W001 -- Catalog Module Collision

W001 reports a module name collision while loading catalog modules. Two modules claim the same name, and letting filesystem scan order decide which one wins would make builds non-deterministic, so the compiler warns instead.

Message shape

warning[W001]: module 'name' is provided by more than one catalog entry

The diagnostic has no source line; it is reported against <catalog>.

Fix

• Rename one of the modules so catalog names are unique.
• If a duplicate comes from a stale build artifact or a second standard library checkout, remove the extra copy and rebuild.

Notes

• The build continues, but which module resolves can depend on the catalog order; fix the collision rather than ignoring it.
• W001 never appears for files that are not part of module resolution.