Explain rules-editor operator operand mismatches
Invalid addition reports Type error without naming either operand type. Add structured expected and actual types.
- Focused work estimate
- 1h 30m + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Diagnostics · Type rules
Estimated field mix
- Compiler and language tooling100%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
Review it, then add it to your workspace.
The board opens an editable draft; nothing is saved until you confirm it. Sign-in and workspace permissions apply, and Demo boards remain ephemeral.
Project context
Fictional rules editor Willow supports numbers, strings, booleans, records and functions in a deliberately small language. Define syntax and type rules locally; no arbitrary code execution is needed.
Setup prerequisites
- Create synthetic AST fixtures and a written type-rule table.
- Define source spans and structured diagnostic output.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Valid operands infer result
- Mismatch identifies operator span
- Diagnostic includes both operand types
Implementation constraints
- Keep wording independent from internal object serialization.
Verification to include
- Add two numeric literals
- Add number to unsupported record
Deliverables
- Operator rules and diagnostic cases
Rollout and recovery
Reject ambiguous operators with explicit unsupported message.
Value of the work
For the engineer: Practice type environments, unification and explainable rejection.
For the team: Inspect whether developer tooling catches mistakes without hiding uncertainty.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.