Refactor/printer

[cds-amal]

This PR splits src/printer.rs (~1700 lines) into a src/printer/ directory module with focused submodules, then follows up with doc comments, idiomatic Rust cleanup, and a structural improvement to the phase boundary enforcement.

All integration and UI tests pass unchanged.

Structure

The split creates nine submodules, each with a single responsibility:

Module	Lines	Responsibility
schema.rs	~510	Data model types (SmirJson, Item, AllocInfo, TypeMetadata, LinkMapKey, etc.)
mir_visitor.rs	~430	BodyAnalyzer: single-pass MIR body traversal collecting calls, allocs, types, spans
collect.rs	~230	Three-phase pipeline: collect items, analyze bodies, assemble final output
items.rs	~225	Item construction from MonoItem with optional debug-level details
types.rs	~170	TypeMetadata construction from TyKind + layout
ty_visitor.rs	~120	Recursive type visitor collecting all reachable types with layout info
link_map.rs	~107	Link-time function resolution map (type + instance kind to symbol name)
mod.rs	~83	Module glue: macros, env-var helpers, re-exports, emit_smir
util.rs	~64	Name resolution, attribute queries, small helpers

Changes by commit

1. Split printer.rs into a directory module: mechanical extraction; no code changes beyond moving use / extern crate declarations into each submodule and adjusting visibility.

2. Add module-level doc comments to all printer submodules: //! doc headers describing each module's purpose and key types.

3. Idiomatic Rust cleanup across printer submodules:

   • if let Some(x) = y { x } else { z } to y.unwrap_or_else(|| z)
   • if opt.is_none() { return; } let val = opt.unwrap() to let Some(val) = opt else { return; }
   • Remove unnecessary .clone() calls on key in get_mut / insert
   • Change collect_alloc to take offset: usize by value (was &usize)
   • Extract opaque_placeholder_ty() helper for the Ty::to_val(0) sentinel
   • Doc comments on FnSymType, LinkMapKey, AllocInfo, TypeMetadata, SourceData, SmirJson, SmirJsonDebugInfo

4. Address review feedback and fix doc comment inaccuracies.

5. Remove MonoItem from Item for structural phase enforcement:

   The three-phase collection pipeline has an invariant: phase 3 (assemble_smir) must not call inst.body() or otherwise re-enter rustc. Previously this was enforced by convention only, because Item carried a pub(super) mono_item: MonoItem field that gave any code with an &Item full access to Instance::body().

   This commit removes mono_item from Item entirely, so the invariant is structural: phase 3 code literally cannot call inst.body() because it never has a MonoItem to call it on. The type system enforces what discipline previously had to.

   Concretely: mk_item now returns (MonoItem, Item) instead of Item, and the phase 1+2 maps carry (MonoItem, Item) tuples. The MonoItem lives alongside the Item during collection and analysis, gets passed directly to maybe_add_to_link_map and warn_missing_body (now a free function in collect.rs), and is naturally dropped when only the Item is pushed into all_items. By the time assemble_smir runs, no MonoItem values exist.

   As a bonus, this fixes a latent PartialEq/Ord inconsistency: PartialEq was comparing mono_item while Ord compared symbol_name + item-kind name. PartialEq now delegates to Ord, so the two are consistent.

Test plan

• cargo build succeeds
• cargo clippy clean
• make integration-test passes (28/28)
• make test-ui passes (2875/2875, 0 failures)

[Copilot]

Pull request overview

This PR refactors the Stable MIR JSON “printer” by splitting the former monolithic src/printer.rs into a src/printer/ module directory with focused submodules, keeping the public API via re-exports and adding module-level documentation.

Changes:

• Split src/printer.rs into src/printer/{mod.rs, schema.rs, mir_visitor.rs, collect.rs, items.rs, types.rs, ty_visitor.rs, link_map.rs, util.rs}.
• Added module-level doc comments across the new submodules.
• Small idiomatic cleanups during extraction (option handling, helper extraction, signature tweaks like offset: usize).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
src/printer/mod.rs	New module entrypoint: env-var helpers/macros, submodule wiring, public re-exports, emit_smir.
src/printer/schema.rs	Extracted data model/types for *.smir.json plus serialization helpers and debug-only alloc coherence verification.
src/printer/collect.rs	Extracted 3-phase collection pipeline and final JSON assembly/sorting.
src/printer/items.rs	Extracted Item/MonoItemKind construction and optional debug details/foreign module enumeration.
src/printer/mir_visitor.rs	Extracted MIR traversal (BodyAnalyzer) and allocation/type/span/link-map collection logic.
src/printer/ty_visitor.rs	Extracted recursive type visitor for reachable types + layout capture.
src/printer/types.rs	Extracted TypeMetadata construction from TyKind + layout.
src/printer/link_map.rs	Extracted link-time function resolution map update + symbol classification logic.
src/printer/util.rs	Extracted small helpers (hashing, map queueing, name resolution, attribute queries).
src/printer.rs	Removed old monolithic implementation after split.

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[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.

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