Specify scope arenas, dynamic reuse, and global anchors

README.md

@@ -66,7 +66,7 @@ The spec states *what* the language does; the **why** lives in a parallel set of
 | [`stories/adt.md`](stories/adt.md) | [`spec/adt.md`](spec/adt.md) — splitting `enum` from `variant` against the hype, the shared struct body, escaping the matcher machine with case overloads and the turn to a central `match` block, matching variants rather than patterns, keeping enum data outside the members, reducing a match group to sugar for one arm per case, and building a variant by naming a case rather than calling a constructor |
 | [`stories/generics.md`](stories/generics.md) | [`spec/generics.md`](spec/generics.md) — the parameter model, the `<>`/`()` split, size-in-the-type, and the deferred features |
 | [`stories/dependencies.md`](stories/dependencies.md) | [`spec/dependencies.md`](spec/dependencies.md) — URL identity, the manifest/resolution split, prebuilt distribution, symbol-rewriting, the browsable global cache, the package-graph acyclicity rule, opt-in remapping, and why `core` became a bundled implementation package |
-| [`stories/memory.md`](stories/memory.md) | [`spec/memory.md`](spec/memory.md) — the no-GC-no-lifetimes goal, the move problem and the anchor, lazy backpointer creation, the indexed heap table, the rooted-guest rules and the host/guest terminology split, the collapse to one value/reference axis with a borrowed receiver, and the shift to segmented chunked bump arenas |
+| [`stories/memory.md`](stories/memory.md) | [`spec/memory.md`](spec/memory.md) — the no-GC-no-lifetimes goal, the move problem and the anchor, lazy backpointer creation, the indexed heap table, the rooted-guest rules and the host/guest terminology split, the collapse to one value/reference axis with a borrowed receiver, the shift to segmented chunked bump arenas, and the split into fixed-size and dynamic regions with anchors moved to a runtime-global recyclable pool |
 | [`stories/lifetimes.md`](stories/lifetimes.md) | [`spec/lifetimes.md`](spec/lifetimes.md) — lexical scope in place of a borrow checker, what may be moved, the declaration-block rule that kills flow analysis, downgrade instead of use-after-move, parameter-rooted returned guests, and why each strict rule is the minimal guard against one specific memory corruption |
 | [`stories/effects.md`](stories/effects.md) | [`spec/effects.md`](spec/effects.md) — inferring effects instead of annotating them, receiver-scoped `mut`, capabilities in place of ambient I/O, the four-level ladder and the Total-Pure/Pure split, what deliberately is not an effect, and mutation through a borrowed receiver |
 | [`stories/concurrency.md`](stories/concurrency.md) | [`spec/concurrency.md`](spec/concurrency.md) — the parallelism/concurrency split and the refusal of `async` coloring, why `spawn` marks only a call, water-tower lifetimes, signature-based safety without locks, and value-typed mutation closing the aliased-write gap |

spec/glossary.md

@@ -75,7 +75,7 @@ This file gives short, reusable names to concepts that appear across multiple sp
 - **Canonical home:** [`memory.md`](memory.md) §2.10
 
 ### 3.3 unified type parameters
-- **Meaning:** A type or number parameter is a *type parameter* (`name Type`, an uppercase name such as `T`, ranging over types) or a *number parameter* (`name Number`, a lowercase name such as `n`, ranging over compile-time numbers and resolving to a number value in body positions). A type definition declares its parameters in a `<>` header (their order is applied positionally at use sites); a verb — function, method, or constructor — has no header and introduces each parameter inline within its value parameters, at the parameter's first marked occurrence. Parameters are referenced by bare name; casing carries the kind.
+- **Meaning:** A type or number parameter is a *type parameter* (`name Type`, an uppercase name such as `T`, ranging over types) or a *number parameter* (`name Number`, a lowercase name such as `n`, ranging over compile-time numbers and resolving to a number value in body positions). A type definition declares its parameters in a `<>` header (their order is applied positionally at use sites); a verb — function, method, operator, constructor, or lambda — has no header and introduces each parameter inline within its value parameters, at the parameter's first marked occurrence. Parameters are referenced by bare name; casing carries the kind.
 - **Why this name:** Type and number parameters share one concept-and-reference system (the `Type`/`Number` concepts, bare references, and the casing rule) across types and verbs; only the introduction site differs — a header for types, which are applied positionally, and inline for verbs, whose parameters are always inferred.
 - **Canonical home:** [`generics.md`](generics.md) §3
 
@@ -175,18 +175,18 @@ This file gives short, reusable names to concepts that appear across multiple sp
 - **Canonical home:** [`functions.md`](functions.md) §1
 
 ### 3.23 anchor cell
-- **Meaning:** A runtime `u32` cell holding the current segmented offset of one hosted object — the stable indirection point through which tethers resolve. It is bump-allocated when the first guest is created, in a dedicated anchor-cell region of the host's scope arena.
-- **Why this name:** The cell is the fixed point that lets a moving object remain reachable: rehosting updates the cell while existing tethers keep pointing to it.
+- **Meaning:** An 8-byte runtime cell in the global anchor pool containing a `u32` target and a kind. A payload anchor targets a hosted object's segmented offset; a forwarding anchor targets another anchor after two hosting identities merge. A guest's `u32` tether names an anchor cell and follows forwarding cells until it reaches the terminal payload anchor.
+- **Why this name:** The cell is a stable point through which an older guest identity can remain attached to a moving value, either directly or through another anchor.
 - **Canonical home:** [`memory.md`](memory.md) §4.1
 
 ### 3.24 segmented-offset tether
-- **Meaning:** The internal representation of a guest: a `u32` segmented offset pointing at the host's anchor cell, not a raw pointer. The value `0` means no tether. A tether is a runtime mechanism, distinct from the source-facing `&T` guest (§3.33).
+- **Meaning:** The internal representation of a guest: a `u32` segmented offset pointing at an anchor cell, not a raw pointer. The cell may directly target the hosted payload or forward to another anchor. The value `0` means no tether. A tether is a runtime mechanism, distinct from the source-facing `&T` guest (§3.33).
 - **Why this name:** The tether connects a guest's stored representation to the anchor through which it reaches the hosted object.
 - **Canonical home:** [`memory.md`](memory.md) §4.2
 
 ### 3.25 arena placement
-- **Meaning:** A reference-type instance is bump-allocated in the arena of the scope that creates it, and is copied (promoted) into a parent arena only if it escapes that scope. Only dynamic size or escape changes where an instance lives. Placement is an unobservable implementation choice.
-- **Why this name:** Placement is a choice among **arenas** — the per-scope bump regions — rather than between a stack and a heap; the creating scope's arena is the default, a parent arena the fallback on escape.
+- **Meaning:** A scope's arena has two regions: statically sized storage — value slots, reference-type hosts, and dynamic handles — is bump-allocated inline in the fixed-size region of the scope that creates it, while a resizable backing store goes in that scope's dynamic region. Rehosting copies the complete hosted representation into destination-owned storage: inline bytes move into the destination fixed-size region, each dynamic backing store is relocated into an equal-size destination-region allocation, and the old source storage ceases to be live. The source host-capable slot then stores the terminal tether as a guest. Placement is an unobservable implementation choice.
+- **Why this name:** Placement is a choice among **arenas** — the per-scope regions — rather than between a stack and a heap; the creating scope's arena is the default, a parent arena the fallback on escape.
 - **Canonical home:** [`memory.md`](memory.md) §3.5
 
 ### 3.26 capability marker