(fix): similar! to preserve view semantics

[mgyoo86]

Summary

similar!(pool, x) always returned a raw Array even when x was a view from acquire_view!. This broke the semantic contract that similar! should preserve the "kind" of its input array.

Bug

aa = acquire_view!(pool, Float64, 10)  # SubArray
bb = similar!(pool, aa)                # Expected: SubArray, Got: Array

All 4 _similar_impl! methods unconditionally called _acquire_impl!, ignoring whether the input was a view.

Fix

Added Array-specific dispatch to _similar_impl! (4 methods -> 8 methods):

• _similar_impl!(pool, x::Array, ...) -> _acquire_impl! (returns Array)
• _similar_impl!(pool, x::AbstractArray, ...) -> _acquire_view_impl! (returns view)

Julia's dispatch guarantees Array (concrete type) is always matched before AbstractArray, so existing behavior for plain arrays is unchanged.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.04%. Comparing base (3118fd0) to head (a452775).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #40   +/-   ##
=======================================
  Coverage   96.03%   96.04%           
=======================================
  Files          14       14           
  Lines        3232     3240    +8     
=======================================
+ Hits         3104     3112    +8     
  Misses        128      128           

Files with missing lines	Coverage Δ
src/convenience.jl	98.76% <100.00%> (+0.06%)	⬆️

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[Copilot]

Pull request overview

This PR fixes similar!(pool, x) so it preserves “view semantics” when the template x is a view returned by acquire_view!, instead of always returning a raw Array.

Changes:

• Split _similar_impl! dispatch to treat x::Array differently from other AbstractArray inputs.
• Route non-Array templates through _acquire_view_impl! so views stay views.
• Add tests covering similar! behavior for 1D/2D views, type changes, and dimension changes.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/convenience.jl	Updates _similar_impl! dispatch to return pooled Array for Array templates and pooled views for non-Array templates.
test/test_convenience.jl	Adds a dedicated testset ensuring similar! preserves view-ness when the input is a view.

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[mgyoo86]

Closing: Base.similar() always returns Array regardless of input type — the original behavior was correct, not a bug. similar\!(pool, view) → Array is consistent with Julia's contract. Users who need a view should use acquire_view\!(pool, eltype(x), size(x)) directly.