETIRED (lane-A audit, #709) — the parser always materializes a
    /// `FILE_PATH` node inside `INCLUDE_STMT` (possibly empty) and reports
    /// missing path as E037 (`parser/declaration.rs::include_statement`).
    /// Code kept reserved, not reused.
    E011,

    // ── Control flow ────────────────────────────────────────────
    /// Divert is missing a target.
    E012,
    /// RETIRED (lane-A audit, #709) — `parser/divert.rs::path` always creates
    /// a `PATH` node (empty on error + E037), so `ThreadStart::target()` is
    /// never `None`. Code kept reserved, not reused.
    E013,
    /// Logic line has no effect (bare `~`).
    E014,

    // ── Expressions ─────────────────────────────────────────────
    /// Expression is missing an operand.
    E015,
    /// Unknown or unsupported operator.
    E016,
    /// Function call is missing a name.
    E017,
    /// RETIRED (lane-A audit, #709) — `parser/divert.rs::path` always creates
    /// a `PATH` node (empty on error + E037), so `DivertTargetExpr::target()`
    /// is never `None`. Code kept reserved, not reused.
    E018,

    // ── Choices ─────────────────────────────────────────────────
    /// RETIRED (lane-A audit, #709) — the parser only builds a `CHOICE` node
    /// after seeing a bullet token, so a bullet-less choice CST cannot exist.
    /// Code kept reserved, not reused.
    E019,

    // ── Inline logic ────────────────────────────────────────────
    /// Inline conditional is missing a condition.
    E020,
    /// Inline sequence has no branches.
    E021,

    // ── Cross-file analysis ──────────────────────────────────────
    /// Duplicate knot definition.
    E022,
    /// Duplicate variable/constant definition.
    E023,
    /// Unresolved divert target.
    E024,
    /// Unresolved variable reference.
    E025,
    /// Duplicate list item.
    E026,
    /// Ambiguous bare list item reference.
    E027,
    /// RETIRED (lane-A audit, #709) — circular INCLUDE is detected at the
    /// discovery phase and surfaces as `CompileError::CircularInclude`, not as
    /// a per-construct diagnostic. Code kept reserved, not reused.
    E028,

    // ── Compile errors ────────────────────────────────────────────
    /// Choice nested in conditional without explicit divert.
    E029,

    // ── Warnings ─────────────────────────────────────────────────
    /// String interpolation in constant initializer is ignored.
    E030,
    /// Function call argument count mismatch.
    E031,

    // ── Structural validation ───────────────────────────────────
    /// Return statement outside function.
    E032,
    /// Unreachable code after divert.
    E033,
    /// Choice set has only fallback choices.
    E034,
    /// Name shadows a built-in function.
    E035,
    /// Expected diagnostic not produced (`// brink-expect`).
    E036,
    /// Syntax error reported by the parser (malformed source).
    E037,
    /// Malformed `///` doc-comment tag on a declaration.
    E038,

    // ── Host manifest (external-function vocabulary) ─────────────
    /// Registered host manifest disagrees with the ink `EXTERNAL` arity.
    E039,
    /// Doc-comment / manifest references an unknown semantic type.
    E040,
    /// External call argument type mismatches the manifest signature.
    E041,
    /// External call argument violates a closed-domain constraint.
    E042,
    /// Well-formed `///` doc-comment tag that doesn't apply to this
    /// declaration kind (e.g. `@kind` on a knot, `@param` on a VAR).
    E043,

    // ── Directives (`#@…` — docs/directive-annotations-spec.md) ──
    /// Unknown directive name (e.g. `#@locale`).
    E044,
    /// Directive has no valid target in this position.
    E045,
    /// Directive contains dynamic inline logic — directives are static text.
    E046,
    /// Directive must be the only tag on its line.
    E047,
    /// Duplicate directive on one target.
    E048,
    /// Directive not supported on this target (e.g. `@local` on CONST).
    E049,
    /// Directive does not take arguments or trailing text.
    E050,

    // ── T1b dialect gate (docs/t1b-surface-spec.md §1) ────────────
    /// A brink-extension construct (block, sigil literal, indexing) was
    /// used under the `strict-ink` dialect.
    E051,
    /// A brink-extension construct parses and analyzes cleanly under the
    /// `brink` dialect, but its LIR lowering hasn't landed yet. Originally
    /// minted for T1b-1 (every T1b construct lowers since T1b-2, #570), then
    /// revived by T1c-1 (#699) as the `#fn(…)` lowering fence, retired again by
    /// T1c-2 (#700). **Now the `await` fence** (FS-2,
    /// docs/flow-suspension-spec.md §3, issue #928): `await <cond>` /
    /// `while await <cond>` parse to HIR and pass the effect-free purity gate
    /// (E105), but their runtime spill/restore semantics are FS-3 — every
    /// `await` construct is fenced here at LIR lowering until that lands. The
    /// code stays a general "parses/analyzes before its lowering lands" fence,
    /// reused as each new extension needs it.
    E052,
    /// RETIRED (T1b-2, #570) — previously a non-suppressible backstop
    /// rejecting T1b brink-extension HIR nodes (`LogicBlock`, `ArrayLiteral`,
    /// `MapLiteral`, `Index`) at LIR lowering. T1b-2 completed real lowering
    /// for all such constructs, making the backstop obsolete. Code kept
    /// reserved, not reused, for diagnostic-code stability.
    E053,
    /// A block-scoped `temp` (`~ { … }`, docs/t1b-surface-spec.md §2) or
    /// `for` loop variable shadows an already-visible temp/param — either an
    /// enclosing `~ { … }` block scope or an outer classic `~ temp`.
    E054,

    // ── T1b stdlib slice 1 (docs/t1b-surface-spec.md §5) ──────────────
    /// `push`/`insert`/`remove`'s first argument is not an lvalue (a
    /// variable, temp, or indexed path) — mutators require a place to
    /// write the mutated container back into.
    E055,
    /// `push`/`insert`/`remove` was used in expression position — they
    /// return nothing and are only valid as a statement.
    E056,

    // ── T1b logic blocks (docs/t1b-surface-spec.md §2) ────────────────
    /// `break`/`continue` used outside any enclosing `while`/`for` loop.
    E057,
    /// Collection mutator (`push`/`insert`/`remove`) called with the wrong
    /// number of arguments — a targeted compile error naming the expected
    /// signature (replaces the generic `E031` warning + silently-dropped
    /// RMW lowering, RULED 2026-07-12, see `docs/decision-log.md`).
    E058,

    // ── Weave-in-inline-content backstop (sibling of #578, #585) ──────
    /// A choice set, labeled gather block, multi-line conditional, or
    /// sequence was found nested inside inline content (e.g. a choice's own
    /// display/bracket/inner text) where it would need a child container
    /// that position structurally cannot hold.
    E059,

    // ── Codegen defense-in-depth backstop (#586) ──────────────────────
    /// `brink-codegen-inkb` refused to emit bytecode for a `Program` that
    /// violates an invariant an earlier, non-suppressible compiler stage is
    /// supposed to guarantee (currently: an out-of-loop `LogicBreak`/
    /// `LogicContinue`, normally rejected at `E057`). Reaching this from a
    /// normal compile is a compiler bug, not an authoring mistake — this
    /// code exists so that bug fails loudly instead of silently corrupting
    /// bytecode.
    E060,

    // ── TM-2 inline type annotations (docs/typed-mode-spec.md §3) ────
    /// A type annotation names something that isn't a recognized nominal
    /// type (`int`/`float`/`bool`/`string`/`divert`/`void`), a `List<L>`
    /// naming a declared `LIST`, `Array<T>`, or `Map<K, V>` — declared
    /// struct names arrive in TM-4.
    E061,
    /// RETIRED (T1c-1, #699): previously "`fn(T…): R` function-type
    /// annotation used — parses, but types as reserved until T1c". T1c
    /// unfroze the form (docs/t1c-spec.md §4: "boundary annotations gain
    /// the `fn(T…): R` form"), so it now resolves to a real checker type.
    /// Code kept reserved, not reused, for diagnostic-code stability — no
    /// longer emitted by any pass.
    E062,
    /// A param/return/`VAR` type annotation disagrees with the type
    /// TM-1's body inference would otherwise derive. Advisory only in this
    /// slice (gradual policy) — strict-mode severity is TM-3's call.
    E063,

    // ── TM-3 strict typed-mode policy (docs/typed-mode-spec.md §1/§9-3) ──
    /// `types = strict` was requested but the project's dialect isn't
    /// `brink` — strict typing is a brink-dialect extension (its annotation
    /// syntax is extension syntax), so `types = strict` + `dialect =
    /// strict-ink` is a config error, not a per-construct diagnostic.
    E064,
    /// Under `types = strict`, a def's inferred signature or body slot
    /// (param, return, or temp) resolved to `Unknown` after the SCC
    /// fixpoint with no annotation to supply a concrete type — "annotate or
    /// restructure" (spec §1). Legal under `types = gradual`.
    E065,
    /// Under `types = strict`, a def's inferred signature or body slot
    /// resolved to `Ty::Conflicted` (#627) — the body's own uses disagree
    /// on the slot's type. Legal (advisory-only, unreported) under `types =
    /// gradual`.
    E066,
    /// Under `types = strict`, a `~ x = f()` / `~ temp x = f()` assigns the
    /// result of a call whose resolved def is a `void`-returning function
    /// (docs/typed-mode-spec.md §3: "assigning a `void` call is an error in
    /// strict mode"). Only the assignment/temp-decl's RHS *root* call is
    /// checked — a statement-position call (`~ f()`) or a call nested inside
    /// interpolation is never flagged. Never emitted under `types = gradual`.
    E067,

    // ── TM-4b structs (docs/typed-mode-spec.md §6) ────────────────────
    /// A struct construction literal's leading shape name (`Name#{…}`)
    /// doesn't name any declared `STRUCT`.
    E068,
    /// Under `types = strict`, a struct construction literal omits a
    /// declared field — names the missing field.
    E069,
    /// A struct construction literal supplies a field the shape doesn't
    /// declare — names the extra field.
    E070,
    /// Under `types = strict`, a struct construction literal's field
    /// initializer disagrees with the field's declared type — names the
    /// field.
    E071,
    /// RETIRED (TM-4c, #666): previously a non-suppressible backstop
    /// rejecting *every* struct construct/field access reaching LIR
    /// lowering, back when codegen for structs didn't exist yet. Structs
    /// now lower for real (`E073` is TM-4c's narrower replacement
    /// backstop). Code kept reserved, not reused, for diagnostic-code
    /// stability — no longer emitted by any pass.
    E072,
    /// Non-suppressible defense-in-depth backstop, mirroring `E053`/`E060`/
    /// (former) `E072`: a struct construction literal referencing a shape
    /// name that doesn't resolve to any declared `STRUCT` reached LIR
    /// lowering. Reaching this from a normal compile means
    /// `brink-analyzer`'s `resolve::resolve_struct_ref` diagnostic (`E068`)
    /// was suppressed (`// brink-disable-all`), not a compiler bug on its
    /// own — `RecordNew` needs a real `ShapeId` at compile time; there is no
    /// dynamic "construct with unknown shape" concept in this design.
    E073,
    /// A field-write target (`p.field = expr`) is a *chained* projection —
    /// `p.a.b = v` or a mixed `p.a[i].b = v` — never a bare `ident.field`
    /// on a resolvable root. TM-4c ships single-level field writes only
    /// (mirrors `lower_indexed_assignment`'s `n == 1` fast path); chained
    /// writes are an explicit, permanent T1e boundary (`docs/
    /// typed-mode-spec.md` §6), not a "not implemented yet" gap — this is a
    /// real, reachable, non-suppressible diagnostic authors can hit by
    /// writing ordinary (if currently unsupported) ink, not a defensive
    /// backstop for a suppressed analysis diagnostic.
    ///
    /// Also covers a write ending in an *index* rather than a field, whose
    /// index chain's root is itself a struct-field projection or a mixed
    /// index/field access — `p.field[i] = v`, `p.a[i].b[j] = v`, or the
    /// mutator spelling (`push(p.field[i], v)`) — same T1e boundary,
    /// reached via `reject_field_projection_index_root` (issue #2121) from
    /// `lower_indexed_assignment`/`lower_lvalue_container_chain` rather than
    /// `try_lower_field_assignment`.
    E074,

    // ── decls constant-folding backstops (#673) ───────────────────────
    /// A struct construction literal used as a `VAR`/`CONST` declaration
    /// default doesn't match its declared shape: it omits a declared field,
    /// or supplies one the shape doesn't declare.
    ///
    /// A *well-formed* construction literal is a legal declaration default
    /// (issue #1530): `eval_const_struct_literal` folds it into
    /// `lir::ConstValue::Record`, which is what makes a struct-typed durable
    /// global — and therefore the T1e projection-receiver path
    /// (`docs/t1e-spec.md` §2, which requires a durable root) — spellable at
    /// all. Before #1530 this code was the blanket refusal of *every* struct
    /// literal in that position, because `ConstValue` had no record-carrying
    /// variant.
    ///
    /// Mid-story `p = Point#{…}` construction with a mismatched shape is a
    /// runtime construction fault (`RecordNew` against an invalid shape id,
    /// value-model-spec §11c's gradual path); a declaration default is baked
    /// into `StoryData` with no runtime construction step to fault at, so
    /// this is the compile-time equivalent — a real, non-suppressible error,
    /// never a half-built record. Under `types = strict` `brink-analyzer`'s
    /// `structs::check` reports the more precise [`Self::E069`]/
    /// [`Self::E070`] for the same literal; this backstop is
    /// policy-independent.
    E075,
    /// A map literal used as a `VAR`/`CONST` declaration default has a key
    /// that isn't a compile-time-constant scalar in the ratified map-key
    /// domain (int/string/bool — value-model-spec §4). Mid-story map
    /// construction (`MapNew`) faults on this at runtime
    /// (`InvalidMapKeyType`); a declaration default has no runtime
    /// construction step to fault at, so this is the compile-time
    /// equivalent — a real error, never a silent `Null`.
    E076,
    /// An array element, map value, struct field, or `#fn` bound `val` arg
    /// nested inside a `VAR`/`CONST` declaration default has a source
    /// expression kind that can never constant-fold — a function call,
    /// postfix indexing, field access, `++`/`--`, or (#743) a bare
    /// reference to another `VAR`. A declaration default is baked into
    /// `StoryData` at compile time, so there is no runtime construction
    /// step left to evaluate the element at; without this diagnostic the
    /// element recursed into `eval_const_expr`'s `Path`
    /// (`SymbolKind::Variable`) arm or catch-all and silently became `Null`
    /// — #673's silent-`Null` bug one level down, inside the literal (#679
    /// review; the `Path`-to-`Variable` case one level in was left
    /// deliberately unchanged there and closed by #743). Keyed off the
    /// source expression *kind*, never the folded result: an `Expr::Null`
    /// produced by HIR error recovery must not double-report, and a `Path`
    /// resolving to a `CONST`/list item/knot/stitch/function still folds
    /// for real and is not flagged — only a resolved `SymbolKind::Variable`
    /// (or an unresolved path, left to the analyzer's own diagnostic) is
    /// exempt from the fold-for-real behavior, matching
    /// `is_const_foldable_decl_default`'s top-level twin (`E083`). (Since
    /// #1530 a struct literal at this position folds for real, so a
    /// never-foldable *field* of a nested construction literal reaches this
    /// arm exactly as an array element or map value does; before #1530 the
    /// whole literal was unconditionally `E075` regardless of field
    /// content.)
    E077,
    // ── TM-3 completion: conversion intrinsics (docs/typed-mode-spec.md
    // §4, maintainer ruling 2026-07-13, issue #659) ──────────────────────
    /// Under `types = strict`, an unresolved (builtin, not author-shadowed)
    /// call to `int(x)`/`float(x)` where `x` is statically a divert-target,
    /// LIST, array, map, or struct construction literal — outside the
    /// permissive numeric+bool domain (ruling 2: "compile error under
    /// `types = strict`, runtime fault under gradual"). `string(x)` accepts
    /// every type and is never checked here.
    E078,

    // ── T1c function values (docs/t1c-spec.md §2/§8, issue #699) ─────
    /// `#fn(name, …)`'s target does not resolve to a statically-named
    /// function definition (`=== function name ===`) — it resolved to a
    /// variable/list/external/label/non-function knot or stitch, or it
    /// names a builtin/stdlib intrinsic (which has no definition to take a
    /// token of). Only fires under `dialect = brink` — under `strict-ink`
    /// the whole literal is already rejected as extension syntax (E051),
    /// and content diagnostics on rejected syntax are noise (the TM-2
    /// suppression precedent, maintainer ruling 2026-07-13).
    E079,
    /// A `ref` param of a `#fn` target is not bound in the creation-site
    /// prefix, or is bound to a non-durable lvalue. All `ref` params must
    /// be bound at creation, and each must capture a durable cell — a
    /// global `VAR` (flow-local `#@local` VARs included); a `temp`/param
    /// is a compile error (temps die with the frame, value-model §11), a
    /// `CONST` is not a mutable cell, and a bare (unmarked) rvalue/field
    /// reference is not a cell at all.
    ///
    /// T1e (docs/t1e-spec.md §2/§6, issue #831) extends this same code —
    /// "reuse the E080-family message shape" — to the explicit `ref
    /// lvalue-path` projection form (`heal(ref npc.hp, 5)`,
    /// `#fn(heal, ref party[leader].hp)`, `bind(f, ref inventory[idx])`):
    /// the *root* of the path (the innermost variable the segments walk
    /// from) must still be a durable global `VAR`, by the same rule —
    /// `temp`/param roots remain a compile error, a `CONST` root is not a
    /// mutable cell. A projection's own *segments* (dotted fields, `[…]`
    /// indices) are a separate check (`E098`, strict-mode statically-known
    /// shapes only) — this code is the root-durability obligation alone.
    E080,
    /// `#fn(name, args…)` binds more arguments than the target declares —
    /// the bound-arg row is a *prefix* of the declared param row
    /// (docs/t1c-spec.md §2: "binding more args than the target declares
    /// is a compile error").
    E081,

    // ── T1b block-temp scoping (docs/t1b-surface-spec.md §2, issue #680) ──
    /// A T1b block-scoped `temp` (`~ { … }`) — or a `for`-loop variable,
    /// which desugars the same way — was referenced (by value or by `ref`
    /// argument) after its own `~ { … }`/`while`/`for`/`if` block already
    /// closed. Root-caused for #680: LIR lowering's fallback for "temp not
    /// currently visible" (used for inklecate-compat forward-reference
    /// emulation of *classic* temps) previously also caught this case,
    /// silently emitting a phantom hashed `GetGlobal`/`RefGlobal` id that
    /// was never registered as a real global — a runtime-only
    /// `UnresolvedGlobal` fault with no compile diagnostic.
    E082,

    // ── Declaration-default constness, top level (issue #692, sibling to
    // #673/#679's collection-element E075/E076/E077) ─────────────────────
    /// A scalar `VAR`/`CONST` declaration default whose *source expression
    /// kind* can never be a compile-time constant — a bare reference to
    /// another `VAR` (`VAR x = someOtherVar`) or a function call
    /// (`VAR x = f()`), including either wrapped in a prefix/infix
    /// operation. `eval_const_expr`'s `Path` arm (`SymbolKind::Variable`)
    /// and its catch-all previously folded both silently to `Null` with no
    /// diagnostic — the same silent-fold bug #673/#679 fixed one level
    /// down, inside array/map/struct literals, left unfixed at this top
    /// level. Keyed off the source expression kind, never the folded
    /// result, same as `E077`. Does not fire for a `Path` nested inside a
    /// collection/struct/fn literal (array element, map value, struct
    /// field, `#fn` argument) — those recurse through their own existing
    /// `E075`/`E076`/`E077` per-element checks one level in, which
    /// deliberately still leave a `VAR`-reference gap unchanged (#679 scope
    /// notes) pending its own follow-up.
    E083,

    // ── TM-5 struct construction literals (docs/typed-mode-spec.md §6,
    // decision-log "Struct construction literals: source-order evaluation,
    // duplicate field is a compile error" 2026-07-14, issues #675/#676) ──
    /// A struct construction literal (`Name#{…}`) supplies the same field
    /// name more than once. Previously a silent last-wins: only the final
    /// initializer's value was placed, and — because the well-formed
    /// `RecordNew` lowering path discarded every non-placed lowered
    /// expression tree wholesale — an earlier duplicate's initializer
    /// (including any observable side effect, e.g. a function call) never
    /// actually ran at all, with no diagnostic (#675's RCA). Now a real
    /// compile error naming the repeated field, under both
    /// `types = gradual` and `types = strict` — unlike `E069`/`E070`/
    /// `E071` (which need a resolved shape to check missing/extra/mistyped
    /// fields against, and are strict-mode-only), a duplicate field is a
    /// structural authoring mistake detectable from the literal alone,
    /// independent of type-checking policy or whether the shape name even
    /// resolves.
    E084,

    // ── M-1 modules (docs/modules-spec.md §1/§5) ──────────────────
    /// An *undeclared* file whose module (its file stem) collides with a
    /// *declared* module's name (`#@module(name)` elsewhere). Accidental
    /// membership with mixed visibility defaults is the one footgun the
    /// module model forbids (modules-spec §1). Fix: declare the file with
    /// the same `#@module(name)`, or rename it.
    E085,
    /// A malformed `#@module(…)` directive: a missing or empty name
    /// argument, or a second `#@module` in the same file. `#@module`
    /// takes exactly one non-empty module name and appears at most once
    /// per file (modules-spec §1).
    E086,

    // ── M-2 imports + visibility (docs/modules-spec.md §2/§4/§7) ───
    /// A reference resolves to a `#@private` definition in another module.
    /// Private names are module-internal; the referrer is outside that
    /// module. Fix: make the definition `#@public` and `IMPORT` it, or move
    /// the reference into the module (modules-spec §4/§7).
    E087,
    /// A bare-form `IMPORT { name } FROM mod` / native `use mod::name;`
    /// whose trailing segment `name` names neither a definition `mod`
    /// publicly exports **nor a declared submodule of `mod`** (dual-reading,
    /// issue #1592 — a trailing segment that resolves to a module licenses
    /// it instead, matching Rust's `use`; §13.2). Only enforced against
    /// *declared* modules — an import naming an unknown/undeclared module is
    /// not itself flagged by this code, since that module's export/submodule
    /// set isn't visible to the check (modules-spec §2/§7).
    E088,
    /// An `IMPORT` brings the same local name into scope twice (a repeated
    /// bare import, or two imports whose names/aliases collide) — the
    /// reference would be ambiguous (modules-spec §2/§7).
    E089,
    /// An `IMPORT` names the importing file's own module — a module cannot
    /// import itself; its own names are already bare (modules-spec §2/§7).
    E090,
    /// A qualified access `a.b` is ambiguous: `a` is both a module imported
    /// in this file and a visible definition. Fix with an `AS` alias — no
    /// silent precedence (modules-spec §2/§7).
    E091,
    /// A `#@public`/`#@private` override that restates the module's default
    /// (e.g. `#@public` in an undeclared module, `#@private` in a declared
    /// one) — redundant, no effect (warning, modules-spec §4/§7).
    E092,
    /// Conflicting or repeated visibility directives on one declaration
    /// (both `#@private` and `#@public`, or the same one twice). A
    /// declaration takes at most one visibility directive (modules-spec §4).
    E093,

    // ── M-3 renames (docs/modules-spec.md §5/§7) ────────────────────
    /// A malformed `#@was(…)` directive: a missing or empty old-name
    /// argument (`#@was`, `#@was()`). `#@was` takes exactly one non-empty
    /// name (modules-spec §5).
    E094,
    /// `#@was(name)` names the thing's own *current* name — a self-alias
    /// that would be a no-op entry in the compiled alias table. Nothing to
    /// migrate; likely a stale directive left over from a previous rename
    /// (warning, modules-spec §5/§7).
    E095,

    // ── M-2c cross-module collisions (issue #784, decision-log
    // "Cross-module name collisions" 2026-07-14) ────────────────────────
    /// Two *declared* modules (`#@module(name)`, different names) each
    /// define a same-name, same-kind symbol. Escalated from the
    /// `E022`/`E023`/`E026` inklecate-compat duplicate warning to a hard
    /// error under `dialect = brink` only: flat resolution (unchanged by
    /// this stopgap — true import-scoped resolution is #790's job) binds a
    /// bare name to whichever declared-module definition merge happens to
    /// see first, so two declared modules sharing a name make that binding
    /// silently order-dependent for one of them. A duplicate *within* one
    /// module (same declared module name across its files, or any
    /// undeclared/legacy file) keeps the existing warning — this code
    /// fires only when both colliding definitions' owning files declared
    /// *different* modules. Reported once per colliding definition (both
    /// spans), under `strict-ink` this code never fires (compat corpus
    /// untouched).
    E096,

    // ── T1e-1 path projections (docs/t1e-spec.md §2/§6, issue #831,
    // tracking #828) ──────────────────────────────────────────────────
    /// A `ref lvalue-path` projection expression (`ref npc.hp`,
    /// `ref inventory[idx]`) appears somewhere other than ref-argument
    /// position (a direct argument of a call, `#fn(…)`, or `bind(…)`) — a
    /// standalone projection value (`temp r = ref a[0]`), one nested inside
    /// another expression, or any other position. Deliberate v1 posture
    /// (t1e-spec §2: "projections exist only where `ref` already exists:
    /// argument binding"); first-class standalone projection values are a
    /// future round, tracked as icebox #825 — not a permanent rejection.
    E097,
    /// A `ref lvalue-path` projection's segment (a dotted field, or a
    /// `[…]` index) disagrees with the root's statically-known shape, under
    /// `types = strict` only — a dotted field the declared `STRUCT` shape
    /// doesn't have, or a `[…]` index against a declared shape that isn't a
    /// collection (mirrors `structs::check`'s missing/extra-field
    /// machinery, `E069`–`E071`, applied to path segments instead of
    /// construction-literal fields; "Unknown never disagrees" for any
    /// segment whose base type isn't statically known this way — silently
    /// unchecked, same spirit as `E071`).
    E098,
    /// A `ref lvalue-path` projection with at least one path segment
    /// (dotted field or `[…]` index — a *real* projection, not a bare
    /// single-name `ref`) reached LIR lowering. T1e-1 (docs/t1e-spec.md §8
    /// sequencing item 1) ships grammar + HIR + analyzer only — the
    /// `MakeProjection`/`ProjRead`/`ProjWrite` opcodes a projection needs to
    /// actually run land in T1e-2 (tracking #828). The E052-fence pattern:
    /// every other check (`E080` durable root, `E097` position, `E098`
    /// strict segment shape) already ran and passed, so this is a clean,
    /// deliberate "not yet lowerable" stop, not a silent drop or a
    /// miscompile — see `brink-ir::lir::lower::mod`'s backstop doctrine. A
    /// bare single-name `ref x` (zero segments) never hits this — it lowers
    /// exactly like today's unmarked ref-argument binding.
    E099,

    // ── T2-2 `#@effects(…)` assertion surface (docs/effects-spec.md §10,
    // issue #861) ──────────────────────────────────────────────────
    /// `#@effects` with no argument at all (`#@effects`, `#@effects()`, or
    /// an argument that parses to nothing) — the directive always requires
    /// either `pure` or at least one `reads:`/`writes:`/`calls:` clause.
    E100,
    /// A malformed `#@effects(…)` argument: an unrecognized clause keyword
    /// (only `reads`/`writes`/`calls` are valid), a value that isn't a bare
    /// identifier, or a bare value with no preceding clause to attach to.
    E101,
    /// A `#@effects(…)` clause names an identifier that isn't a declared
    /// global `VAR`/`CONST` (for `reads`/`writes`) or a declared `EXTERNAL`
    /// (for `calls`) anywhere in the project.
    E102,
    /// **The exceedance error** (docs/effects-spec.md §10, sitting 2,
    /// 2026-07-14 ruling): the definition's inferred effect row is not
    /// covered by (`⊄`) its `#@effects(…)` assertion's declared upper
    /// bound. Per the ruling, this is the *only* diagnostic the assertion
    /// surface ever produces — an inferred row that is narrower than the
    /// bound is silent; there is no drift policy.
    E103,

    // ── Computed-callee call attempt (docs/t1c-spec.md §3/§10, issue #869) ──
    /// A call `expr(args…)` whose callee isn't a bare variable/temp/param
    /// name (an `INDEX_EXPR`, `FIELD_ACCESS_EXPR`, chained call result,
    /// parenthesized expr, …). Direct-call syntax is RULED (t1c-spec §3) to
    /// a bare-name callee only; "method-call syntax" through a computed
    /// callee is explicitly out of T1c (§10). Always rejected — every
    /// dialect, every mode — pointing at the ratified `call(f, args…)`
    /// form, which already dispatches through exactly this class of
    /// expression correctly. Replaces the pre-existing silent drop (the
    /// parser used to leave `(args…)` unconsumed, so it resurfaced as
    /// trailing prose text on the content line and the call itself
    /// vanished) with a loud, unconditional compile error.
    E104,

    // ── `await` condition purity gate (docs/flow-suspension-spec.md §3/§5, ──
    // ── issue #928, FS-2) ─────────────────────────────────────────────────
    /// An `await <cond>` / `while await <cond>` condition is not effect-free.
    /// The condition is captured as a compiler-synthesized *pure* function
    /// (docs/flow-suspension-spec.md §5): its effect row must be read-only —
    /// reads are the wake map's dependency set, but a transitive **write** to a
    /// global cell, or an effectful host **call**, makes the condition
    /// re-evaluation itself observable, which the wake contract forbids. Built
    /// on the effects machinery (#859): the condition's transitive effect row
    /// (via the whole-project [`crate`]-level effect table) must have empty
    /// `writes`/`calls` and not be opaque. Brink-only (under strict-ink the
    /// whole `await` is already `E051`); a bare fn-value reference used as a
    /// dynamic condition (`await some_fn_value`, no call syntax) is read-only
    /// by construction and never flagged.
    E105,

    // ── T1b map-literal key-domain warning (docs/t1b-surface-spec.md §3,
    // issue #598) ──────────────────────────────────────────────────────
    /// A `#{key: expr, …}` map-literal key is a statically-classifiable
    /// literal outside the ratified int/string/bool key domain — a float,
    /// array (`#[...]`), nested map (`#{...}`), struct (`Name#{...}`),
    /// function-value (`#fn(...)`), ink `LIST`, or divert-target literal
    /// used directly as a key. §3 rules the key domain to
    /// int/string/bool at runtime (`RuntimeError::InvalidMapKeyType`) and
    /// says the analyzer warns on statically-visible non-key types; this was
    /// the missing half (`MapLiteral` lowering did zero key-domain checking).
    /// A dynamic key (a variable, call, index, or any other non-literal
    /// expression) is not statically visible and is never flagged here —
    /// the runtime fault remains the sole backstop for those.
    E106,

    // ── NS-A1 Option[T] (docs/stdlib-spec.md §1.4, issue #1107) ────────
    /// A fresh, un-annotated declaration (`VAR x = none`, `CONST x = none`,
    /// `~ temp x = none`) whose initializer is the bare `none` Option
    /// literal. §1.4's ruled rule: "a bare `none` needs a type from
    /// context (concrete sites fine; a fresh un-annotated `var x = none`
    /// errors — the empty-collection posture)." A declaration site IS the
    /// slot's type origin, so there is no context to take the element type
    /// from — the fix is to initialize from a real Option-producing
    /// expression (`some(x)`, or an Option-returning verb like
    /// `find`/`get`/`pop`). Error in both dialects and both `types`
    /// policies: the rule is part of the Option package itself, not a
    /// strict-mode refinement.
    E107,

    // ── NS-A2 effect-row extension (issue #1108; docs/stdlib-spec.md
    // §1.2/§9.2, issues #1087/#1097) ───────────────────────────────────
    /// `@[effects(silent)]` exceedance: the definition's inferred row can
    /// produce content (`emits`, incl. transitively through callees, or an
    /// opaque/unbounded row). Exceedance-only, like `E103` — asserting less
    /// than reality is legal, asserting more is not.
    E108,
    /// `@[effects(total)]` exceedance: the definition's inferred row can
    /// raise a turn-terminating fault (`faults`, incl. transitively, or an
    /// opaque/unbounded row). Exceedance-only, like `E103`.
    E109,
    /// The deprecated `#@effects(…)` tag-channel spelling — superseded by
    /// the `@[effects(…)]` annotation final form (stdlib-spec §9.2, ruled
    /// 2026-07-18). Warning: the alias keeps parsing (it shipped in
    /// released surface, `@brink-lang/web@0.11.1`).
    E110,
    /// An `@[…]` annotation line naming something outside the channel's
    /// closed name set: `effects` on the ink surface, `effects` or the
    /// file-level `was` on the native `.brink` surface. Tag-channel
    /// directive names do not alias into it.
    E111,
    /// An `@[…]` annotation line outside a recognized placement — ink's
    /// leading run at the top of a knot/stitch body, or native's Rust-shaped
    /// position directly above a `flow`/`fn` declaration (issue #1563; the
    /// file-level `@[was]` record for native modules). Never a silent drop,
    /// never content — the `E045` posture, on the annotation channel.
    E112,

    // ── NS-A3 protocol registry (issue #1109; docs/stdlib-spec.md §9.6)
    /// A declaration named after a registry protocol method — `display`,
    /// `compare`, or `next` (F6, ruled 2026-07-19): the names are RESERVED
    /// under the brink dialect, and an author declaration of any callable
    /// or value-bindable kind (knot/stitch/function, param, temp, VAR,
    /// CONST, EXTERNAL, for-loop variable) is a **hard error**, not an
    /// E035-lineage shadowing warning — a shadowed `display` would make
    /// interpolation untrustworthy.
    E113,
    /// A registered protocol impl's inferred effect row exceeds its
    /// protocol's effect contract (`display`/`compare`: pure·silent·total;
    /// `iterate`'s `next`: writes-receiver·silent·total — the receiver is
    /// a `ref` param, invisible to the global row, so every v1 contract
    /// bounds the *global* row at empty). Exceedance-only, the
    /// `E103`/`E108`/`E109` posture; an opaque row exceeds every contract.
    E114,
    /// An ill-formed protocol impl registration: the named type isn't a
    /// declared `STRUCT`, the impl target isn't a declared function, the
    /// signature shape is wrong (arity, `ref`-ness, or a contradicting
    /// type annotation), or the (protocol, type) pair is already
    /// registered.
    E115,

    // ── F27: Option has no truthiness (docs/stdlib-spec.md §1.6, ruled
    // 2026-07-19, issue #1120) ─────────────────────────────────────────
    /// A condition-position expression (an `if`/`while` condition, a
    /// `{cond: …}` conditional branch, a choice guard, an `await`
    /// condition) whose statically-known type is `Option[T]`. Option has
    /// **no** truthiness — truthiness is a quiet coercion of exactly the
    /// kind `Option[T] ≠ T` exists to ban — so a strict-mode author writes
    /// `== none` / `== some(x)`, or the `as`-binding (B1b, issue #1475,
    /// `brink-analyzer::option_conditions::check_binding_condition`); a
    /// bound condition never fires this check. Strict-mode-only,
    /// best-effort static (the "Unknown never disagrees"
    /// posture: an unclassifiable condition stays silently unchecked);
    /// under `types = gradual` the same condition is the
    /// `RuntimeError::OptionTruthiness` turn-terminating fault — the
    /// runtime backstop that catches every case either way. Supersedes
    /// NS-A1's shipped falsy-none truthiness.
    E116,
    // ── NS-A5 the inhabited-range refinement (issue #1111;
    // docs/stdlib-spec.md §7, F7/F8 ruled 2026-07-19) ──────────────────
    /// A range-refinement violation under `types = strict` (the E078
    /// precedent — strict-only; gradual mode is inert and leaves the
    /// runtime fault residual, F8's general rule): `int(r)` demands
    /// `NonEmptyRange` evidence, and either (a) the range literal in
    /// argument position is **provably empty** (`0..0`, `5..=2` — bounds
    /// fold statically, CONST refs included), or (b) the argument's type
    /// carries no inhabitedness evidence (a possibly-empty range — route
    /// computed bounds through `non_empty(r)`, parse-don't-validate).
    E117,

    // ── NS-A8: the numeric tower (docs/tower-mini-spec.md, issue #1114) ──
    /// A protocol impl registration named a numeric-tower kind
    /// (`vec2`/`vec3`/`vec4`/`quat`/`mat2`/`mat3`/`mat4`) as its type.
    /// Tower kinds are compiler-known value kinds, not user structs: their
    /// `display` is the fixed structural form, their equality is
    /// componentwise IEEE (T4), and they are NOT orderable — a `compare`
    /// impl for a tower kind would contradict the ruled §4b doctrine, and
    /// `display`/`iterate` impls would shadow compiler-owned behavior. The
    /// rejection is unconditional — it wins even over a user STRUCT
    /// declared with the same name (tower type names are global like
    /// `int`).
    E118,

    // ── NS-A4: the ordering doctrine (docs/stdlib-spec.md §4b, issue
    // #1110) ─────────────────────────────────────────────────────────────
    /// A `sort_by`/`sorted_by` comparator provably breaks the pure·silent
    /// contract (§4b: "the comparator falls under the trio's pure·silent
    /// rule plus the consistent-total-order LAW"). Exceedance-only, the
    /// E114 posture: flagged when the comparator is a statically-named
    /// `#fn(target)` whose inferred row shows a global read/write, an
    /// external call, a content emission, or a tag touch — an opaque or
    /// unresolvable comparator is not *proven* in violation and passes
    /// (the gradual posture; the VM's isolation and
    /// `ComparatorEscaped` fault are the runtime residual).
    E119,
    /// NS-A7 `Weighted[T]` construction refusal (`docs/stdlib-spec.md` §8,
    /// issue #1113): the compile-classifiable half of the E078-style
    /// evidence-by-construction split. Fired by the `weighted(…)` lowering
    /// for a statically-malformed table — an empty pair row, an odd
    /// (dangling-weight) argument count, or a **literal** weight that is
    /// not a positive int (zero, negative, float/string/bool). Computed
    /// weights are not classifiable here; they carry the construction
    /// *fault* residual instead (`RuntimeError::WeightedBadWeight`), so a
    /// table that exists is always rollable.
    E120,

    // ── B0.3 HIR admission validator (docs/hir-admission-contract.md §4.2) ──
    //
    // Reserved range for the loud, non-suppressible `validate_admission`
    // pass wired at the AST→HIR seam (issue #1172, docs/b0-sequencing.md
    // §B0.3). Each check is a hard error — a malformed `(HirFile,
    // SymbolManifest)` triple is a frontend bug, not a story-author mistake,
    // so these never carry the warning-severity carve-out other codes do.
    /// Contract §4.2 check 1a (manifest ⇄ HIR agreement): an
    /// `UnresolvedRef.range` in the manifest has no matching
    /// referencing-expression range anywhere in the file's HIR body — the
    /// range-equality resolution join (Q2(a)) would silently fail to find
    /// this reference at all.
    E121,
    /// Contract §4.2 check 1b (manifest ⇄ HIR agreement): a manifest-declared
    /// symbol has no corresponding HIR declaration node of the same name —
    /// the manifest and the HIR body have drifted apart.
    E122,
    /// Contract §4.2 check 1c (manifest ⇄ HIR agreement, F-I#4): a `Knot`'s
    /// `is_function` flag disagrees with whether its declared symbol carries
    /// the `"function"` detail sentinel.
    E123,
    /// Contract §4.2 check 2a (range well-formedness): a HIR node's source
    /// range is empty or extends past the end of the source file — ranges
    /// are resolution join keys and IDE geometry, so a garbage range would
    /// otherwise corrupt resolution silently instead of erroring loudly.
    /// Exempts the `Option<Provenance>`-carrying synthesized nodes
    /// (`Content.ptr`/`Divert.ptr`/`Return.ptr`) when `None` (B0.1 finding
    /// F-B2) — this fires only on a range that is present but malformed.
    E124,
    /// Contract §4.2 check 2b (join-key uniqueness, Q2(a)): two distinct
    /// `UnresolvedRef` entries in the manifest share an identical source
    /// range — the range-equality join can no longer distinguish them.
    E125,
    /// Contract §4.2 check 3 (name-convention conformance, F-I#3): a
    /// declared symbol's qualified name does not match the dot-qualification
    /// shape its `SymbolKind` requires (bare for knots/globals, `knot.stitch`
    /// for stitches, `List.item` for list items, `knot[.stitch].label` for
    /// labels).
    E126,
    /// Contract §4.2 check 4 (control-flow classification, F-I#7): a
    /// terminal statement (`Divert`/`Return`) is not the last statement in
    /// an inline conditional or sequence branch.
    E127,
    /// Contract §4.2 check 5 (provenance-kind ⇄ `SymbolKind` consistency,
    /// F-I#5, the #626 floating-stitch trap): a `Knot`/`Stitch` HIR node's
    /// provenance class disagrees with the `SymbolKind` bucket its declared
    /// symbol was indexed under in the manifest.
    E128,

    // ── B0.6 native frontend (docs/b0-sequencing.md §B0.6) ──
    //
    // The native `.brink` declaration lowering (`hir::lower_native`) is
    // deliberately partial — bodies are B0.7/B0.8, and a handful of
    // declaration-layer constructs (nested modules, `fn` nested below top
    // level, the `@[…]` annotation channel, lambda expressions in value
    // position) have no HIR representation yet. Per the contract's §4.4
    // additive-open/closed-to-silent-extension posture, every such
    // construct is a loud diagnostic, never a silent drop.
    /// A native construct parses cleanly but has no HIR lowering yet in
    /// this slice (a nested `module { … }` block, a `fn` declared below top
    /// level, an `@[…]` annotation line, a lambda expression in value
    /// position, or any other CST shape `hir::lower_native` does not yet
    /// recognize). The construct is skipped — not silently: this diagnostic
    /// names exactly what was skipped and why.
    ///
    /// Also raised by `brink_analyzer::modules::check` (issue #1592,
    /// #1686 review) for the whole-project-only instance of the same gap:
    /// a bare `use`/`IMPORT` item's trailing segment that is both aliased
    /// and — only knowable once whole-project module data resolves the
    /// dual-reading — a declared **submodule**. Aliasing an entire
    /// imported module's export set has no `Import`/`ImportItem`
    /// representation, same as the single-segment `use a as m;` form
    /// `lower_native::import::lower_use_decl` already rejects with this
    /// code; this later firing exists only because that verdict isn't
    /// decidable until the analyzer's whole-project pass.
    E129,
    /// A native `flow` is declared more than two levels deep (a `flow`
    /// nested inside another nested `flow`'s body) — the contract's Q4(b)
    /// fence (`docs/hir-admission-contract.md` §5 Q4): exactly two
    /// container levels for v1, addressing model written to generalize.
    /// Depth-3+ nesting parses and is rejected here, never silently
    /// flattened into a 2-level shape.
    E130,
    /// `<-` (splice) used outside a choice point (issue #1263, ruled
    /// #1260 on #1256): charter §11 narrows threads to scoped splices
    /// inside `{? … }` choice points, so this has no structural meaning —
    /// but `<-` can also be literal dialogue punctuation, so this is
    /// **warning severity, never blocking** (see `DiagnosticCode::severity`
    /// below). The construct still parses as ordinary text; nothing is
    /// dropped or rejected. `brink-syntax-native`'s
    /// `parser::choice::splice_outside_choice_point` raises the
    /// `ParseSeverity::Warning` diagnostic this code carries once it
    /// reaches `brink-db`'s `lower_native_file`.
    E131,
    /// A native file-level `@[was(…)]` rename record (issue #1286) carries no
    /// quoted old module path — a missing argument, or one that is not a
    /// string literal. Native module paths are `::`-separated and travel as a
    /// string (`::` is not annotation-argument grammar), so the migration
    /// target must be spelled `@[was("story::old::path")]`. **Warning
    /// severity, never blocking** (see `DiagnosticCode::severity`): the
    /// malformed directive is skipped — no alias is produced — but the file
    /// still compiles. `brink-ir::hir::lower_native::module::lower_file_module`
    /// raises it rather than silently dropping the authored record.
    E132,

    // ── B0.9 native accept-list admission gate (docs/hir-admission-contract.md
    // §4.4/§5 Q6, docs/b0-sequencing.md §B0.9, issue #1179) ──
    //
    // The inverse of the ink `dialect_gate` reject-list: `brink_analyzer::
    // validate_native_accept_list` enumerates the HIR shapes a well-formed
    // native lowering is allowed to produce and refuses everything else,
    // loudly, at the same non-suppressible seam B0.3's `validate_admission`
    // runs at. Native-only — never raised against ink-produced HIR.
    /// A native file's `root_content` carries something other than the one
    /// documented shape a native lowering may leave there: empty, or the
    /// single synthesized `flow main()` entry divert (maintainer-ruled
    /// 2026-07-21, `docs/decision-log.md` "Native story-entry convention").
    /// Anything else — real weave content, more than one statement, a
    /// source-backed divert — is ink-only baggage: ink's pre-first-knot root
    /// weave has no native equivalent.
    E133,
    /// A native file's HIR carries an `IncludeSite` — native has no textual
    /// `INCLUDE` graph (charter §13.2, "the tree is the compilation
    /// universe"); `hir::lower_native::lower` always leaves `includes`
    /// empty, so any entry here is ink-only baggage that reached native HIR
    /// some other way.
    E134,
    /// A `ThreadStart` (`<- target`) appears somewhere other than the two
    /// legal native splice positions B0.7's choice-point lowering produces:
    /// immediately preceding the `ChoiceSet` it preambles, or as the
    /// trailing statement(s) of a `Choice`'s own body
    /// (`hir::lower_native::choice::lower_choice_point`). An "ambient"
    /// thread start anywhere else has no structural meaning on the native
    /// surface (charter §11 narrows threads to scoped splices inside `{?
    /// … }` choice points).
    E135,
    /// A native `ChoiceSet` carries a `depth`/`context` other than the
    /// B0.7-documented neutral values (`depth = 0`, `context = Inline`,
    /// `docs/hir-admission-contract.md` §3 D4) every native choice set
    /// stamps uniformly — native has no weave fold to report a real value
    /// from, so any other value means a weave-fold concept leaked in from
    /// somewhere it shouldn't have.
    E136,
    /// The B0.9 native strict-only enforcement point (docs/b0-sequencing.md
    /// §B0.9, decision-log 2026-07-19 "Typing posture ruled"): a native
    /// `.brink` file was compiled with an explicit `types = gradual` knob.
    /// Gradual typing does not exist on the native surface — `types` is not
    /// a project knob there the way it is for the transitional brink
    /// dialect, so an explicit `gradual` setting reaching a `.brink` compile
    /// is refused, loudly, rather than silently accepted.
    E137,

    // ── B5: the construction initializer (issue #1464, #1103 RULED
    //    2026-07-23, `docs/stdlib-spec.md` §9.6) ────────────────────────
    /// A map literal supplies the same key twice (`Map { k: 1, k: 2 }`).
    /// The E076-lineage cascade ruling (A) of #1103: a duplicate key is a
    /// **compile error**, consistent with a struct literal's duplicate
    /// field ([`Self::E084`]) — last-wins would silently swallow the typo.
    /// Only *statically comparable* literal keys can collide here
    /// (int/string/bool, the `E106` key domain); a dynamic key is left to
    /// the runtime, exactly as the key-domain check leaves it.
    E138,
    /// A construction literal's entries are not in the form its target type
    /// constructs from — `Map { a }` (element form for a key/value target)
    /// or `Flags { A: 1 }` (key/value form for an element target). The
    /// brace *tokens* are one fixed grammar; the entry form each type
    /// consumes is the `construct` protocol's business
    /// ([`crate::hir::construct::ConstructTarget::form`]), so a mismatch is
    /// caught at dispatch rather than by the parser.
    E139,

    // ── B3a: UFCS resolution (issue #1482, D1–D5 RULED 2026-07-26,
    //    `docs/decision-log.md` "UFCS resolution pass designed") ────────
    /// **D1**: `recv.name(args)`'s receiver type declares a field `name`,
    /// but that field is not function-typed. Field access *wins outright* —
    /// a matching-but-non-callable field is a hard error, never a silent
    /// fall-through to a free function of the same name, so that a call's
    /// meaning can never hinge on a field's type.
    E140,
    /// `recv.name(args)` resolved as neither: the receiver's type declares
    /// no field `name`, **and** no free function `name` is visible in
    /// ordinary lexical scope (D4 — the candidate set is lexical scope only;
    /// there are no method sets or inherent impls). One diagnostic naming
    /// both attempts, so the author sees the whole search that failed.
    E141,
    /// **D3**: `recv.name(args)`'s receiver type is not known at the
    /// resolution point, so field-access-wins is unanswerable. An annotation
    /// is demanded rather than the resolution being deferred (E107-family
    /// posture). Explicitly a *for now* trade — smarter inference ordering
    /// is planned and additive when it lands.
    E142,
    /// **D5**: `recv.name(args)` resolved to a free function whose first
    /// parameter is declared `ref`, so the receiver is auto-ref'd
    /// (`party.leader.heal(5)` → `heal(ref party.leader, 5)`, issue
    /// #1462) — but *this* receiver cannot be written through: a `CONST`, or
    /// a projection whose root is a frame-local (T1e's durable-root rule,
    /// `docs/t1e-spec.md` §2), or — once the grammar can spell them — an
    /// rvalue such as `[1,2].push(3)`. Refused rather than silently
    /// desugared by value, which would drop the mutation. A non-`ref` first
    /// parameter never reaches this code: the by-value desugar puts no
    /// lvalue requirement on its receiver.
    E143,
    /// A UFCS call site that `brink-analyzer::ufcs` **resolved** cleanly has
    /// reached LIR lowering, which does not consume the verdict side table
    /// yet. Refused loudly rather than lowered: the callee path's resolution
    /// record names the *receiver* (the D2 side table is what names the real
    /// target), so lowering it as an ordinary call would emit a call against
    /// a local's id and silently produce a wrong program. Same "parses/
    /// resolves but has no lowering yet" posture as [`Self::E129`], one
    /// layer further down.
    E144,

    // ── B1b: the `as` binding (issue #1475, RULED `docs/decision-log.md`
    //    2026-07-26 "The `as` binding") ─────────────────────────────────
    /// The v1 whole-condition restriction: an `as` binding was written over
    /// a `&&`/`||` composition (`if a && find(x) as s { … }`). The ruling
    /// fixes the binding as the **entire** condition for v1 — let-chains
    /// can land later, additively — so a boolean composition under the
    /// binding is refused rather than silently binding the composite (which
    /// is never an `Option[T]` anyway). The mirror spelling, an operator
    /// *after* the binding (`if find(x) as s && …`), is caught one layer
    /// earlier as a parse error (`brink-syntax-native::parser::binding`).
    E145,
    /// RETIRED (issue #1508) — previously "an `as` binding in a choice
    /// guard (`* {if EXPR as name} [text]`) is ruled but not yet
    /// implemented". `hir::lower_native::choice::lower_choice` now lowers
    /// it for real: capture-at-presentation, by-value COW
    /// (`docs/decision-log.md` 2026-07-26, "Choice-guard `as`
    /// un-deferred"), reusing the same `OptionBind`/frame-slot machinery
    /// `IfStmt::binding` already used — the guard's `OptionBind` writes
    /// into the same frame `BeginChoice`'s `fork_thread` snapshots into
    /// the pending choice, so the captured value rides along with no
    /// separate wire-level capture needed. Code kept reserved, not reused,
    /// for diagnostic-code stability — no longer emitted by any pass.
    E146,
    /// An `as` binding whose condition is a statically-known **non-Option**
    /// type (`if 5 as n { … }`). The binding unwraps `Option[T]` to `T`;
    /// there is nothing to unwrap here. Strict-mode-only and
    /// classification-gated, exactly like its F27 twin [`Self::E116`]: an
    /// `Unknown`/`Conflicted` condition stays unjudged rather than
    /// guessing.
    E147,
    /// A write to an `as` binding — `if find(s) as i { i = 0; }`, `pop(i)`,
    /// `i[0] = x`, `bump(ref i)`, `b.field = v`, `push(b.field, v)`, … The
    /// binding is **immutable** by ruling (`docs/decision-log.md`
    /// 2026-07-26): it names the unwrapped payload the condition proved
    /// present, and rebinding it would make the narrowing guarantee a lie.
    /// Raised via the shared `lir::lower::stmts::reject_as_binding_write`
    /// check (issue #2122) for: plain/compound assignment, an
    /// indexed-assignment root, and a bare in-place mutator, all via
    /// `lir::lower::stmts::lower_assign_target` itself; a single-level
    /// struct-field write (`lir::lower::blocks::lower_single_level_field_write`)
    /// and a struct-field mutator (`lir::lower::blocks::lower_field_mutator`),
    /// which resolve a `Param`/`Temp` root's slot independently of
    /// `lower_assign_target` (their root is the *head* of a two-segment
    /// path, not the whole target) and so call the shared check directly
    /// instead; and separately at the `ref`-argument choke points
    /// (`lir::lower::expr::lower_ref_path_call_arg`,
    /// `lower_ref_projection_arg`), since passing the binding by `ref`
    /// hands the callee a raw pointer to the slot without ever routing
    /// through ordinary assignment lowering.
    E148,
    /// A `remove(a, i)` call whose first argument is statically known to be
    /// an array (issue #1532, the #1501 review's migration-tail finding):
    /// `remove` went map-only in #1484 (identity-based, idempotent-total
    /// key removal; `docs/t1b-surface-spec.md` §5), and the array-index leg
    /// it used to also serve moved to its own verb, `remove_at(a, i)`. With
    /// no compatibility shim, an un-migrated `remove(array, i)` call site
    /// still parses and type-checks as a call to the (now map-only)
    /// builtin — `infer::body`'s `remove` arm already has `Ty::Array` in
    /// hand at the call site — and previously reached codegen clean, only
    /// faulting at runtime against `MapRemove`'s domain check. Strict-mode-
    /// only (`infer::body::InferPass::array_remove_calls`,
    /// `strict::check_array_remove_calls`), matching every other TM-3
    /// typed-mismatch check in this range — the brink dialect's own
    /// implicit default is `types = strict` (issue #1127), so this fires
    /// for the common case; under `types = gradual` the `MapRemove`
    /// runtime fault stays the backstop, same posture as the rest of TM-3.
    E149,
    /// A def (function or value-returning flow/stitch) declares a non-`void`
    /// return type but its body may fall through without ever executing a
    /// value-carrying `return <expr>` (issue #1551, `docs/decision-log.md`
    /// 2026-07-22 implicit-end ruling item 3: "a flow that declares a
    /// return type must produce a value... falling through without a value
    /// is a checker error", ratified for a return-typed flow/stitch and now
    /// extended to the identical `fn` shape). Strict-mode-only
    /// (`strict::check_def`'s escape check, extended by #1551 to run for
    /// any def carrying a declared return type, not just `is_function`);
    /// deliberately distinct from [`Self::E065`] Unknown-escape — the
    /// annotation-fallback in `infer::body::infer_def_body` backfills a
    /// no-return body's inferred return type from the annotation itself,
    /// so the type comes out concrete (`Clean`, not `Unknown`) and E065's
    /// classification can never see this mistake; only a direct
    /// `has_value_return` check catches it. An implicit `-> DONE` is never
    /// treated as satisfying this — DONE ends the *turn*, not the value
    /// contract.
    E150,

    // ── Native lint: asymmetric choice-branch dead-end (issue #1219,
    //    decision-log 2026-07-22 "Flows end implicitly (native)" item 4) ──
    /// A native `{? … }` choice's own body falls through (no divert/return)
    /// while a sibling choice in the same set diverts onward, at a genuine
    /// dead end (nothing follows the choice point to reconverge into) — the
    /// residual value of ink's retired "ran out of content" error,
    /// relocated to a narrow, **opt-in, warning-severity** lint
    /// (`brink_analyzer::native_choice_dead_end`) rather than a blocking
    /// runtime fault. Fires only for the *mixed* case — some siblings
    /// divert, at least one doesn't — never for a choice set where every
    /// branch falls through (an ordinary menu that ends) or where the
    /// choice set's `continuation` is non-empty (native has no gather,
    /// `docs/native-surface-charter.md` §5 — a non-empty continuation is
    /// the dissolved gather, and every falling-through branch reconverging
    /// there is ordinary weave structure, not a mistake).
    E151,

    /// A `contains(m, needle)` call whose `needle` argument is statically
    /// visible as outside the map key domain (int/string/bool) while `m`
    /// is statically visible as a map — companion to the #580 ruling
    /// (`docs/decision-log.md` 2026-07-12 "contains(map, non-key-domain
    /// needle) returns false"): the call can never do anything but return
    /// `false` at runtime, so the always-false result is a compile-time
    /// warning rather than a silent footgun. Strict-mode-only
    /// (`brink_analyzer::contains_domain`, wired into `strict::check`
    /// alongside `conversions`/`range_refinement` — the same
    /// inference-substrate-backed domain-check family): needs the
    /// project's whole-program `InferenceResult`
    /// (`structs::classify_expr_ty`) to classify a variable/call/
    /// index-valued needle, which is only ever computed under `types =
    /// strict`. Under `types = gradual` this stays silent and the
    /// runtime's total `false` return is the sole (correct, non-faulting)
    /// backstop. `Warning`-severity like `E106`'s map-literal-key sibling
    /// check, so it flows through the ordinary suppressible `diagnostics`
    /// channel and is re-levelable via the project's `[lints]` table.
    E152,

    // ── `@[allow(…)]` source-level suppression (issue #1161) ───────
    /// An `@[allow(…)]` argument is not a diagnostic code this compiler
    /// knows (`DiagnosticCode::from_str_code` says no) — a typo like
    /// `@[allow(E1511)]` or a name like `@[allow(dead_code)]`.
    ///
    /// A hard error by construction, and deliberately so: the whole point
    /// of a suppression directive is that the author believes a diagnostic
    /// is being silenced, so a misspelled code that silently does nothing
    /// is the worst possible outcome (the #1374 reserved-keys lesson, and
    /// the `@`-namespace rule in `docs/directive-annotations-spec.md` §1.1
    /// — every `@`-mark is a valid directive in a valid placement or a hard
    /// error).
    E153,

    /// An `@[allow(…)]` names a real diagnostic code that is **not
    /// suppressible**: one whose default severity
    /// ([`DiagnosticCode::severity`]) is `Error`.
    ///
    /// Source-level suppression only ever reaches the warning/lint tier. An
    /// error means the compiler cannot produce a correct artifact, so
    /// letting an annotation silence one would be a way to ship broken
    /// code; the B0.3 admission-validator family (`E121`–`E128`) is covered
    /// by the same rule (all `Error`-severity) *and* structurally, since
    /// admission diagnostics never route through
    /// [`crate::suppressions::apply_suppressions`] at all. This mirrors the
    /// `[lints]` table's own hard-error exemption (issue #1160, step 2 of
    /// `brink_analyzer::effective_severity`): rather than curating which
    /// `Error` codes are "safe" to relax, none of them are reachable.
    E154,

    /// An `@[allow(…)]` whose argument list is missing, empty, or not a
    /// flat list of bare code identifiers (`@[allow]`, `@[allow()]`,
    /// `@[allow("E151")]`, `@[allow(reads(x))]`).
    ///
    /// The grammar counterpart of `E100` on the `@[effects(…)]` channel:
    /// the annotation parses as an annotation but declares nothing this
    /// channel can act on.
    E155,

    // ── Lambdas (native surface, issue #1685) ──────────────────────
    /// A lambda body assigns to a **captured binding** — a `let`/param
    /// binding declared outside the lambda and read inside it.
    ///
    /// A hard error by the 2026-07-19 ruling ("assignment to a captured
    /// binding is a compile error"): brink lambdas capture BY VALUE always
    /// (Rust's `move` as the only mode, no keyword, no ref captures in v1),
    /// so the binding a lambda body writes to is its own *snapshot* — the
    /// write can never be observed by the enclosing scope. A snapshot write
    /// is always a lost write, and this kills the closure-mutation
    /// confusion structurally rather than letting authors discover it as a
    /// silent no-op at runtime.
    ///
    /// Writes to a *global* (a module-level `var` cell) are not captures
    /// and are not flagged: a global is a durable cell reached by name, not
    /// a snapshotted binding.
    E156,

    // ── Anonymous-container state lint (issue #1674, gap 4 of the identity
    //    cluster; ruled 2026-07-27 in PR #1670) ─────────────────────────
    /// An unnamed once-only choice, or an unnamed sequence (`{cycle: …}` /
    /// `{stopping: …}` / `{once: …}` / `{shuffle: …}` and combinations), that
    /// genuinely carries durable visit/turn-count state with no author name
    /// to anchor it — the choice/sequence's compiled scope id is purely
    /// structural (a positional hash, `brink_ir::hir::stamp`), so a content
    /// edit anywhere earlier in the same scope can shift it, orphaning the
    /// saved count under the old id. The observable fallout is bounded (only
    /// visit/turn counts key on a scope id — see
    /// `brink_format::LoadReport::anonymous_states_dropped`): a once-only
    /// choice may reappear, or a sequence may restart from its first branch.
    ///
    /// Naming is the opt-in fix — a labeled choice (`* (label) …`) resolves
    /// its identity by name instead of position (`stamp::stamp_stmt`'s
    /// `lookup_label_id` branch), immune to this drift. Sequences have no
    /// label syntax of their own; the mitigation is structural (isolate the
    /// sequence in its own small, stably-named stitch so nothing can be
    /// inserted ahead of it).
    ///
    /// **Off/info by default, tier-able through `[lints]`** like any other
    /// diagnostic (`brink_analyzer::strict::effective_severity` — this is
    /// the one code whose *default* severity is `Info`, not `Warning`; see
    /// that function's doc for how `[lints]` still reaches it). A
    /// single-shot project that never patches its content is never nagged;
    /// a live-ops/UGC project can raise it to `warn`/`deny`.
    ///
    /// Precision over recall (`brink_analyzer::anonymous_stateful`): a `+`
    /// sticky/repeatable choice never triggers this (no once-only gating,
    /// no state) and a single-branch, non-`once` sequence never triggers
    /// this either (its computed index is `0` regardless of visit count —
    /// genuinely stateless despite the syntax).
    E157,

    // ── Lambda lifting, LIR (issue #1709 review) ───────────────────
    /// A lambda body reads a name that the analyzer resolved as a
    /// `Temp`/`Param` of the enclosing frame, but that lifting's free-name
    /// scan cannot see as a capturable local at the point it runs — in
    /// practice, the lambda's own not-yet-bound `let` name, read
    /// recursively (`let f = |x| f(x - 1);`): the initializer is scanned
    /// for captures *before* the `let` finishes binding `f`, so `f` has no
    /// temp slot yet in the enclosing frame.
    ///
    /// A hard error rather than a silent fall-through: an unresolved free
    /// name that is not a real local (a global `var`, a knot/function
    /// name) is left alone and resolved by name from inside the lifted
    /// function, which is correct. But a name the analyzer says *is* a
    /// local must not take that same silent path — falling through would
    /// let call lowering target the `let`'s own `DefinitionId` as though
    /// it were a callable container, a miscompile that only surfaces as a
    /// runtime fault. Recursive lambdas are not supported in this slice;
    /// this refuses them at compile time instead of shipping a broken
    /// call.
    E158,

    // ── `@[element]` / `@[style]` declaration surface (issue #1719,
    //    `docs/prose-dialect-spec.md` §3.5b sitting 4 addenda 2–4) ───────
    /// An `@[element(…)]` annotation whose `args` clause is missing, or
    /// whose value is not a quoted string, or whose value does not compile
    /// as a portable-regex pattern (`regex::Regex::new`).
    ///
    /// The grammar counterpart of `E100`/`E155` on the `@[effects]`/
    /// `@[allow]` channels: the annotation parses as an annotation but
    /// declares a pattern this channel can't act on.
    E159,
    /// An `@[element(args = "…")]` pattern's named capture group does not
    /// match the name of any parameter on the annotated declaration.
    ///
    /// The capture contract (§3.5b: "named captures bind params by name
    /// (compile-checked)") is enforced here, at the declaration, rather
    /// than deferred to the `!name` dispatch site — a capture that can
    /// never bind anything is a static defect in the pattern itself, not
    /// a per-call-site concern.
    E160,
    /// An `@[style(…)]` clause is not the `key = "value"` shape (a bare
    /// identifier, a nested paren-clause, or a non-string value), or the
    /// argument list is missing or empty.
    E161,
    /// An `@[style(…)]` clause's key is neither `line`, `dispatch`, nor
    /// the name of a named capture group in the paired `@[element(…)]`
    /// pattern on the same declaration.
    ///
    /// Validated against the real capture set rather than accepted
    /// blind — a typo'd key would otherwise silently style nothing
    /// (`CLAUDE.md` "flag silent data drops").
    E162,
    /// An `@[style(…)]` annotation with no paired `@[element(…)]` on the
    /// same declaration.
    ///
    /// `@[style]` is a *companion* annotation (§3.5b addendum 4): its keys
    /// name `@[element]`'s captures (plus the two special keys, `line` and
    /// `dispatch`), so a style declaration with nothing to style against
    /// is malformed rather than silently inert.
    E163,

    // ── Host manifest (inline-markup vocabulary, issue #1733,
    //    `docs/prose-dialect-spec.md` §4.2) ──────────────────────────────
    /// An inline markup span (`<name>…</name>`) whose tag name is not
    /// declared in the host manifest's markup vocabulary.
    ///
    /// Only ever reachable once a host *declares* a vocabulary: markup is
    /// freeform by default (§4.2), so with no declared span kinds this code
    /// cannot fire at all. `Warning` by default and therefore
    /// `[lints]`-configurable and `@[allow(E164)]`-suppressible — the
    /// "configurable severity" half of §4.2's ruling.
    E164,
    /// An inline markup span carries an attribute the host manifest does not
    /// declare for that span kind.
    ///
    /// The per-kind counterpart of `E164`, and gated the same way: it fires
    /// only for a span whose *name* the manifest does declare (an undeclared
    /// name reports `E164` alone rather than cascading one report per
    /// attribute).
    E165,

    // ── `@[element(…, block)]` declaration surface (issue #1839,
    //    `docs/decision-log.md` 2026-07-31 "Conventions are annotated
    //    handlers") ──────────────────────────────────────────────────────
    /// A `block`-flagged `@[element(…)]` annotation whose declaration has
    /// no trailing `content`-typed parameter to receive the captured run,
    /// or whose would-be receiver is also one of the pattern's own named
    /// captures.
    ///
    /// `block` widens the same capture contract [`Self::E160`] enforces
    /// for `args`' named captures — the ruling's `content` param ("the
    /// following run … the same first-class fragment-capture path `!radio`
    /// uses for the rest of its line") is a *structural* requirement on
    /// the declaration, checked here rather than deferred to dispatch: a
    /// `block` annotation with nothing to bind the captured run to is a
    /// static defect in the declaration, not a per-call-site concern. The
    /// dispatch and capture rewrite itself — matching the terminator,
    /// building the `FragmentRef`, calling the handler — is issue #1838's
    /// natural-notation dispatch, not yet implemented; see
    /// [`crate::ElementAnnotation::block`]'s own doc.
    E166,

    // ── Natural-notation element dispatch (issue #1838,
    //    `docs/decision-log.md` 2026-07-31 "Conventions are annotated
    //    handlers") ───────────────────────────────────────────────────────
    /// A natural-notation `@[convention(claims = "…", order = N)]` handler declares a
    /// parameter that its pattern never captures, so a claimed line has
    /// nothing to bind it to.
    ///
    /// The other half of `E160`'s contract, and the half only *claiming*
    /// handlers need: a `!name`-dispatched handler can be called by hand
    /// with ordinary arguments, but a claimed line is rewritten to exactly
    /// one call whose every argument comes from a named capture — so the
    /// pattern's capture set and the handler's parameter list must match
    /// exactly, not merely one-way.
    ///
    /// Renumbered to `E167` (from a since-vacated `E166`) when this landed
    /// alongside issue #1839's `block` declaration surface, which claimed
    /// `E166` first (merged into `main` first) — see that code's own doc.
    E167,
    /// Two `@[convention(claims = "…", order = N)]` handlers declare byte-identical
    /// patterns, and the later-declared one never actually won a claim in
    /// this file — so it is dead code.
    ///
    /// Issue #1848: dispatch order is first-match-wins over the module's
    /// claiming handlers, ordered by `@[convention]`'s required `order`
    /// property (issue #2164 — declaration order, the interim pre-#2164
    /// rule, no longer applies; `hir::lower_native::element::try_claim`'s
    /// own doc) — an undocumented rule until this issue, and one with no
    /// diagnostic when two patterns can both claim the same line. This is
    /// the *sound*, narrow slice of that check: identical patterns provably match
    /// identical inputs, so the overlap is certain, not merely possible.
    ///
    /// A byte-identical twin is not *unconditionally* dead, though:
    /// `try_claim` excludes a handler from claiming lines inside its own
    /// declaration (the staging rule), and that exclusion does not extend
    /// to a later twin — the later twin is exactly the handler that *can*
    /// claim a line living inside the earlier one's own body. So this
    /// diagnosis runs after the whole file is lowered and only fires when
    /// the later twin produced zero actual claims
    /// (`hir::lower_native::element::diagnose_duplicate_patterns`'s own
    /// doc) — a later twin that is live for even one line is not flagged.
    ///
    /// General overlap between two *different* patterns (e.g. one whose
    /// matches are a strict subset of the other's) is real and valuable —
    /// the issue's own framing calls it "the genuinely valuable half" —
    /// but is **not** detected here: proving it soundly needs either a
    /// witness string both patterns can be shown to accept or a full
    /// regex-intersection analysis, neither of which this slice builds.
    /// Tracked as a follow-up, not silently out of scope — see the
    /// issue thread. `Warning` by default (`@[allow(E168)]`-suppressible,
    /// like every other `Warning`-tier code) since a duplicate claim is
    /// dead code, not a hard error the way an unregistered claim (`E112`)
    /// is.
    E168,
    /// A top-level `fn` carries an `@[convention(claims = "…", order = N)]` pattern-
    /// claiming annotation, but this file is not the project's configured
    /// conventions module — the module half of the 2026-07-31 §9.1 ruling's
    /// item (4) asymmetry (issue #1844; #1838 landed the *placement* half,
    /// `E112`, and #1847 the module-nesting corner of it): "pattern-
    /// claiming is confined to ONE module — the conventions module named in
    /// `brink.toml`. `!name`-dispatched handlers stay legal anywhere
    /// precisely because they self-announce." A sigil-dispatched line
    /// announces itself at the call site; a claiming pattern can silently
    /// reinterpret ordinary prose, so the auditability the ruling protects
    /// depends on every claim living in the one file an author (or
    /// reviewer) knows to open.
    ///
    /// Only fires when `brink.toml`'s `[project] conventions` key (renamed
    /// from `elements` by issue #2180) names a project-relative `.brink`
    /// path (`conventions = "conventions.brink"`) — a bare built-in preset
    /// name (`conventions = "screenplay"`) points at a
    /// `std::conventions::*` module with no project file to compare
    /// against, and an unset `conventions` key means no conventions module
    /// is configured at all, so there is nothing to confine against yet
    /// (`brink_db::queries::analysis::conventions_confinement_diagnostics_query`'s
    /// own doc). `Error` by default, the same posture as `E112`: a
    /// misplaced claim is not a style nit, it is a claim that violates the
    /// one property the whole mechanism depends on.
    E169,
    /// Two claiming handlers' patterns are textually different but can both
    /// match the same line of prose — they silently race, with the earlier
    /// one winning (issue #1859, follow-up to #1848).
    ///
    /// `E168` catches the narrow case: byte-identical patterns provably
    /// match identical inputs. This code catches the more common and more
    /// valuable instance: two *different* patterns whose matched-line sets
    /// overlap (one a strict subset of the other, an alternation branch
    /// shared between them, two competing prefixes, etc.).
    ///
    /// Detection uses a sound-but-incomplete heuristic: finding a concrete
    /// witness string demonstrably accepted by both compiled patterns. The
    /// heuristic checks:
    /// - Whether the patterns share a literal prefix (both start with the
    ///   same fixed text, before any regex metacharacters)
    /// - Whether one pattern's literal parts are a subset of the other's
    ///   (e.g. `^A$` is subsumed by `^AB?$` if the second can match `A`)
    /// - Whether generated test strings match both patterns
    ///
    /// A witness found proves overlap; none found does not prove they
    /// never overlap. This is the safer alternative to a textual heuristic
    /// that could produce false positives (e.g. "shares a literal prefix"
    /// without confirming both patterns actually match anything starting
    /// with that prefix — `^A$` and `^AB$` share the prefix `A` but never
    /// both match any input). Only reports what it can prove.
    ///
    /// Reported **at most once** per later-handler, against the first
    /// earlier handler it provably overlaps with. A handler that overlaps
    /// multiple earlier ones is not re-reported. `Warning` severity, like
    /// `E168`, since a silent race is a real problem but not a hard error.
    ///
    /// See also: `E168` (byte-identical patterns), `docs/prose-dialect-
    /// spec.md` §3.5b ("pattern power proportional to auditability").
    E170,
    /// A natural-notation `@[convention(claims = "…", order = N)]` handler declares a
    /// parameter, bound by a named capture, whose declared type is neither
    /// `string` nor absent nor `content` — `int`, `float`, `bool`, a
    /// struct name, a generic, or a `fn` type.
    ///
    /// Filed from adversarial review of PR #1845 (issue #1849, itself
    /// closing part of #1838): `hir::lower_native::element::try_claim`
    /// binds **every** matched capture as a plain `Expr::String` literal,
    /// unconditionally, regardless of the receiving parameter's declared
    /// type — so `@[convention(claims = "^Take (?<n>\\d+)$", order = N)] fn
    /// take(n: int)` could never actually receive an `int`. Numeric capture
    /// coercion is `docs/prose-dialect-spec.md` §3.5b's own Deferred list
    /// — the underlying gap is ruled-deferred, not itself a bug — but
    /// leaving the mismatch silent is: without this check it was, and
    /// remains, silent — nothing checks a direct call's arguments against
    /// the callee's declared parameter types yet. That generic check
    /// (`E063` for this shape) is exactly what open issue #1864 asks to
    /// build.
    ///
    /// `content` is deliberately **not** in this code's target set even
    /// though a capture can no more produce a `FragmentRef` than an `int`
    /// — it already has an established, ruled, and tested story of its
    /// own (the spec's own `fn radio(chan: string, text: content)`
    /// example, and the `tier1-native/annotations-element` golden
    /// fixture, both compile clean today); see `hir::lower_native::
    /// annotation::is_satisfiable_by_a_string_capture`'s own doc for why.
    ///
    /// Reported at the declaration — the same static-defect-in-the-
    /// declaration posture `E160`/`E166`/`E167` already take — pointing
    /// at the offending param's own type annotation range (an untyped or
    /// `content`-typed param never triggers this code, so the annotation
    /// is always present and non-`content` when it fires). `Error` by
    /// default: unlike `E168`/`E170`'s "silent race" posture, this is a
    /// param that can never receive a value of its declared type, not a
    /// stylistic ambiguity.
    E171,
    /// A native tag (`#…`) whose text begins with `@` — the shape of an
    /// ink-dialect compiler directive (`#@private`, `#@was(…)`,
    /// `#@local`, `#@module(…)`, `#@effects(…)`) — is lowered by a `.brink`
    /// file (issue #1835).
    ///
    /// `#@…` is not its own grammar production in either dialect: it is an
    /// ordinary tag (`HASH` + free text), and only ink's HIR lowerer
    /// (`hir::lower::directive::parse_directive_tag`) gives a leading `@`
    /// special, compile-time-consumed meaning. `#` is already the runtime-
    /// tag sigil in native content position (that is exactly *why* `#@…`
    /// parses as a tag rather than a directive there too), and
    /// `hir::lower_native` has no matching check — so before this code, an
    /// author porting a file from ink, or splitting time between the two
    /// dialects, got no error and no warning: the directive text became
    /// ordinary tag content on the compiled story, silently, which is worse
    /// than a plain no-op because it surfaces as mysterious runtime output
    /// rather than a compile-time failure.
    ///
    /// `Warning` by default, not `Error`: a literal `@`-led tag can be a
    /// deliberate runtime convention for a host that wants one (the issue's
    /// own caution), so the diagnostic is `[lints]`-configurable and
    /// `@[allow(E172)]`-suppressible rather than blocking, the same posture
    /// as `E132`/`E168`/`E170`. `hir::lower_native::body::lower_tag` raises
    /// it, naming the native spelling to use instead when the tag names a
    /// real ink directive that has one (`@[was(…)]`, `@[effects(…)]`) and
    /// saying so plainly when it does not (`module`, `public`, `private`,
    /// `local` have no native annotation counterpart yet). `#@allow` is
    /// its own case — ink's directive recognizer does not know `allow`
    /// either, so the message never calls it an ink-dialect spelling; it
    /// only notes that native's own `@[allow(…)]` annotation (an unrelated
    /// diagnostic-suppression channel) happens to share the name. Any other
    /// unrecognized name gets a shape-only wording that never asserts ink
    /// membership.
    E172,

    // ── Required markup attributes (issue #1780 gap 1, ruled by #1997)
    //    ────────────────────────────────────────────────────────────────
    /// An inline markup span of a declared kind is missing an attribute the
    /// host manifest marks `required` for that kind.
    ///
    /// The counterpart `E164`/`E165` never caught: `attrs` was an
    /// *allow*-list only until #1997, so a declared attribute simply absent
    /// from a span went undiagnosed. Gated the same way as `E165`: it only
    /// ever fires for a span whose *name* the manifest does declare (an
    /// undeclared name reports `E164` alone), and only for attributes the
    /// declaring kind actually marks `required` — a kind with none required
    /// never raises this for any span of that kind. One report per missing
    /// attribute, not one combined message, mirroring `E165`'s
    /// one-per-attribute posture rather than `E164`'s one-per-span.
    ///
    /// `Warning` by default, the same posture as `E164`/`E165`, for the same
    /// reason: only a `Warning`-base code is `[lints]`-configurable and
    /// `@[allow(…)]`-suppressible, and a host that wants a required
    /// attribute to be binding raises it with `[lints] E173 = "deny"`.
    E173,
    /// A lambda's own **written annotation** (a param's `: T` or the
    /// lambda's `: R` return annotation) disagrees with its body-derived
    /// type (issue #1994, RULED 2026-08-01, closing #1932: "the written
    /// annotation takes priority... an incompatible body is an eager error
    /// at the lambda, not a deferred surprise at the call site").
    ///
    /// `#1910`/PR #1928 made `infer::body::InferPass::infer_lambda` read a
    /// lambda's body-derived param/return types back — the same overlay
    /// `infer_def_body` already applies for a top-level `fn`/`flow` — which
    /// silently let a *wrong* body derivation override a *correct* written
    /// annotation with no diagnostic anywhere (a standalone `let f = |k:
    /// int|: int { "wrong" };` with no call site produced nothing at all).
    /// This code closes that gap for the annotated case specifically: a
    /// lambda's own written per-param/return annotation now always governs
    /// that slot's resulting type, and this diagnostic fires the moment the
    /// body-derived type (when it resolves to anything concrete) disagrees
    /// with it — deliberately **not** gradual/advisory like `E063`, since
    /// the annotation is the ruled source of truth for a lambda's own
    /// signature, not a hint to double-check later.
    ///
    /// `#1910`'s own fix is unchanged for the *unannotated* case — a
    /// lambda param/return with no written annotation still exports
    /// whatever its body derives, exactly as before.
    ///
    /// Native-only (`LAMBDA_EXPR` has no `brink-syntax` counterpart, same
    /// posture as `E156`/`E158`): raised only from
    /// `infer::body::InferPass::infer_lambda`, reported by
    /// `strict::check_lambda_annotation_mismatches` under `types = strict`.
    E174,
    /// RETIRED (issue #2165) — was `register`'s comptime-only-intrinsic
    /// confinement check (issue #1840 Q5): `register` was legal only inside
    /// the project's configured conventions module's `fn conventions()`,
    /// enforced here. The 2026-08-03 ruling (`docs/decision-log.md`, "`fn
    /// conventions()` is DISSOLVED") removed `fn conventions()` and
    /// `register` from the design entirely — precedence is now a static
    /// `order` property on `@[convention]` (issue #2164), needing no
    /// comptime evaluator and so no confinement diagnostic to raise. Code
    /// kept reserved, not reused.
    E175,
    /// A divert-with-args site (`-> knot(args)`, `->-> tunnel(args)`, or
    /// `<- thread(args)`) supplies a number of arguments that does not
    /// match its resolved target's declared parameter count (issue #2156).
    ///
    /// PR #2150 (issue #2136) wired native's `-> knot(args)` call-args
    /// syntax into `DivertTarget::args` for the first time — before that,
    /// the shape hard-failed `E129` on native and never reached this check
    /// at all. Investigating that newly-reachable path found the arity gap
    /// was real on **both** dialects: `brink_ir::symbols::project`'s
    /// `walk_divert_target`/`Expr::DivertTarget` ref-pushing sites always
    /// recorded `arg_count: None` for a `RefKind::Divert` reference,
    /// unconditionally discarding `DivertTarget::args.len()` — so
    /// `brink_analyzer::resolve::check_arity` (`E031`, gated on
    /// `arg_count.is_some()`) could never fire for a divert, on either
    /// dialect, regardless of how many arguments were supplied. `E176` is
    /// `E031`'s sibling for the divert call shape, kept as its own code
    /// (rather than widening `E031`'s own message, which names *function*
    /// calls) so the two diagnostics can be told apart and suppressed
    /// independently.
    ///
    /// Scoped to a resolution that names a `Knot`/`Stitch`/`Label` (the
    /// only symbol kinds with their own declared parameter row) —
    /// deliberately **not** checked when the divert resolves through a
    /// `Variable` or a divert-typed local `Param` (a stored/forwarded
    /// divert-target value, e.g. the ink docs' `-> generic_sleep (->
    /// waking_in_the_hut)` — see "Advanced: sending divert targets as
    /// parameters"), whose underlying target's arity is not known
    /// statically at the indirection site. `resolve_function`'s own
    /// `check_arity` call sites already draw this same line (only
    /// `External`/`Knot` resolutions are checked; `Variable`/local
    /// resolutions are not).
    ///
    /// `Warning`-tier by default, matching `E031`'s own severity precedent
    /// for the identical arity-mismatch shape at an ordinary call site —
    /// `lir::lower::stmts::lower_divert_target` still lowers a mismatched
    /// site (`lower_call_args` pushes exactly as many `CallArg`s as the
    /// divert supplies, not the target's declared count), so this stays
    /// advisory rather than blocking, and is `[lints]`-configurable /
    /// `@[allow(E176)]`-suppressible like every other `Warning`-base code.
    E176,

    // ── `@[convention]` / `@[element]` split (issue #2164,
    //    `docs/decision-log.md` 2026-08-03) — E177 was reserved for #2156
    //    at the time this range was assigned; #2156 landed as E176 only
    //    (see above), leaving E177 itself unclaimed and unused ────────
    /// A `@[convention(claims = "…")]` annotation with no `order` clause.
    ///
    /// `order` is **required**, not optional (`docs/decision-log.md`
    /// 2026-08-03 "`order` is REQUIRED on `@[convention]`…"): a claiming
    /// handler competes for lines it did not announce, so its precedence
    /// against every other claiming handler in the same module must be
    /// total, explicit, and authored — there is no default to fall back
    /// to, and the compiler never infers one from declaration position.
    /// Reported at the annotation line, the same posture `E159` already
    /// takes for a missing/malformed `claims` value; yields no
    /// `ConventionAnnotation` at all (never a partial one with a made-up
    /// order).
    E178,
    /// Two `@[convention]` declarations in the same module carry the same
    /// `order` value.
    ///
    /// Ties are **rejected**, not resolved (the same ruling as `E178`):
    /// "there is no tie-breaking rule, because ties are rejected rather
    /// than resolved." Reported against **every** conflicting declaration —
    /// the duplicate-definition posture, not a single "first one wins,
    /// second one is the problem" report — so an author sees the whole
    /// conflicting group regardless of which one they open first.
    E179,
    /// A `@[convention(…, attach = StructName)]` clause names a struct the
    /// declaration's own return type does not agree with (issue #2178,
    /// split from #2164's 2026-08-03 design-backport comment "item 2":
    /// "The attachment schema is a STRUCT — do not invent a DSL").
    ///
    /// `docs/decision-log.md` 2026-08-03 states the governing split
    /// plainly: *"keys are declared, values are computed"* — `attach`
    /// declares which keys a handler attaches and their types by naming an
    /// ordinary `struct`; the handler body computes the values. That only
    /// holds if the handler's own declared return type actually **is**
    /// the named struct — a mismatch (a different type, a generic, a
    /// `fn` type, or no declared return type at all) means the projection
    /// and the handler's real output could never agree, so this is
    /// reported at the `attach` clause's own value rather than silently
    /// trusting the name. Reported the same "never a partial one" way
    /// `E159`/`E178` are: no `ConventionAnnotation` at all results, rather
    /// than one carrying a schema its own declaration cannot honor.
    ///
    /// Declaration-surface-only, like every other check in this module:
    /// this compares `attach`'s name against the return type's own bare
    /// name, and never checks whether a struct of that name is actually
    /// *declared* anywhere — that is real name resolution's job (out of
    /// scope for this code, same posture `E171`'s own doc explains for
    /// captured-parameter types).
    E180,

    // ── TM-4c struct-shape resolution backstop (docs/typed-mode-spec.md
    //    §6, issue #2240) ─────────────────────────────────────────────
    /// `lir::lower::structs::build_shape_table`'s own
    /// `decls::lookup_global(index, file_id, name, SymbolKind::Struct)`
    /// call — resolving a declared `STRUCT`'s **own** `DefinitionId`,
    /// using its own declaring file as referrer — came back `None`.
    ///
    /// This is a non-suppressible defense-in-depth backstop, the
    /// `E060`/`E073` posture: it should never fire from a normal compile.
    /// The exact-file arm always matches a struct against itself *unless*
    /// `brink-analyzer` already dropped this HIR decl's own symbol entry
    /// as a true intra-module duplicate (`E023`, same declared module as
    /// an earlier same-name declaration) — and even then,
    /// `lookup_global`'s unscoped fallback normally rescues the
    /// surviving sibling's id (which is exactly what lets
    /// `build_shape_table`'s own `by_def.contains_key` dedup recognize
    /// "true intra-module duplicate" and skip it a second time, rather
    /// than minting a fresh, wrong shape). This code fires only in the
    /// narrower case the fallback itself cannot rescue: **every**
    /// surviving same-name candidate is std-declared, so the fallback's
    /// own std-exclusion (issue #2197) empties the search too. Before
    /// this code existed, that combination silently dropped the struct
    /// from both `ShapeTable` and `NameTable` seeding with no diagnostic
    /// at all — shifting every subsequent `ShapeId`/`NameId` and the
    /// bytecode built from them (CLAUDE.md: "silent drops are always
    /// bugs until proven otherwise").
    ///
    /// Reachable **today**, not merely in principle (review finding on
    /// #2240): any project whose own declaring file is not all-native
    /// (`project_is_all_native`) and whose own `STRUCT`/`struct` shares a
    /// name with one the std-mounted screenplay preset declares (`Cue`,
    /// `Parenthetical`) collides with it — neither side needs a `#@module`
    /// for this to happen. `symbol_index_query` builds the shared index
    /// from every `set_file`-registered file regardless of the
    /// compilation closure, so the mounted std declaration sits in the
    /// index even for an ink entry whose LIR closure never reaches it.
    /// With neither declaration module-qualified (or the project simply
    /// not `Dialect::Brink`), M-2d cross-declared-module coexistence
    /// (`is_cross_declared_module_collision`) never applies, so the pair
    /// collapses to an ordinary same-module duplicate — and it is the
    /// *project's* declaration that gets dropped whenever its own file
    /// sorts after the std key in `FileId`-mint order (any project file
    /// named e.g. `story.ink`, `world.ink`, `types.ink` does, since
    /// `"std/…"` sorts first). See `brink-environment`'s
    /// `e181_is_reachable_from_an_ordinary_ink_project_colliding_with_a_std_preset_name`
    /// for this compiled end to end through the real analyzer drop, not a
    /// hand-built `SymbolIndex`.
    ///
    /// `build_struct_shape_data` (the `NameId`-free, cutoff-friendly
    /// twin `struct_shape_data_query` memoizes for the per-knot chunk
    /// lowering path) performs the textually identical lookup and has no
    /// diagnostic sink of its own to push into — it is a pure,
    /// `Eq`-cutoff salsa data query, not a lowering pass threading a
    /// `Vec<Diagnostic>` accumulator. It is deliberately left silent
    /// there rather than given a redundant sink: every real compile
    /// (`brink-db`'s `lir_query`) always computes `build_shape_table`
    /// (via `lir_prelude_decls_query`) and `build_struct_shape_data` (via
    /// `struct_shape_data_query` → `chunk_lowering_ctx_query` →
    /// `lir_knot_chunk_query`) in the same salsa revision, over the same
    /// `resolutions_index_query` index and the same files' `structs`
    /// HIR — so the exact same drop condition always fires this
    /// diagnostic from the prelude side in the same compile. See that
    /// function's own doc comment for the full argument.
    E181,

    // ── #2179: `@[convention]` no-world-reads fence ────────────────────
    /// A `@[convention]` handler's transitive call closure reaches an
    /// `EXTERNAL` classified [`crate::ExternalKind::Query`] (a world read)
    /// or left [`crate::ExternalKind::Plain`] (unclassified) —
    /// `docs/decision-log.md` 2026-08-06 "No-world-reads fence: analyzer
    /// effect-row check; unclassified externals are diagnosed".
    ///
    /// A claiming handler competes for lines it never announced, which
    /// only holds together if classification is a pure function of the
    /// text: if it depended on game state, the editor could never display
    /// it, the projection could never be cached, and explain-match would
    /// depend on a save file. So a handler may call pure functions and
    /// [`crate::ExternalKind::Effect`]/[`crate::ExternalKind::Presentation`]
    /// externals ("commands"), but never one that reads world state — and
    /// an unclassified (`Plain`, the default) external is treated the same
    /// as a proven read, not the same as a proven pure call: "unprovable
    /// is not passable." The fix is classifying the external, via an
    /// inline `@kind` doc tag or the registered host manifest.
    ///
    /// Computed by `brink_analyzer::no_world_reads` over the **transitive**
    /// call closure — a handler calling a helper `fn` that itself calls a
    /// `Query`/`Plain` external is diagnosed exactly like a direct call —
    /// reusing the same call-graph substrate
    /// (`brink_analyzer::infer::{collect_defs,call_edges,def_body}`) T2-1's
    /// effect rows are built from, per the #2179 decline comment's finding
    /// that the aggregated row/`compute_container_access` route has no
    /// span to diagnose with: this walks for the real call-site span the
    /// aggregated row structurally cannot carry. Reported at the offending
    /// call's own site, which may be inside a different definition (and a
    /// different file) than the handler's own declaration.
    E182,
    /// `brink_ir::lir::lower::expr::lower_call`'s resolved-target match
    /// found a symbol kind that is not callable — a `ListItem`, `Label`,
    /// `Stitch`, `Param`, `Temp`, or `Struct` sitting at a call position
    /// (issue #2837, filed from the #2836/w187 review). `SymbolKind::Knot`
    /// is the one non-`External`/`List`/`Variable`/`Constant` kind that
    /// *is* callable — ink allows any knot as a function via tunnels, per
    /// `brink_analyzer::resolve::resolve_function`'s own comment — so it
    /// keeps its own `lir::ExprKind::Call` arm.
    ///
    /// This *is* reachable from ordinary author source, not only from a
    /// hypothetical future resolution regression: `Temp`/`Param` reach this
    /// arm whenever `ctx.temp_slot` does not have the name open at the call
    /// site — which is the normal, expected shape of two ordinary author
    /// mistakes, not a `temp_slot` bug. Calling a T1b block-scoped temp
    /// (`~ { … }`) after its own block has closed is diverted to
    /// [`Self::E082`] instead (mirroring `lower_path`'s own guard for the
    /// same case), but a genuine forward reference — calling a name before
    /// its declaring `temp`/param binding — falls through to this arm and
    /// reports `E183` today; that reproduces on the plain `.ink` surface
    /// with no `--dialect brink` needed. `Stitch`, `ListItem`, `Label`, and
    /// `Struct` remain analyzer-unreachable for a real call site as far as
    /// this code can tell (`resolve_function` never hands back `Stitch`/
    /// `Label`/`Struct` there, and only hands back a bare `ListItem` for a
    /// `#fn(target)` literal, which never reaches `lower_call` at all) —
    /// those four are the defensive-backstop part of this diagnostic.
    ///
    /// Refused loudly rather than silently emitting `lir::ExprKind::Call`
    /// against the resolved id: that catch-all is exactly the mechanism
    /// that let PR #2836's first attempt compile a program clean — 7,941
    /// tests, the oracle ratchet, and clippy all green — while it then
    /// faulted at runtime with `UnresolvedDefinition(ListItem(..))`. Same
    /// "compile error over runtime fault" posture as [`Self::E144`]'s UFCS
    /// refusal in the same module.
    E183,

    // ── issue #2262: E181's own drop class, for every OTHER declaration
    //    kind `lir::lower::decls::lookup_global` self-resolves ─────────
    /// `lir::lower::decls`'s own `lookup_global(index, file_id, name,
    /// kind)` self-declaration lookup — for a `CONST`
    /// (`collect_globals`'s constants pass), a `VAR` (`collect_globals`'s
    /// variables pass), or an `EXTERNAL` (`collect_externals`) — came back
    /// `None`.
    ///
    /// The exact same non-suppressible defense-in-depth posture as
    /// [`Self::E181`], for the exact same reason: this is [`Self::E181`]'s
    /// own struct-shape drop class recurring at three more call sites in
    /// the same file, all sharing `lookup_global`'s doc comment and none
    /// fixed by #2240/#2258 (issue #2262, filed from that PR's own review —
    /// "#2240 under-captured the class"). The exact-file arm always
    /// matches a declaration against itself *unless* `brink-analyzer`
    /// already dropped this HIR decl's own symbol entry as a true
    /// intra-module duplicate (`E023`) — and even then, `lookup_global`'s
    /// unscoped fallback normally rescues the surviving sibling's id. This
    /// code fires only when that fallback also misses: **every** surviving
    /// same-name/same-kind candidate is std-declared, so the fallback's
    /// own std-visibility carve-out (issue #2197) excludes it too. Before
    /// this code existed, that combination silently dropped the
    /// `CONST`/`VAR`/`EXTERNAL` from `PreludeDecls` (no `lir::GlobalDef`
    /// or `lir::ExternalDef` at all) with no diagnostic whatsoever
    /// (CLAUDE.md: "silent drops are always bugs until proven otherwise").
    ///
    /// **Reachable today**, exactly as [`Self::E181`]'s own doc found for
    /// `STRUCT` (review finding on #2240): an ordinary project — no
    /// `#@module`, no `dialect` override even needed for `EXTERNAL` (core
    /// ink syntax, unlike `STRUCT`) — that declares its own `EXTERNAL
    /// scene_entered(…)` collides with the std-mounted screenplay
    /// preset's own `extern scene_entered`
    /// (`std/conventions/screenplay.brink`). Neither declares a module, so
    /// M-2d cross-declared-module coexistence never applies and
    /// `insert_symbol` treats the pair as a true intra-module duplicate,
    /// dropping whichever one's `FileId` sorts after the other's in mint
    /// order. See `brink-environment`'s
    /// `external_self_declaration_silently_drops_when_colliding_with_a_std_preset_name`
    /// for this compiled end to end through the real analyzer drop. `std`
    /// declares no `CONST`/`VAR` today, so the `CONST`/`VAR` call sites
    /// stay reachable only in principle (a future std module adding one),
    /// same status `E181` itself carried before its own reachable case was
    /// found — not a reason to leave them undiagnosed.
    E184,

    /// Issue #1944: a plain dotted assignment target (`~ p.bogus = 1`)
    /// names a field its receiver's *resolved* struct shape doesn't
    /// declare — the `E070` mirror for a construction-literal's own
    /// unknown-field check (`structs::check`'s "Extra" case,
    /// `docs/typed-mode-spec.md` §6), but for `Stmt::Assignment`/
    /// `BlockStmt::Assignment` targets instead of a `#{...}` literal.
    ///
    /// PR #1939's `check_declared_field_assign_target` deliberately stays
    /// silent on an unresolvable field — it only compares a *resolved*
    /// field's declared type against the RHS ("Unknown never disagrees").
    /// `ref_projection::check_strict`'s `E098` covers an unknown segment
    /// only in `ref`-argument position (`ref npc.bogus`), not a plain
    /// assignment target. Before this code existed, the issue's exact
    /// repro —
    ///
    /// ```text
    /// STRUCT Point = #{x: float, y: float}
    /// VAR p: Point = Point#{x: 0.0, y: 0.0}
    /// ~ p.bogus = 1
    /// -> DONE
    /// ```
    ///
    /// — compiled clean under `types = strict` with zero diagnostics.
    ///
    /// Reported from `structs::check_field_assign_mismatch`, the same
    /// function `E063` (field-type mismatch on a *resolved* field) comes
    /// from — fired only once the walk has resolved the receiver's shape
    /// (`shapes.resolve` succeeded) and the shape itself declares no field
    /// by this name. An Unknown/untyped root never reaches this arm at
    /// all: the walk's own guard above (`let Ty::Struct(shape_name) =
    /// &current else { return; }`) returns silently the moment `current`
    /// isn't a resolved struct type, so "Unknown never disagrees" holds
    /// for the receiver exactly as it does for `E063`. A chained target
    /// (`o.i.a = v`, 3+ segments) never reaches this function at all —
    /// `check_declared_field_assign_target`'s own `segments.len() == 2`
    /// fence means no `FieldAssignMismatch` fact is ever recorded for one;
    /// LIR's `try_lower_field_assignment` already rejects it outright with
    /// the non-suppressible `E074`, regardless of whether the field name
    /// exists.
    E185,

    /// Issue #2264: a `@[convention(…)]` handler declares BOTH `block` and
    /// `attach = StructName` on the same declaration — `parse_convention`
    /// (`annotation.rs`) now rejects the combination outright rather than
    /// silently accepting it. Before this code existed, nothing diagnosed
    /// the co-occurrence at all: `try_claim`'s dispatch (`element.rs`) is
    /// an `if is_block { .. } else if is_attach { .. }` with no exclusivity
    /// check anywhere upstream — `block` always won the `if`, `attach` was
    /// parsed and stored on `ConventionAnnotation` but never consulted, and
    /// the author got zero signal that half of what they wrote did
    /// nothing (verified: `red_probe_block_and_attach_together_compile_clean_with_attach_inert_today`
    /// in `lower_native::tests`, run BEFORE this code existed, proves the
    /// silent-drop shape end to end).
    ///
    /// This is deliberately a hard rejection, not an attempt to define what
    /// "wrap AND attach" would mean together — that is an open design
    /// question (issue #2264's own body: "Define what the combination is
    /// supposed to mean and implement it — but that's a design question
    /// (rule 7), not a good first assumption") with no ruling and no test
    /// pinning any combined
    /// semantics, so nothing here invents one. `parse_convention` returns
    /// `None` (never a partial `ConventionAnnotation`) — the same "never a
    /// partial one" posture `E159`/`E166`/`E167`/`E178`/`E180` already take
    /// — so a handler declaring both is never registered as a claiming
    /// handler at all, not merely warned about.
    ///
    /// Also reachable through the compact-cue desugar (`@NAME: text`,
    /// issue #2079) — it dispatches through the exact same `try_claim`
    /// function, so a compact-cue-claiming handler declaring both clauses
    /// hits this same check (confirmed on the issue by PR #2341's review).
    E186,

    /// Issue #2201: a write to a `CONST` — plain/compound assignment, a
    /// postfix `++`/`--`, an indexed-assignment root, a bare in-place
    /// mutator (`pop`/`heap_pop`), a struct-field write/mutator whose root
    /// is a `CONST`, or passing the `CONST` by `ref` (bare or as a
    /// projection root). ink semantics (`ink/compiler/ParsedHierarchy/
    /// VariableAssignment.cs`, "Can't re-assign to a constant") reject this
    /// at compile time; before this code existed, `lir::lower::stmts::
    /// lower_assign_target` treated `SymbolKind::Constant` identically to
    /// `SymbolKind::Variable` — every one of the write channels above
    /// silently mutated the constant's storage cell with zero diagnostics
    /// anywhere in the pipeline.
    ///
    /// Raised via the shared `lir::lower::stmts::reject_const_write` check —
    /// the `CONST` analog of [`Self::E148`]'s `reject_as_binding_write` —
    /// called from every choke point that resolves a `Global` write root's
    /// `SymbolInfo`: `lower_assign_target` itself (plain/compound
    /// assignment, postfix's bare-target conversion, the
    /// indexed-assignment root via `lower_indexed_assignment`, and a bare
    /// mutator's root via `pop`/`heap_pop`, all of which call
    /// `lower_assign_target` for their root); `lower_single_level_field_write`/
    /// `lower_field_mutator` (their two-segment field-root
    /// `SymbolKind::Constant` arm, which resolves the root independently of
    /// `lower_assign_target` — the same reason `reject_as_binding_write`
    /// needs a direct call there too, per #2122); and the `ref`-argument
    /// choke points `lower_ref_path_call_arg`/`lower_ref_projection_arg`
    /// (passing a `CONST` by `ref` hands the callee a raw pointer to the
    /// cell, bypassing assignment lowering entirely).
    ///
    /// Deliberately a LIR-lowering refusal (this code's precedent is
    /// [`Self::E074`]/[`Self::E148`], not an analyzer diagnostic like
    /// [`Self::E185`]): the write-channel enumeration above already lives
    /// entirely in `lir::lower` — duplicating it in `brink-analyzer` would
    /// re-run the exact same channel-undercounting risk that made this
    /// issue's own premise true (#2122 named only two of the seven channels
    /// `CONST` reassignment turned out to have). Applies to both surfaces —
    /// `.ink` and `.brink` — since this mirrors ink's own compile-time
    /// rejection, not a native-only extension; `SymbolKind::Constant` is
    /// resolved identically for both frontends by the time LIR lowering
    /// sees it.
    E187,

    // ── TM-2 reserved-type-name shadowing (issue #1865) ───────────────
    /// A declared `STRUCT`'s own name collides with one of the fixed names
    /// `annotations::resolve`'s `TypeExpr::Named` arm resolves *before* it
    /// ever consults `names.structs` — a builtin leaf
    /// (`int`/`float`/`bool`/`string`/`content`/`divert`) or an NS-A8 tower
    /// kind (`vec2`/`vec3`/`vec4`/`quat`/`mat2`/`mat3`/`mat4`). That
    /// ordering is deliberate and unchanged by this code (`resolve`'s own
    /// doc: "checked before the struct lookup... the same ordering that
    /// keeps int/float unshadowable") — this diagnostic does not re-order
    /// resolution, it names the consequence: every bare type annotation
    /// spelling the colliding name (`VAR v: content = ...`, a param/return
    /// annotation, …) silently resolves to the builtin/tower type, never to
    /// the struct, with previously no diagnostic in either direction.
    ///
    /// Deliberately does **not** cover the generic heads
    /// (`List`/`Array`/`Map`/`Option`/`Weighted`/`Handle`): those names are
    /// special-cased only inside `TypeExpr::Generic`'s own dispatch (e.g.
    /// `Array<T>`) — a *bare* `Named` reference to a struct sharing one of
    /// those names (`f: Array`, no `<...>`) still falls through to the
    /// ordinary `names.structs` lookup and resolves to the struct
    /// correctly; there is no actual collision to diagnose for those names.
    /// Also does not cover `void` — unlike the leaves above, `resolve`'s
    /// `Named` arm has no explicit `"void"` case at all, so a struct named
    /// `void` resolves fine too. Also does not cover a name shared with a
    /// declared `LIST` or a registered `Handle<K>` kind: `names.lists`/
    /// `names.handles` are only ever consulted inside `List<L>`/`Handle<K>`'s
    /// own generic-argument position, never against a bare `Named`
    /// annotation — a different namespace, no collision.
    ///
    /// A construction literal (`Name#{...}`) is unaffected by this
    /// shadowing for every name this code covers:
    /// `resolve::resolve_struct_ref`/`resolve_type_ref` resolve a `STRUCT`
    /// reference by ordinary `SymbolKind::Struct` lookup alone, with no
    /// builtin/tower precedence check at all — so `content#{...}` still
    /// constructs the user's struct even though `VAR v: content = ...`
    /// cannot name it.
    ///
    /// Warning-tier, not a rejected declaration (matches [`Self::E035`]'s
    /// "name shadows a built-in function" precedent, and the "deliberate"
    /// framing `resolve`'s own doc already gives this exact ordering) — a
    /// `STRUCT` named this way still compiles and constructs normally; only
    /// its *annotation* spelling is shadowed.
    E188,

    /// Renaming an `EXTERNAL` changes the host binding (ruled 2026-08-24,
    /// "External renames: allowed behind the always-unsafe Force gate").
    ///
    /// Synthesized by the IDE's safe-rename gate, never emitted by
    /// compilation: an external's name is the story↔engine contract, so the
    /// story-side rename is always reported as breakage — the engine must
    /// re-register the function under the new name — and applies only
    /// through the report's Force path.
    E190,

    /// An ink `TODO:` author note (issue #3050).
    ///
    /// Not a defect at all: `AUTHOR_WARNING` lines are the language's own
    /// work-remains marker, and until #3050 lowering dropped them silently.
    /// Surfacing each as an `Info`-default diagnostic (the [`Self::E157`]
    /// tier precedent) puts TODOs in the Problems panel and gives the
    /// studio's TODO panel a single source to consume, while never gating a
    /// compile and staying `[lints]`-tierable like every other code.
    E189,

    /// A content line's inline stateful alternatives enumerate to more
    /// whole-line variants than the variant-group cap admits (#3274).
    ///
    /// The stage-2 flip compiles a line of textual alternatives into one
    /// enumerated variant group — each variant a real line-table entry, a
    /// translation unit, and a VO slot — so the product of the
    /// alternatives' branch counts is bounded
    /// (`lir::lower::recognize::VARIANT_CAP`). Breaching it is a worded
    /// hard error, never a silent fallback: an author whose line quietly
    /// stopped being VO-addressable would have no way to notice. The fix
    /// is to split the line or move an alternative to its own line.
    E191,

    /// A `brink-`prefixed comment the suppression parser did not understand
    /// (#3259).
    ///
    /// Directives were matched by exact string equality and anything else
    /// was dropped in silence — so `// brink-disable-file E157`, which looks
    /// exactly like the line-scoped form that DOES take codes, suppressed
    /// nothing and reported nothing. The author got neither the behaviour
    /// they asked for nor a reason, which is the silent-drop shape this
    /// project treats as a bug by default.
    ///
    /// `Warning`-tier: the file still compiles. The harm is that a
    /// suppression the author believes is in force is not.
    E192,

    /// A `~ temp` is read on a path its declaration does not dominate
    /// (#3354, RULED 2026-09-01 option C).
    ///
    /// The declaration and the read live in the same call frame, so the
    /// read resolves to the temp's own slot — but nothing guarantees the
    /// declaring statement ran first. The three shapes the ruling names are
    /// a sibling choice branch, a gather reached from a branch that did not
    /// declare, and a read written textually ahead of the declaration. (A
    /// fourth shape the ruling originally enumerated — a stitch reading a
    /// temp declared at its knot's root — is not a dominance question at
    /// all: the PR #3369 review found it warns on a knot/stitch divert that
    /// runs the declaration and then plays correctly, and the 2026-09-01
    /// follow-up ruling on #3373 moved it out of `E193` entirely into its
    /// own compat-deny code, [`Self::E194`].)
    ///
    /// `Warning`-tier, `[lints]`-overridable: the story still runs. The
    /// runtime reads an uninitialized slot as ink's missing-variable
    /// default (`0`, which is also `false`) and warns — matching the C#
    /// reference, so what plays in Inky plays in brink — and this
    /// diagnostic is what tells the author before they play.
    E193,

    /// A knot's `~ temp` (native `~ let`) is read from one of that knot's
    /// stitches (#3373, RULED 2026-09-01) — split out of [`Self::E193`]'s
    /// former shape 4 during PR #3369's review.
    ///
    /// Brink's `lir::lower::temps::alloc_temps` treats a knot and every one
    /// of its stitches as one shared call frame with one `TempMap`, so a
    /// stitch's reference to a name the knot's root declares resolves to
    /// that same slot and the story plays correctly. Ink's own compiler
    /// does not extend a knot's `~ temp` visibility into its stitches at
    /// all — the identical program is a compile-time
    /// `Unresolved variable` error in inklecate. This is brink accepting a
    /// strict superset of ink, not a defect in either compiler, which makes
    /// it the first member of the **compat-deny** tier (`docs/compiler-spec.md`
    /// "Compat-deny diagnostics"): `Error` by default (inklecate rejects
    /// the program, so brink does too until a project opts in) but, unlike
    /// every other `Error`-default code, `[lints]`-overridable — all the
    /// way to `allow` — because the admission invariant that tier requires
    /// is met: downgraded, brink produces a working program.
    E194,

    /// A choice with neither display/bracket text nor a divert (#3365),
    /// matching inklecate's own "Choice is completely empty" warning
    /// (`InkParser/InkParser_Choices.cs:84-86`; line 90 guards a different
    /// warning — "Blank choice", on the `* [] some text` shape — which this
    /// code deliberately does not cover).
    ///
    /// Raised from `hir::lower::choice::LowerChoice::lower_choice` (the ink
    /// surface only — see this code's doc page for why the native `{? … }`
    /// surface is deliberately not wired to it), where the same-line
    /// evidence the check needs — whether a `->`/divert token was written at
    /// all, even an empty one — is still available. Once lowered into
    /// `hir::Choice`, an explicit-but-empty divert (`* ->`) and no divert at
    /// all (`* []`) are indistinguishable (both leave no `Stmt::Divert` in
    /// the choice's body), so the check cannot be reconstructed later from
    /// the HIR alone the way `E034`'s all-fallback check can.
    ///
    /// Fires only when the choice has none of: a same-line divert (with or
    /// without a target), a tag directly on the choice line, or actual text
    /// in any of its three content regions (`start`/`bracket`/`inner`). A
    /// `(label)` or `{condition}` guard does NOT exempt a choice — matching
    /// the reference, which has no such carve-out either. `Warning`,
    /// `[lints]`-overridable, matching the sibling markup/shadow-warning
    /// family (`E164`/`E188`/…) — the story still compiles.
    E195,
}

impl DiagnosticCode {
    /// Every `DiagnosticCode` variant, in declaration order.
    ///
    /// Kept in sync with the enum by hand (there is no derive-based
    /// enumeration here), but exercised by
    /// `brink-test-harness/tests/diagnostic_docs_validation.rs`'s
    /// `diagnostic_codes_are_unique` test: that test asserts `ALL.len()`
    /// matches the number of code strings `from_str_code` recognizes, so a
    /// variant added to the enum but missed here fails CI immediately
    /// instead of silently under-covering the uniqueness/round-trip checks.
    pub const ALL: &'static [Self] = &[
        Self::E001,
        Self::E002,
        Self::E003,
        Self::E004,
        Self::E005,
        Self::E006,
        Self::E007,
        Self::E008,
        Self::E009,
        Self::E010,
        Self::E011,
        Self::E012,
        Self::E013,
        Self::E014,
        Self::E015,
        Self::E016,
        Self::E017,
        Self::E018,
        Self::E019,
        Self::E020,
        Self::E021,
        Self::E022,
        Self::E023,
        Self::E024,
        Self::E025,
        Self::E026,
        Self::E027,
        Self::E028,
        Self::E029,
        Self::E030,
        Self::E031,
        Self::E032,
        Self::E033,
        Self::E034,
        Self::E035,
        Self::E036,
        Self::E037,
        Self::E038,
        Self::E039,
        Self::E040,
        Self::E041,
        Self::E042,
        Self::E043,
        Self::E044,
        Self::E045,
        Self::E046,
        Self::E047,
        Self::E048,
        Self::E049,
        Self::E050,
        Self::E051,
        Self::E052,
        Self::E053,
        Self::E054,
        Self::E055,
        Self::E056,
        Self::E057,
        Self::E058,
        Self::E059,
        Self::E060,
        Self::E061,
        Self::E062,
        Self::E063,
        Self::E064,
        Self::E065,
        Self::E066,
        Self::E067,
        Self::E068,
        Self::E069,
        Self::E070,
        Self::E071,
        Self::E072,
        Self::E073,
        Self::E074,
        Self::E075,
        Self::E076,
        Self::E077,
        Self::E078,
        Self::E079,
        Self::E080,
        Self::E081,
        Self::E082,
        Self::E083,
        Self::E084,
        Self::E085,
        Self::E086,
        Self::E087,
        Self::E088,
        Self::E089,
        Self::E090,
        Self::E091,
        Self::E092,
        Self::E093,
        Self::E094,
        Self::E095,
        Self::E096,
        Self::E097,
        Self::E098,
        Self::E099,
        Self::E100,
        Self::E101,
        Self::E102,
        Self::E103,
        Self::E104,
        Self::E105,
        Self::E106,
        Self::E107,
        Self::E108,
        Self::E109,
        Self::E110,
        Self::E111,
        Self::E112,
        Self::E113,
        Self::E114,
        Self::E115,
        Self::E116,
        Self::E117,
        Self::E118,
        Self::E119,
        Self::E120,
        Self::E121,
        Self::E122,
        Self::E123,
        Self::E124,
        Self::E125,
        Self::E126,
        Self::E127,
        Self::E128,
        Self::E129,
        Self::E130,
        Self::E131,
        Self::E132,
        Self::E133,
        Self::E134,
        Self::E135,
        Self::E136,
        Self::E137,
        Self::E138,
        Self::E139,
        Self::E140,
        Self::E141,
        Self::E142,
        Self::E143,
        Self::E144,
        Self::E145,
        Self::E146,
        Self::E147,
        Self::E148,
        Self::E149,
        Self::E150,
        Self::E151,
        Self::E152,
        Self::E153,
        Self::E154,
        Self::E155,
        Self::E156,
        Self::E157,
        Self::E158,
        Self::E159,
        Self::E160,
        Self::E161,
        Self::E162,
        Self::E163,
        Self::E164,
        Self::E165,
        Self::E166,
        Self::E167,
        Self::E168,
        Self::E169,
        Self::E170,
        Self::E171,
        Self::E172,
        Self::E173,
        Self::E174,
        Self::E175,
        Self::E176,
        Self::E178,
        Self::E179,
        Self::E180,
        Self::E181,
        Self::E182,
        Self::E183,
        Self::E184,
        Self::E185,
        Self::E186,
        Self::E187,
        Self::E188,
        Self::E189,
        Self::E190,
        Self::E191,
        Self::E192,
        Self::E193,
        Self::E194,
        Self::E195,
    ];

    /// The stable string representation (e.g., `"E001"`).
    #[must_use]
    #[expect(
        clippy::too_many_lines,
        reason = "a flat one-arm-per-code table that necessarily grows with the diagnostic set"
    )]
    pub fn as_str(self) -> &'static str {
        match self {
            Self::E001 => "E001",
            Self::E002 => "E002",
            Self::E003 => "E003",
            Self::E004 => "E004",
            Self::E005 => "E005",
            Self::E006 => "E006",
            Self::E007 => "E007",
            Self::E008 => "E008",
            Self::E009 => "E009",
            Self::E010 => "E010",
            Self::E011 => "E011",
            Self::E012 => "E012",
            Self::E013 => "E013",
            Self::E014 => "E014",
            Self::E015 => "E015",
            Self::E016 => "E016",
            Self::E017 => "E017",
            Self::E018 => "E018",
            Self::E019 => "E019",
            Self::E020 => "E020",
            Self::E021 => "E021",
            Self::E022 => "E022",
            Self::E023 => "E023",
            Self::E024 => "E024",
            Self::E025 => "E025",
            Self::E026 => "E026",
            Self::E027 => "E027",
            Self::E028 => "E028",
            Self::E029 => "E029",
            Self::E030 => "E030",
            Self::E031 => "E031",
            Self::E032 => "E032",
            Self::E033 => "E033",
            Self::E034 => "E034",
            Self::E035 => "E035",
            Self::E036 => "E036",
            Self::E037 => "E037",
            Self::E038 => "E038",
            Self::E039 => "E039",
            Self::E040 => "E040",
            Self::E041 => "E041",
            Self::E042 => "E042",
            Self::E043 => "E043",
            Self::E044 => "E044",
            Self::E045 => "E045",
            Self::E046 => "E046",
            Self::E047 => "E047",
            Self::E048 => "E048",
            Self::E049 => "E049",
            Self::E050 => "E050",
            Self::E051 => "E051",
            Self::E052 => "E052",
            Self::E053 => "E053",
            Self::E054 => "E054",
            Self::E055 => "E055",
            Self::E056 => "E056",
            Self::E057 => "E057",
            Self::E058 => "E058",
            Self::E059 => "E059",
            Self::E060 => "E060",
            Self::E061 => "E061",
            Self::E062 => "E062",
            Self::E063 => "E063",
            Self::E064 => "E064",
            Self::E065 => "E065",
            Self::E066 => "E066",
            Self::E067 => "E067",
            Self::E068 => "E068",
            Self::E069 => "E069",
            Self::E070 => "E070",
            Self::E071 => "E071",
            Self::E072 => "E072",
            Self::E073 => "E073",
            Self::E074 => "E074",
            Self::E075 => "E075",
            Self::E076 => "E076",
            Self::E077 => "E077",
            Self::E078 => "E078",
            Self::E079 => "E079",
            Self::E080 => "E080",
            Self::E081 => "E081",
            Self::E082 => "E082",
            Self::E083 => "E083",
            Self::E084 => "E084",
            Self::E085 => "E085",
            Self::E086 => "E086",
            Self::E087 => "E087",
            Self::E088 => "E088",
            Self::E089 => "E089",
            Self::E090 => "E090",
            Self::E091 => "E091",
            Self::E092 => "E092",
            Self::E093 => "E093",
            Self::E094 => "E094",
            Self::E095 => "E095",
            Self::E096 => "E096",
            Self::E097 => "E097",
            Self::E098 => "E098",
            Self::E099 => "E099",
            Self::E100 => "E100",
            Self::E101 => "E101",
            Self::E102 => "E102",
            Self::E103 => "E103",
            Self::E104 => "E104",
            Self::E105 => "E105",
            Self::E106 => "E106",
            Self::E107 => "E107",
            Self::E108 => "E108",
            Self::E109 => "E109",
            Self::E110 => "E110",
            Self::E111 => "E111",
            Self::E112 => "E112",
            Self::E113 => "E113",
            Self::E114 => "E114",
            Self::E115 => "E115",
            Self::E116 => "E116",
            Self::E117 => "E117",
            Self::E118 => "E118",
            Self::E119 => "E119",
            Self::E120 => "E120",
            Self::E121 => "E121",
            Self::E122 => "E122",
            Self::E123 => "E123",
            Self::E124 => "E124",
            Self::E125 => "E125",
            Self::E126 => "E126",
            Self::E127 => "E127",
            Self::E128 => "E128",
            Self::E129 => "E129",
            Self::E130 => "E130",
            Self::E131 => "E131",
            Self::E132 => "E132",
            Self::E133 => "E133",
            Self::E134 => "E134",
            Self::E135 => "E135",
            Self::E136 => "E136",
            Self::E137 => "E137",
            Self::E138 => "E138",
            Self::E139 => "E139",
            Self::E140 => "E140",
            Self::E141 => "E141",
            Self::E142 => "E142",
            Self::E143 => "E143",
            Self::E144 => "E144",
            Self::E145 => "E145",
            Self::E146 => "E146",
            Self::E147 => "E147",
            Self::E148 => "E148",
            Self::E149 => "E149",
            Self::E150 => "E150",
            Self::E151 => "E151",
            Self::E152 => "E152",
            Self::E153 => "E153",
            Self::E154 => "E154",
            Self::E155 => "E155",
            Self::E156 => "E156",
            Self::E157 => "E157",
            Self::E158 => "E158",
            Self::E159 => "E159",
            Self::E160 => "E160",
            Self::E161 => "E161",
            Self::E162 => "E162",
            Self::E163 => "E163",
            Self::E164 => "E164",
            Self::E165 => "E165",
            Self::E166 => "E166",
            Self::E167 => "E167",
            Self::E168 => "E168",
            Self::E169 => "E169",
            Self::E170 => "E170",
            Self::E171 => "E171",
            Self::E172 => "E172",
            Self::E173 => "E173",
            Self::E174 => "E174",
            Self::E175 => "E175",
            Self::E176 => "E176",
            Self::E178 => "E178",
            Self::E179 => "E179",
            Self::E180 => "E180",
            Self::E181 => "E181",
            Self::E182 => "E182",
            Self::E183 => "E183",
            Self::E184 => "E184",
            Self::E185 => "E185",
            Self::E186 => "E186",
            Self::E187 => "E187",
            Self::E188 => "E188",
            Self::E189 => "E189",
            Self::E190 => "E190",
            Self::E191 => "E191",
            Self::E192 => "E192",
            Self::E193 => "E193",
            Self::E194 => "E194",
            Self::E195 => "E195",
        }
    }

    /// Short human-readable title for this diagnostic code.
    #[must_use]
    #[expect(
        clippy::too_many_lines,
        reason = "a flat one-arm-per-code message table that necessarily grows with the diagnostic set"
    )]
    pub fn title(self) -> &'static str {
        match self {
            Self::E001 => "knot is missing a name",
            Self::E002 => "stitch is missing a name",
            Self::E003 => "parameter is missing a name",
            Self::E004 => "VAR declaration is missing a name",
            Self::E005 => "VAR declaration is missing an initializer",
            Self::E006 => "CONST declaration is missing a name",
            Self::E007 => "CONST declaration is missing an initializer",
            Self::E008 => "LIST declaration is missing a name",
            Self::E009 => "LIST member is missing a name",
            Self::E010 => "EXTERNAL declaration is missing a name",
            Self::E011 => "retired (lane-A audit) — parser always creates FILE_PATH",
            Self::E012 => "divert is missing a target",
            Self::E013 | Self::E018 => "retired (lane-A audit) — parser always creates PATH node",
            Self::E014 => "logic line has no effect",
            Self::E015 => "expression is missing an operand",
            Self::E016 => "unknown or unsupported operator",
            Self::E017 => "function call is missing a name",
            Self::E019 => "retired (lane-A audit) — parser guarantees bullet markers",
            Self::E020 => "inline conditional is missing a condition",
            Self::E021 => "inline sequence has no branches",
            Self::E022 => "duplicate knot definition",
            Self::E023 => "duplicate variable/constant definition",
            Self::E024 => "unresolved divert target",
            Self::E025 => "unresolved variable reference",
            Self::E026 => "duplicate list item",
            Self::E027 => "ambiguous bare list item reference",
            Self::E028 => "retired (lane-A audit) — circular INCLUDE surfaces as CompileError",
            Self::E029 => "choice in conditional must explicitly divert",
            Self::E030 => "string interpolation in constant initializer is ignored",
            Self::E031 => "function call argument count mismatch",
            Self::E032 => "return statement outside function",
            Self::E033 => "unreachable code after divert",
            Self::E034 => "choice set has only fallback choices",
            Self::E035 => "name shadows a built-in function",
            Self::E036 => "expected diagnostic not produced",
            Self::E037 => "syntax error",
            Self::E038 => "malformed doc-comment tag",
            Self::E039 => "manifest disagrees with EXTERNAL arity",
            Self::E040 => "unknown semantic type",
            Self::E041 => "external argument type mismatch",
            Self::E042 => "external argument out of domain",
            Self::E043 => "doc-comment tag not applicable to this declaration",
            Self::E044 => "unknown directive",
            Self::E045 => "directive has no valid target here",
            Self::E046 => "directive must be static text",
            Self::E047 => "directive must be the only tag on its line",
            Self::E048 => "duplicate directive",
            Self::E049 => "directive not supported on this target",
            Self::E050 => "directive does not take arguments",
            Self::E051 => "brink extension used under strict-ink dialect",
            Self::E052 => "brink extension not yet implemented",
            Self::E053 => "retired (T1b-2) — T1b extension lowering is complete",
            Self::E054 => "block-scoped temp shadows an already-visible temp",
            Self::E055 => "collection mutator's first argument is not an lvalue",
            Self::E056 => "collection mutator used in expression position",
            Self::E057 => "break/continue outside a loop",
            Self::E058 => "collection mutator argument count mismatch",
            Self::E059 => "choice/gather construct nested inside inline content",
            Self::E060 => "internal codegen error",
            Self::E061 => "unknown type name in annotation",
            Self::E062 => "retired (T1c-1) — fn(T…): R annotations now resolve for real",
            Self::E063 => "type annotation disagrees with inferred type",
            Self::E064 => "strict types require the brink dialect",
            Self::E065 => "type escapes strict inference as Unknown",
            Self::E066 => "type is Conflicted under strict inference",
            Self::E067 => "assigning the result of a void function",
            Self::E068 => "struct construction literal names an undeclared STRUCT",
            Self::E069 => "struct construction literal is missing a declared field",
            Self::E070 => "struct construction literal supplies an undeclared field",
            Self::E071 => "struct construction literal field disagrees with the declared type",
            Self::E072 => "retired (TM-4c) — struct constructs now lower for real",
            Self::E073 => {
                "struct construction literal names an unresolved STRUCT shape at LIR lowering"
            }
            Self::E074 => "chained field-write projection (p.a.b = v) is not supported",
            Self::E075 => {
                "struct construction literal in a VAR/CONST declaration default does not match its declared shape"
            }
            Self::E076 => {
                "map literal key in a VAR/CONST declaration default is not a compile-time-constant scalar (int/string/bool)"
            }
            Self::E077 => {
                "array element, map value, or #fn bound value argument in a VAR/CONST declaration default is not a compile-time-constant expression"
            }
            Self::E078 => "int()/float() argument is outside the permissive numeric+bool domain",
            Self::E079 => "#fn target is not a statically-named function definition",
            Self::E080 => {
                "ref-argument (#fn, call, or bind) does not bind a durable cell at creation"
            }
            Self::E081 => "#fn binds more arguments than the target declares",
            Self::E082 => "block-scoped temp referenced after its block has closed",
            Self::E083 => "VAR/CONST declaration default is not a compile-time-constant expression",
            Self::E084 => "struct construction literal supplies a duplicate field",
            Self::E085 => {
                "file's module (its stem) collides with a declared module of the same name"
            }
            Self::E086 => {
                "`#@module` requires exactly one module name and may appear at most once per file"
            }
            Self::E087 => "reference to a `#@private` definition in another module",
            Self::E088 => {
                "bare `IMPORT { name } FROM mod` names a definition the declared module does not export"
            }
            Self::E089 => "`IMPORT` brings the same name into scope more than once",
            Self::E090 => "a module cannot `IMPORT` itself",
            Self::E091 => {
                "qualified access is ambiguous: the name is both an imported module and a definition"
            }
            Self::E092 => "redundant `#@public`/`#@private` — restates the module default",
            Self::E093 => "conflicting or repeated visibility directives on one declaration",
            Self::E094 => "`#@was` requires exactly one non-empty old-name argument",
            Self::E095 => "`#@was` names the definition's own current name — nothing to migrate",
            Self::E096 => "duplicate definition declared in two different modules",
            Self::E097 => "`ref` projection expression outside ref-argument position",
            Self::E098 => "ref-argument path segment disagrees with the statically-known shape",
            Self::E099 => "path-projection ref-argument is not yet lowerable (T1e-2, #828)",
            Self::E100 => "`#@effects` requires `pure` or at least one reads/writes/calls clause",
            Self::E101 => "malformed `#@effects` clause (unknown keyword or non-identifier value)",
            Self::E102 => "`#@effects` clause names an unknown global cell or external",
            Self::E103 => "inferred effects exceed the `#@effects` assertion's declared bound",
            Self::E104 => {
                "direct-call syntax requires a bare variable/temp/param callee — use `call(f, args…)` for a computed callee"
            }
            Self::E105 => {
                "`await` condition must be effect-free (read-only) — it writes a global or performs an effectful call"
            }
            Self::E106 => "map-literal key is outside the int/string/bool key domain",
            Self::E107 => "bare `none` needs a type from context",
            Self::E108 => {
                "inferred effects exceed the `@[effects(silent)]` assertion (the definition can produce content)"
            }
            Self::E109 => {
                "inferred effects exceed the `@[effects(total)]` assertion (the definition can raise a turn-terminating fault)"
            }
            Self::E110 => {
                "`#@effects(…)` is deprecated; use the `@[effects(…)]` annotation spelling"
            }
            Self::E111 => {
                "unknown annotation name (the `@[…]` channel recognizes `effects`, plus `was` and `allow` on the native surface)"
            }
            Self::E112 => {
                "annotation line outside a recognized placement (ink: top of a knot/stitch body; native: directly above a `flow`/`fn`, or above any declaration or statement for `allow`)"
            }
            Self::E113 => {
                "reserved protocol method name (`display`/`compare`/`next` belong to the protocol registry)"
            }
            Self::E114 => "protocol impl exceeds its protocol's effect contract",
            Self::E115 => "ill-formed protocol impl registration",
            Self::E116 => {
                "an `Option[T]` has no truthiness — test `== none` / `== some(x)` in the condition"
            }
            Self::E117 => "`int(r)` requires an inhabited range (NonEmptyRange)",
            Self::E118 => {
                "numeric-tower kinds are compiler-known and cannot implement registry protocols"
            }
            // Two verb families share this code because one sitting ruled
            // both: NS-A4's `sort_by`/`sorted_by` comparators and the
            // fn-value verb layer's pure trio `map`/`filter`/`fold`
            // (issue #1679). The title names the shared requirement; the
            // per-site message names the verb and its callback's role.
            Self::E119 => "callback must be a pure, silent function",
            Self::E120 => "`weighted` requires weight/value pairs with positive int weights",
            Self::E121 => {
                "admission: unresolved reference has no matching referencing expression in the HIR body"
            }
            Self::E122 => "admission: declared symbol has no corresponding HIR declaration node",
            Self::E123 => {
                "admission: knot's `is_function` disagrees with its indexed function sentinel"
            }
            Self::E124 => "admission: node range is empty or extends past the end of the file",
            Self::E125 => "admission: two references share an identical source range",
            Self::E126 => {
                "admission: declared symbol's name does not match its kind's qualification shape"
            }
            Self::E127 => {
                "admission: divert or return is not the last statement in an inline conditional/sequence branch"
            }
            Self::E128 => {
                "admission: container's provenance kind disagrees with its indexed symbol kind"
            }
            Self::E129 => "native: construct parses but has no HIR lowering yet",
            Self::E130 => "native: `flow` nested more than two levels deep is not yet supported",
            Self::E131 => "native: `<-` (splice) used outside a choice point has no effect",
            Self::E132 => {
                "native: `@[was]` needs a quoted old module path, e.g. `@[was(\"story::old::path\")]`"
            }
            Self::E133 => {
                "native accept-list: root_content must be empty or the synthesized `flow main()` entry divert"
            }
            Self::E134 => {
                "native accept-list: INCLUDE sites are ink-only baggage, never legal in native HIR"
            }
            Self::E135 => "native accept-list: thread-start outside choice-point splice position",
            Self::E136 => "native accept-list: choice set carries a non-neutral weave-fold value",
            Self::E137 => "native .brink compile requires types = strict",
            Self::E138 => "map construction literal supplies a duplicate key",
            Self::E139 => "construction literal entries do not match the target type's form",
            Self::E140 => "method-call syntax matched a field that is not callable",
            Self::E141 => "method-call syntax matched neither a field nor a free function",
            Self::E142 => "method-call receiver type is unknown — annotate it",
            Self::E143 => "method-call auto-ref needs a receiver that can be written through",
            Self::E144 => "native: method call resolves but has no LIR lowering yet",
            Self::E145 => {
                "the `as` binding must be the entire condition (no `&&`/`||` composition)"
            }
            Self::E146 => "retired (issue #1508) — choice-guard `as` bindings now lower for real",
            Self::E147 => "the `as` binding requires an `Option[T]` condition",
            Self::E148 => "an `as` binding is immutable and cannot be assigned to",
            Self::E149 => "`remove` is map-only — did you mean `remove_at`?",
            Self::E150 => {
                "declares a return type but the body may fall through without returning a value"
            }
            Self::E151 => {
                "native: this choice branch falls through while a sibling diverts — did you mean to add `-> …`, or `-> DONE` to end deliberately?"
            }
            Self::E152 => {
                "`contains`'s needle is statically outside the map key domain — this call always returns `false`"
            }
            Self::E153 => "`@[allow(…)]` names a diagnostic code this compiler does not know",
            Self::E154 => {
                "`@[allow(…)]` names a non-suppressible diagnostic — only codes whose default severity is not `Error` can be silenced at the source"
            }
            Self::E155 => {
                "`@[allow(…)]` needs at least one bare diagnostic code, e.g. `@[allow(E151)]`"
            }
            Self::E156 => {
                "a lambda cannot assign to a captured binding — captures are by value, so the write would be lost"
            }
            Self::E157 => {
                "this once-only choice or sequence carries durable state but has no name to anchor its identity across edits"
            }
            Self::E158 => {
                "a lambda cannot capture this local here — most likely its own `let` name read recursively, before the `let` finishes binding"
            }
            Self::E159 => {
                "`@[element(…)]` needs exactly one of `args = \"…\"` / `claims = \"…\"`, whose value compiles as a portable-regex pattern"
            }
            Self::E160 => {
                "`@[element(…)]`'s pattern names a capture group that does not match any parameter on the annotated declaration"
            }
            Self::E161 => {
                "`@[style(…)]` clauses must be `key = \"value\"` pairs, e.g. `@[style(line = \"dim\")]`"
            }
            Self::E162 => {
                "`@[style(…)]` names a key that is neither `line`, `dispatch`, nor a capture declared by the paired `@[element(…)]`"
            }
            Self::E163 => "`@[style(…)]` needs a paired `@[element(…)]` on the same declaration",
            Self::E164 => {
                "inline markup tag is not declared in the host manifest's markup vocabulary"
            }
            Self::E165 => {
                "inline markup attribute is not declared for this span kind in the host manifest"
            }
            Self::E166 => {
                "a block `@[element(…, block)]` / `@[convention(…, block)]` needs a trailing `content`-typed parameter that is not one of its own named captures"
            }
            Self::E167 => {
                "a `@[convention(claims = \"…\", order = N)]` handler declares a parameter its pattern never captures"
            }
            Self::E168 => {
                "this `@[convention(claims = \"…\", order = N)]` pattern is byte-identical to an earlier-declared handler's, and never won a claim of its own — it is dead code"
            }
            Self::E169 => {
                "a pattern-claiming `@[convention(claims = \"…\", order = N)]` handler is legal only in the project's configured conventions module (`brink.toml`'s `[project] conventions`)"
            }
            Self::E170 => {
                "this `@[convention(claims = \"…\", order = N)]` pattern can overlap with an earlier-declared handler's pattern — they silently race, with the lower-`order` one winning"
            }
            Self::E171 => {
                "a `@[convention(claims = \"…\", order = N)]` handler's captured parameter is declared `string`-incompatible — every capture binds as a plain string literal until numeric coercion lands"
            }
            Self::E172 => {
                "native: a `#…` tag beginning with `@` is the ink-dialect compiler-directive shape (`#@private`/`#@was`/`#@local`/…) — native has no such directive channel, so it lowers as an ordinary runtime tag"
            }
            Self::E173 => {
                "inline markup tag is missing an attribute the host manifest marks required for this span kind"
            }
            Self::E174 => {
                "a lambda's written parameter/return annotation disagrees with the type its body actually infers"
            }
            Self::E175 => {
                "retired (issue #2165) — `fn conventions()`/`register` were dissolved from the design"
            }
            Self::E176 => {
                "a divert-with-args site (`-> knot(args)`, tunnel call, or thread-start) supplies the wrong number of arguments for its resolved target's declared parameters"
            }
            Self::E178 => "`@[convention(…)]` needs a required `order = N` clause",
            Self::E179 => "two `@[convention]` declarations in this module carry the same `order`",
            Self::E180 => {
                "a `@[convention(…, attach = StructName)]` clause disagrees with the handler's own declared return type"
            }
            Self::E181 => {
                "a declared STRUCT's own definition could not be resolved while building the struct-shape table — every surviving same-name candidate is std-declared"
            }
            Self::E182 => {
                "a `@[convention]` handler's call closure reaches a world-reading (or unclassified) `EXTERNAL` — handlers may call pure functions and commands, but never read world state"
            }
            Self::E183 => "call target resolved to a symbol kind that is not callable",
            Self::E184 => {
                "a declared CONST/VAR/EXTERNAL's own definition could not be resolved while lowering — every surviving same-name candidate is std-declared"
            }
            Self::E185 => "plain assignment target names a field its struct shape does not declare",
            Self::E186 => {
                "`@[convention(…)]` declares both `block` and `attach = StructName` — mutually exclusive clauses"
            }
            Self::E187 => {
                "write to a CONST — CONST is immutable and can never be reassigned, mutated, or passed by `ref`"
            }
            Self::E188 => {
                "declared STRUCT name collides with a reserved builtin/tower type name and is unreachable in type annotations"
            }
            Self::E189 => "ink `TODO:` author note — work the author marked as remaining",
            Self::E190 => {
                "renaming an EXTERNAL changes the host binding — the engine must re-register the new name"
            }
            Self::E191 => {
                "inline alternatives on one line enumerate to more whole-line variants than the cap allows"
            }
            Self::E192 => {
                "unrecognized `brink-` directive comment — it suppresses nothing as written"
            }
            Self::E193 => "`temp` read on a path its declaration does not dominate",
            Self::E194 => "a knot's temp is not visible from its stitches",
            Self::E195 => "choice has neither display text nor a divert",
        }
    }

    /// Default severity for this diagnostic code.
    #[must_use]
    pub fn severity(self) -> Severity {
        match self {
            Self::E014
            | Self::E022
            | Self::E023
            | Self::E026
            | Self::E030
            | Self::E031
            | Self::E033
            | Self::E034
            | Self::E035
            | Self::E038
            | Self::E043
            | Self::E054
            | Self::E063
            | Self::E092
            | Self::E095
            | Self::E106
            | Self::E110
            | Self::E131
            | Self::E132
            | Self::E151
            | Self::E152
            // Issue #1733 / §4.2: markup vocabulary checks are `Warning` by
            // default so they stay `[lints]`-configurable and
            // `@[allow(…)]`-suppressible (only `Warning`-base codes are —
            // see `crate::suppressions`). A host that wants a declared
            // vocabulary to be binding raises them with
            // `[lints] E164 = "deny"`. Issue #1780/#1997 adds `E173`
            // (missing required attribute) to the same family, same
            // rationale.
            | Self::E164
            | Self::E165
            | Self::E173
            // Issue #1848: a duplicate claiming pattern is dead code (the
            // earlier-declared handler always wins first), not a hard
            // error — `Warning`-tier so it stays `[lints]`-configurable and
            // `@[allow(E168)]`-suppressible, same posture as E164/E165.
            | Self::E168
            // Non-identical patterns that can overlap: same rationale as E168.
            | Self::E170
            // Issue #1835: a project may legitimately want a literal
            // `@`-led runtime tag (the issue's own caution) — `Warning`
            // plus `@[allow(E172)]` is the escape valve, same posture as
            // E132's malformed-directive-tag report.
            | Self::E172
            // Issue #2156: `E031`'s sibling for a divert-with-args call
            // site — same severity precedent as the call-expression arity
            // check it extends.
            | Self::E176
            // Issue #1865: matches E035's "name shadows a built-in
            // function" precedent — a declared STRUCT colliding with a
            // reserved builtin/tower type name is legal (the declaration
            // still compiles and constructs normally), just worth
            // surfacing so the author doesn't lose the annotation spelling
            // by accident. `resolve`'s own doc already calls this ordering
            // "deliberate", the same posture E035's shadow warning takes.
            | Self::E188
            // E190 (external-rename host-binding breakage, ruled 2026-08-24)
            // is Warning-tier: it is the always-unsafe verdict entry behind
            // the rename Force gate, synthesized by the IDE, never emitted
            // by compilation.
            | Self::E190
            // E192 (#3259): a directive that suppresses nothing is a
            // warning, not an error — the file still compiles, and the harm
            // is a suppression the author thinks is in force but is not.
            | Self::E192
            // E193 (#3354, RULED 2026-09-01 option C): a temp read that its
            // declaration does not dominate is a warning, not an error —
            // the story still plays (the runtime reads ink's
            // missing-variable default and warns), and the ruling asks
            // specifically for a `[lints]`-overridable warning so a project
            // that leans on the pattern deliberately can turn it down.
            | Self::E193
            // E195 (#3365): a choice with no text and no divert compiles
            // and plays — inklecate's own C# parser only ever *warns* on
            // this shape too (`InkParser_Choices.cs`), never rejects it —
            // so `Warning`-tier, `[lints]`-overridable like the rest of
            // this family.
            | Self::E195 => Severity::Warning,
            // Issue #1674: the one code whose *default* is the `Info`
            // advisory tier rather than `Warning` — RULED "off or info by
            // default" (a single-shot project should not be nagged) while
            // staying tier-able through `[lints]` like every other code
            // (`brink_analyzer::strict::effective_severity` widens its
            // overridable set past `Warning`-base codes to cover this one,
            // issue #1674).
            // E189 (issue #3050): `TODO:` author notes are advisory by
            // definition — the same `Info`-default posture, tierable via
            // `[lints]` like every other code.
            Self::E157 | Self::E189 => Severity::Info,
            // E194 (#3373, RULED 2026-09-01) falls through to the `Error`
            // default below like every other hard error: inklecate rejects
            // the program, so brink does too until a project opts in. What
            // makes it different from every other `Error`-default code is
            // [`Self::is_overridable`], not `severity` — see that method
            // and [`Self::is_compat_deny`].
            _ => Severity::Error,
        }
    }

    /// Whether this code is a member of the **compat-deny** tier (#3373,
    /// RULED 2026-09-01): "inklecate rejects this; brink can run it; you
    /// must opt in." `docs/compiler-spec.md` "Compat-deny diagnostics" owns
    /// the tier's admission invariant — a code may join only when brink
    /// produces a *working* program with the code downgraded, so every
    /// member needs its own fixture proving that.
    ///
    /// This is the one predicate [`Self::is_overridable`] widens past its
    /// old "not `Error`-by-default" rule for: every compat-deny code keeps
    /// `severity() == Error` (matching ink's own hard rejection) while
    /// still being `[lints]`-overridable, all the way to `allow` — the
    /// ruling's explicit ask ("we should allow it to be turned off if the
    /// user wants, it's annoying").
    #[must_use]
    pub fn is_compat_deny(self) -> bool {
        matches!(self, Self::E194)
    }

    /// Whether this code can only ever arise on the NATIVE (`.brink`)
    /// surface (#3169).
    ///
    /// Which surface can produce a diagnostic is a property of the
    /// diagnostic, not of any consumer — an ink-only project cannot produce
    /// these no matter who is asking, so the answer belongs here rather
    /// than in whichever tool happens to want it.
    ///
    /// **Everything not listed defaults to "both surfaces", deliberately.**
    /// No analysis pass declares the surface it can fire on, so this is
    /// read from what each diagnostic MEANS — and the two ways of being
    /// wrong are not symmetric. Claiming native-only wrongly hides a
    /// setting from an author who is actually seeing the diagnostic;
    /// claiming both wrongly shows one that cannot fire. The second is
    /// clutter, the first is a dead end, so a code earns its place here
    /// only when the compiler itself says so, and everything uncertain
    /// stays visible.
    ///
    /// Deliberately a predicate rather than a `Surface` set: nothing is
    /// ink-only today, and would be a real surprise if it were — the ink
    /// surface is the compatibility floor and native is a superset of it.
    /// If an ink-only code ever appears, this wants to become a set rather
    /// than gain a second predicate.
    #[must_use]
    pub fn is_native_only(self) -> bool {
        matches!(
            self,
            // "native is the only frontend that can spell markup"
            // — brink-analyzer/src/markup_check.rs
            Self::E164 | Self::E165 | Self::E173
            // These say it in their own titles.
            | Self::E131 // "native: `<-` (splice) used outside a choice point…"
            | Self::E132 // "A native file-level `@[was(…)]` rename record…"
            | Self::E151 // "A native `{? … }` choice's own body falls through…"
            | Self::E172 // "A native (`.brink`) tag whose text begins with `@`…"
        )
    }

    /// The written explanation for this code, or `None` when nobody has
    /// written one yet (#3169).
    ///
    /// The prose lives in `docs/diagnostics/Exxx.md` under `## Explanation`.
    /// Every code has a file; only 31 of 189 have that section filled in, so
    /// `None` is the common answer and callers must render something else —
    /// [`Self::title`] is the intended fallback. Returning `None` rather than
    /// an empty string is deliberate: a caller that forgets to check gets a
    /// type error instead of a blank panel.
    #[must_use]
    pub fn explanation(self) -> Option<&'static str> {
        super::diagnostic_explanations::EXPLANATIONS
            .iter()
            .find(|(code, _)| *code == self)
            .map(|(_, text)| *text)
    }

    /// Whether `[lints]` can override this code's severity (#1160).
    ///
    /// Everything except a hard error: `brink_analyzer::validate_lint_code`
    /// accepts any code whose default severity is not `Error`, and refuses
    /// the rest with a `ConfigWarning` rather than applying them. You cannot
    /// `allow` something that stops the compile.
    ///
    /// That deliberately INCLUDES the advisory tiers — `E189`, the ink
    /// `TODO:` note, is `Info` by default and is exactly the sort of thing
    /// an author wants to turn off (ruled 2026-08-27). An earlier version of
    /// this predicate said `Warning` only, which silently hid every
    /// `Info`-default code from the settings surface; the analyzer would
    /// have accepted them all along.
    ///
    /// It also INCLUDES the **compat-deny** tier (#3373, RULED 2026-09-01):
    /// [`Self::is_compat_deny`] members keep `severity() == Error` — brink
    /// rejects the program by default, exactly as inklecate does — but stay
    /// `[lints]`-overridable specifically because the ruling's admission
    /// invariant requires each member to produce a *working* program once
    /// downgraded. This is the one deliberate exception to "a hard error
    /// can never be downgraded"; every other `Error`-default code stays
    /// non-overridable.
    ///
    /// `agrees_with_the_analyzers_own_gate` in `brink-analyzer` pins this
    /// against `apply_lint_overrides` itself rather than against a restated
    /// rule — the earlier mistake survived a test that compared this
    /// predicate to its own implementation.
    #[must_use]
    pub fn is_overridable(self) -> bool {
        !matches!(self.severity(), Severity::Error) || self.is_compat_deny()
    }

    /// Parse a diagnostic code from its string representation (e.g., `"E027"`).
    #[must_use]
    #[expect(
        clippy::too_many_lines,
        reason = "a flat one-arm-per-code table that necessarily grows with the diagnostic set"
    )]
    pub fn from_str_code(s: &str) -> Option<Self> {
        match s {
            "E001" => Some(Self::E001),
            "E002" => Some(Self::E002),
            "E003" => Some(Self::E003),
            "E004" => Some(Self::E004),
            "E005" => Some(Self::E005),
            "E006" => Some(Self::E006),
            "E007" => Some(Self::E007),
            "E008" => Some(Self::E008),
            "E009" => Some(Self::E009),
            "E010" => Some(Self::E010),
            "E011" => Some(Self::E011),
            "E012" => Some(Self::E012),
            "E013" => Some(Self::E013),
            "E014" => Some(Self::E014),
            "E015" => Some(Self::E015),
            "E016" => Some(Self::E016),
            "E017" => Some(Self::E017),
            "E018" => Some(Self::E018),
            "E019" => Some(Self::E019),
            "E020" => Some(Self::E020),
            "E021" => Some(Self::E021),
            "E022" => Some(Self::E022),
            "E023" => Some(Self::E023),
            "E024" => Some(Self::E024),
            "E025" => Some(Self::E025),
            "E026" => Some(Self::E026),
            "E027" => Some(Self::E027),
            "E028" => Some(Self::E028),
            "E029" => Some(Self::E029),
            "E030" => Some(Self::E030),
            "E031" => Some(Self::E031),
            "E032" => Some(Self::E032),
            "E033" => Some(Self::E033),
            "E034" => Some(Self::E034),
            "E035" => Some(Self::E035),
            "E036" => Some(Self::E036),
            "E037" => Some(Self::E037),
            "E038" => Some(Self::E038),
            "E039" => Some(Self::E039),
            "E040" => Some(Self::E040),
            "E041" => Some(Self::E041),
            "E042" => Some(Self::E042),
            "E043" => Some(Self::E043),
            "E044" => Some(Self::E044),
            "E045" => Some(Self::E045),
            "E046" => Some(Self::E046),
            "E047" => Some(Self::E047),
            "E048" => Some(Self::E048),
            "E049" => Some(Self::E049),
            "E050" => Some(Self::E050),
            "E051" => Some(Self::E051),
            "E052" => Some(Self::E052),
            "E053" => Some(Self::E053),
            "E054" => Some(Self::E054),
            "E055" => Some(Self::E055),
            "E056" => Some(Self::E056),
            "E057" => Some(Self::E057),
            "E058" => Some(Self::E058),
            "E059" => Some(Self::E059),
            "E060" => Some(Self::E060),
            "E061" => Some(Self::E061),
            "E062" => Some(Self::E062),
            "E063" => Some(Self::E063),
            "E064" => Some(Self::E064),
            "E065" => Some(Self::E065),
            "E066" => Some(Self::E066),
            "E067" => Some(Self::E067),
            "E068" => Some(Self::E068),
            "E069" => Some(Self::E069),
            "E070" => Some(Self::E070),
            "E071" => Some(Self::E071),
            "E072" => Some(Self::E072),
            "E073" => Some(Self::E073),
            "E074" => Some(Self::E074),
            "E075" => Some(Self::E075),
            "E076" => Some(Self::E076),
            "E077" => Some(Self::E077),
            "E078" => Some(Self::E078),
            "E079" => Some(Self::E079),
            "E080" => Some(Self::E080),
            "E081" => Some(Self::E081),
            "E082" => Some(Self::E082),
            "E083" => Some(Self::E083),
            "E084" => Some(Self::E084),
            "E085" => Some(Self::E085),
            "E086" => Some(Self::E086),
            "E087" => Some(Self::E087),
            "E088" => Some(Self::E088),
            "E089" => Some(Self::E089),
            "E090" => Some(Self::E090),
            "E091" => Some(Self::E091),
            "E092" => Some(Self::E092),
            "E093" => Some(Self::E093),
            "E094" => Some(Self::E094),
            "E095" => Some(Self::E095),
            "E096" => Some(Self::E096),
            "E097" => Some(Self::E097),
            "E098" => Some(Self::E098),
            "E099" => Some(Self::E099),
            "E100" => Some(Self::E100),
            "E101" => Some(Self::E101),
            "E102" => Some(Self::E102),
            "E103" => Some(Self::E103),
            "E104" => Some(Self::E104),
            "E105" => Some(Self::E105),
            "E106" => Some(Self::E106),
            "E107" => Some(Self::E107),
            "E108" => Some(Self::E108),
            "E109" => Some(Self::E109),
            "E110" => Some(Self::E110),
            "E111" => Some(Self::E111),
            "E112" => Some(Self::E112),
            "E113" => Some(Self::E113),
            "E114" => Some(Self::E114),
            "E115" => Some(Self::E115),
            "E116" => Some(Self::E116),
            "E117" => Some(Self::E117),
            "E118" => Some(Self::E118),
            "E119" => Some(Self::E119),
            "E120" => Some(Self::E120),
            "E121" => Some(Self::E121),
            "E122" => Some(Self::E122),
            "E123" => Some(Self::E123),
            "E124" => Some(Self::E124),
            "E125" => Some(Self::E125),
            "E126" => Some(Self::E126),
            "E127" => Some(Self::E127),
            "E128" => Some(Self::E128),
            "E129" => Some(Self::E129),
            "E130" => Some(Self::E130),
            "E131" => Some(Self::E131),
            "E132" => Some(Self::E132),
            "E133" => Some(Self::E133),
            "E134" => Some(Self::E134),
            "E135" => Some(Self::E135),
            "E136" => Some(Self::E136),
            "E137" => Some(Self::E137),
            "E138" => Some(Self::E138),
            "E139" => Some(Self::E139),
            "E140" => Some(Self::E140),
            "E141" => Some(Self::E141),
            "E142" => Some(Self::E142),
            "E143" => Some(Self::E143),
            "E144" => Some(Self::E144),
            "E145" => Some(Self::E145),
            "E146" => Some(Self::E146),
            "E147" => Some(Self::E147),
            "E148" => Some(Self::E148),
            "E149" => Some(Self::E149),
            "E150" => Some(Self::E150),
            "E151" => Some(Self::E151),
            "E152" => Some(Self::E152),
            "E153" => Some(Self::E153),
            "E154" => Some(Self::E154),
            "E155" => Some(Self::E155),
            "E156" => Some(Self::E156),
            "E157" => Some(Self::E157),
            "E158" => Some(Self::E158),
            "E159" => Some(Self::E159),
            "E160" => Some(Self::E160),
            "E161" => Some(Self::E161),
            "E162" => Some(Self::E162),
            "E163" => Some(Self::E163),
            "E164" => Some(Self::E164),
            "E165" => Some(Self::E165),
            "E166" => Some(Self::E166),
            "E167" => Some(Self::E167),
            "E168" => Some(Self::E168),
            "E169" => Some(Self::E169),
            "E170" => Some(Self::E170),
            "E171" => Some(Self::E171),
            "E172" => Some(Self::E172),
            "E173" => Some(Self::E173),
            "E174" => Some(Self::E174),
            "E175" => Some(Self::E175),
            "E176" => Some(Self::E176),
            "E178" => Some(Self::E178),
            "E179" => Some(Self::E179),
            "E180" => Some(Self::E180),
            "E181" => Some(Self::E181),
            "E182" => Some(Self::E182),
            "E183" => Some(Self::E183),
            "E184" => Some(Self::E184),
            "E185" => Some(Self::E185),
            "E186" => Some(Self::E186),
            "E187" => Some(Self::E187),
            "E188" => Some(Self::E188),
            "E189" => Some(Self::E189),
            "E190" => Some(Self::E190),
            "E191" => Some(Self::E191),
            "E192" => Some(Self::E192),
            "E193" => Some(Self::E193),
            "E194" => Some(Self::E194),
            "E195" => Some(Self::E195),
            _ => None,
        }
    }
}

// ── Issue #3169: the registry the settings UI reads ────────────────

#[cfg(test)]
mod registry_tests {
    use super::{DiagnosticCode, Severity};

    /// Read the `## Explanation` section out of a doc file, the same way the
    /// generator does.
    fn doc_explanation(text: &str) -> String {
        let Some((_, rest)) = text.split_once("## Explanation\n") else {
            return String::new();
        };
        rest.split("\n## ").next().unwrap_or("").trim().to_owned()
    }

    fn docs_dir() -> std::path::PathBuf {
        std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("../../../docs/diagnostics")
    }

    #[test]
    fn explanations_match_the_docs() {
        // The table is embedded (the docs live outside this crate's package
        // directory, and the wasm build has no filesystem), so nothing keeps
        // it in step with the markdown except this test. It runs in the
        // workspace, where `docs/` exists — which is also the only place the
        // drift can happen.
        let root = docs_dir();
        assert!(
            root.is_dir(),
            "expected diagnostics docs at {}",
            root.display()
        );

        let mut wrong = Vec::new();
        for code in DiagnosticCode::ALL {
            let text = std::fs::read_to_string(root.join(format!("{}.md", code.as_str())))
                .unwrap_or_default();
            if doc_explanation(&text) != code.explanation().unwrap_or("") {
                wrong.push(code.as_str());
            }
        }
        assert!(
            wrong.is_empty(),
            "diagnostic_explanations.rs is out of step with docs/diagnostics for {wrong:?} \
             — regenerate it so the settings UI does not show stale prose"
        );
    }

    #[test]
    fn every_code_has_an_explanation_file() {
        let root = docs_dir();
        let missing: Vec<_> = DiagnosticCode::ALL
            .iter()
            .filter(|c| !root.join(format!("{}.md", c.as_str())).is_file())
            .map(|c| c.as_str())
            .collect();
        assert!(
            missing.is_empty(),
            "codes with no explanation file: {missing:?}"
        );
    }

    #[test]
    fn no_explanation_is_a_leftover_placeholder() {
        // The generated stubs carried bracketed placeholder prose. Embedding
        // one would put "[Detailed explanation of this diagnostic...]" in
        // front of an author, which is worse than showing nothing at all.
        for code in DiagnosticCode::ALL {
            if let Some(text) = code.explanation() {
                assert!(
                    !text.contains("[Detailed explanation"),
                    "{} still carries placeholder text",
                    code.as_str()
                );
                assert!(
                    !text.is_empty(),
                    "{} has an empty explanation",
                    code.as_str()
                );
            }
        }
    }

    #[test]
    fn native_only_codes_say_so_in_their_own_text() {
        // The list is judgement, so it is held to its own standard: a code
        // is native-only only when the compiler itself says so. Every entry
        // must be justified by its title or its explanation naming the
        // native surface — if one is not, either the claim is wrong or the
        // title needs to state what the code is for.
        //
        // Markup is the documented exception: `markup_check.rs` says
        // "native is the only frontend that can spell markup", which is not
        // repeated in each code's own title.
        const MARKUP: &[DiagnosticCode] = &[
            DiagnosticCode::E164,
            DiagnosticCode::E165,
            DiagnosticCode::E173,
        ];
        for code in DiagnosticCode::ALL.iter().filter(|c| c.is_native_only()) {
            if MARKUP.contains(code) {
                continue;
            }
            let title = code.title().to_lowercase();
            let explanation = code.explanation().unwrap_or("").to_lowercase();
            assert!(
                title.contains("native")
                    || title.contains(".brink")
                    || explanation.contains("native")
                    || explanation.contains(".brink"),
                "{} is marked native-only but nothing in its own text says so",
                code.as_str()
            );
        }
    }

    #[test]
    fn native_only_is_the_exception() {
        // The default is "both surfaces", and that is load-bearing: hiding
        // a code an author is actually seeing is worse than showing one
        // that cannot fire. If most codes became native-only, the default
        // has stopped being a default and this design wants revisiting
        // rather than the list growing.
        let native_only = DiagnosticCode::ALL
            .iter()
            .filter(|c| c.is_native_only())
            .count();
        assert!(
            native_only * 4 < DiagnosticCode::ALL.len(),
            "native-only is no longer an exception: {native_only} of {}",
            DiagnosticCode::ALL.len()
        );
    }

    #[test]
    fn a_hard_error_is_never_overridable_and_an_advisory_always_is() {
        // Stated as the RULE, not as a copy of the implementation. The
        // version of this test that said `== matches!(severity, Warning)`
        // could not catch the predicate being wrong, because it asserted
        // the predicate against itself — and it did not catch it: every
        // `Info`-default code (`E189`, the ink TODO note) was hidden from
        // the settings surface for exactly that reason.
        for code in DiagnosticCode::ALL {
            match code.severity() {
                // #3373's compat-deny tier is the one deliberate exception:
                // `Error`-default AND overridable, exactly the members
                // `is_compat_deny` names. Every other `Error`-default code
                // must stay non-overridable.
                Severity::Error => assert_eq!(
                    code.is_overridable(),
                    code.is_compat_deny(),
                    "{}: an Error-default code is overridable only when it is a \
                     compat-deny tier member",
                    code.as_str()
                ),
                Severity::Warning | Severity::Info | Severity::Hint => {
                    assert!(code.is_overridable(), "{}", code.as_str());
                }
            }
        }
        assert!(
            DiagnosticCode::E189.is_overridable(),
            "the ink TODO: note must be configurable (ruled 2026-08-27)"
        );
        assert!(
            DiagnosticCode::E194.is_overridable() && DiagnosticCode::E194.is_compat_deny(),
            "the compat-deny tier's first member must be Error-default yet overridable \
             (ruled 2026-09-01, #3373)"
        );
        let overridable = DiagnosticCode::ALL
            .iter()
            .filter(|c| c.is_overridable())
            .count();
        assert!(
            overridable > 0 && overridable < DiagnosticCode::ALL.len(),
            "a flag that is true (or false) for every code would be pointless: \
             {overridable} of {}",
            DiagnosticCode::ALL.len()
        );
    }

    #[test]
    fn compat_deny_tier_is_error_default_and_overridable() {
        // The tier's own invariant, stated directly against every current
        // member rather than folded into the general hard-error test above
        // — so a future member that gets `is_compat_deny` right but
        // `severity` wrong (or vice versa) fails here with a name attached.
        for code in DiagnosticCode::ALL.iter().filter(|c| c.is_compat_deny()) {
            assert_eq!(
                code.severity(),
                Severity::Error,
                "{}: a compat-deny member's default must match inklecate's rejection",
                code.as_str()
            );
            assert!(
                code.is_overridable(),
                "{}: a compat-deny member must be [lints]-overridable",
                code.as_str()
            );
        }
    }
}