From 8dd737801355427c558876bbcb299926d47b8269 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Thu, 22 Apr 2021 19:21:50 -0700
Subject: [PATCH] delete packed enums from the language

No need for any such thing. Instead, provide an integer tag type for the
enum.
---
 doc/langref.html.in      | 21 +--------------------
 lib/std/os/linux/bpf.zig | 12 ++++++------
 2 files changed, 7 insertions(+), 26 deletions(-)

diff --git a/doc/langref.html.in b/doc/langref.html.in
index 63e4c946b6..155fcbf468 100644
--- a/doc/langref.html.in
+++ b/doc/langref.html.in
@@ -2588,7 +2588,7 @@ test "default struct initialization fields" {
         exactly their bit width.
         </li>
         <li>{#syntax#}bool{#endsyntax#} fields use exactly 1 bit.</li>
-        <li>A {#link|packed enum#} field uses exactly the bit width of its integer tag type.</li>
+        <li>An {#link|enum#} field uses exactly the bit width of its integer tag type.</li>
         <li>A {#link|packed union#} field uses exactly the bit width of the union field with
         the largest bit width.</li>
         <li>Non-ABI-aligned fields are packed into the smallest possible
@@ -2983,25 +2983,6 @@ export fn entry(foo: Foo) void { }
       {#code_end#}
       {#header_close#}
 
-      {#header_open|packed enum#}
-      <p>By default, the size of enums is not guaranteed.</p>
-      <p>{#syntax#}packed enum{#endsyntax#} causes the size of the enum to be the same as the size of the
-      integer tag type of the enum:</p>
-      {#code_begin|test#}
-const std = @import("std");
-
-test "packed enum" {
-    const Number = packed enum(u8) {
-        one,
-        two,
-        three,
-    };
-    std.testing.expect(@sizeOf(Number) == @sizeOf(u8));
-}
-      {#code_end#}
-      <p>This makes the enum eligible to be in a {#link|packed struct#}.</p>
-      {#header_close#}
-
       {#header_open|Enum Literals#}
       <p>
       Enum literals allow specifying the name of an enum field without specifying the enum type:
diff --git a/lib/std/os/linux/bpf.zig b/lib/std/os/linux/bpf.zig
index 0d7e0a19ed..d8b78d5029 100644
--- a/lib/std/os/linux/bpf.zig
+++ b/lib/std/os/linux/bpf.zig
@@ -398,10 +398,10 @@ pub const Insn = packed struct {
 
     /// r0 - r9 are general purpose 64-bit registers, r10 points to the stack
     /// frame
-    pub const Reg = packed enum(u4) { r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10 };
-    const Source = packed enum(u1) { reg, imm };
+    pub const Reg = enum(u4) { r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10 };
+    const Source = enum(u1) { reg, imm };
 
-    const Mode = packed enum(u8) {
+    const Mode = enum(u8) {
         imm = IMM,
         abs = ABS,
         ind = IND,
@@ -410,7 +410,7 @@ pub const Insn = packed struct {
         msh = MSH,
     };
 
-    const AluOp = packed enum(u8) {
+    const AluOp = enum(u8) {
         add = ADD,
         sub = SUB,
         mul = MUL,
@@ -426,14 +426,14 @@ pub const Insn = packed struct {
         arsh = ARSH,
     };
 
-    pub const Size = packed enum(u8) {
+    pub const Size = enum(u8) {
         byte = B,
         half_word = H,
         word = W,
         double_word = DW,
     };
 
-    const JmpOp = packed enum(u8) {
+    const JmpOp = enum(u8) {
         ja = JA,
         jeq = JEQ,
         jgt = JGT,