Improve core performance

**Problem**
When working with types, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

No files or tests are named in the issue. Start by locating the core type-handling and error-reporting entry points, then determine which cases currently produce insufficient messages. Done means the intended error-handling scope is defined, messages are more descriptive, and relevant tests cover the new behavior.

Written by the indexing model from the issue text.