diff --git a/.github/actions/setup/directories/action.yml b/.github/actions/setup/directories/action.yml
index c0fc75ad7d9b2f..f93733a919066c 100644
--- a/.github/actions/setup/directories/action.yml
+++ b/.github/actions/setup/directories/action.yml
@@ -88,7 +88,7 @@ runs:
         git config --global init.defaultBranch garbage
 
     - if: inputs.checkout
-      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
       with:
         path: ${{ inputs.srcdir }}
         fetch-depth: ${{ inputs.fetch-depth }}
diff --git a/configure.ac b/configure.ac
index 339ee3b2f2e66e..55d65534db9ee6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -526,6 +526,7 @@ AS_CASE(["$target_os"],
 	RT_VER=`echo "$rb_cv_msvcrt" | tr -cd [0-9]`
 	test "$RT_VER" = "" && RT_VER=60
 	test "$rb_cv_msvcrt" = "ucrt" && RT_VER=140
+	AS_IF([test $RT_VER -lt 120], AC_MSG_ERROR(Runtime library $RT_VER is not supported))
 	AC_DEFINE_UNQUOTED(RUBY_MSVCRT_VERSION, $RT_VER)
 	sysconfdir=
     ])
diff --git a/debug.c b/debug.c
index 4717a0bc9c5e90..b92faa8f369398 100644
--- a/debug.c
+++ b/debug.c
@@ -168,9 +168,7 @@ ruby_debug_breakpoint(void)
 }
 
 #if defined _WIN32
-# if RUBY_MSVCRT_VERSION >= 80
 extern int ruby_w32_rtc_error;
-# endif
 #endif
 #if defined _WIN32 || defined __CYGWIN__
 #include <windows.h>
@@ -233,9 +231,7 @@ ruby_env_debug_option(const char *str, int len, void *arg)
     SET_WHEN("ci", ruby_on_ci, 1);
     SET_WHEN_UINT("rgengc", &ruby_rgengc_debug, 1, ruby_rgengc_debug = 1);
 #if defined _WIN32
-# if RUBY_MSVCRT_VERSION >= 80
     SET_WHEN("rtc_error", ruby_w32_rtc_error, 1);
-# endif
 #endif
 #if defined _WIN32 || defined __CYGWIN__
     SET_WHEN_UINT("codepage", ruby_w32_codepage, numberof(ruby_w32_codepage),
diff --git a/doc/string.rb b/doc/string.rb
index 4304b96aee7f9a..b37cb5d324ec95 100644
--- a/doc/string.rb
+++ b/doc/string.rb
@@ -322,8 +322,7 @@
 # _Substitution_
 #
 # - #dump: Returns a printable version of +self+, enclosed in double-quotes.
-# - #undump: Returns a copy of +self+ with all <tt>\xNN</tt> notations replaced by <tt>\uNNNN</tt> notations
-#   and all escaped characters unescaped.
+# - #undump: Inverse of #dump; returns a copy of +self+ with changes of the kinds made by #dump "undone."
 # - #sub: Returns a copy of +self+ with the first substring matching a given pattern
 #   replaced with a given replacement string.
 # - #gsub: Returns a copy of +self+ with each substring that matches a given pattern
diff --git a/doc/string/dump.rdoc b/doc/string/dump.rdoc
index a5ab0bb42f2464..2ab9521540dcda 100644
--- a/doc/string/dump.rdoc
+++ b/doc/string/dump.rdoc
@@ -1,52 +1,97 @@
-Returns a printable version of +self+, enclosed in double-quotes:
+For an ordinary string, this method, +String#dump+,
+returns a printable ASCII-only version of +self+, enclosed in double-quotes.
 
-  'hello'.dump     # => "\"hello\""
+For a dumped string, method String#undump is the inverse of +String#dump+;
+it returns a "restored" version of +self+,
+where all the dumping changes have been undone.
 
-Certain special characters are rendered with escapes:
+In the simplest case, the dumped string contains the original string,
+enclosed in double-quotes;
+this example is done in +irb+ (interactive Ruby), which uses method `inspect` to render the results:
 
-  '"'.dump  # => "\"\\\"\""
-  '\\'.dump # => "\"\\\\\""
+  s = 'hello'   # => "hello"
+  s.dump        # => "\"hello\""
+  s.dump.undump # => "hello"
 
-Non-printing characters are rendered with escapes:
+Keep in mind that in the second line above:
+
+- The outer double-quotes are put on by +inspect+,
+  and _are_ _not_ part of the output of #dump.
+- The inner double-quotes _are_ part of the output of +dump+,
+  and are escaped by +inspect+ because they are within the outer double-quotes.
+
+To avoid confusion, we'll use this helper method to omit the outer double-quotes:
+
+  def dump(s)
+    print "String:   ", s, "\n"
+    print "Dumped:   ", s.dump, "\n"
+    print "Undumped: ", s.dump.undump, "\n"
+  end
+
+So that for string <tt>'hello'</tt>, we'll see:
+
+  String:    hello
+  Dumped:    "hello"
+  Undumped:  hello
+
+In a dump, certain special characters are escaped:
+
+  String:    "
+  Dumped:    "\""
+  Undumped:  "
+
+  String:    \
+  Dumped:    "\\"
+  Undumped:  \
+
+In a dump, unprintable characters are replaced by printable ones;
+the unprintable characters are the whitespace characters (other than space itself);
+here we see the ordinals for those characers, together with explanatory text:
+
+  h = {
+     7 => 'Alert (BEL)',
+     8 => 'Backspace (BS)',
+     9 => 'Horizontal tab (HT)',
+    10 => 'Linefeed (LF)',
+    11 => 'Vertical tab (VT)',
+    12 => 'Formfeed (FF)',
+    13 => 'Carriage return (CR)'
+  }
+
+In this example, the dumped output is printed by method #inspect,
+and so contains both outer double-quotes and escaped inner double-quotes:
 
   s = ''
-  s << 7   # Alarm (bell).
-  s << 8   # Back space.
-  s << 9   # Horizontal tab.
-  s << 10  # Line feed.
-  s << 11  # Vertical tab.
-  s << 12  # Form feed.
-  s << 13  # Carriage return.
-  s        # => "\a\b\t\n\v\f\r"
-  s.dump   # => "\"\\a\\b\\t\\n\\v\\f\\r\""
-
-If +self+ is encoded in UTF-8 and contains Unicode characters, renders Unicode
-characters in Unicode escape sequence:
-
-  'тест'.dump     # => "\"\\u0442\\u0435\\u0441\\u0442\""
-  'こんにちは'.dump # => "\"\\u3053\\u3093\\u306B\\u3061\\u306F\""
-
-If the encoding of +self+ is not ASCII-compatible (i.e., +self.encoding.ascii_compatible?+
-returns +false+), renders all ASCII-compatible bytes as ASCII characters and all
-other bytes as hexadecimal. Appends <tt>.dup.force_encoding(\"encoding\")</tt>, where
-<tt><encoding></tt> is +self.encoding.name+:
-
-  s = 'hello'
-  s.encoding                # => #<Encoding:UTF-8>
-  s.dump                    # => "\"hello\""
-  s.encode('utf-16').dump   # => "\"\\xFE\\xFF\\x00h\\x00e\\x00l\\x00l\\x00o\".dup.force_encoding(\"UTF-16\")"
-  s.encode('utf-16le').dump # => "\"h\\x00e\\x00l\\x00l\\x00o\\x00\".dup.force_encoding(\"UTF-16LE\")"
-
-  s = 'тест'
-  s.encoding                # => #<Encoding:UTF-8>
-  s.dump                    # => "\"\\u0442\\u0435\\u0441\\u0442\""
-  s.encode('utf-16').dump   # => "\"\\xFE\\xFF\\x04B\\x045\\x04A\\x04B\".dup.force_encoding(\"UTF-16\")"
-  s.encode('utf-16le').dump # => "\"B\\x045\\x04A\\x04B\\x04\".dup.force_encoding(\"UTF-16LE\")"
-
-  s = 'こんにちは'
-  s.encoding                # => #<Encoding:UTF-8>
-  s.dump                    # => "\"\\u3053\\u3093\\u306B\\u3061\\u306F\""
-  s.encode('utf-16').dump   # => "\"\\xFE\\xFF0S0\\x930k0a0o\".dup.force_encoding(\"UTF-16\")"
-  s.encode('utf-16le').dump # => "\"S0\\x930k0a0o0\".dup.force_encoding(\"UTF-16LE\")"
-
-Related: see {Converting to New String}[rdoc-ref:String@Converting+to+New+String].
+  h.keys.each {|i| s << i } # => [7, 8, 9, 10, 11, 12, 13]
+  s                         # => "\a\b\t\n\v\f\r"
+  s.dump                    # => "\"\\a\\b\\t\\n\\v\\f\\r\""
+
+If +self+ is encoded in UTF-8 and contains Unicode characters,
+each Unicode character is dumped as a Unicode escape sequence:
+
+  String:    тест
+  Dumped:    "\u0442\u0435\u0441\u0442"
+  Undumped:  тест
+
+  String:    こんにちは
+  Dumped:    "\u3053\u3093\u306B\u3061\u306F"
+  Undumped:  こんにちは
+
+If the encoding of +self+ is not ASCII-compatible
+(i.e., if <tt>self.encoding.ascii_compatible?</tt> returns +false+),
+each ASCII-compatible byte is dumped as an ASCII character,
+and all other bytes are dumped as hexadecimal;
+also appends <tt>.dup.force_encoding(\"encoding\")</tt>,
+where <tt><encoding></tt> is <tt>self.encoding.name</tt>:
+
+  String:    hello
+  Dumped:    "\xFE\xFF\x00h\x00e\x00l\x00l\x00o".dup.force_encoding("UTF-16")
+  Undumped:  hello
+
+  String:    тест
+  Dumped:    "\xFE\xFF\x04B\x045\x04A\x04B".dup.force_encoding("UTF-16")
+  Undumped:  тест
+
+  String:    こんにちは
+  Dumped:    "\xFE\xFF0S0\x930k0a0o".dup.force_encoding("UTF-16")
+  Undumped:  こんにちは
diff --git a/doc/string/unicode_normalize.rdoc b/doc/string/unicode_normalize.rdoc
new file mode 100644
index 00000000000000..5f733c0fb84f58
--- /dev/null
+++ b/doc/string/unicode_normalize.rdoc
@@ -0,0 +1,28 @@
+Returns a copy of +self+ with
+{Unicode normalization}[https://unicode.org/reports/tr15] applied.
+
+Argument +form+ must be one of the following symbols
+(see {Unicode normalization forms}[https://unicode.org/reports/tr15/#Norm_Forms]):
+
+- +:nfc+: Canonical decomposition, followed by canonical composition.
+- +:nfd+: Canonical decomposition.
+- +:nfkc+: Compatibility decomposition, followed by canonical composition.
+- +:nfkd+: Compatibility decomposition.
+
+The encoding of +self+ must be one of:
+
+- <tt>Encoding::UTF_8</tt>.
+- <tt>Encoding::UTF_16BE</tt>.
+- <tt>Encoding::UTF_16LE</tt>.
+- <tt>Encoding::UTF_32BE</tt>.
+- <tt>Encoding::UTF_32LE</tt>.
+- <tt>Encoding::GB18030</tt>.
+- <tt>Encoding::UCS_2BE</tt>.
+- <tt>Encoding::UCS_4BE</tt>.
+
+Examples:
+
+  "a\u0300".unicode_normalize       # => "à"  # Lowercase 'a' with grave accens.
+  "a\u0300".unicode_normalize(:nfd) # => "à"  # Same.
+
+Related: see {Converting to New String}[rdoc-ref:String@Converting+to+New+String].
diff --git a/error.c b/error.c
index abf50b696aefa6..f452f7b01cf23b 100644
--- a/error.c
+++ b/error.c
@@ -1076,7 +1076,7 @@ NORETURN(static void die(void));
 static void
 die(void)
 {
-#if defined(_WIN32) && defined(RUBY_MSVCRT_VERSION) && RUBY_MSVCRT_VERSION >= 80
+#if defined(_WIN32)
     _set_abort_behavior( 0, _CALL_REPORTFAULT);
 #endif
 
diff --git a/ext/etc/etc.c b/ext/etc/etc.c
index 66ef8fc9a4f3d0..8d50a96a621035 100644
--- a/ext/etc/etc.c
+++ b/ext/etc/etc.c
@@ -832,11 +832,7 @@ etc_uname(VALUE obj)
 			 rb_w32_conv_from_wchar(v.szCSDVersion, rb_utf8_encoding()));
     rb_hash_aset(result, SYMBOL_LIT("version"), version);
 
-# if defined _MSC_VER && _MSC_VER < 1300
-#   define GET_COMPUTER_NAME(ptr, plen) GetComputerNameW(ptr, plen)
-# else
 #   define GET_COMPUTER_NAME(ptr, plen) GetComputerNameExW(ComputerNameDnsFullyQualified, ptr, plen)
-# endif
     GET_COMPUTER_NAME(NULL, &len);
     buf = ALLOCV_N(WCHAR, vbuf, len);
     if (GET_COMPUTER_NAME(buf, &len)) {
diff --git a/ext/etc/etc.gemspec b/ext/etc/etc.gemspec
index 3facc7486669a9..0e9803dc624cb1 100644
--- a/ext/etc/etc.gemspec
+++ b/ext/etc/etc.gemspec
@@ -40,5 +40,5 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
   spec.extensions    = %w{ext/etc/extconf.rb}
 
-  spec.required_ruby_version = ">= 2.6.0"
+  spec.required_ruby_version = ">= 2.7.0"
 end
diff --git a/ext/socket/getaddrinfo.c b/ext/socket/getaddrinfo.c
index 5b824996552e5f..9a65490b1d662d 100644
--- a/ext/socket/getaddrinfo.c
+++ b/ext/socket/getaddrinfo.c
@@ -62,9 +62,6 @@
 #endif
 #include <unistd.h>
 #else
-#if defined(_MSC_VER) && _MSC_VER <= 1200
-#include <windows.h>
-#endif
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #include <io.h>
diff --git a/ext/socket/getnameinfo.c b/ext/socket/getnameinfo.c
index ffda7f98c73f6d..98da8c1647afb9 100644
--- a/ext/socket/getnameinfo.c
+++ b/ext/socket/getnameinfo.c
@@ -55,9 +55,6 @@
 #endif
 #endif
 #ifdef _WIN32
-#if defined(_MSC_VER) && _MSC_VER <= 1200
-#include <windows.h>
-#endif
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #define snprintf _snprintf
diff --git a/ext/socket/rubysocket.h b/ext/socket/rubysocket.h
index 29b8afc1634b80..1adccee4276da0 100644
--- a/ext/socket/rubysocket.h
+++ b/ext/socket/rubysocket.h
@@ -510,8 +510,6 @@ extern ID tcp_fast_fallback;
 const char *inet_ntop(int, const void *, char *, size_t);
 #elif defined __MINGW32__
 # define inet_ntop(f,a,n,l)      rb_w32_inet_ntop(f,a,n,l)
-#elif defined _MSC_VER && RUBY_MSVCRT_VERSION < 90
-const char *WSAAPI inet_ntop(int, const void *, char *, size_t);
 #endif
 
 #endif
diff --git a/gc.c b/gc.c
index 74502dc21b74a5..c9fa18f42b8e8e 100644
--- a/gc.c
+++ b/gc.c
@@ -3332,7 +3332,13 @@ rb_gc_obj_optimal_size(VALUE obj)
             return sizeof(struct RObject);
         }
         else {
-            return rb_obj_embedded_size(ROBJECT_FIELDS_CAPACITY(obj));
+            size_t size = rb_obj_embedded_size(ROBJECT_FIELDS_CAPACITY(obj));
+            if (rb_gc_size_allocatable_p(size)) {
+                return size;
+            }
+            else {
+                return sizeof(struct RObject);
+            }
         }
 
       case T_STRING:
diff --git a/gc/mmtk/mmtk.c b/gc/mmtk/mmtk.c
index 0d78d61b7fb4b6..e1678dcf6ab0b4 100644
--- a/gc/mmtk/mmtk.c
+++ b/gc/mmtk/mmtk.c
@@ -32,6 +32,7 @@ struct objspace {
     unsigned long live_ractor_cache_count;
 
     pthread_mutex_t mutex;
+    rb_atomic_t mutator_blocking_count;
     bool world_stopped;
     pthread_cond_t cond_world_stopped;
     pthread_cond_t cond_world_started;
@@ -131,7 +132,9 @@ rb_mmtk_block_for_gc(MMTk_VMMutatorThread mutator)
     struct objspace *objspace = rb_gc_get_objspace();
 
     size_t starting_gc_count = objspace->gc_count;
+    RUBY_ATOMIC_INC(objspace->mutator_blocking_count);
     int lock_lev = RB_GC_VM_LOCK();
+    RUBY_ATOMIC_DEC(objspace->mutator_blocking_count);
     int err;
     if ((err = pthread_mutex_lock(&objspace->mutex)) != 0) {
         rb_bug("ERROR: cannot lock objspace->mutex: %s", strerror(err));
@@ -1049,7 +1052,25 @@ rb_gc_impl_before_fork(void *objspace_ptr)
 {
     struct objspace *objspace = objspace_ptr;
 
+  retry:
     objspace->fork_hook_vm_lock_lev = RB_GC_VM_LOCK();
+    rb_gc_vm_barrier();
+
+    /* At this point, we know that all the Ractors are paused because of the
+     * rb_gc_vm_barrier above. Since rb_mmtk_block_for_gc is a barrier point,
+     * one or more Ractors could be paused there. However, mmtk_before_fork is
+     * not compatible with that because it assumes that the MMTk workers are idle,
+     * but the workers are not idle because they are busy working on a GC.
+     *
+     * This essentially implements a trylock. It will optimistically lock but will
+     * release the lock if it detects that any other Ractors are waiting in
+     * rb_mmtk_block_for_gc.
+     */
+    rb_atomic_t mutator_blocking_count = RUBY_ATOMIC_LOAD(objspace->mutator_blocking_count);
+    if (mutator_blocking_count != 0) {
+        RB_GC_VM_UNLOCK(objspace->fork_hook_vm_lock_lev);
+        goto retry;
+    }
 
     mmtk_before_fork();
 }
diff --git a/include/ruby/internal/compiler_is/msvc.h b/include/ruby/internal/compiler_is/msvc.h
index 8a864ea558a53f..824f0ecc21e83a 100644
--- a/include/ruby/internal/compiler_is/msvc.h
+++ b/include/ruby/internal/compiler_is/msvc.h
@@ -38,19 +38,8 @@
 # define RBIMPL_COMPILER_VERSION_MINOR (_MSC_FULL_VER % 10000000 / 100000)
 # define RBIMPL_COMPILER_VERSION_PATCH (_MSC_FULL_VER            % 100000)
 
-#elif defined(_MSC_FULL_VER)
-# define RBIMPL_COMPILER_IS_MSVC 1
-# /* _MSC_FULL_VER = XXYYZZZZ */
-# define RBIMPL_COMPILER_VERSION_MAJOR (_MSC_FULL_VER / 1000000)
-# define RBIMPL_COMPILER_VERSION_MINOR (_MSC_FULL_VER % 1000000 / 10000)
-# define RBIMPL_COMPILER_VERSION_PATCH (_MSC_FULL_VER           % 10000)
-
 #else
-# define RBIMPL_COMPILER_IS_MSVC 1
-# /* _MSC_VER = XXYY */
-# define RBIMPL_COMPILER_VERSION_MAJOR (_MSC_VER / 100)
-# define RBIMPL_COMPILER_VERSION_MINOR (_MSC_VER % 100)
-# define RBIMPL_COMPILER_VERSION_PATCH 0
+# error Unsupported MSVC version
 #endif
 
 #endif /* RBIMPL_COMPILER_IS_MSVC_H */
diff --git a/include/ruby/win32.h b/include/ruby/win32.h
index 69e92ed9ffa1ba..8d9f9ddd80be6b 100644
--- a/include/ruby/win32.h
+++ b/include/ruby/win32.h
@@ -30,15 +30,10 @@ extern "C++" {			/* template without extern "C++" */
 #if !defined(_WIN64) && !defined(WIN32)
 #define WIN32
 #endif
-#if defined(_MSC_VER) && _MSC_VER <= 1200
-#include <windows.h>
-#endif
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #include <mswsock.h>
-#if !defined(_MSC_VER) || _MSC_VER >= 1400
 #include <iphlpapi.h>
-#endif
 #if defined(__cplusplus) && defined(_MSC_VER)
 }
 #endif
@@ -59,13 +54,7 @@ extern "C++" {			/* template without extern "C++" */
 #include <direct.h>
 #include <process.h>
 #include <time.h>
-#if defined(__cplusplus) && defined(_MSC_VER) && _MSC_VER == 1200
-extern "C++" {			/* template without extern "C++" */
-#endif
 #include <math.h>
-#if defined(__cplusplus) && defined(_MSC_VER) && _MSC_VER == 1200
-}
-#endif
 #include <signal.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -353,7 +342,7 @@ extern int rb_w32_dup2(int, int);
 
 #include <float.h>
 
-#if defined _MSC_VER && _MSC_VER >= 1800 && defined INFINITY
+#if defined _MSC_VER && defined INFINITY
 #pragma warning(push)
 #pragma warning(disable:4756)
 static inline float
@@ -436,11 +425,6 @@ extern int rb_w32_utruncate(const char *path, rb_off_t length);
 #define HAVE_TRUNCATE 1
 #define truncate rb_w32_utruncate
 
-#if defined(_MSC_VER) && _MSC_VER >= 1400 && _MSC_VER < 1800
-#define strtoll  _strtoi64
-#define strtoull _strtoui64
-#endif
-
 /*
  * stubs
  */
diff --git a/internal/bits.h b/internal/bits.h
index 2b5aecf1128a72..bbd59ffaca5cbc 100644
--- a/internal/bits.h
+++ b/internal/bits.h
@@ -30,13 +30,13 @@
 #include <stdint.h>             /* for uintptr_t */
 #include "internal/compilers.h" /* for MSC_VERSION_SINCE */
 
-#if MSC_VERSION_SINCE(1310)
+#ifdef _MSC_VER
 # include <stdlib.h>            /* for _byteswap_uint64 */
 #endif
 
 #if defined(HAVE_X86INTRIN_H)
 # include <x86intrin.h>         /* for _lzcnt_u64 */
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
 # include <intrin.h>            /* for the following intrinsics */
 #endif
 
@@ -50,16 +50,13 @@
 # pragma intrinsic(__lzcnt64)
 #endif
 
-#if MSC_VERSION_SINCE(1310)
+#if defined(_MSC_VER)
 # pragma intrinsic(_rotl)
 # pragma intrinsic(_rotr)
 # ifdef _WIN64
 #  pragma intrinsic(_rotl64)
 #  pragma intrinsic(_rotr64)
 # endif
-#endif
-
-#if MSC_VERSION_SINCE(1400)
 # pragma intrinsic(_BitScanForward)
 # pragma intrinsic(_BitScanReverse)
 # ifdef _WIN64
@@ -266,7 +263,7 @@ ruby_swap16(uint16_t x)
 #if __has_builtin(__builtin_bswap16)
     return __builtin_bswap16(x);
 
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
     return _byteswap_ushort(x);
 
 #else
@@ -281,7 +278,7 @@ ruby_swap32(uint32_t x)
 #if __has_builtin(__builtin_bswap32)
     return __builtin_bswap32(x);
 
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
     return _byteswap_ulong(x);
 
 #else
@@ -298,7 +295,7 @@ ruby_swap64(uint64_t x)
 #if __has_builtin(__builtin_bswap64)
     return __builtin_bswap64(x);
 
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
     return _byteswap_uint64(x);
 
 #else
@@ -323,7 +320,7 @@ nlz_int32(uint32_t x)
 #elif defined(__x86_64__) && defined(__LZCNT__)
     return (unsigned int)_lzcnt_u32(x);
 
-#elif MSC_VERSION_SINCE(1400) /* &&! defined(__AVX2__) */
+#elif defined(_MSC_VER) /* &&! defined(__AVX2__) */
     unsigned long r;
     return _BitScanReverse(&r, x) ? (31 - (int)r) : 32;
 
@@ -352,7 +349,7 @@ nlz_int64(uint64_t x)
 #elif defined(__x86_64__) && defined(__LZCNT__)
     return (unsigned int)_lzcnt_u64(x);
 
-#elif defined(_WIN64) && MSC_VERSION_SINCE(1400) /* &&! defined(__AVX2__) */
+#elif defined(_WIN64) && defined(_MSC_VER) /* &&! defined(__AVX2__) */
     unsigned long r;
     return _BitScanReverse64(&r, x) ? (63u - (unsigned int)r) : 64;
 
@@ -538,7 +535,7 @@ ntz_int32(uint32_t x)
 #if defined(__x86_64__) && defined(__BMI__)
     return (unsigned)_tzcnt_u32(x);
 
-#elif MSC_VERSION_SINCE(1400)
+#elif defined(_MSC_VER)
     /* :FIXME: Is there any way to issue TZCNT instead of BSF, apart from using
      *         assembly?  Because issuing LZCNT seems possible (see nlz.h). */
     unsigned long r;
@@ -559,8 +556,8 @@ ntz_int64(uint64_t x)
 {
 #if defined(__x86_64__) && defined(__BMI__)
     return (unsigned)_tzcnt_u64(x);
-
-#elif defined(_WIN64) && MSC_VERSION_SINCE(1400)
+`
+#elif defined(_WIN64) && defined(_MSC_VER)
     unsigned long r;
     return _BitScanForward64(&r, x) ? (int)r : 64;
 
@@ -608,10 +605,10 @@ RUBY_BIT_ROTL(VALUE v, int n)
 #elif __has_builtin(__builtin_rotateleft64) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return __builtin_rotateleft64(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 32)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 32)
     return _rotl(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 64)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return _rotl64(v, n);
 
 #elif defined(_lrotl) && (SIZEOF_VALUE == SIZEOF_LONG)
@@ -632,10 +629,10 @@ RUBY_BIT_ROTR(VALUE v, int n)
 #elif __has_builtin(__builtin_rotateright64) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return __builtin_rotateright64(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 32)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 32)
     return _rotr(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 64)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return _rotr64(v, n);
 
 #elif defined(_lrotr) && (SIZEOF_VALUE == SIZEOF_LONG)
diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index 86b86b359fcf82..79f93a7784734c 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -107,7 +107,22 @@ def cli_help
       shell.say
       self.class.send(:class_options_help, shell)
     end
-    default_task(Bundler.settings[:default_cli_command])
+
+    def self.default_command(meth = nil)
+      return super if meth
+
+      default_cli_command = Bundler.settings[:default_cli_command]
+      return default_cli_command if default_cli_command
+
+      Bundler.ui.warn(<<~MSG)
+        In the next version of Bundler, running `bundle` without argument will no longer run `bundle install`.
+        Instead, the `help` command will be displayed.
+
+        If you'd like to keep the previous behaviour please run `bundle config set default_cli_command install --global`.
+      MSG
+
+      "install"
+    end
 
     class_option "no-color", type: :boolean, desc: "Disable colorization in output"
     class_option "retry", type: :numeric, aliases: "-r", banner: "NUM",
diff --git a/lib/bundler/self_manager.rb b/lib/bundler/self_manager.rb
index 7db6c9f6f1cd9e..1db77fd46b3fef 100644
--- a/lib/bundler/self_manager.rb
+++ b/lib/bundler/self_manager.rb
@@ -97,7 +97,7 @@ def needs_switching?(restart_version)
     end
 
     def autoswitching_applies?
-      ENV["BUNDLER_VERSION"].nil? &&
+      (ENV["BUNDLER_VERSION"].nil? || ENV["BUNDLER_VERSION"].empty?) &&
         ruby_can_restart_with_same_arguments? &&
         lockfile_version
     end
diff --git a/lib/bundler/settings.rb b/lib/bundler/settings.rb
index 81f1857eec7648..fb1b875b264500 100644
--- a/lib/bundler/settings.rb
+++ b/lib/bundler/settings.rb
@@ -83,7 +83,6 @@ class Settings
       "BUNDLE_VERSION" => "lockfile",
       "BUNDLE_LOCKFILE_CHECKSUMS" => true,
       "BUNDLE_CACHE_ALL" => true,
-      "BUNDLE_DEFAULT_CLI_COMMAND" => "cli_help",
       "BUNDLE_PLUGINS" => true,
       "BUNDLE_GLOBAL_GEM_CACHE" => false,
       "BUNDLE_UPDATE_REQUIRES_ALL_FLAG" => false,
diff --git a/lib/rubygems/bundler_version_finder.rb b/lib/rubygems/bundler_version_finder.rb
index 4ebbad1c0cfa33..ac8988dea577bb 100644
--- a/lib/rubygems/bundler_version_finder.rb
+++ b/lib/rubygems/bundler_version_finder.rb
@@ -3,6 +3,7 @@
 module Gem::BundlerVersionFinder
   def self.bundler_version
     v = ENV["BUNDLER_VERSION"]
+    v = nil if v&.empty?
 
     v ||= bundle_update_bundler_version
     return if v == true
diff --git a/numeric.c b/numeric.c
index 731a8095239107..3d6648f7d6fbd7 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1591,17 +1591,11 @@ rb_float_equal(VALUE x, VALUE y)
     }
     else if (RB_FLOAT_TYPE_P(y)) {
         b = RFLOAT_VALUE(y);
-#if MSC_VERSION_BEFORE(1300)
-        if (isnan(b)) return Qfalse;
-#endif
     }
     else {
         return num_equal(x, y);
     }
     a = RFLOAT_VALUE(x);
-#if MSC_VERSION_BEFORE(1300)
-    if (isnan(a)) return Qfalse;
-#endif
     return RBOOL(a == b);
 }
 
@@ -1734,16 +1728,10 @@ rb_float_gt(VALUE x, VALUE y)
     }
     else if (RB_FLOAT_TYPE_P(y)) {
         b = RFLOAT_VALUE(y);
-#if MSC_VERSION_BEFORE(1300)
-        if (isnan(b)) return Qfalse;
-#endif
     }
     else {
         return rb_num_coerce_relop(x, y, '>');
     }
-#if MSC_VERSION_BEFORE(1300)
-    if (isnan(a)) return Qfalse;
-#endif
     return RBOOL(a > b);
 }
 
@@ -1777,16 +1765,10 @@ flo_ge(VALUE x, VALUE y)
     }
     else if (RB_FLOAT_TYPE_P(y)) {
         b = RFLOAT_VALUE(y);
-#if MSC_VERSION_BEFORE(1300)
-        if (isnan(b)) return Qfalse;
-#endif
     }
     else {
         return rb_num_coerce_relop(x, y, idGE);
     }
-#if MSC_VERSION_BEFORE(1300)
-    if (isnan(a)) return Qfalse;
-#endif
     return RBOOL(a >= b);
 }
 
@@ -1819,16 +1801,10 @@ flo_lt(VALUE x, VALUE y)
     }
     else if (RB_FLOAT_TYPE_P(y)) {
         b = RFLOAT_VALUE(y);
-#if MSC_VERSION_BEFORE(1300)
-        if (isnan(b)) return Qfalse;
-#endif
     }
     else {
         return rb_num_coerce_relop(x, y, '<');
     }
-#if MSC_VERSION_BEFORE(1300)
-    if (isnan(a)) return Qfalse;
-#endif
     return RBOOL(a < b);
 }
 
@@ -1862,16 +1838,10 @@ flo_le(VALUE x, VALUE y)
     }
     else if (RB_FLOAT_TYPE_P(y)) {
         b = RFLOAT_VALUE(y);
-#if MSC_VERSION_BEFORE(1300)
-        if (isnan(b)) return Qfalse;
-#endif
     }
     else {
         return rb_num_coerce_relop(x, y, idLE);
     }
-#if MSC_VERSION_BEFORE(1300)
-    if (isnan(a)) return Qfalse;
-#endif
     return RBOOL(a <= b);
 }
 
@@ -1899,10 +1869,7 @@ rb_float_eql(VALUE x, VALUE y)
     if (RB_FLOAT_TYPE_P(y)) {
         double a = RFLOAT_VALUE(x);
         double b = RFLOAT_VALUE(y);
-#if MSC_VERSION_BEFORE(1300)
-        if (isnan(a) || isnan(b)) return Qfalse;
-#endif
-    return RBOOL(a == b);
+        return RBOOL(a == b);
     }
     return Qfalse;
 }
diff --git a/parser_bits.h b/parser_bits.h
index ca7535280efb61..cbe42db39631be 100644
--- a/parser_bits.h
+++ b/parser_bits.h
@@ -30,13 +30,13 @@
 #include <stdint.h>             /* for uintptr_t */
 #include "internal/compilers.h" /* for MSC_VERSION_SINCE */
 
-#if MSC_VERSION_SINCE(1310)
+#if defined(_MSC_VER)
 # include <stdlib.h>            /* for _byteswap_uint64 */
 #endif
 
 #if defined(HAVE_X86INTRIN_H)
 # include <x86intrin.h>         /* for _lzcnt_u64 */
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
 # include <intrin.h>            /* for the following intrinsics */
 #endif
 
@@ -50,7 +50,7 @@
 # pragma intrinsic(__lzcnt64)
 #endif
 
-#if MSC_VERSION_SINCE(1310)
+#if defined(_MSC_VER)
 # pragma intrinsic(_rotl)
 # pragma intrinsic(_rotr)
 # ifdef _WIN64
@@ -59,7 +59,7 @@
 # endif
 #endif
 
-#if MSC_VERSION_SINCE(1400)
+#if defined(_MSC_VER)
 # pragma intrinsic(_BitScanForward)
 # pragma intrinsic(_BitScanReverse)
 # ifdef _WIN64
@@ -180,7 +180,7 @@ ruby_swap16(uint16_t x)
 #if __has_builtin(__builtin_bswap16)
     return __builtin_bswap16(x);
 
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
     return _byteswap_ushort(x);
 
 #else
@@ -195,7 +195,7 @@ ruby_swap32(uint32_t x)
 #if __has_builtin(__builtin_bswap32)
     return __builtin_bswap32(x);
 
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
     return _byteswap_ulong(x);
 
 #else
@@ -212,7 +212,7 @@ ruby_swap64(uint64_t x)
 #if __has_builtin(__builtin_bswap64)
     return __builtin_bswap64(x);
 
-#elif MSC_VERSION_SINCE(1310)
+#elif defined(_MSC_VER)
     return _byteswap_uint64(x);
 
 #else
@@ -237,7 +237,7 @@ nlz_int32(uint32_t x)
 #elif defined(__x86_64__) && defined(__LZCNT__)
     return (unsigned int)_lzcnt_u32(x);
 
-#elif MSC_VERSION_SINCE(1400) /* &&! defined(__AVX2__) */
+#elif defined(_MSC_VER) /* &&! defined(__AVX2__) */
     unsigned long r;
     return _BitScanReverse(&r, x) ? (31 - (int)r) : 32;
 
@@ -266,7 +266,7 @@ nlz_int64(uint64_t x)
 #elif defined(__x86_64__) && defined(__LZCNT__)
     return (unsigned int)_lzcnt_u64(x);
 
-#elif defined(_WIN64) && MSC_VERSION_SINCE(1400) /* &&! defined(__AVX2__) */
+#elif defined(_WIN64) && defined(_MSC_VER) /* &&! defined(__AVX2__) */
     unsigned long r;
     return _BitScanReverse64(&r, x) ? (63u - (unsigned int)r) : 64;
 
@@ -452,7 +452,7 @@ ntz_int32(uint32_t x)
 #if defined(__x86_64__) && defined(__BMI__)
     return (unsigned)_tzcnt_u32(x);
 
-#elif MSC_VERSION_SINCE(1400)
+#elif defined(_MSC_VER)
     /* :FIXME: Is there any way to issue TZCNT instead of BSF, apart from using
      *         assembly?  Because issuing LZCNT seems possible (see nlz.h). */
     unsigned long r;
@@ -474,7 +474,7 @@ ntz_int64(uint64_t x)
 #if defined(__x86_64__) && defined(__BMI__)
     return (unsigned)_tzcnt_u64(x);
 
-#elif defined(_WIN64) && MSC_VERSION_SINCE(1400)
+#elif defined(_WIN64) && defined(_MSC_VER)
     unsigned long r;
     return _BitScanForward64(&r, x) ? (int)r : 64;
 
@@ -522,10 +522,10 @@ RUBY_BIT_ROTL(VALUE v, int n)
 #elif __has_builtin(__builtin_rotateleft64) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return __builtin_rotateleft64(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 32)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 32)
     return _rotl(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 64)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return _rotl64(v, n);
 
 #elif defined(_lrotl) && (SIZEOF_VALUE == SIZEOF_LONG)
@@ -546,10 +546,10 @@ RUBY_BIT_ROTR(VALUE v, int n)
 #elif __has_builtin(__builtin_rotateright64) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return __builtin_rotateright64(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 32)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 32)
     return _rotr(v, n);
 
-#elif MSC_VERSION_SINCE(1310) && (SIZEOF_VALUE * CHAR_BIT == 64)
+#elif defined(_MSC_VER) && (SIZEOF_VALUE * CHAR_BIT == 64)
     return _rotr64(v, n);
 
 #elif defined(_lrotr) && (SIZEOF_VALUE == SIZEOF_LONG)
diff --git a/prism/config.yml b/prism/config.yml
index e57aa850445c5d..69a46de628e63c 100644
--- a/prism/config.yml
+++ b/prism/config.yml
@@ -2628,11 +2628,18 @@ nodes:
       - name: block
         type: node?
         kind: BlockNode
+        comment: |
+          All other arguments are forwarded as normal, except the original block is replaced with the new block.
     comment: |
-      Represents the use of the `super` keyword without parentheses or arguments.
+      Represents the use of the `super` keyword without parentheses or arguments, but which might have a block.
 
           super
           ^^^^^
+
+          super { 123 }
+          ^^^^^^^^^^^^^
+
+      If it has any other arguments, it would be a `SuperNode` instead.
   - name: GlobalVariableAndWriteNode
     fields:
       - name: name
@@ -4508,6 +4515,7 @@ nodes:
       - name: arguments
         type: node?
         kind: ArgumentsNode
+        comment: "Can be only `nil` when there are empty parentheses, like `super()`."
       - name: rparen_loc
         type: location?
       - name: block
@@ -4523,6 +4531,8 @@ nodes:
 
           super foo, bar
           ^^^^^^^^^^^^^^
+
+      If no arguments are provided (except for a block), it would be a `ForwardingSuperNode` instead.
   - name: SymbolNode
     flags: SymbolFlags
     fields:
diff --git a/random.c b/random.c
index bf5588186c2771..0fd953b81e9eed 100644
--- a/random.c
+++ b/random.c
@@ -230,7 +230,7 @@ int_pair_to_real_inclusive(uint32_t a, uint32_t b)
     const uint128_t m = ((uint128_t)1 << dig) | 1;
     uint128_t x = ((uint128_t)a << 32) | b;
     r = (double)(uint64_t)((x * m) >> 64);
-#elif defined HAVE_UINT64_T && !MSC_VERSION_BEFORE(1300)
+#elif defined HAVE_UINT64_T
     uint64_t x = ((uint64_t)a << dig_u) +
         (((uint64_t)b + (a >> dig_u)) >> dig_r64);
     r = (double)x;
diff --git a/regint.h b/regint.h
index 9924e5f62ab5f3..9d69e2d25e51a8 100644
--- a/regint.h
+++ b/regint.h
@@ -215,9 +215,7 @@
 #define xmemcpy     memcpy
 #define xmemmove    memmove
 
-#if ((defined(RUBY_MSVCRT_VERSION) && RUBY_MSVCRT_VERSION >= 90) \
-        || (!defined(RUBY_MSVCRT_VERSION) && defined(_WIN32))) \
-    && !defined(__GNUC__)
+#if defined(_WIN32) && !defined(__GNUC__)
 # define xalloca     _alloca
 # define xvsnprintf(buf,size,fmt,args)  _vsnprintf_s(buf,size,_TRUNCATE,fmt,args)
 # define xsnprintf   sprintf_s
@@ -266,19 +264,6 @@
 # include <stdio.h>
 #endif
 
-#ifdef _WIN32
-# if defined(_MSC_VER) && (_MSC_VER < 1300)
-#  ifndef _INTPTR_T_DEFINED
-#   define _INTPTR_T_DEFINED
-typedef int intptr_t;
-#  endif
-#  ifndef _UINTPTR_T_DEFINED
-#   define _UINTPTR_T_DEFINED
-typedef unsigned int uintptr_t;
-#  endif
-# endif
-#endif /* _WIN32 */
-
 #ifndef PRIdPTR
 # ifdef _WIN64
 #  define PRIdPTR	"I64d"
diff --git a/spec/bundler/bundler/cli_spec.rb b/spec/bundler/bundler/cli_spec.rb
index b3a97e72ceb2d8..ee3c0d0fd50ff5 100644
--- a/spec/bundler/bundler/cli_spec.rb
+++ b/spec/bundler/bundler/cli_spec.rb
@@ -87,14 +87,10 @@ def out_with_macos_man_workaround
   end
 
   context "with no arguments" do
-    it "prints a concise help message by default" do
-      bundle ""
-      expect(err).to be_empty
-      expect(out).to include("Bundler version #{Bundler::VERSION}").
-        and include("\n\nBundler commands:\n\n").
-        and include("\n\n  Primary commands:\n").
-        and include("\n\n  Utilities:\n").
-        and include("\n\nOptions:\n")
+    it "installs and log a warning by default" do
+      bundle "", raise_on_error: false
+      expect(err).to include("running `bundle` without argument will no longer run `bundle install`.")
+      expect(err).to include("Could not locate Gemfile")
     end
 
     it "prints a concise help message when default_cli_command set to cli_help" do
diff --git a/string.c b/string.c
index 827555d9e0faab..d78d7320be2b2b 100644
--- a/string.c
+++ b/string.c
@@ -7628,17 +7628,11 @@ static VALUE rb_str_is_ascii_only_p(VALUE str);
 
 /*
  *  call-seq:
- *    undump -> string
+ *    undump -> new_string
  *
- *  Returns an unescaped version of +self+:
- *
- *    s_orig = "\f\x00\xff\\\""    # => "\f\u0000\xFF\\\""
- *    s_dumped = s_orig.dump       # => "\"\\f\\x00\\xFF\\\\\\\"\""
- *    s_undumped = s_dumped.undump # => "\f\u0000\xFF\\\""
- *    s_undumped == s_orig         # => true
- *
- *  Related: String#dump (inverse of String#undump).
+ *  Inverse of String#dump; returns a copy of +self+ with changes of the kinds made by String#dump "undone."
  *
+ *  Related: see {Converting to New String}[rdoc-ref:String@Converting+to+New+String].
  */
 
 static VALUE
@@ -11932,34 +11926,8 @@ unicode_normalize_common(int argc, VALUE *argv, VALUE str, ID id)
  *  call-seq:
  *    unicode_normalize(form = :nfc) -> string
  *
- *  Returns a copy of +self+ with
- *  {Unicode normalization}[https://unicode.org/reports/tr15] applied.
- *
- *  Argument +form+ must be one of the following symbols
- *  (see {Unicode normalization forms}[https://unicode.org/reports/tr15/#Norm_Forms]):
- *
- *  - +:nfc+: Canonical decomposition, followed by canonical composition.
- *  - +:nfd+: Canonical decomposition.
- *  - +:nfkc+: Compatibility decomposition, followed by canonical composition.
- *  - +:nfkd+: Compatibility decomposition.
- *
- *  The encoding of +self+ must be one of:
- *
- *  - Encoding::UTF_8
- *  - Encoding::UTF_16BE
- *  - Encoding::UTF_16LE
- *  - Encoding::UTF_32BE
- *  - Encoding::UTF_32LE
- *  - Encoding::GB18030
- *  - Encoding::UCS_2BE
- *  - Encoding::UCS_4BE
- *
- *  Examples:
- *
- *    "a\u0300".unicode_normalize      # => "a"
- *    "\u00E0".unicode_normalize(:nfd) # => "a "
+ *  :include: doc/string/unicode_normalize.rdoc
  *
- *  Related: String#unicode_normalize!, String#unicode_normalized?.
  */
 static VALUE
 rb_str_unicode_normalize(int argc, VALUE *argv, VALUE str)
diff --git a/test/ruby/test_gc_compact.rb b/test/ruby/test_gc_compact.rb
index 32b0a5def0b8f5..a03535171c42e8 100644
--- a/test/ruby/test_gc_compact.rb
+++ b/test/ruby/test_gc_compact.rb
@@ -361,6 +361,22 @@ def add_ivars
     end;
   end
 
+  def test_compact_objects_of_varying_sizes
+    omit if GC::INTERNAL_CONSTANTS[:SIZE_POOL_COUNT] == 1
+
+    assert_separately([], "#{<<~"begin;"}\n#{<<~"end;"}", timeout: 10)
+    begin;
+      $objects = []
+      160.times do |n|
+        obj = Class.new.new
+        n.times { |i| obj.instance_variable_set("@foo" + i.to_s, 0) }
+        $objects << obj
+      end
+
+      GC.verify_compaction_references(expand_heap: true, toward: :empty)
+    end;
+  end
+
   def test_moving_strings_up_heaps
     omit if GC::INTERNAL_CONSTANTS[:SIZE_POOL_COUNT] == 1
 
diff --git a/test/rubygems/test_gem_bundler_version_finder.rb b/test/rubygems/test_gem_bundler_version_finder.rb
index 39255bc4e1d7cb..908f9278323c09 100644
--- a/test/rubygems/test_gem_bundler_version_finder.rb
+++ b/test/rubygems/test_gem_bundler_version_finder.rb
@@ -32,6 +32,11 @@ def test_bundler_version_with_env_var
     assert_equal v("1.1.1.1"), bvf.bundler_version
   end
 
+  def test_bundler_version_with_empty_env_var
+    ENV["BUNDLER_VERSION"] = ""
+    assert_nil bvf.bundler_version
+  end
+
   def test_bundler_version_with_bundle_update_bundler
     ARGV.replace %w[update --bundler]
     assert_nil bvf.bundler_version
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 1b1eeb69d9ffb4..8495ee59ef438e 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -2518,15 +2518,6 @@ opt_equality_specialized(VALUE recv, VALUE obj)
         double a = RFLOAT_VALUE(recv);
         double b = RFLOAT_VALUE(obj);
 
-#if MSC_VERSION_BEFORE(1300)
-        if (isnan(a)) {
-            return Qfalse;
-        }
-        else if (isnan(b)) {
-            return Qfalse;
-        }
-        else
-#endif
         return RBOOL(a == b);
     }
     else if (RBASIC_CLASS(recv) == rb_cString && EQ_UNREDEFINED_P(STRING)) {
@@ -2624,37 +2615,27 @@ check_match(rb_execution_context_t *ec, VALUE pattern, VALUE target, enum vm_che
 }
 
 
-#if MSC_VERSION_BEFORE(1300)
-#define CHECK_CMP_NAN(a, b) if (isnan(a) || isnan(b)) return Qfalse;
-#else
-#define CHECK_CMP_NAN(a, b) /* do nothing */
-#endif
-
 static inline VALUE
 double_cmp_lt(double a, double b)
 {
-    CHECK_CMP_NAN(a, b);
     return RBOOL(a < b);
 }
 
 static inline VALUE
 double_cmp_le(double a, double b)
 {
-    CHECK_CMP_NAN(a, b);
     return RBOOL(a <= b);
 }
 
 static inline VALUE
 double_cmp_gt(double a, double b)
 {
-    CHECK_CMP_NAN(a, b);
     return RBOOL(a > b);
 }
 
 static inline VALUE
 double_cmp_ge(double a, double b)
 {
-    CHECK_CMP_NAN(a, b);
     return RBOOL(a >= b);
 }
 
@@ -6878,7 +6859,6 @@ vm_opt_lt(VALUE recv, VALUE obj)
     else if (RBASIC_CLASS(recv) == rb_cFloat &&
              RBASIC_CLASS(obj)  == rb_cFloat &&
              BASIC_OP_UNREDEFINED_P(BOP_LT, FLOAT_REDEFINED_OP_FLAG)) {
-        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
         return RBOOL(RFLOAT_VALUE(recv) < RFLOAT_VALUE(obj));
     }
     else {
@@ -6903,7 +6883,6 @@ vm_opt_le(VALUE recv, VALUE obj)
     else if (RBASIC_CLASS(recv) == rb_cFloat &&
              RBASIC_CLASS(obj)  == rb_cFloat &&
              BASIC_OP_UNREDEFINED_P(BOP_LE, FLOAT_REDEFINED_OP_FLAG)) {
-        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
         return RBOOL(RFLOAT_VALUE(recv) <= RFLOAT_VALUE(obj));
     }
     else {
@@ -6928,7 +6907,6 @@ vm_opt_gt(VALUE recv, VALUE obj)
     else if (RBASIC_CLASS(recv) == rb_cFloat &&
              RBASIC_CLASS(obj)  == rb_cFloat &&
              BASIC_OP_UNREDEFINED_P(BOP_GT, FLOAT_REDEFINED_OP_FLAG)) {
-        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
         return RBOOL(RFLOAT_VALUE(recv) > RFLOAT_VALUE(obj));
     }
     else {
@@ -6953,7 +6931,6 @@ vm_opt_ge(VALUE recv, VALUE obj)
     else if (RBASIC_CLASS(recv) == rb_cFloat &&
              RBASIC_CLASS(obj)  == rb_cFloat &&
              BASIC_OP_UNREDEFINED_P(BOP_GE, FLOAT_REDEFINED_OP_FLAG)) {
-        CHECK_CMP_NAN(RFLOAT_VALUE(recv), RFLOAT_VALUE(obj));
         return RBOOL(RFLOAT_VALUE(recv) >= RFLOAT_VALUE(obj));
     }
     else {
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 81a33277afb161..f95b583fb82a5e 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -130,6 +130,11 @@ TEST_RUNNABLE = yes
 
 CAT_DEPEND = type
 
+!if !defined(MSC_VER)
+! error MSC_VER not defined.  Retry from configure pass.
+!else if $(MSC_VER) < 1900
+! error MSVC $(MSC_VER) is not supported
+!endif
 !if !defined(MACHINE)
 MACHINE = x86
 !endif
@@ -140,9 +145,6 @@ PROCESSOR_LEVEL = 5
 !if 6 < $(PROCESSOR_LEVEL)
 PROCESSOR_LEVEL = 6
 !endif
-!if $(MSC_VER) < 1400
-PROCESSOR_FLAG = -G$(PROCESSOR_LEVEL)
-!endif
 CPU = i$(PROCESSOR_LEVEL)86
 ARCH = i386
 !else
@@ -159,15 +161,9 @@ XCFLAGS = $(XCFLAGS) -DRUBY_DEVEL=1
 XCFLAGS = $(XCFLAGS) -Dmodular_gc_dir="$(modular_gc_dir)"
 !endif
 !if !defined(OPTFLAGS)
-!if $(MSC_VER) < 1400
-OPTFLAGS = -O2b2xg-
-!else
 OPTFLAGS = -O2sy-
 !endif
-!endif
-!if $(MSC_VER) >= 1900
 OPTFLAGS = $(OPTFLAGS) -Zc:inline
-!endif
 !if !defined(incflags)
 incflags =
 !endif
@@ -176,6 +172,8 @@ PLATFORM = mswin32
 !endif
 !if !defined(RT)
 !error RT not defined.  Retry from configure pass.
+!else if $(RT_VER) < 140
+! error Runtime library $(RT_VER) is not supported
 !endif
 !ifndef NTVER
 NTVER = _WIN32_WINNT_WIN8
@@ -262,11 +260,7 @@ OUTFLAG       = -Fe
 COUTFLAG      = -Fo
 !endif
 !if !defined(CPPOUTFLAG)
-! if $(MSC_VER) < 1600
-CPPOUTFLAG    = >
-! else
 CPPOUTFLAG    = -Fi
-! endif
 !endif
 !if !defined(CSRCFLAG)
 CSRCFLAG      = -Tc
@@ -278,13 +272,9 @@ RUNTIMEFLAG   = -MD
 COMPILERFLAG  = -Zm600
 !endif
 !if !defined(WARNFLAGS)
-!if $(MSC_VER) >= 1400
 WARNFLAGS = -W2 -wd4100 -wd4127 -wd4210 -wd4214 -wd4255 -wd4574 \
 	    -wd4668 -wd4710 -wd4711 -wd4820 -wd4996 \
 	    -we4028 -we4142 -we4047 -we4013
-!else
-WARNFLAGS = -W2
-!endif
 !if $(MSC_VER) >= 1944
 # https://developercommunity.visualstudio.com/t/warning-C5287:-operands-are-different-e/10877942
 WARNFLAGS = $(WARNFLAGS) -wd5287
@@ -318,9 +308,7 @@ EXTSOLIBS =
 !endif
 !if !defined(LIBS)
 LIBS = user32.lib advapi32.lib shell32.lib ws2_32.lib
-!if $(MSC_VER) >= 1400
 LIBS = $(LIBS) iphlpapi.lib
-!endif
 !if defined(USE_GMP)
 LIBS = $(LIBS) gmp.lib
 !endif
@@ -328,9 +316,6 @@ LIBS = $(LIBS) imagehlp.lib shlwapi.lib bcrypt.lib $(EXTLIBS)
 !endif
 !if !defined(MISSING)
 MISSING = crypt.obj ffs.obj langinfo.obj lgamma_r.obj strlcat.obj strlcpy.obj win32/win32.obj win32/file.obj setproctitle.obj
-!if $(RT_VER) < 120
-MISSING = $(MISSING) acosh.obj cbrt.obj erf.obj nan.obj tgamma.obj
-!endif
 MISSING = $(MISSING) explicit_bzero.obj
 !endif
 DLNOBJ = dln.obj
@@ -353,15 +338,7 @@ ARFLAGS = -machine:$(MACHINE) -out:
 LD = $(CC)
 LDSHARED = $(LD) -LD
 XCFLAGS = -DRUBY_EXPORT $(INCFLAGS) $(XCFLAGS) $(XINCFLAGS)
-!if $(MSC_VER) >= 1800
 LDFLAGS = $(LDFLAGS) -manifest:embed,ID=2
-!elseif $(MSC_VER) >= 1400
-# Prevents VC++ 2005 (cl ver 14) warnings
-MANIFESTTOOL = mt -nologo
-LDSHARED_0 = @if exist $(@).manifest $(MINIRUBY) -run -e wait_writable -- -n 10 $@
-LDSHARED_1 = @if exist $(@).manifest $(MANIFESTTOOL) -manifest $(@).manifest -outputresource:$(@);2
-LDSHARED_2 = @if exist $(@).manifest @$(RM) $(@:/=\).manifest
-!endif
 CPPFLAGS = $(DEFS) $(ARCHDEFS) $(CPPFLAGS)
 !if "$(USE_RUBYGEMS)" == "no"
 CPPFLAGS = -DDISABLE_RUBYGEMS $(CPPFLAGS)
@@ -373,10 +350,8 @@ MAINLIBS = $(LIBS)
 SOLIBS =
 RCFILES = $(RUBY_INSTALL_NAME).rc $(RUBYW_INSTALL_NAME).rc $(RUBY_SO_NAME).rc
 !ifndef RCFLAGS
-!if $(MSC_VER) >= 1600
 RCFLAGS=-nologo
 !endif
-!endif
 
 ENABLE_SHARED = yes
 LIBRUBY_LDSHARED = $(LDSHARED)
@@ -687,9 +662,7 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define STDC_HEADERS 1
 #define HAVE_SYS_TYPES_H 1
 #define HAVE_SYS_STAT_H 1
-!if $(MSC_VER) >= 1800
 #define HAVE_STDBOOL_H 1
-!endif
 #define HAVE_STDLIB_H 1
 #define HAVE_STDDEF_H 1
 #define HAVE_STRING_H 1
@@ -697,11 +670,7 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 !if $(MSC_VER) >= 1920
 #define HAVE_AFUNIX_H 1
 !endif
-!if $(MSC_VER) >= 1400
 #define HAVE_LONG_LONG 1
-!else
-#define ULL_TO_DOUBLE(n) ((double)(unsigned long)((n)>>32) * (1I64 << 32) + (unsigned long)(n))
-!endif
 #define HAVE_OFF_T 1
 #define rb_off_t __int64
 #define SIGNEDNESS_OF_OFF_T -1
@@ -710,11 +679,7 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define SIZEOF_INT 4
 #define SIZEOF_SHORT 2
 #define SIZEOF_LONG 4
-!if $(MSC_VER) >= 1400
 #define SIZEOF_LONG_LONG 8
-!else
-#define SIZEOF_LONG_LONG 0
-!endif
 #define SIZEOF___INT64 8
 #ifndef _INTEGRAL_MAX_BITS
 #define _INTEGRAL_MAX_BITS 64
@@ -729,15 +694,9 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define SIZEOF_DOUBLE 8
 #define SIGNEDNESS_OF_TIME_T -1
 #define NEGATIVE_TIME_T 1
-!if $(RT_VER) >= 80
 #define SIZEOF_TIME_T 8
 #define TIMET2NUM(v) LL2NUM(v)
 #define NUM2TIMET(v) NUM2LL(v)
-!else
-#define SIZEOF_TIME_T 4
-#define TIMET2NUM(v) LONG2NUM(v)
-#define NUM2TIMET(v) NUM2LONG(v)
-!endif
 #define CLOCKID2NUM(v) INT2NUM(v)
 #define NUM2CLOCKID(v) NUM2INT(v)
 #define SIZEOF_CLOCK_T 4
@@ -753,22 +712,11 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define SIZEOF_INTPTR_T 4
 #define SIZEOF_UINTPTR_T 4
 !endif
-!if $(MSC_VER) < 1400
-#define SIZE_MAX UINT_MAX
-!endif
-!if $(MSC_VER) >= 1800
 #define HAVE_VA_COPY 1
-!else
-#define HAVE_VA_COPY_VIA_STRUCT_ASSIGNMENT 1
-!endif
-!if $(MSC_VER) > 1100
 #define NORETURN(x) __declspec(noreturn) x
-!endif
-!if $(MSC_VER) >= 1300
 #define DEPRECATED(x) __declspec(deprecated) x
 #define RUBY_CXX_DEPRECATED(mesg) __declspec(deprecated(mesg))
 #define NOINLINE(x) __declspec(noinline) x
-!endif
 #define ALWAYS_INLINE(x) __forceinline x
 #define WARN_UNUSED_RESULT(x) x
 #define MAYBE_UNUSED(x) x
@@ -776,11 +724,9 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define FUNC_STDCALL(x) __stdcall x
 #define FUNC_CDECL(x) __cdecl x
 #define FUNC_FASTCALL(x) __fastcall x
-!if $(MSC_VER) >= 1500
 #define RUBY_FUNCTION_NAME_STRING __FUNCTION__
 #define RBIMPL_ATTR_PACKED_STRUCT_BEGIN() __pragma(pack(push, 1))
 #define RBIMPL_ATTR_PACKED_STRUCT_END() __pragma(pack(pop))
-!endif
 #define RUBY_EXTERN extern __declspec(dllimport)
 #define RUBY_FUNC_EXPORTED extern __declspec(dllexport)
 #define RUBY_ALIGNAS(n) __declspec(align(n))
@@ -796,34 +742,9 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define rb_uid_t int
 #define HAVE_STRUCT_STAT_ST_RDEV 1
 #define HAVE_STRUCT_TIMEVAL 1
-!if $(MSC_VER) >= 1900
 #define HAVE_STRUCT_TIMESPEC
-!endif
-!if $(MSC_VER) >= 1600
 #define HAVE_INTTYPES_H 1
 #define HAVE_STDINT_H 1
-!else
-#define int8_t signed char
-#define uint8_t unsigned char
-#define int16_t short
-#define uint16_t unsigned short
-#define int32_t int
-#define uint32_t unsigned int
-#define int64_t __int64
-#define uint64_t unsigned __int64
-#define INT8_MIN _I8_MIN
-#define INT8_MAX _I8_MAX
-#define UINT8_MAX _UI8_MAX
-#define INT16_MIN _I16_MIN
-#define INT16_MAX _I16_MAX
-#define UINT16_MAX _UI16_MAX
-#define INT32_MIN _I32_MIN
-#define INT32_MAX _I32_MAX
-#define UINT32_MAX _UI32_MAX
-#define INT64_MIN _I64_MIN
-#define INT64_MAX _I64_MAX
-#define UINT64_MAX _UI64_MAX
-!endif
 #define HAVE_INT8_T 1
 #define HAVE_UINT8_T 1
 #define SIZEOF_INT8_T 1
@@ -854,7 +775,6 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define PRI_PIDT_PREFIX PRI_INT_PREFIX
 #define GETGROUPS_T int
 #define TYPEOF_TIMEVAL_TV_SEC long
-!if $(RT_VER) >= 120
 #define HAVE_ACOSH 1
 #define HAVE_ASINH 1
 #define HAVE_ATANH 1
@@ -866,7 +786,6 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define HAVE_ROUND 1
 #define HAVE_TGAMMA 1
 #define HAVE_NEXTAFTER 1
-!endif
 #define HAVE_ALLOCA 1
 #define HAVE_DUP2 1
 #define HAVE_MEMCMP 1
@@ -883,14 +802,10 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define HAVE_STRCHR 1
 #define HAVE_STRSTR 1
 #define HAVE_FLOCK 1
-!if $(MSC_VER) >= 1800
 #define HAVE_ISINF 1
-!endif
 #define HAVE_ISNAN 1
 #define HAVE_FINITE 1
-!if $(RT_VER) >= 120
 #define HAVE_NAN 1
-!endif
 #define HAVE_HYPOT 1
 #define HAVE_FMOD 1
 #define HAVE_FREXP 1
@@ -936,13 +851,9 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define HAVE_SYSTEM 1
 #define HAVE_TZSET 1
 #define HAVE_UMASK 1
-!if $(RT_VER) > 120
 #define HAVE_QSORT_S
-!endif
 #define HAVE_TYPE_NET_LUID 1
-!if $(MSC_VER) >= 1600
 #define HAVE_NULLPTR 1
-!endif
 #define SETPGRP_VOID 1
 #define RSHIFT(x,y) ((x)>>(int)y)
 #define HAVE_RB_FD_INIT 1
@@ -951,11 +862,7 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define RUBY_JMP_BUF jmp_buf
 #ifndef __cplusplus
 #define inline __inline
-!if $(MSC_VER) >= 1800
 #define restrict __restrict
-!else
-#define restrict /* not supported */
-!endif
 #endif
 #define NEED_IO_SEEK_BETWEEN_RW 1
 !if "$(MACHINE)" == "x86" || "$(ARCH)" == "x64"
@@ -1119,11 +1026,6 @@ s,@LIBPATHFLAG@,-libpath:%s,;t t
 s,@RPATHFLAG@,,;t t
 s,@LIBARG@,%s.lib,;t t
 s,@LINK_SO@,$$(LDSHARED) -Fe$$(@) $$(OBJS) $$(LIBS) $$(LOCAL_LIBS) -link $$(DLDFLAGS) -implib:$$(*F:.so=)-$$(arch).lib -pdb:$$(*F:.so=)-$$(arch).pdb -def:$$(DEFFILE),;t t
-!if $(MSC_VER) >= 1400 && $(MSC_VER) < 1800
-s,@LINK_SO@,@if exist $$(@).manifest $$(RUBY) -run -e wait_writable -- -n 10 $$(@),;t t
-s,@LINK_SO@,@if exist $$(@).manifest $(MANIFESTTOOL) -manifest $$(@).manifest -outputresource:$$(@);2,;t t
-s,@LINK_SO@,@if exist $$(@).manifest $$(RM) $$(@:/=\).manifest,;t t
-!endif
 s,@COMPILE_C@,$$(CC) $$(INCFLAGS) $$(CFLAGS) $$(CPPFLAGS) $$(COUTFLAG)$$(@) -c $$(CSRCFLAG)$$(<:\=/),;t t
 s,@COMPILE_CXX@,$$(CXX) $$(INCFLAGS) $$(CXXFLAGS) $$(CPPFLAGS) $$(COUTFLAG)$$(@) -c -Tp$$(<:\=/),;t t
 s,@ASSEMBLE_C@,$$(CC) $$(CFLAGS) $$(CPPFLAGS) -Fa$$(@) -c $$(CSRCFLAG)$$(<:\=/),;t t
@@ -1205,11 +1107,6 @@ $(PROGRAM):	$(MAINOBJ) $(LIBRUBY_SO) $(RUBY_INSTALL_NAME).res
 		$(ECHO) linking $(@:\=/)
 		$(Q) $(PURIFY) $(CC) $(MAINOBJ) $(EXTOBJS) $(RUBY_INSTALL_NAME).res \
 			$(OUTFLAG)$@ $(LIBRUBYARG) -link $(LDFLAGS) $(XLDFLAGS)
-! if defined(LDSHARED_0)
-		$(Q) $(LDSHARED_0)
-		$(Q) $(LDSHARED_1)
-		$(Q) $(LDSHARED_2)
-! endif
 !endif
 
 !if "$(WPROGRAM)" != ""
@@ -1218,11 +1115,6 @@ $(WPROGRAM):	$(MAINOBJ) $(WINMAINOBJ) $(LIBRUBY_SO) $(RUBYW_INSTALL_NAME).res
 		$(Q) $(PURIFY) $(CC) $(MAINOBJ) $(WINMAINOBJ) \
 			$(RUBYW_INSTALL_NAME).res $(OUTFLAG)$@ $(LIBRUBYARG) \
 			-link $(LDFLAGS) $(XLDFLAGS) -subsystem:Windows
-! if defined(LDSHARED_0)
-		$(Q) $(LDSHARED_0)
-		$(Q) $(LDSHARED_1)
-		$(Q) $(LDSHARED_2)
-! endif
 !endif
 
 !if "$(STUBPROGRAM)" != ""
@@ -1230,11 +1122,6 @@ $(STUBPROGRAM):	rubystub.$(OBJEXT) $(LIBRUBY) $(LIBRUBY_SO) $(RUBY_INSTALL_NAME)
 		$(ECHO) linking $(@:\=/)
 		$(Q) $(PURIFY) $(CC) rubystub.$(OBJEXT) $(RUBY_INSTALL_NAME).res \
 			$(OUTFLAG)$@ $(LIBRUBYARG) -link $(LDFLAGS) $(XLDFLAGS)
-! if defined(LDSHARED_0)
-		$(Q) $(LDSHARED_0)
-		$(Q) $(LDSHARED_1)
-		$(Q) $(LDSHARED_2)
-! endif
 !endif
 
 !if "$(LIBRUBY_SO_UPDATE)" == ""
@@ -1265,12 +1152,6 @@ $(LIBRUBY_SO):	$(LIBRUBY_A) $(DLDOBJS) $(RUBYDEF) $(RUBY_SO_NAME).res
 			$(OUTFLAG)$@ -link $(LDFLAGS) $(XLDFLAGS) \
 			$(LIBRUBY_DLDFLAGS)
 		@$(RM) dummy.lib dummy.exp
-!if defined(LDSHARED_0)
-		$(Q) $(LDSHARED_0)
-		$(Q) $(LDSHARED_1)
-		$(Q) $(LDSHARED_2)
-# | findstr -v -c:LNK4049 -c:LNK4217
-!endif
 
 $(RUBYDEF):	$(LIBRUBY_A) $(RBCONFIG)
 		$(ECHO) generating $(@:\=/)
@@ -1505,11 +1386,6 @@ rubyspec-capiext: $(RUBYSPEC_CAPIEXT_EXTS)
 	$(Q)$(MAKEDIRS) $(@D)
 	$(Q)(echo EXPORTS&&echo Init_$(*F))> $*.def
 	$(Q)$(LDSHARED) -Fe$(@) -Fo$(*).obj $(INCFLAGS) $(CFLAGS) $(CPPFLAGS) $< $(LIBRUBYARG) -link $(DLDFLAGS) $(XLDFLAGS) $(LIBS) $(LOCAL_LIBS) -implib:$*.lib -pdb:$*.pdb -def:$*.def
-!if defined(LDSHARED_0)
-	$(Q)$(LDSHARED_0)
-	$(Q)$(LDSHARED_1)
-	$(Q)$(LDSHARED_2)
-!endif
 	$(Q)$(RM) $*.def $*.exp $*.lib $*.obj $*.pdb
 
 exts: rubyspec-capiext
diff --git a/win32/file.c b/win32/file.c
index f137f04c43db94..26b99715cd6ca8 100644
--- a/win32/file.c
+++ b/win32/file.c
@@ -629,14 +629,10 @@ rb_freopen(VALUE fname, const char *mode, FILE *file)
     len = MultiByteToWideChar(CP_UTF8, 0, name, n, wname, len);
     wname[len] = L'\0';
     RB_GC_GUARD(fname);
-#if RUBY_MSVCRT_VERSION < 80 && !defined(HAVE__WFREOPEN_S)
-    e = _wfreopen(wname, wmode, file) ? 0 : errno;
-#else
     {
         FILE *newfp = 0;
         e = _wfreopen_s(&newfp, wname, wmode, file);
     }
-#endif
     ALLOCV_END(wtmp);
     return e;
 }
diff --git a/win32/win32.c b/win32/win32.c
index e7dfe2b065975a..66ce195092f5e5 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -21,6 +21,10 @@
 
 #undef __STRICT_ANSI__
 
+/* Visual C++ 2015 (14.0):
+ * - _MSC_VER: 1900
+ * - MSVCRT_VERSION: 140
+ */
 #include "ruby/ruby.h"
 #include "ruby/encoding.h"
 #include "ruby/io.h"
@@ -42,7 +46,7 @@
 #include <shlobj.h>
 #include <mbstring.h>
 #include <shlwapi.h>
-#if defined _MSC_VER && _MSC_VER >= 1400
+#if defined _MSC_VER
 #include <crtdbg.h>
 #include <rtcapi.h>
 #endif
@@ -65,10 +69,6 @@
 #include "encindex.h"
 #define isdirsep(x) ((x) == '/' || (x) == '\\')
 
-#if defined _MSC_VER && _MSC_VER <= 1200
-# define CharNextExA(cp, p, flags) CharNextExA((WORD)(cp), (p), (flags))
-#endif
-
 static int w32_wopen(const WCHAR *file, int oflag, int perm);
 static int w32_stati128(const char *path, struct stati128 *st, UINT cp, BOOL lstat);
 static char *w32_getenv(const char *name, UINT cp);
@@ -113,10 +113,8 @@ static char *w32_getenv(const char *name, UINT cp);
 #undef dup2
 #undef strdup
 
-#if RUBY_MSVCRT_VERSION >= 140
-# define _filbuf _fgetc_nolock
-# define _flsbuf _fputc_nolock
-#endif
+#define _filbuf _fgetc_nolock
+#define _flsbuf _fputc_nolock
 #define enough_to_get(n) (--(n) >= 0)
 #define enough_to_put(n) (--(n) >= 0)
 
@@ -503,11 +501,6 @@ rb_w32_special_folder(int type)
     return rb_w32_conv_from_wchar(path, rb_filesystem_encoding());
 }
 
-#if defined _MSC_VER && _MSC_VER <= 1200
-/* License: Ruby's */
-#define GetSystemWindowsDirectoryW GetWindowsDirectoryW
-#endif
-
 /* License: Ruby's */
 UINT
 rb_w32_system_tmpdir(WCHAR *path, UINT len)
@@ -629,7 +622,6 @@ init_env(void)
 
 static void init_stdhandle(void);
 
-#if RUBY_MSVCRT_VERSION >= 80
 /* License: Ruby's */
 static void
 invalid_parameter(const wchar_t *expr, const wchar_t *func, const wchar_t *file, unsigned int line, uintptr_t dummy)
@@ -639,7 +631,7 @@ invalid_parameter(const wchar_t *expr, const wchar_t *func, const wchar_t *file,
 
 int ruby_w32_rtc_error;
 
-# ifndef __MINGW32__
+#ifndef __MINGW32__
 /* License: Ruby's */
 RBIMPL_ATTR_NONNULL((5))
 RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 5, 6)
@@ -658,7 +650,6 @@ rtc_error_handler(int e, const char *src, int line, const char *exe, const char
     rb_write_error2(RSTRING_PTR(str), RSTRING_LEN(str));
     return 0;
 }
-# endif
 #endif
 
 static CRITICAL_SECTION select_mutex;
@@ -852,13 +843,11 @@ socklist_delete(SOCKET *sockp, int *flagp)
     return ret;
 }
 
-#if RUBY_MSVCRT_VERSION >= 80
 # ifdef __MINGW32__
 #  define _CrtSetReportMode(type,mode) ((void)0)
 #  define _RTC_SetErrorFunc(func) ((void)0)
 # endif
 static void set_pioinfo_extra(void);
-#endif
 static int w32_cmdvector(const WCHAR *, char ***, UINT, rb_encoding *);
 //
 // Initialization stuff
@@ -867,13 +856,10 @@ static int w32_cmdvector(const WCHAR *, char ***, UINT, rb_encoding *);
 void
 rb_w32_sysinit(int *argc, char ***argv)
 {
-#if RUBY_MSVCRT_VERSION >= 80
-
     _CrtSetReportMode(_CRT_ASSERT, 0);
     _set_invalid_parameter_handler(invalid_parameter);
     _RTC_SetErrorFunc(rtc_error_handler);
     set_pioinfo_extra();
-#endif
     SetErrorMode(SEM_FAILCRITICALERRORS|SEM_NOGPFAULTERRORBOX);
 
     get_version();
@@ -2413,7 +2399,6 @@ rb_w32_closedir(DIR *dirp)
     return 0;
 }
 
-#if RUBY_MSVCRT_VERSION >= 140
 typedef struct {
     union
     {
@@ -2433,14 +2418,8 @@ typedef struct {
 #define FILE_COUNT(stream) ((vcruntime_file*)stream)->_cnt
 #define FILE_READPTR(stream) ((vcruntime_file*)stream)->_ptr
 #define FILE_FILENO(stream) ((vcruntime_file*)stream)->_file
-#else
-#define FILE_COUNT(stream) stream->_cnt
-#define FILE_READPTR(stream) stream->_ptr
-#define FILE_FILENO(stream) stream->_file
-#endif
 
 /* License: Ruby's */
-#if RUBY_MSVCRT_VERSION >= 140
 typedef char lowio_text_mode;
 typedef char lowio_pipe_lookahead[3];
 
@@ -2457,32 +2436,14 @@ typedef struct {
     uint8_t dbcsBufferUsed   : 1; // Is the dbcsBuffer in use?
     char    dbcsBuffer;           // Buffer for the lead byte of DBCS when converting from DBCS to Unicode
 } ioinfo;
-#else
-typedef struct	{
-    intptr_t osfhnd;	/* underlying OS file HANDLE */
-    char osfile;	/* attributes of file (e.g., open in text mode?) */
-    char pipech;	/* one char buffer for handles opened on pipes */
-    int lockinitflag;
-    CRITICAL_SECTION lock;
-#if RUBY_MSVCRT_VERSION >= 80
-    char textmode;
-    char pipech2[2];
-#endif
-}	ioinfo;
-#endif
 
 #if !defined _CRTIMP || defined __MINGW32__
 #undef _CRTIMP
 #define _CRTIMP __declspec(dllimport)
 #endif
 
-#if RUBY_MSVCRT_VERSION >= 140
 static ioinfo ** __pioinfo = NULL;
 #define IOINFO_L2E 6
-#else
-EXTERN_C _CRTIMP ioinfo * __pioinfo[];
-#define IOINFO_L2E 5
-#endif
 static inline ioinfo* _pioinfo(int);
 
 
@@ -2492,20 +2453,18 @@ static inline ioinfo* _pioinfo(int);
 #define rb_acrt_lowio_lock_fh(i)   EnterCriticalSection(&_pioinfo(i)->lock)
 #define rb_acrt_lowio_unlock_fh(i) LeaveCriticalSection(&_pioinfo(i)->lock)
 
-#if RUBY_MSVCRT_VERSION >= 80
 static size_t pioinfo_extra = 0;	/* workaround for VC++8 SP1 */
 
 /* License: Ruby's */
 static void
 set_pioinfo_extra(void)
 {
-#if RUBY_MSVCRT_VERSION >= 140
-# define FUNCTION_RET 0xc3 /* ret */
-# ifdef _DEBUG
-#  define UCRTBASE "ucrtbased.dll"
-# else
-#  define UCRTBASE "ucrtbase.dll"
-# endif
+#define FUNCTION_RET 0xc3 /* ret */
+#ifdef _DEBUG
+# define UCRTBASE "ucrtbased.dll"
+#else
+# define UCRTBASE "ucrtbase.dll"
+#endif
     /* get __pioinfo addr with _isatty */
     /*
      * Why Ruby depends to _pioinfo is
@@ -2640,7 +2599,6 @@ set_pioinfo_extra(void)
     __pioinfo = *(ioinfo***)(p);
 #endif
 #endif /* _M_ARM64 */
-#endif /* RUBY_MSVCRT_VERSION */
     int fd;
 
     fd = _open("NUL", O_RDONLY);
@@ -2656,9 +2614,6 @@ set_pioinfo_extra(void)
         pioinfo_extra = 0;
     }
 }
-#else
-#define pioinfo_extra 0
-#endif
 
 static inline ioinfo*
 _pioinfo(int fd)
@@ -4235,7 +4190,6 @@ socketpair(int af, int type, int protocol, int *sv)
     return 0;
 }
 
-#if !defined(_MSC_VER) || _MSC_VER >= 1400
 /* License: Ruby's */
 static void
 str2guid(const char *str, GUID *guid)
@@ -4361,7 +4315,6 @@ freeifaddrs(struct ifaddrs *ifp)
         ifp = next;
     }
 }
-#endif
 
 #if 0 // Have never been used
 //
@@ -7592,20 +7545,6 @@ rb_w32_write_console(uintptr_t strarg, int fd)
     return (long)reslen;
 }
 
-#if RUBY_MSVCRT_VERSION < 80 && !defined(HAVE__GMTIME64_S)
-/* License: Ruby's */
-static int
-unixtime_to_filetime(time_t time, FILETIME *ft)
-{
-    ULARGE_INTEGER tmp;
-
-    tmp.QuadPart = unix_to_filetime((ULONGLONG)time);
-    ft->dwLowDateTime = tmp.LowPart;
-    ft->dwHighDateTime = tmp.HighPart;
-    return 0;
-}
-#endif
-
 /* License: Ruby's */
 static int
 timespec_to_filetime(const struct timespec *ts, FILETIME *ft)
@@ -7982,23 +7921,6 @@ rb_w32_isatty(int fd)
     return 1;
 }
 
-#if defined(_MSC_VER) && RUBY_MSVCRT_VERSION <= 60
-extern long _ftol(double);
-/* License: Ruby's */
-long
-_ftol2(double d)
-{
-    return _ftol(d);
-}
-
-/* License: Ruby's */
-long
-_ftol2_sse(double d)
-{
-    return _ftol(d);
-}
-#endif
-
 #ifndef signbit
 /* License: Ruby's */
 int
@@ -8030,68 +7952,6 @@ rb_w32_fd_is_text(int fd)
     return _osfile(fd) & FTEXT;
 }
 
-#if RUBY_MSVCRT_VERSION < 80 && !defined(HAVE__GMTIME64_S)
-/* License: Ruby's */
-static int
-unixtime_to_systemtime(const time_t t, SYSTEMTIME *st)
-{
-    FILETIME ft;
-    if (unixtime_to_filetime(t, &ft)) return -1;
-    if (!FileTimeToSystemTime(&ft, st)) return -1;
-    return 0;
-}
-
-/* License: Ruby's */
-static void
-systemtime_to_tm(const SYSTEMTIME *st, struct tm *t)
-{
-    int y = st->wYear, m = st->wMonth, d = st->wDay;
-    t->tm_sec  = st->wSecond;
-    t->tm_min  = st->wMinute;
-    t->tm_hour = st->wHour;
-    t->tm_mday = st->wDay;
-    t->tm_mon  = st->wMonth - 1;
-    t->tm_year = y - 1900;
-    t->tm_wday = st->wDayOfWeek;
-    switch (m) {
-      case 1:
-        break;
-      case 2:
-        d += 31;
-        break;
-      default:
-        d += 31 + 28 + (!(y % 4) && ((y % 100) || !(y % 400)));
-        d += ((m - 3) * 153 + 2) / 5;
-        break;
-    }
-    t->tm_yday = d - 1;
-}
-
-/* License: Ruby's */
-static int
-systemtime_to_localtime(TIME_ZONE_INFORMATION *tz, SYSTEMTIME *gst, SYSTEMTIME *lst)
-{
-    TIME_ZONE_INFORMATION stdtz;
-    SYSTEMTIME sst;
-
-    if (!SystemTimeToTzSpecificLocalTime(tz, gst, lst)) return -1;
-    if (!tz) {
-        GetTimeZoneInformation(&stdtz);
-        tz = &stdtz;
-    }
-    if (tz->StandardBias == tz->DaylightBias) return 0;
-    if (!tz->StandardDate.wMonth) return 0;
-    if (!tz->DaylightDate.wMonth) return 0;
-    if (tz != &stdtz) stdtz = *tz;
-
-    stdtz.StandardDate.wMonth = stdtz.DaylightDate.wMonth = 0;
-    if (!SystemTimeToTzSpecificLocalTime(&stdtz, gst, &sst)) return 0;
-    if (lst->wMinute == sst.wMinute && lst->wHour == sst.wHour)
-        return 0;
-    return 1;
-}
-#endif
-
 #ifdef HAVE__GMTIME64_S
 # ifndef HAVE__LOCALTIME64_S
 /* assume same as _gmtime64_s() */
@@ -8115,17 +7975,8 @@ gmtime_r(const time_t *tp, struct tm *rp)
         errno = e;
         return NULL;
     }
-#if RUBY_MSVCRT_VERSION >= 80 || defined(HAVE__GMTIME64_S)
     e = gmtime_s(rp, tp);
     if (e != 0) goto error;
-#else
-    {
-        SYSTEMTIME st;
-        if (unixtime_to_systemtime(*tp, &st)) goto error;
-        rp->tm_isdst = 0;
-        systemtime_to_tm(&st, rp);
-    }
-#endif
     return rp;
 }
 
@@ -8139,17 +7990,8 @@ localtime_r(const time_t *tp, struct tm *rp)
         errno = e;
         return NULL;
     }
-#if RUBY_MSVCRT_VERSION >= 80 || defined(HAVE__LOCALTIME64_S)
     e = localtime_s(rp, tp);
     if (e) goto error;
-#else
-    {
-        SYSTEMTIME gst, lst;
-        if (unixtime_to_systemtime(*tp, &gst)) goto error;
-        rp->tm_isdst = systemtime_to_localtime(NULL, &gst, &lst);
-        systemtime_to_tm(&lst, rp);
-    }
-#endif
     return rp;
 }
 
@@ -8366,10 +8208,6 @@ rb_w32_set_thread_description_str(HANDLE th, VALUE name)
 
 VALUE (*const rb_f_notimplement_)(int, const VALUE *, VALUE, VALUE) = rb_f_notimplement;
 
-#if RUBY_MSVCRT_VERSION < 120
-#include "missing/nextafter.c"
-#endif
-
 void *
 rb_w32_mmap(void *addr, size_t len, int prot, int flags, int fd, rb_off_t offset)
 {