# This is a combination of 2 commits.

# This is the 1st commit message:

Add documentation for `Macro.prewalk/2` (elixir-lang#10951)


# This is the commit message #2:

Bump OTP version and fix CI on Windows (elixir-lang#10952)

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        otp_release: ['OTP-23.0', 'OTP-22.3', 'OTP-22.0']
+        otp_release: ['OTP-23.3', 'OTP-23.0', 'OTP-22.3', 'OTP-22.0']
         development: [false]
         include:
           - otp_release: master
@@ -58,7 +58,7 @@ jobs:
     name: Windows, OTP-${{ matrix.otp_release }}, Windows Server 2019
     strategy:
       matrix:
-        otp_release: ['22.0']
+        otp_release: ['22.3']
     runs-on: windows-2019
     steps:
       - name: Configure Git
@@ -84,7 +84,9 @@ jobs:
       - name: Erlang test suite
         run: make --keep-going test_erlang
       - name: Elixir test suite
-        run: make --keep-going test_elixir
+        run: |
+          del c:/Windows/System32/drivers/etc/hosts
+          make --keep-going test_elixir
 
   check_posix_compliant:
     name: Check POSIX-compliant

lib/elixir/lib/macro.ex

@@ -490,6 +490,23 @@ defmodule Macro do
 
   @doc """
   Performs a depth-first, pre-order traversal of quoted expressions.
+
+  Returns a new ast where each node is the result of invoking `fun` on each
+  corresponding node of `ast`.
+
+  ## Examples
+
+      iex> ast = quote do: 5 + 3 * 7
+      iex> new_ast = Macro.prewalk(ast, fn
+      ...>   {:+, meta, children} -> {:*, meta, children}
+      ...>   {:*, meta, children} -> {:+, meta, children}
+      ...>   other -> other
+      ...> end)
+      iex> Code.eval_quoted(ast)
+      {26, []}
+      iex> Code.eval_quoted(new_ast)
+      {50, []}
+
   """
   @spec prewalk(t, (t -> t)) :: t
   def prewalk(ast, fun) when is_function(fun, 1) do