fix: type checker accepts out-of-range numeric indices on arrays (#77)#98
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fix: type checker accepts out-of-range numeric indices on arrays (#77)#98
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ECMA-262 array indices are integers in [0, 2^32 - 2]. Numeric literals
outside that range — e.g. `a[4294967295]` or `a[-1]` — are spec-equivalent
to ordinary string-keyed property assignments and do not write into an
array element slot. The element-type compatibility check in CheckSetIndex
/ CheckSetIndexOnType incorrectly fired for these, blocking Test262 cases
like `built-ins/Array/15.4.5.1-5-2.js` from ever reaching the runtime.
Gate the element-type throw on a new `IsArrayIndexInRange` helper that
returns false for numeric literals (including unary-minus literals) outside
the valid array-index range. Non-literal indices keep the strict check —
TypeScript-default behavior is preserved for typical code.
Test262 baseline movement: `built-ins/Array/15.4.5.1-5-2.js`
TypeCheckError → RuntimeError in both interpreted and compiled buckets,
matching the issue's stated acceptance ("some to RuntimeError where a
distinct bug is exposed"). The remaining RangeError on assignment to
index 2^32-1 is a runtime-side concern (next-layer sparse array work),
not in scope for this issue.
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ECMA-262 array indices are integers in [0, 2^32 - 2]. Numeric literals outside that range — e.g.
a[4294967295]ora[-1]— are spec-equivalent to ordinary string-keyed property assignments and do not write into an array element slot. The element-type compatibility check in CheckSetIndex / CheckSetIndexOnType incorrectly fired for these, blocking Test262 cases likebuilt-ins/Array/15.4.5.1-5-2.jsfrom ever reaching the runtime.Gate the element-type throw on a new
IsArrayIndexInRangehelper that returns false for numeric literals (including unary-minus literals) outside the valid array-index range. Non-literal indices keep the strict check — TypeScript-default behavior is preserved for typical code.Test262 baseline movement:
built-ins/Array/15.4.5.1-5-2.jsTypeCheckError → RuntimeError in both interpreted and compiled buckets, matching the issue's stated acceptance ("some to RuntimeError where a distinct bug is exposed"). The remaining RangeError on assignment to index 2^32-1 is a runtime-side concern (next-layer sparse array work), not in scope for this issue.