A const array can grow: push/pop/splice on an annotated const - #387
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`const a: number[] = [1, 2]; a.push(3)` failed with "Can't get reference of the array, ensure const array is not used", and so did a const holding an array returned by a call. Only an unannotated array literal (!ts.const_array) was given storage; a const already typed !ts.array<T> stayed a bare SSA value, and push/pop/unshift/splice/length= change the array through a reference to it. A const of array type now gets storage like `let`. Two cases keep what they had: a ConstRef, which already aliases the storage it was read from, and a narrowed view (addSafeCastStatement), which is the narrowed variable seen through another type - giving it storage put a release at function scope for a value defined inside the branch. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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const a: number[] = [1, 2]; a.push(3)failed to compile:The same happened with a const holding an array returned by a call (
const c = make(); c.push(9)). Aconstbinding only forbids reassigning the name, not changing the array, so both should work.Cause: #344 gave storage only to an unannotated array literal (
!ts.const_array<T,N>). A const already typed!ts.array<T>stayed a bare SSA value, and push, pop, unshift, splice andlength =change the array through a reference to it.Fix: a const of array type now gets storage, the same as
let(processConstRef,MLIRGenImpl.h). Two cases are unchanged:ConstRef(an internal flag used by for-of) already aliases the storage it was read from.addSafeCastStatement, whose initializer is aSafeCastOp) is the narrowed variable seen through another type, not a new array. My first version gave it storage too, and that broketypeof u === "array"andif (results)narrowing: the release landed at function scope, outside the branch where the value is defined.Test:
00const_array_push.ts, registered for compile, jit and the corpus. It covers an annotated local, a call result, and a module-level const, using push, pop, unshift, splice andlength =. It fails on main with the error above.Results: the suite passes locally, 3017/3017. The new test also runs clean under
-mm=rc --verify-ownership.Not changed: arrays are value-typed here. After
let b = a; b.push(2),a.lengthis still the old length, and the same holds forconst items = holder.items. That was true before this change, and it's a separate issue.🤖 Generated with Claude Code