diff --git a/doc/windows.md b/doc/windows.md
index 4ea03d0507d2b7..dd2ed273ae1f30 100644
--- a/doc/windows.md
+++ b/doc/windows.md
@@ -285,6 +285,7 @@ Any icon files(`*.ico`) in the build directory, directories specified with
 _icondirs_ make variable and `win32` directory under the ruby
 source directory will be included in DLL or executable files, according
 to their base names.
+
     $(RUBY_INSTALL_NAME).ico or ruby.ico   --> $(RUBY_INSTALL_NAME).exe
     $(RUBYW_INSTALL_NAME).ico or rubyw.ico --> $(RUBYW_INSTALL_NAME).exe
     the others                             --> $(RUBY_SO_NAME).dll
diff --git a/hash.c b/hash.c
index 8b1d5fde8b555a..7b523ba23561ef 100644
--- a/hash.c
+++ b/hash.c
@@ -6912,7 +6912,7 @@ static const rb_data_type_t env_data_type = {
  *  A \Hash object maps each of its unique keys to a specific value.
  *
  *  A hash has certain similarities to an Array, but:
-
+ *
  *  - An array index is always an integer.
  *  - A hash key can be (almost) any object.
  *
@@ -7313,7 +7313,7 @@ static const rb_data_type_t env_data_type = {
  *  - #keys: Returns an array containing all keys in +self+.
  *  - #rassoc: Returns a 2-element array consisting of the key and value
  *    of the first-found entry having a given value.
- *  - #values: Returns an array containing all values in +self+/
+ *  - #values: Returns an array containing all values in +self+.
  *  - #values_at: Returns an array containing values for given keys.
  *
  *  ==== Methods for Assigning
@@ -7362,7 +7362,6 @@ static const rb_data_type_t env_data_type = {
  *
  *  ==== Methods for Transforming Keys and Values
  *
- *  - #flatten!: Returns +self+, flattened.
  *  - #invert: Returns a hash with the each key-value pair inverted.
  *  - #transform_keys: Returns a copy of +self+ with modified keys.
  *  - #transform_keys!: Modifies keys in +self+
diff --git a/tool/lib/memory_status.rb b/tool/lib/memory_status.rb
index 60632523a88a17..429e5f6a1d3fa9 100644
--- a/tool/lib/memory_status.rb
+++ b/tool/lib/memory_status.rb
@@ -20,48 +20,68 @@ def self.read_status
     data.scan(pat) {|k, v| keys << k.downcase.intern}
 
   when /mswin|mingw/ =~ RUBY_PLATFORM
-    require 'fiddle/import'
-    require 'fiddle/types'
-
-    module Win32
-      extend Fiddle::Importer
-      dlload "kernel32.dll", "psapi.dll"
-      include Fiddle::Win32Types
-      typealias "SIZE_T", "size_t"
-
-      PROCESS_MEMORY_COUNTERS = struct [
-        "DWORD  cb",
-        "DWORD  PageFaultCount",
-        "SIZE_T PeakWorkingSetSize",
-        "SIZE_T WorkingSetSize",
-        "SIZE_T QuotaPeakPagedPoolUsage",
-        "SIZE_T QuotaPagedPoolUsage",
-        "SIZE_T QuotaPeakNonPagedPoolUsage",
-        "SIZE_T QuotaNonPagedPoolUsage",
-        "SIZE_T PagefileUsage",
-        "SIZE_T PeakPagefileUsage",
-      ]
-
-      typealias "PPROCESS_MEMORY_COUNTERS", "PROCESS_MEMORY_COUNTERS*"
-
-      extern "HANDLE GetCurrentProcess()", :stdcall
-      extern "BOOL GetProcessMemoryInfo(HANDLE, PPROCESS_MEMORY_COUNTERS, DWORD)", :stdcall
-
-      module_function
-      def memory_info
-        size = PROCESS_MEMORY_COUNTERS.size
-        data = PROCESS_MEMORY_COUNTERS.malloc
-        data.cb = size
-        data if GetProcessMemoryInfo(GetCurrentProcess(), data, size)
+    keys.push(:size, :rss, :peak)
+
+    begin
+      require 'fiddle/import'
+      require 'fiddle/types'
+    rescue LoadError
+      # Fallback to PowerShell command to get memory information for current process
+      def self.read_status
+        cmd = [
+          "powershell.exe", "-NoProfile", "-Command",
+          "Get-Process -Id #{$$} | " \
+          "% { Write-Output $_.PagedMemorySize64 $_.WorkingSet64 $_.PeakWorkingSet64 }"
+        ]
+
+        IO.popen(cmd, "r", err: [:child, :out]) do |out|
+          if /^(\d+)\n(\d+)\n(\d+)$/ =~ out.read
+            yield :size, $1.to_i
+            yield :rss, $2.to_i
+            yield :peak, $3.to_i
+          end
+        end
+      end
+    else
+      module Win32
+        extend Fiddle::Importer
+        dlload "kernel32.dll", "psapi.dll"
+        include Fiddle::Win32Types
+        typealias "SIZE_T", "size_t"
+
+        PROCESS_MEMORY_COUNTERS = struct [
+          "DWORD  cb",
+          "DWORD  PageFaultCount",
+          "SIZE_T PeakWorkingSetSize",
+          "SIZE_T WorkingSetSize",
+          "SIZE_T QuotaPeakPagedPoolUsage",
+          "SIZE_T QuotaPagedPoolUsage",
+          "SIZE_T QuotaPeakNonPagedPoolUsage",
+          "SIZE_T QuotaNonPagedPoolUsage",
+          "SIZE_T PagefileUsage",
+          "SIZE_T PeakPagefileUsage",
+        ]
+
+        typealias "PPROCESS_MEMORY_COUNTERS", "PROCESS_MEMORY_COUNTERS*"
+
+        extern "HANDLE GetCurrentProcess()", :stdcall
+        extern "BOOL GetProcessMemoryInfo(HANDLE, PPROCESS_MEMORY_COUNTERS, DWORD)", :stdcall
+
+        module_function
+        def memory_info
+          size = PROCESS_MEMORY_COUNTERS.size
+          data = PROCESS_MEMORY_COUNTERS.malloc
+          data.cb = size
+          data if GetProcessMemoryInfo(GetCurrentProcess(), data, size)
+        end
       end
-    end
 
-    keys.push(:size, :rss, :peak)
-    def self.read_status
-      if info = Win32.memory_info
-        yield :size, info.PagefileUsage
-        yield :rss, info.WorkingSetSize
-        yield :peak, info.PeakWorkingSetSize
+      def self.read_status
+        if info = Win32.memory_info
+          yield :size, info.PagefileUsage
+          yield :rss, info.WorkingSetSize
+          yield :peak, info.PeakWorkingSetSize
+        end
       end
     end
   when (require_relative 'find_executable'