[shunichironomura]

Warning

This content was written by an AI agent and must be verified by a human developer. After human verification, this alert may be removed.

Summary

• Preserve the source alias boundary alongside declaration resolution, so HIR lowering does not classify a successfully resolved alias again. Keep separate classification only for elaborated overlay bindings the resolver cannot reach.
• Keep resolver facts in a small upstream contracts module; update the layer map and regenerate the reading order without introducing cycles or exceptions.
• Add resolver and HIR tests for local/selective-import paths, imported/include aliases, nested paths, and overlay bindings. Language syntax, diagnostics, and editor features remain unchanged.

Closes #1952; relates to #1947.

The three unused eval API removals for #1949 are now on the separate lower branch refactor/remove-unused-eval-apis. This PR targets that branch and contains only the resolver refactor.

Validation

• The combined tree is unchanged by the branch split. Before splitting, just test passed, including Lean conformance, workspace tests, playground tests, and embedded-engine/report runtime tests; CI passed.
• Workspace Clippy (all features and no default features), Rustfmt, docs with warnings denied, Cargo check, fuzz metadata, playground checks, dependency-layer checks, refactor metrics, and reading-order checks passed.
• just lint stopped at the RustSec advisory refresh because the local SSH agent could not authenticate. Both dependency audits passed separately using --no-fetch against the existing advisory database, and all remaining lint steps passed.

AI assistance

• AI used: yes — investigation, implementation, tests, branch split, and PR preparation.
• Human review of AI-assisted code: pending.

Breaking changes

• No breaking changes
• Breaking changes; the breaking change label is applied