Module closures 

The Closure value descriptor (§4.10).

A closure value carries a function pointer (the JIT’d entry point of the closure’s synthetic function) plus a captured environment (the values it closes over, each a GcRef). A single CLOSURE descriptor serves every closure because the per-closure knowledge (arity, env size) lives in the payload.

Per §5.5, function and closure values are never equatable or hashable — they have no structural identity. The equals/hash callbacks are None.

Calling convention

The closure’s synthetic function takes the closure value itself as a hidden first explicit parameter (after the implicit ctx): its MIR signature is fn(ctx, closure_self, params...). At entry, a prologue loads each captured value via praxis_closure_capture and binds it to a local. Calling a closure value is an indirect call: the call site reads fn_ptr via praxis_closure_fn_ptr, then emits a native call_indirect passing [ctx, closure, args...]. Keeping the closure value intact at the call site (rather than spreading the env into trailing params) makes the indirect call uniform per-arity and keeps the closure self-contained for fault snapshots and future borrow/move semantics.

Structs

ClosurePayload

The runtime payload of a closure value: the function pointer plus the captured environment values (one GcRef per captured variable, in capture order established by the HIR capture analysis).

Statics

CLOSURE

Descriptor for the Closure value type (§4.10). Closures are never equatable or hashable (§5.5: function values have no structural identity).