Cross-file Analysis

Problem Description

In early implementations, check_files_with_diagnostics created an independent Compiler for each file, making it impossible to detect cross-file references. pub functions defined in fileA could not be recognized in fileB.

Solution

Use a shared TypeEnvironment and check all modules in dependency order.

Implementation Flow

1. Parse all .yx files in parallel → Vec<(PathBuf, ModuleId, AST)>
2. Build the dependency graph using ModuleDependencyGraph::build_from_ast
3. detect_cycles() checks for circular dependencies → report errors
4. topological_sort() gets the compilation order
5. Type check in order:
   a. Create a shared TypeEnvironment (including std module)
   b. For each module: register its exports into the shared environment → type check
   c. Collect diagnostics
6. Return CheckResult

Namespace Isolation

Use the module_name.symbol_name format to store exported symbols, avoiding conflicts between symbols with the same name in different modules.

Known Limitations

• traits/ placeholder implementations (coherence/impl_check/object_safety/resolution) are incomplete
• check_single_module still creates an independent Compiler for each module (passing type information from the shared env has not been fully implemented)

Future Work

• T8: End-to-end test for cross-file type checking
• A4: Shared trait_table and native_signatures