Module Resolution & Hierarchical Loading

[rz1989s]

Description

Implement the ModuleResolver to handle hierarchical module loading with mod name; declarations.

This is part of the nested module system implementation (#53), broken down into manageable sub-issues.

Tasks

• Create module_resolver.rs with ModuleResolver struct
• Implement resolve_module_declaration() for mod foo; → foo.lumos or foo/mod.lumos
• Add module tree construction (parent-child relationships)
• Implement path resolution for crate::, super::, self::
• Add circular module dependency detection
• Update FileResolver to use ModuleResolver
• Add module resolution tests (10+ test cases)

Acceptance Criteria

• mod models; correctly resolves to models.lumos or models/mod.lumos
• Module tree structure tracks parent-child relationships
• crate::models::User resolves from any module
• super::types::UserId resolves relative to parent
• Circular module dependencies detected with clear error
• All existing tests pass + 10 new module resolution tests

Technical Details

Resolution Algorithm:
For mod foo; in file path/to/file.lumos:

1. Check path/to/foo.lumos (sibling file)
2. If not found, check path/to/foo/mod.lumos (directory module)
3. If neither exists, error: module not found

Path Resolution:

• crate:: - Absolute from root
• super:: - Parent module
• self:: - Current module
• module:: - Relative child

Estimated Time

4-6 hours

Dependencies

• Depends On: #53a (completed - AST foundations with visibility)
• Blocks: #53c (generator updates)
• Part Of: Add nested module support to LUMOS #53 (nested module support)

Priority

High - Core functionality needed for module system