From 56ca4d24036195455a2b44b8b04df53f509c14e9 Mon Sep 17 00:00:00 2001
From: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
Date: Tue, 27 Apr 2021 10:23:28 -0400
Subject: [PATCH 1/4] one-array in-place map

---
 base/abstractarray.jl | 22 ++++++++++++++++++++--
 test/abstractarray.jl |  2 +-
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index a5782b99e581c..5a7d8e05b0dbc 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -2452,11 +2452,29 @@ julia> map!(+, zeros(Int, 5), 100:999, 1:3)
 ```
 """
 function map!(f::F, dest::AbstractArray, As::AbstractArray...) where {F}
-    isempty(As) && throw(ArgumentError(
-        """map! requires at least one "source" argument"""))
+    @assert !isempty(As) # should dispatch to map!(f, A)
     map_n!(f, dest, As)
 end
 
+"""
+    map!(function, array)
+
+Like [`map`](@ref), but stores the result in the same array. 
+
+# Examples
+```jldoctest
+julia> a = [1 2 3; 4 5 6];
+
+julia> map!(x -> x^3, a);
+
+julia> a
+2×3 Matrix{$Int}:
+  1    8   27
+ 64  125  216
+```
+"""
+map!(f::F, inout::AbstractArray) where F = map!(f, inout, inout)
+
 map(f) = f()
 map(f, iters...) = collect(Generator(f, iters...))
 
diff --git a/test/abstractarray.jl b/test/abstractarray.jl
index b75869f3ed9d6..a8748da11e759 100644
--- a/test/abstractarray.jl
+++ b/test/abstractarray.jl
@@ -776,7 +776,7 @@ test_ind2sub(TestAbstractArray)
 
 include("generic_map_tests.jl")
 generic_map_tests(map, map!)
-@test_throws ArgumentError map!(-, [1])
+@test map!(-, [1]) == [-1]
 
 test_UInt_indexing(TestAbstractArray)
 test_13315(TestAbstractArray)

From a803cda021d662df5b3121b495fe152a13e6c4ae Mon Sep 17 00:00:00 2001
From: Lilith Orion Hafner <lilithhafner@gmail.com>
Date: Fri, 9 Feb 2024 16:52:09 +0000
Subject: [PATCH 2/4] Fix whitespace

---
 base/abstractarray.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index 6596e3bd426c5..26fb5627437b5 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -3396,7 +3396,7 @@ end
 """
     map!(function, array)
 
-Like [`map`](@ref), but stores the result in the same array. 
+Like [`map`](@ref), but stores the result in the same array.
 
 # Examples
 ```jldoctest

From b7857b62c1012c29f213bde5aae684157e4b87b7 Mon Sep 17 00:00:00 2001
From: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
Date: Fri, 9 Feb 2024 13:34:29 -0500
Subject: [PATCH 3/4] Update NEWS.md

---
 NEWS.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/NEWS.md b/NEWS.md
index 6db22fa1f8be7..46734bd9b5cc3 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -107,6 +107,7 @@ New library features
   automatically.
 * `@timed` now additionally returns the elapsed compilation and recompilation time ([#52889])
 * `filter` can now act on a `NamedTuple` ([#50795]).
+* `map!(f, A)` now stores the results in `A`, like `map!(f, A, A)`. or `A .= f.(A)` ([#40632]).
 
 Standard library changes
 ------------------------

From 5e9c04573867e004ca25d27a0d907358709452df Mon Sep 17 00:00:00 2001
From: Lilith Orion Hafner <lilithhafner@gmail.com>
Date: Tue, 7 Jan 2025 07:27:16 -0600
Subject: [PATCH 4/4] Add compat annotation

Co-authored-by: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
---
 base/abstractarray.jl | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index ba212a86e6762..a370b79976ab0 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -3511,6 +3511,9 @@ end
     map!(function, array)
 
 Like [`map`](@ref), but stores the result in the same array.
+!!! compat "Julia 1.12"
+    This method requires Julia 1.12 or later. To support previous versions too,
+    use the equivalent `map!(function, array, array)`.
 
 # Examples
 ```jldoctest