Make copymutable public and add clarification to some docstrings

base/abstractarray.jl

@@ -1198,10 +1198,12 @@ end
 """
     copymutable(a)
 
-Make a mutable copy of an array or iterable `a`.  For `a::Array`,
-this is equivalent to `copy(a)`, but for other array types it may
-differ depending on the type of `similar(a)`.  For generic iterables
-this is equivalent to `collect(a)`.
+Make a mutable copy of an array or iterable `a`. The result should have the same content as
+`a`, but support mutation. For `Array`s and most iterables this is equivalent to
+`collect(a)`, but for other array types it may differ depending on the type of `similar(a)`.
+
+To change the behavior of `copymutable` on a custom collection, define [`similar`](@ref)
+for that collection.
 
 # Examples
 ```jldoctest
@@ -1213,6 +1215,20 @@ julia> Base.copymutable(tup)
  1
  2
  3
+
+julia> using StaticArrays
+
+julia> s = SVector{3}(1,2,3)
+3-element SVector{3, Int64} with indices SOneTo(3):
+ 1
+ 2
+ 3
+
+julia> Base.copymutable(s)
+3-element MVector{3, Int64} with indices SOneTo(3):
+ 1
+ 2
+ 3
 ```
 """
 function copymutable(a::AbstractArray)

base/exports.jl

@@ -1114,6 +1114,7 @@ public
     split_rest,
     tail,
     checked_length,
+    copymutable,
 
 # Loading
     DL_LOAD_PATH,

base/sort.jl

@@ -1475,7 +1475,8 @@ end
 Variant of [`sort!`](@ref) that returns a sorted copy of `v` leaving `v` itself unmodified.
 
 Returns something [`similar`](@ref) to `v` when `v` is an `AbstractArray` and uses
-[`collect`](@ref) to support arbitrary non-`AbstractArray` iterables.
+[`collect`](@ref) to support arbitrary non-`AbstractArray` iterables. some types have
+specialized versions of `sort`, such as `NTuples` (`sort(::NTuple)` returns an `NTuple`)
 
 !!! compat "Julia 1.10"
     `sort` of arbitrary iterables requires at least Julia 1.10.

doc/src/base/collections.md

@@ -137,6 +137,7 @@ Base.tail
 Base.step
 Base.collect(::Any)
 Base.collect(::Type, ::Any)
+Base.copymutable(::Any)
 Base.filter
 Base.filter!
 Base.replace(::Any, ::Pair...)