Add type-stable getindex for vec[end, col] pattern

- Add specialized getindex method for (RaggedEnd, Int) to handle vec[end, col]
- Fix test to use lastindex(vec, 1) for row index instead of lastindex(vec)
- Fix typo in test assertion (misplaced parenthesis)

Addresses review feedback from JoshuaLampert.

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: claude

src/vector_of_array.jl

@@ -580,6 +580,21 @@ Base.@propagate_inbounds function Base.getindex(
     end
 end
 
+# Specialized method for type stability when first index is RaggedEnd (row dimension)
+# This handles the common case: vec[end, col] where end -> RaggedEnd(1, 0)
+Base.@propagate_inbounds function Base.getindex(
+        A::AbstractVectorOfArray, re::RaggedEnd, col::Int
+    )
+    if re.dim == 0
+        # Sentinel case: RaggedEnd(0, offset) means offset is a plain index
+        return A.u[col][re.offset]
+    else
+        # Non-sentinel case: resolve the ragged index for the given column
+        resolved_idx = lastindex(A.u[col], re.dim) + re.offset
+        return A.u[col][resolved_idx]
+    end
+end
+
 @inline function _is_ragged_dim(VA::AbstractVectorOfArray, d::Integer)
     length(VA.u) <= 1 && return false
     first_size = size(VA.u[1], d)

test/interface_tests.jl

@@ -75,9 +75,9 @@ last_col = lastindex(testva_end, 2)
 last_col = lastindex(testva_end)
 @inferred testva_end[1, last_col]
 @test testva_end[1, last_col] == 2.0
-last_row = lastindex(testva_end)
+last_row = lastindex(testva_end, 1)
 @inferred testva_end[last_row, 1]
-@test testva_end[last_row, 1 == 2.0]
+@test testva_end[last_row, 1] == 2.0
 
 # mapreduce
 testva = VectorOfArray([[1, 2, 3], [4, 5, 6], [7, 8, 9]])