Iterator Element Ownership Protocol

6 sections

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Section 1 Sources: Increment on Yield Section 2 Adapters: Decrement on Discard Section 3 Consumers: Decrement After Use Section 4 Codegen: Parameter Plumbing Section 5 AIMS: Owned Element Contract Section 6 Verification Matrix
Overview

Establish a uniform element ownership contract for the C iterator runtime protocol: every element yielded by IterState::next() is owned (+1 RC) by the consumer. Consumers dec after use; adapters that discard elements dec before discarding. This eliminates BUG-05-003 (leaked owned elements from map/flat_map adapters) and the broader class of borrow-vs-own ambiguity bugs across all 11 consumer functions, 11 adapter variants, and the AIMS analysis pipeline.

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Planned

6 sections
Section 1 Not Started

Sources: Increment on Yield

Every source iterator's next_* function yields owned (+1 RC) elements

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Section 2 Not Started

Adapters: Decrement on Discard

Adapters that discard elements (filter, skip) call elem_dec_fn; adapters that pass through or produce inherit correct ownership

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Section 3 Not Started

Consumers: Decrement After Use

Every consumer function receives elem_dec_fn and calls it after consuming each element

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Section 4 Not Started

Codegen: Parameter Plumbing

LLVM codegen passes elem_inc_fn and elem_dec_fn to all runtime functions that need them

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Section 5 Not Started

AIMS: Owned Element Contract

AIMS analysis treats iterator-yielded elements as owned, removing borrowed suppression rules

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Section 6 Not Started

Verification Matrix

Full consumer x adapter x type test matrix with leak checking

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