moonbitlang / core / 3132

96%

Build Type

push

github

Committed by bobzhang

Commit Message

fix(immut/array): add bounds checking to at() and set()

T::at (the [] operator) and T::set had no bounds checking.
Out-of-bounds indices were silently mapped to valid positions via
bitmask wrapping in the radix tree, causing reads/writes to the
wrong element instead of panicking.

For example:
- makei(32, i => i)[-1] returned 31 instead of panicking
- makei(1024, i => i)[1024] returned 0 instead of panicking
- makei(32, i => i).set(-1, 999) silently overwrote slot 31

Add guard checks that panic on negative or >= size indices.
Add panic tests for at() with negative, out-of-bounds, and empty
array cases.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Run Details

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1 existing line in 1 file now uncovered.

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