nocter-declaration-lowering

Responsibility

Lower one closed compile input into an immutable declaration program, validate all declaration-level contracts, and publish accepted or explicitly recoverable declaration evidence.

Contract

The crate consumes syntax, compile-unit topology, target selection, toolchain/runtime contracts, and model construction authority. It produces DeclarationProgram, AcceptedDeclarationProgram, and one source-neutral ReusableDeclarations result containing the accepted authority, primitive bindings, and FrontendProjectionRecipe. The recipe materializes frontend bindings, diagnostic origins, and source projection together for one current syntax generation. It does not check callable bodies.

Internal Responsibilities

• deterministic identity reservation and definition
• one canonical DeclarationSurface topology consumed by both reservation and focused topology tests
• define-once semantic projection recipes and current-generation materialization
• declaration-only authority projection separated from current body imports and spellings
• stable path-plus-block identities mapping body query keys to declaration-owned BodyId values
• canonical source-domain and body-import rebinding for reused declarations
• module namespaces, imports, visibility, and exports
• generic and type-position normalization
• one-way binding of authored callable guarantees into declaration and structural-type contracts
• construction-time binding of inherited associated names before declaration capability freeze
• declaration surfaces and contract/definition joins
• primitive, builtin, standard-role, and package-target projection
• declaration recovery and diagnostic classification

Invariants

• Accepted declaration semantics are built once and cannot contain a deferred invalid edge.
• The eager whole-stage convenience entry exists only behind the test-api feature or the crate's own test build. Production consumers can use reusable query contracts but cannot invoke a second declaration scheduler.
• Target directives, primitive roles, and standard roles are selected once upstream or here.
• SourceIndex is output projection, never semantic input.
• A projection recipe contains semantic identities and declaration-surface locators, never SourceId, NodeId, token ranges, documentation text, or body-local syntax.
• A recipe retains the source-neutral module identity, canonical path, and source kind for every source ordinal. Current materialization rejects a different domain before resolving any locator.
• FrontendBindings and SourceIndex are both interpreted from the same recipe. Documentation is read from the current syntax tree during materialization, so trivia-only edits cannot retain stale hover text.
• Current checking materialization computes the exact body-symbol suffix once and returns it with frontend bindings and source projection. Session cannot rescan syntax to construct a parallel symbol domain.
• Body-local imports remain current body input and cannot enter the reusable declaration recipe. Their current syntax identities are joined only through the exact source-neutral module mapping frozen with ReusableDeclarations; materialization neither repeats module lookup nor declaration lowering.
• Contract and private definition joins use exact identities, not text matching downstream.
• Public contracts and private bodies must retain the same authored guarantee fingerprint before either occurrence reaches semantic declaration storage.
• A derived associated binding resolves through bound prerequisite identities to the original declaration; lowering never creates an alias declaration for inheritance. The accepted declaration graph then freezes the effective identity so later stages do not repeat this binding.
• Declaration recovery remains one closed product across the computation and session boundary; consumers cannot recombine its graph, type authority, source ownership, and source projection.