06. Const functions in type positions

Goal

Proposal §11 (Phase 5): const functions usable in type positions (where-clause computations).

Implementation Items

• Const-function requirements (§11.2)
• Built-in const functions (§11.3)
• where-clause examples (§11.4)

Spec References

proposal §11.

Intelligence Reconnaissance

• Graph-grounded during BUG-06-005 investigation + the dual-source /tp-help consensus (bug-tracker/plans/BUG-06-005/section-02-fix-consensus.md): reviewers ran file-symbols / callers / callees / symbols over ori_parse/grammar/item, ori_ir/ast/items/types.rs, ori_types/check/registration, ori_fmt, ori_eval/derives, ori_llvm/codegen/derive_codegen. Per-section graph queries to be re-run at /review-plan pre-implementation gate. (2026-06-01)