diff --git a/std/darwin.zig b/std/darwin.zig
index 0bf8b62f58..9f00cc06dc 100644
--- a/std/darwin.zig
+++ b/std/darwin.zig
@@ -1,7 +1,7 @@
 
 const arch = switch (@compileVar("arch")) {
-    x86_64 => @import("darwin_x86_64.zig"),
-    else => @compile_err("unsupported arch"),
+    Arch.x86_64 => @import("darwin_x86_64.zig"),
+    else => @compileError("unsupported arch"),
 };
 
 const errno = @import("errno.zig");
@@ -88,7 +88,7 @@ pub fn fstat(fd: i32, stat_buf: &stat) -> usize {
     arch.syscall2(arch.SYS_fstat, usize(fd), usize(stat_buf))
 }
 
-pub error Unexpected;
+error Unexpected;
 
 pub fn getrandom(buf: &u8, count: usize) -> usize {
     const rr = open_c(c"/dev/urandom", O_LARGEFILE | O_RDONLY, 0);
diff --git a/std/darwin_x86_64.zig b/std/darwin_x86_64.zig
index 2dc98513e9..742f937978 100644
--- a/std/darwin_x86_64.zig
+++ b/std/darwin_x86_64.zig
@@ -57,7 +57,7 @@ pub inline fn syscall3(number: usize, arg1: usize, arg2: usize, arg3: usize) ->
 
 
 
-export struct stat {
+pub const stat = extern struct {
     dev: u32,
     mode: u16,
     nlink: u16,
@@ -78,9 +78,9 @@ export struct stat {
     lspare: i32,
     qspare: [2]u64,
 
-}
+};
 
-export struct timespec {
+pub const timespec = extern struct {
     tv_sec: isize,
     tv_nsec: isize,
-}
+};
diff --git a/std/debug.zig b/std/debug.zig
index 2f78a6c7ce..05e895db5d 100644
--- a/std/debug.zig
+++ b/std/debug.zig
@@ -5,9 +5,9 @@ const elf = @import("elf.zig");
 const DW = @import("dwarf.zig");
 const List = @import("list.zig").List;
 
-pub error MissingDebugInfo;
-pub error InvalidDebugInfo;
-pub error UnsupportedDebugInfo;
+error MissingDebugInfo;
+error InvalidDebugInfo;
+error UnsupportedDebugInfo;
 
 pub fn assert(b: bool) {
     if (!b) @unreachable()
@@ -20,7 +20,7 @@ pub fn printStackTrace() -> %void {
 
 pub fn writeStackTrace(out_stream: &io.OutStream) -> %void {
     switch (@compileVar("object_format")) {
-        elf => {
+        ObjectFormat.elf => {
             var stack_trace = ElfStackTrace {
                 .self_exe_stream = undefined,
                 .elf = undefined,
@@ -57,13 +57,13 @@ pub fn writeStackTrace(out_stream: &io.OutStream) -> %void {
                 maybe_fp = *(&const ?&const u8)(fp);
             }
         },
-        coff => {
+        ObjectFormat.coff => {
             out_stream.write("(stack trace unavailable for COFF object format)\n");
         },
-        macho => {
+        ObjectFormat.macho => {
             %return out_stream.write("(stack trace unavailable for Mach-O object format)\n");
         },
-        unknown => {
+        ObjectFormat.unknown => {
             out_stream.write("(stack trace unavailable for unknown object format)\n");
         },
     }
diff --git a/std/elf.zig b/std/elf.zig
index f2d597fb98..40e24f56af 100644
--- a/std/elf.zig
+++ b/std/elf.zig
@@ -4,7 +4,7 @@ const math = @import("math.zig");
 const mem = @import("mem.zig");
 const debug = @import("debug.zig");
 
-pub error InvalidFormat;
+error InvalidFormat;
 
 pub const SHT_NULL = 0;
 pub const SHT_PROGBITS = 1;
diff --git a/std/index.zig b/std/index.zig
index 0b7333b138..0f6fe974ef 100644
--- a/std/index.zig
+++ b/std/index.zig
@@ -10,11 +10,11 @@ pub const hash_map = @import("hash_map.zig");
 pub const mem = @import("mem.zig");
 pub const debug = @import("debug.zig");
 pub const linux = switch(@compileVar("os")) {
-    linux => @import("linux.zig"),
+    Os.linux => @import("linux.zig"),
     else => null_import,
 };
 pub const darwin = switch(@compileVar("os")) {
-    darwin => @import("darwin.zig"),
+    Os.darwin => @import("darwin.zig"),
     else => null_import,
 };
 const null_import = @import("empty.zig");
diff --git a/std/linux.zig b/std/linux.zig
index 813a2ea824..de6712507c 100644
--- a/std/linux.zig
+++ b/std/linux.zig
@@ -456,9 +456,9 @@ pub fn accept4(fd: i32, noalias addr: &sockaddr, noalias len: &socklen_t, flags:
     arch.syscall4(arch.SYS_accept4, usize(fd), usize(addr), usize(len), flags)
 }
 
-// pub error NameTooLong;
-// pub error SystemResources;
-// pub error Io;
+// error NameTooLong;
+// error SystemResources;
+// error Io;
 // 
 // pub fn if_nametoindex(name: []u8) -> %u32 {
 //     var ifr: ifreq = undefined;
diff --git a/std/mem.zig b/std/mem.zig
index 03d131c95d..451e2c2167 100644
--- a/std/mem.zig
+++ b/std/mem.zig
@@ -5,7 +5,7 @@ const io = @import("io.zig");
 
 pub const Cmp = math.Cmp;
 
-pub error NoMem;
+error NoMem;
 
 pub type Context = u8;
 pub const Allocator = struct {
diff --git a/std/net.zig b/std/net.zig
index d6ff2b7cff..7464e9c7e7 100644
--- a/std/net.zig
+++ b/std/net.zig
@@ -3,15 +3,15 @@ const errno = @import("errno.zig");
 const assert = @import("debug.zig").assert;
 const endian = @import("endian.zig");
 
-pub error SigInterrupt;
-pub error Unexpected;
-pub error Io;
-pub error TimedOut;
-pub error ConnectionReset;
-pub error ConnectionRefused;
-pub error NoMem;
-pub error NotSocket;
-pub error BadFd;
+error SigInterrupt;
+error Unexpected;
+error Io;
+error TimedOut;
+error ConnectionReset;
+error ConnectionRefused;
+error NoMem;
+error NotSocket;
+error BadFd;
 
 const Connection = struct {
     socket_fd: i32,
@@ -139,7 +139,7 @@ pub fn connect(hostname: []const u8, port: u16) -> %Connection {
     return connectAddr(main_addr, port);
 }
 
-pub error InvalidIpLiteral;
+error InvalidIpLiteral;
 
 pub fn parseIpLiteral(buf: []const u8) -> %Address {
     switch (parseIp4(buf)) {
diff --git a/std/os.zig b/std/os.zig
index 8def16601d..6c2bcd71ea 100644
--- a/std/os.zig
+++ b/std/os.zig
@@ -1,11 +1,11 @@
 const system = switch(@compileVar("os")) {
-    linux => @import("linux.zig"),
-    darwin => @import("darwin.zig"),
+    Os.linux => @import("linux.zig"),
+    Os.darwin => @import("darwin.zig"),
     else => @compileError("Unsupported OS"),
 };
 const errno = @import("errno.zig");
 
-pub error Unexpected;
+error Unexpected;
 
 pub fn getRandomBytes(buf: []u8) -> %void {
     while (true) {