docstring setindex (#32738)

* docstring setindex

* add bound check

* fix selectdim implementation

base/abstractarraymath.jl

@@ -119,7 +119,7 @@ julia> selectdim(A, 2, 3)
  7
 ```
 """
-@inline selectdim(A::AbstractArray, d::Integer, i) = _selectdim(A, d, i, setindex(map(Slice, axes(A)), i, d))
+@inline selectdim(A::AbstractArray, d::Integer, i) = _selectdim(A, d, i, _setindex(i, d, map(Slice, axes(A))...))
 @noinline function _selectdim(A, d, i, idxs)
     d >= 1 || throw(ArgumentError("dimension must be ≥ 1, got $d"))
     nd = ndims(A)

base/tuple.jl

@@ -28,7 +28,25 @@ getindex(t::Tuple, b::AbstractArray{Bool,1}) = length(b) == length(t) ? getindex
 getindex(t::Tuple, c::Colon) = t
 
 # returns new tuple; N.B.: becomes no-op if i is out-of-bounds
-setindex(x::Tuple, v, i::Integer) = (@_inline_meta; _setindex(v, i, x...))
+
+"""
+    setindex(c::Tuple, v, i::Integer)
+
+Creates a new tuple similar to `x` with the value at index `i` set to `v`.
+Throws a `BoundsError` when out of bounds.
+
+# Examples
+```jldoctest
+julia> Base.setindex((1, 2, 6), 2, 3) == (1, 2, 2)
+true
+```
+"""
+function setindex(x::Tuple, v, i::Integer)
+    @boundscheck 1 <= i <= length(x) || throw(BoundsError(x, i))
+    @_inline_meta
+    _setindex(v, i, x...)
+end
+
 function _setindex(v, i::Integer, first, tail...)
     @_inline_meta
     return (ifelse(i == 1, v, first), _setindex(v, i - 1, tail...)...)