Cross-module mutual recursion is not supported

LIMIT-EVALUATION-002

Superseded by GAP-MODULES-001: the scenario needs a circular import, which the spec forbids.

Lifecycle

superseded

Owner

metel-interpreter

Scope

architecture/spec/evaluation.md#evaluation

Origin

metel-interpreter/docs/evaluator.md, "Known Limitations", #189

Affects · linked records

arch.evaluation.requirement-1architecture requirement

GAP-MODULES-001gap

limitationKnown limitations ↗

Limitation

run_passes runs all three passes (1a placeholders, 1b closures, 2 bindings) for one module before moving to the next. If function foo in module A calls bar in module B and bar calls foo, a specific multi-module structure (A and B peers, both importing a third module C) requires B's environment to exist while A is still being evaluated — but it doesn't yet, so A's closures cannot capture B's functions. The documented fix requires running Pass 1a for every module before Pass 1b for any module. No current test program exercises this pattern, per the source's own note.

Impact

That one specific circular multi-module dependency shape is unsupported.

Affects

• arch.evaluation.requirement-1
• GAP-MODULES-001

Resolution

Superseded by GAP-MODULES-001 (ADR-0057 §5). The scenario this record describes needs A and B to call each other, which requires a circular import; the Language Spec makes that a compile error (spec.modules.module-graph-loading.legality-2, fixture module_loading/rejects_circular_module_graph), so the evaluator's pass ordering is never exercised by it. The cited #189 is closed (v0.6.3).