diff --git a/lib/std/core/string.c3 b/lib/std/core/string.c3
index a7c91a0e3..645b71c76 100644
--- a/lib/std/core/string.c3
+++ b/lib/std/core/string.c3
@@ -2,6 +2,7 @@ module std::core::string;
 import std::ascii;
 
 def ZString = distinct inline char*;
+def WString = distinct inline Char16*;
 def Char32 = uint;
 def Char16 = ushort;
 
@@ -352,6 +353,8 @@ fn Char16[]! String.to_utf16(String s, Allocator* using = mem::heap())
 	return data[:len16];
 }
 
+fn WString! String.to_wstring(String s, Allocator* using = mem::heap()) => (WString)s.to_utf16(using).ptr;
+
 fn Char32[]! String.to_utf32(String s, Allocator* using = mem::heap())
 {
 	usz codepoints = conv::utf8_codepoints(s);
@@ -405,11 +408,11 @@ fn String! from_utf16(Char16[] utf16, Allocator* using = mem::heap())
 	return (String)data[:len];
 }
 
-fn String! from_zutf16(Char16* utf16_pointer, Allocator* using = mem::heap())
+fn String! from_wstring(WString wstring, Allocator* using = mem::heap())
 {
 	usz utf16_len;
-	while (utf16_pointer[utf16_len] != 0) utf16_len++;
-	Char16[] utf16 = utf16_pointer[:utf16_len];
+	while (wstring[utf16_len] != 0) utf16_len++;
+	Char16[] utf16 = wstring[:utf16_len];
 	return from_utf16(utf16, using);
 }
 
@@ -497,6 +500,7 @@ macro String.to_integer(string, $Type)
 
 
 fn Char16[]! String.to_temp_utf16(s) => s.to_utf16(mem::temp());
+fn WString! String.to_temp_wstring(s) => s.to_wstring(mem::temp());
 
 fn int128! String.to_int128(s) => s.to_integer(int128);
 fn long! String.to_long(s) => s.to_integer(long);
diff --git a/lib/std/io/os/file_libc.c3 b/lib/std/io/os/file_libc.c3
index 3b1dd352b..2a9abbfe8 100644
--- a/lib/std/io/os/file_libc.c3
+++ b/lib/std/io/os/file_libc.c3
@@ -10,7 +10,7 @@ fn void*! native_fopen(String filename, String mode) @inline
 	@pool()
 	{
 		$if env::WIN32:
-			void* file = libc::_wfopen(filename.to_temp_utf16(), filename.to_temp_utf16())!;
+			void* file = libc::_wfopen(filename.to_temp_wstring(), filename.to_temp_wstring())!;
 		$else
 			void* file = libc::fopen(filename.zstr_tcopy(), mode.zstr_tcopy());
 		$endif
@@ -23,7 +23,7 @@ fn void! native_remove(String filename)
 	@pool()
 	{
 		$if env::WIN32:
-			CInt result = libc::_wremove(filename.to_temp_utf16())!;
+			CInt result = libc::_wremove(filename.to_temp_wstring())!;
 		$else
 			CInt result = libc::remove(filename.zstr_tcopy());
 		$endif
@@ -50,7 +50,7 @@ fn void*! native_freopen(void* file, String filename, String mode) @inline
 	@pool()
 	{
 		$if env::WIN32:
-			file = libc::_wfreopen(filename.to_temp_utf16(), mode.to_temp_utf16(), file)!;
+			file = libc::_wfreopen(filename.to_temp_wstring(), mode.to_temp_wstring(), file)!;
 		$else
 			file = libc::freopen(filename.zstr_tcopy(), mode.zstr_tcopy(), file);
 		$endif
diff --git a/lib/std/io/os/fileinfo.c3 b/lib/std/io/os/fileinfo.c3
index 4352eab2f..d8a73163a 100644
--- a/lib/std/io/os/fileinfo.c3
+++ b/lib/std/io/os/fileinfo.c3
@@ -44,9 +44,8 @@ fn usz! native_file_size(String path) @if(env::WIN32)
 {
 	@pool()
 	{
-		Char16[] path16 = path.to_temp_utf16()!;
 		Win32_FILE_ATTRIBUTE_DATA data;
-		win32::getFileAttributesExW(path16, Win32_GET_FILEEX_INFO_LEVELS.STANDARD, &data);
+		win32::getFileAttributesExW(path.to_temp_wstring()!, Win32_GET_FILEEX_INFO_LEVELS.STANDARD, &data);
 		Win32_LARGE_INTEGER size;
 		size.lowPart = data.nFileSizeLow;
 		size.highPart = data.nFileSizeHigh;
diff --git a/lib/std/io/os/getcwd.c3 b/lib/std/io/os/getcwd.c3
index 010915cb8..ba737fca5 100644
--- a/lib/std/io/os/getcwd.c3
+++ b/lib/std/io/os/getcwd.c3
@@ -7,7 +7,7 @@ macro String! getcwd(Allocator* using = mem::heap())
 		$case env::WIN32:
 			const DEFAULT_BUFFER = 256;
 			Char16[DEFAULT_BUFFER] buffer;
-			Char16 *res = win32::_wgetcwd(&buffer, DEFAULT_BUFFER);
+			WString res = win32::_wgetcwd(&buffer, DEFAULT_BUFFER);
 			bool free = false;
 			defer if (free) libc::free(res);
 			if (!res)
diff --git a/lib/std/io/os/ls.c3 b/lib/std/io/os/ls.c3
index f41006d89..e7d30309f 100644
--- a/lib/std/io/os/ls.c3
+++ b/lib/std/io/os/ls.c3
@@ -28,7 +28,7 @@ fn PathList! native_ls(Path dir, bool no_dirs, bool no_symlinks, String mask, Al
 	list.init(.using = using);
     @stack_mem(1024; Allocator* mem)
     {
-	    Char16* result = dir.as_str().concat(`\*`).to_utf16(.using = mem)!!;
+	    WString result = dir.as_str().concat(`\*`).to_wstring(.using = mem)!!;
 	    Win32_WIN32_FIND_DATAW find_data;
         Win32_HANDLE find = win32::findFirstFileW(result, &find_data);
         if (find == win32::INVALID_HANDLE_VALUE) return IoError.CANNOT_READ_DIR?;
@@ -38,7 +38,7 @@ fn PathList! native_ls(Path dir, bool no_dirs, bool no_symlinks, String mask, Al
             if (no_dirs && (find_data.dwFileAttributes & win32::FILE_ATTRIBUTE_DIRECTORY)) continue;
             @stack_mem(480; Allocator* mem2)
             {
-				String filename = string::from_zutf16(&find_data.cFileName, mem2)!;
+				String filename = string::from_wstring((WString)&find_data.cFileName, mem2)!;
                 if (filename == ".." || filename == ".") continue;
 	            list.append(path::new(filename, using));
             };
diff --git a/lib/std/io/os/rmtree.c3 b/lib/std/io/os/rmtree.c3
index 7849285dd..0f224b62e 100644
--- a/lib/std/io/os/rmtree.c3
+++ b/lib/std/io/os/rmtree.c3
@@ -44,17 +44,20 @@ fn void! native_rmtree(Path path)
     defer win32::findClose(find);
 	do
 	{
-		String filename = string::from_zutf16(&find_data.cFileName, mem::temp())!;
-		if (filename == "." || filename == "..") continue;
-		Path file_path = path.tappend(filename)!;
-		if (find_data.dwFileAttributes & win32::FILE_ATTRIBUTE_DIRECTORY)
+		@pool()
 		{
-			native_rmtree(file_path)!;
-		}
-		else
-		{
-			win32::deleteFileW(file_path.as_str().to_utf16(mem::temp()));
-		}
+			String filename = string::from_wstring((WString)&find_data.cFileName, mem::temp())!;
+			if (filename == "." || filename == "..") continue;
+			Path file_path = path.tappend(filename)!;
+			if (find_data.dwFileAttributes & win32::FILE_ATTRIBUTE_DIRECTORY)
+			{
+				native_rmtree(file_path)!;
+			}
+			else
+			{
+				win32::deleteFileW(file_path.as_str().to_temp_wstring()!!);
+			}
+		};
 	} while (win32::findNextFileW(find, &find_data) != 0);
     os::native_rmdir(path)!;
 }
diff --git a/lib/std/io/path.c3 b/lib/std/io/path.c3
index 6eb6835b2..6f7ac8164 100644
--- a/lib/std/io/path.c3
+++ b/lib/std/io/path.c3
@@ -111,11 +111,11 @@ fn Path! new(String path, Allocator* using = mem::heap(), PathEnv path_env = DEF
 	return { normalize(path.copy(using), path_env), path_env };
 }
 
-fn Path! new_win32_zutf16(Char16* path, Allocator* using = mem::heap())
+fn Path! new_win32_wstring(WString path, Allocator* using = mem::heap())
 {
 	@stack_mem(480; Allocator* mem)
 	{
-		return path::new(string::from_zutf16(path, .using = mem)!, .using = using);
+		return path::new(string::from_wstring(path, .using = mem)!, .using = using);
 	};
 }
 
diff --git a/lib/std/libc/os/win32.c3 b/lib/std/libc/os/win32.c3
index 549206663..b66169fa0 100644
--- a/lib/std/libc/os/win32.c3
+++ b/lib/std/libc/os/win32.c3
@@ -16,10 +16,10 @@ extern fn Time_t _mktime64(Tm *timeptr); def mktime = _mktime64;
 extern fn usz _msize(void* ptr);
 extern fn CInt _read(Fd fd, void* buffer, CUInt buffer_size);
 extern fn CInt _setjmp(void* frameptr, JmpBuf* buffer) @if(env::WIN32);
-extern fn CFile _wfopen(Char16*, Char16*);
-extern fn CFile _wfreopen(Char16*, Char16*, CFile);
+extern fn CFile _wfopen(WString, WString);
+extern fn CFile _wfreopen(WString, WString, CFile);
 extern fn CInt _write(Fd fd, void* buffer, CUInt count);
-extern fn CInt _wremove(Char16*);
+extern fn CInt _wremove(WString);
 
 // Aliases to simplify libc use
 macro Tm* localtime_r(Time_t* timer, Tm* buf) => _localtime64_s(buf, timer);
diff --git a/lib/std/os/subprocess.c3 b/lib/std/os/subprocess.c3
index d7d8a200d..177017a10 100644
--- a/lib/std/os/subprocess.c3
+++ b/lib/std/os/subprocess.c3
@@ -73,7 +73,7 @@ fn void! create_named_pipe_helper(void** rd, void **wr) @local @if(env::WIN32)
 	};
 }
 
-fn Char16* convert_command_line_win32(String[] command_line) @inline @if(env::WIN32) @local
+fn WString convert_command_line_win32(String[] command_line) @inline @if(env::WIN32) @local
 {
 	DString str;
 	str.tinit(512);
@@ -113,7 +113,7 @@ fn Char16* convert_command_line_win32(String[] command_line) @inline @if(env::WI
 		str.append('"');
 	}
 	str.append('\0');
-	return str.as_str().to_utf16(.using = mem::temp())!!;
+	return str.as_str().to_temp_wstring()!!;
 }
 
 /**
@@ -139,7 +139,7 @@ fn SubProcess! create(String[] command_line, SubProcessOptions options = {}, Str
 	CFile stderr;
     @pool()
     {
-        Char16* used_environment = null;
+        WString used_environment = null;
         if (!options.inherit_environment)
         {
 	        DString env;
@@ -154,7 +154,7 @@ fn SubProcess! create(String[] command_line, SubProcessOptions options = {}, Str
 				env.append("\0");
 			}
 			env.append("\0");
-			used_environment = env.as_str().to_utf16(.using = mem::temp()).ptr!;
+			used_environment = env.as_str().to_temp_wstring()!;
 		}
 		int fd = win32::_open_osfhandle((iptr)wr, 0);
     	if (fd != -1)
diff --git a/lib/std/os/win32/files.c3 b/lib/std/os/win32/files.c3
index e0c1a1517..c51c4ec0a 100644
--- a/lib/std/os/win32/files.c3
+++ b/lib/std/os/win32/files.c3
@@ -90,18 +90,18 @@ extern fn Win32_BOOL readFile(Win32_HANDLE hFile, Win32_LPVOID lpBuffer, Win32_D
   Win32_LPDWORD lpNumberOfBytesRead, Win32_LPOVERLAPPED lpOverlapped
 ) @extern("ReadFile");
 
-extern fn Char16* _wgetcwd(Char16* buffer, int maxlen);
-extern fn usz wcslen(Char16* str);
+extern fn WString _wgetcwd(Char16* buffer, int maxlen);
+extern fn usz wcslen(WString str);
 
 extern fn int _open_osfhandle(iptr osfhandle, int flags);
 extern fn iptr _get_osfhandle(int fd);
 extern fn CFile _fdopen(int fd, ZString mode);
 extern fn CInt _access(ZString path, CInt mode);
-extern fn CInt _waccess(Char16* path, CInt mode);
+extern fn CInt _waccess(WString path, CInt mode);
 
 /*
 extern ulong _win32_GetCurrentDirectoryW(ulong, Char16* buffer) @extern("GetCurrentDirectoryW");
-extern bool _win32_CreateSymbolicLinkW(Char16* symlink_file, Char16* target_file, ulong flags) @extern("CreateSymbolicLinkW");
-extern bool _win32_CopyFileW(Char16* from_file, Char16* to_file, bool no_overwrite) @extern("CopyFileW");
-extern ulong _win32_GetFullPathNameW(Char16* file_name, ulong buffer_len, Char16* buffer, Char16** file_part) @extern("GetFullPathNameW");
+extern bool _win32_CreateSymbolicLinkW(WString symlink_file, WString target_file, ulong flags) @extern("CreateSymbolicLinkW");
+extern bool _win32_CopyFileW(WString from_file, WString to_file, bool no_overwrite) @extern("CopyFileW");
+extern ulong _win32_GetFullPathNameW(WString file_name, ulong buffer_len, Char16* buffer, WString* file_part) @extern("GetFullPathNameW");
 */
diff --git a/lib/std/os/win32/types.c3 b/lib/std/os/win32/types.c3
index 459d5a334..7b980c792 100644
--- a/lib/std/os/win32/types.c3
+++ b/lib/std/os/win32/types.c3
@@ -88,7 +88,7 @@ def Win32_PCHAR = Win32_CHAR*;
 def Win32_PCSTR = Win32_CHAR*;
 def Win32_PCTSTR = Win32_LPCWSTR;
 def Win32_PCUNICODE_STRING = Win32_UNICODE_STRING*;
-def Win32_PCWSTR = Char16*;
+def Win32_PCWSTR = WString;
 def Win32_PDWORD = Win32_DWORD*;
 def Win32_PDWORDLONG = Win32_DWORDLONG*;
 def Win32_PDWORDPTR = Win32_DWORD_PTR*;