Commit 099f3c4039

Tristan Ross <tristan.ross@midstall.com>
2024-02-19 03:28:39
std.builtin: make container layout fields lowercase
1 parent d0c06ca
lib/compiler/aro/aro/Attribute.zig
@@ -653,7 +653,7 @@ pub const Arguments = blk: {
 
     break :blk @Type(.{
         .Union = .{
-            .layout = .Auto,
+            .layout = .auto,
             .tag_type = null,
             .fields = &union_fields,
             .decls = &.{},
lib/std/io/Reader.zig
@@ -326,7 +326,7 @@ pub fn isBytes(self: Self, slice: []const u8) anyerror!bool {
 
 pub fn readStruct(self: Self, comptime T: type) anyerror!T {
     // Only extern and packed structs have defined in-memory layout.
-    comptime assert(@typeInfo(T).Struct.layout != .Auto);
+    comptime assert(@typeInfo(T).Struct.layout != .auto);
     var res: [1]T = undefined;
     try self.readNoEof(mem.sliceAsBytes(res[0..]));
     return res[0];
lib/std/io/Writer.zig
@@ -55,7 +55,7 @@ pub inline fn writeInt(self: Self, comptime T: type, value: T, endian: std.built
 
 pub fn writeStruct(self: Self, value: anytype) anyerror!void {
     // Only extern and packed structs have defined in-memory layout.
-    comptime assert(@typeInfo(@TypeOf(value)).Struct.layout != .Auto);
+    comptime assert(@typeInfo(@TypeOf(value)).Struct.layout != .auto);
     return self.writeAll(mem.asBytes(&value));
 }
 
lib/std/meta/trailer_flags.zig
@@ -32,7 +32,7 @@ pub fn TrailerFlags(comptime Fields: type) type {
             }
             break :blk @Type(.{
                 .Struct = .{
-                    .layout = .Auto,
+                    .layout = .auto,
                     .fields = &fields,
                     .decls = &.{},
                     .is_tuple = false,
lib/std/zig/AstGen.zig
@@ -175,7 +175,7 @@ pub fn generate(gpa: Allocator, tree: Ast) Allocator.Error!Zir {
             &gen_scope.base,
             0,
             tree.containerDeclRoot(),
-            .Auto,
+            .auto,
             0,
         )) |struct_decl_ref| {
             assert(struct_decl_ref.toIndex().? == .main_struct_inst);
@@ -4907,7 +4907,7 @@ fn structDeclInner(
     var backing_int_body_len: usize = 0;
     const backing_int_ref: Zir.Inst.Ref = blk: {
         if (backing_int_node != 0) {
-            if (layout != .Packed) {
+            if (layout != .@"packed") {
                 return astgen.failNode(backing_int_node, "non-packed struct does not support backing integer type", .{});
             } else {
                 const backing_int_ref = try typeExpr(&block_scope, &namespace.base, backing_int_node);
@@ -4958,9 +4958,9 @@ fn structDeclInner(
     } else false;
 
     if (is_tuple) switch (layout) {
-        .Auto => {},
-        .Extern => return astgen.failNode(node, "extern tuples are not supported", .{}),
-        .Packed => return astgen.failNode(node, "packed tuples are not supported", .{}),
+        .auto => {},
+        .@"extern" => return astgen.failNode(node, "extern tuples are not supported", .{}),
+        .@"packed" => return astgen.failNode(node, "packed tuples are not supported", .{}),
     };
 
     if (is_tuple) for (container_decl.ast.members) |member_node| {
@@ -5055,9 +5055,9 @@ fn structDeclInner(
 
         if (is_comptime) {
             switch (layout) {
-                .Packed => return astgen.failTok(member.comptime_token.?, "packed struct fields cannot be marked comptime", .{}),
-                .Extern => return astgen.failTok(member.comptime_token.?, "extern struct fields cannot be marked comptime", .{}),
-                .Auto => any_comptime_fields = true,
+                .@"packed" => return astgen.failTok(member.comptime_token.?, "packed struct fields cannot be marked comptime", .{}),
+                .@"extern" => return astgen.failTok(member.comptime_token.?, "extern struct fields cannot be marked comptime", .{}),
+                .auto => any_comptime_fields = true,
             }
         } else {
             known_non_opv = known_non_opv or
@@ -5082,7 +5082,7 @@ fn structDeclInner(
         }
 
         if (have_align) {
-            if (layout == .Packed) {
+            if (layout == .@"packed") {
                 try astgen.appendErrorNode(member.ast.align_expr, "unable to override alignment of packed struct fields", .{});
             }
             any_aligned_fields = true;
@@ -5229,12 +5229,11 @@ fn unionDeclInner(
     const decl_count = try astgen.scanDecls(&namespace, members);
     const field_count: u32 = @intCast(members.len - decl_count);
 
-    if (layout != .Auto and (auto_enum_tok != null or arg_node != 0)) {
-        const layout_str = if (layout == .Extern) "extern" else "packed";
+    if (layout != .auto and (auto_enum_tok != null or arg_node != 0)) {
         if (arg_node != 0) {
-            return astgen.failNode(arg_node, "{s} union does not support enum tag type", .{layout_str});
+            return astgen.failNode(arg_node, "{s} union does not support enum tag type", .{@tagName(layout)});
         } else {
-            return astgen.failTok(auto_enum_tok.?, "{s} union does not support enum tag type", .{layout_str});
+            return astgen.failTok(auto_enum_tok.?, "{s} union does not support enum tag type", .{@tagName(layout)});
         }
     }
 
@@ -5429,21 +5428,21 @@ fn containerDecl(
 
     switch (token_tags[container_decl.ast.main_token]) {
         .keyword_struct => {
-            const layout = if (container_decl.layout_token) |t| switch (token_tags[t]) {
-                .keyword_packed => std.builtin.Type.ContainerLayout.Packed,
-                .keyword_extern => std.builtin.Type.ContainerLayout.Extern,
+            const layout: std.builtin.Type.ContainerLayout = if (container_decl.layout_token) |t| switch (token_tags[t]) {
+                .keyword_packed => .@"packed",
+                .keyword_extern => .@"extern",
                 else => unreachable,
-            } else std.builtin.Type.ContainerLayout.Auto;
+            } else .auto;
 
             const result = try structDeclInner(gz, scope, node, container_decl, layout, container_decl.ast.arg);
             return rvalue(gz, ri, result, node);
         },
         .keyword_union => {
-            const layout = if (container_decl.layout_token) |t| switch (token_tags[t]) {
-                .keyword_packed => std.builtin.Type.ContainerLayout.Packed,
-                .keyword_extern => std.builtin.Type.ContainerLayout.Extern,
+            const layout: std.builtin.Type.ContainerLayout = if (container_decl.layout_token) |t| switch (token_tags[t]) {
+                .keyword_packed => .@"packed",
+                .keyword_extern => .@"extern",
                 else => unreachable,
-            } else std.builtin.Type.ContainerLayout.Auto;
+            } else .auto;
 
             const result = try unionDeclInner(gz, scope, node, container_decl.ast.members, layout, container_decl.ast.arg, container_decl.ast.enum_token);
             return rvalue(gz, ri, result, node);
lib/std/zig/Server.zig
@@ -250,18 +250,18 @@ fn bswap(x: anytype) @TypeOf(x) {
         .Enum => return @as(T, @enumFromInt(@byteSwap(@intFromEnum(x)))),
         .Int => return @byteSwap(x),
         .Struct => |info| switch (info.layout) {
-            .Extern => {
+            .@"extern" => {
                 var result: T = undefined;
                 inline for (info.fields) |field| {
                     @field(result, field.name) = bswap(@field(x, field.name));
                 }
                 return result;
             },
-            .Packed => {
+            .@"packed" => {
                 const I = info.backing_integer.?;
                 return @as(T, @bitCast(@byteSwap(@as(I, @bitCast(x)))));
             },
-            .Auto => @compileError("auto layout struct"),
+            .auto => @compileError("auto layout struct"),
         },
         else => @compileError("bswap on type " ++ @typeName(T)),
     }
lib/std/builtin.zig
@@ -334,9 +334,9 @@ pub const Type = union(enum) {
     /// This data structure is used by the Zig language code generation and
     /// therefore must be kept in sync with the compiler implementation.
     pub const ContainerLayout = enum(u2) {
-        Auto,
-        Extern,
-        Packed,
+        auto,
+        @"extern",
+        @"packed",
     };
 
     /// This data structure is used by the Zig language code generation and
@@ -353,7 +353,7 @@ pub const Type = union(enum) {
     /// therefore must be kept in sync with the compiler implementation.
     pub const Struct = struct {
         layout: ContainerLayout,
-        /// Only valid if layout is .Packed
+        /// Only valid if layout is .@"packed"
         backing_integer: ?type = null,
         fields: []const StructField,
         decls: []const Declaration,
lib/std/enums.zig
@@ -22,7 +22,7 @@ pub fn EnumFieldStruct(comptime E: type, comptime Data: type, comptime field_def
         }};
     }
     return @Type(.{ .Struct = .{
-        .layout = .Auto,
+        .layout = .auto,
         .fields = fields,
         .decls = &.{},
         .is_tuple = false,
lib/std/io.zig
@@ -688,7 +688,7 @@ pub fn PollFiles(comptime StreamEnum: type) type {
         };
     }
     return @Type(.{ .Struct = .{
-        .layout = .Auto,
+        .layout = .auto,
         .fields = &struct_fields,
         .decls = &.{},
         .is_tuple = false,
lib/std/mem.zig
@@ -238,7 +238,7 @@ pub fn zeroes(comptime T: type) T {
         },
         .Struct => |struct_info| {
             if (@sizeOf(T) == 0) return undefined;
-            if (struct_info.layout == .Extern) {
+            if (struct_info.layout == .@"extern") {
                 var item: T = undefined;
                 @memset(asBytes(&item), 0);
                 return item;
@@ -284,7 +284,7 @@ pub fn zeroes(comptime T: type) T {
             return @splat(zeroes(info.child));
         },
         .Union => |info| {
-            if (info.layout == .Extern) {
+            if (info.layout == .@"extern") {
                 var item: T = undefined;
                 @memset(asBytes(&item), 0);
                 return item;
@@ -429,7 +429,7 @@ pub fn zeroInit(comptime T: type, init: anytype) T {
                         }
                     }
 
-                    var value: T = if (struct_info.layout == .Extern) zeroes(T) else undefined;
+                    var value: T = if (struct_info.layout == .@"extern") zeroes(T) else undefined;
 
                     inline for (struct_info.fields, 0..) |field, i| {
                         if (field.is_comptime) {
lib/std/meta.zig
@@ -269,12 +269,12 @@ test containerLayout {
         a: u8,
     };
 
-    try testing.expect(containerLayout(S1) == .Auto);
-    try testing.expect(containerLayout(S2) == .Packed);
-    try testing.expect(containerLayout(S3) == .Extern);
-    try testing.expect(containerLayout(U1) == .Auto);
-    try testing.expect(containerLayout(U2) == .Packed);
-    try testing.expect(containerLayout(U3) == .Extern);
+    try testing.expect(containerLayout(S1) == .auto);
+    try testing.expect(containerLayout(S2) == .@"packed");
+    try testing.expect(containerLayout(S3) == .@"extern");
+    try testing.expect(containerLayout(U1) == .auto);
+    try testing.expect(containerLayout(U2) == .@"packed");
+    try testing.expect(containerLayout(U3) == .@"extern");
 }
 
 /// Instead of this function, prefer to use e.g. `@typeInfo(foo).Struct.decls`
@@ -1025,7 +1025,7 @@ fn CreateUniqueTuple(comptime N: comptime_int, comptime types: [N]type) type {
     return @Type(.{
         .Struct = .{
             .is_tuple = true,
-            .layout = .Auto,
+            .layout = .auto,
             .decls = &.{},
             .fields = &tuple_fields,
         },
lib/std/multi_array_list.zig
@@ -558,7 +558,7 @@ pub fn MultiArrayList(comptime T: type) type {
                 .alignment = fields[i].alignment,
             };
             break :entry @Type(.{ .Struct = .{
-                .layout = .Extern,
+                .layout = .@"extern",
                 .fields = &entry_fields,
                 .decls = &.{},
                 .is_tuple = false,
src/arch/aarch64/abi.zig
@@ -21,7 +21,7 @@ pub fn classifyType(ty: Type, mod: *Module) Class {
     var maybe_float_bits: ?u16 = null;
     switch (ty.zigTypeTag(mod)) {
         .Struct => {
-            if (ty.containerLayout(mod) == .Packed) return .byval;
+            if (ty.containerLayout(mod) == .@"packed") return .byval;
             const float_count = countFloats(ty, mod, &maybe_float_bits);
             if (float_count <= sret_float_count) return .{ .float_array = float_count };
 
@@ -31,7 +31,7 @@ pub fn classifyType(ty: Type, mod: *Module) Class {
             return .integer;
         },
         .Union => {
-            if (ty.containerLayout(mod) == .Packed) return .byval;
+            if (ty.containerLayout(mod) == .@"packed") return .byval;
             const float_count = countFloats(ty, mod, &maybe_float_bits);
             if (float_count <= sret_float_count) return .{ .float_array = float_count };
 
src/arch/arm/abi.zig
@@ -33,7 +33,7 @@ pub fn classifyType(ty: Type, mod: *Module, ctx: Context) Class {
     switch (ty.zigTypeTag(mod)) {
         .Struct => {
             const bit_size = ty.bitSize(mod);
-            if (ty.containerLayout(mod) == .Packed) {
+            if (ty.containerLayout(mod) == .@"packed") {
                 if (bit_size > 64) return .memory;
                 return .byval;
             }
@@ -56,7 +56,7 @@ pub fn classifyType(ty: Type, mod: *Module, ctx: Context) Class {
         .Union => {
             const bit_size = ty.bitSize(mod);
             const union_obj = mod.typeToUnion(ty).?;
-            if (union_obj.getLayout(ip) == .Packed) {
+            if (union_obj.getLayout(ip) == .@"packed") {
                 if (bit_size > 64) return .memory;
                 return .byval;
             }
src/arch/riscv64/abi.zig
@@ -15,7 +15,7 @@ pub fn classifyType(ty: Type, mod: *Module) Class {
     switch (ty.zigTypeTag(mod)) {
         .Struct => {
             const bit_size = ty.bitSize(mod);
-            if (ty.containerLayout(mod) == .Packed) {
+            if (ty.containerLayout(mod) == .@"packed") {
                 if (bit_size > max_byval_size) return .memory;
                 return .byval;
             }
@@ -44,7 +44,7 @@ pub fn classifyType(ty: Type, mod: *Module) Class {
         },
         .Union => {
             const bit_size = ty.bitSize(mod);
-            if (ty.containerLayout(mod) == .Packed) {
+            if (ty.containerLayout(mod) == .@"packed") {
                 if (bit_size > max_byval_size) return .memory;
                 return .byval;
             }
src/arch/wasm/abi.zig
@@ -29,7 +29,7 @@ pub fn classifyType(ty: Type, mod: *Module) [2]Class {
     switch (ty.zigTypeTag(mod)) {
         .Struct => {
             const struct_type = mod.typeToStruct(ty).?;
-            if (struct_type.layout == .Packed) {
+            if (struct_type.layout == .@"packed") {
                 if (ty.bitSize(mod) <= 64) return direct;
                 return .{ .direct, .direct };
             }
@@ -70,7 +70,7 @@ pub fn classifyType(ty: Type, mod: *Module) [2]Class {
         },
         .Union => {
             const union_obj = mod.typeToUnion(ty).?;
-            if (union_obj.getLayout(ip) == .Packed) {
+            if (union_obj.getLayout(ip) == .@"packed") {
                 if (ty.bitSize(mod) <= 64) return direct;
                 return .{ .direct, .direct };
             }
@@ -113,7 +113,7 @@ pub fn scalarType(ty: Type, mod: *Module) Type {
         },
         .Union => {
             const union_obj = mod.typeToUnion(ty).?;
-            if (union_obj.getLayout(ip) != .Packed) {
+            if (union_obj.getLayout(ip) != .@"packed") {
                 const layout = mod.getUnionLayout(union_obj);
                 if (layout.payload_size == 0 and layout.tag_size != 0) {
                     return scalarType(ty.unionTagTypeSafety(mod).?, mod);
src/arch/wasm/CodeGen.zig
@@ -1018,7 +1018,7 @@ fn typeToValtype(ty: Type, mod: *Module) wasm.Valtype {
             .unrolled => wasm.Valtype.i32,
         },
         .Union => switch (ty.containerLayout(mod)) {
-            .Packed => {
+            .@"packed" => {
                 const int_ty = mod.intType(.unsigned, @as(u16, @intCast(ty.bitSize(mod)))) catch @panic("out of memory");
                 return typeToValtype(int_ty, mod);
             },
@@ -1737,7 +1737,7 @@ fn isByRef(ty: Type, mod: *Module) bool {
         => return ty.hasRuntimeBitsIgnoreComptime(mod),
         .Union => {
             if (mod.typeToUnion(ty)) |union_obj| {
-                if (union_obj.getLayout(ip) == .Packed) {
+                if (union_obj.getLayout(ip) == .@"packed") {
                     return ty.abiSize(mod) > 8;
                 }
             }
@@ -3097,7 +3097,7 @@ fn lowerParentPtr(func: *CodeGen, ptr_val: Value, offset: u32) InnerError!WValue
                     break :blk parent_ty.structFieldOffset(field_index, mod);
                 },
                 .Union => switch (parent_ty.containerLayout(mod)) {
-                    .Packed => 0,
+                    .@"packed" => 0,
                     else => blk: {
                         const layout: Module.UnionLayout = parent_ty.unionGetLayout(mod);
                         if (layout.payload_size == 0) break :blk 0;
@@ -3358,7 +3358,7 @@ fn lowerConstant(func: *CodeGen, val: Value, ty: Type) InnerError!WValue {
                 const struct_type = ip.loadStructType(ty.toIntern());
                 // non-packed structs are not handled in this function because they
                 // are by-ref types.
-                assert(struct_type.layout == .Packed);
+                assert(struct_type.layout == .@"packed");
                 var buf: [8]u8 = .{0} ** 8; // zero the buffer so we do not read 0xaa as integer
                 val.writeToPackedMemory(ty, mod, &buf, 0) catch unreachable;
                 const backing_int_ty = Type.fromInterned(struct_type.backingIntType(ip).*);
@@ -3890,7 +3890,7 @@ fn structFieldPtr(
     const struct_ptr_ty_info = struct_ptr_ty.ptrInfo(mod);
 
     const offset = switch (struct_ty.containerLayout(mod)) {
-        .Packed => switch (struct_ty.zigTypeTag(mod)) {
+        .@"packed" => switch (struct_ty.zigTypeTag(mod)) {
             .Struct => offset: {
                 if (result_ty.ptrInfo(mod).packed_offset.host_size != 0) {
                     break :offset @as(u32, 0);
@@ -3928,7 +3928,7 @@ fn airStructFieldVal(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
     if (!field_ty.hasRuntimeBitsIgnoreComptime(mod)) return func.finishAir(inst, .none, &.{struct_field.struct_operand});
 
     const result = switch (struct_ty.containerLayout(mod)) {
-        .Packed => switch (struct_ty.zigTypeTag(mod)) {
+        .@"packed" => switch (struct_ty.zigTypeTag(mod)) {
             .Struct => result: {
                 const packed_struct = mod.typeToPackedStruct(struct_ty).?;
                 const offset = mod.structPackedFieldBitOffset(packed_struct, field_index);
@@ -5321,7 +5321,7 @@ fn airAggregateInit(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
                 break :result_value result;
             },
             .Struct => switch (result_ty.containerLayout(mod)) {
-                .Packed => {
+                .@"packed" => {
                     if (isByRef(result_ty, mod)) {
                         return func.fail("TODO: airAggregateInit for packed structs larger than 64 bits", .{});
                     }
src/arch/x86_64/abi.zig
@@ -42,7 +42,7 @@ pub fn classifyWindows(ty: Type, mod: *Module) Class {
             1, 2, 4, 8 => return .integer,
             else => switch (ty.zigTypeTag(mod)) {
                 .Int => return .win_i128,
-                .Struct, .Union => if (ty.containerLayout(mod) == .Packed) {
+                .Struct, .Union => if (ty.containerLayout(mod) == .@"packed") {
                     return .win_i128;
                 } else {
                     return .memory;
@@ -238,7 +238,7 @@ pub fn classifySystemV(ty: Type, mod: *Module, ctx: Context) [8]Class {
             // separately.".
             const struct_type = mod.typeToStruct(ty).?;
             const ty_size = ty.abiSize(mod);
-            if (struct_type.layout == .Packed) {
+            if (struct_type.layout == .@"packed") {
                 assert(ty_size <= 16);
                 result[0] = .integer;
                 if (ty_size > 8) result[1] = .integer;
@@ -356,7 +356,7 @@ pub fn classifySystemV(ty: Type, mod: *Module, ctx: Context) [8]Class {
             // separately.".
             const union_obj = mod.typeToUnion(ty).?;
             const ty_size = mod.unionAbiSize(union_obj);
-            if (union_obj.getLayout(ip) == .Packed) {
+            if (union_obj.getLayout(ip) == .@"packed") {
                 assert(ty_size <= 16);
                 result[0] = .integer;
                 if (ty_size > 8) result[1] = .integer;
src/arch/x86_64/CodeGen.zig
@@ -7962,8 +7962,8 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
 
         const src_mcv = try self.resolveInst(operand);
         const field_off: u32 = switch (container_ty.containerLayout(mod)) {
-            .Auto, .Extern => @intCast(container_ty.structFieldOffset(index, mod) * 8),
-            .Packed => if (mod.typeToStruct(container_ty)) |struct_type|
+            .auto, .@"extern" => @intCast(container_ty.structFieldOffset(index, mod) * 8),
+            .@"packed" => if (mod.typeToStruct(container_ty)) |struct_type|
                 mod.structPackedFieldBitOffset(struct_type, index)
             else
                 0,
@@ -17979,7 +17979,7 @@ fn airAggregateInit(self: *Self, inst: Air.Inst.Index) !void {
         switch (result_ty.zigTypeTag(mod)) {
             .Struct => {
                 const frame_index = try self.allocFrameIndex(FrameAlloc.initSpill(result_ty, mod));
-                if (result_ty.containerLayout(mod) == .Packed) {
+                if (result_ty.containerLayout(mod) == .@"packed") {
                     const struct_type = mod.typeToStruct(result_ty).?;
                     try self.genInlineMemset(
                         .{ .lea_frame = .{ .index = frame_index } },
src/codegen/c/type.zig
@@ -1495,7 +1495,7 @@ pub const CType = extern union {
                     }
                 },
 
-                .Struct, .Union => |zig_ty_tag| if (ty.containerLayout(mod) == .Packed) {
+                .Struct, .Union => |zig_ty_tag| if (ty.containerLayout(mod) == .@"packed") {
                     if (mod.typeToPackedStruct(ty)) |packed_struct| {
                         try self.initType(Type.fromInterned(packed_struct.backingIntType(ip).*), kind, lookup);
                     } else {
src/codegen/spirv/Section.zig
@@ -154,7 +154,7 @@ pub fn writeOperand(section: *Section, comptime Operand: type, operand: Operand)
                 }
             },
             .Struct => |info| {
-                if (info.layout == .Packed) {
+                if (info.layout == .@"packed") {
                     section.writeWord(@as(Word, @bitCast(operand)));
                 } else {
                     section.writeExtendedMask(Operand, operand);
@@ -288,7 +288,7 @@ fn operandSize(comptime Operand: type, operand: Operand) usize {
                 }
                 break :blk total;
             },
-            .Struct => |info| if (info.layout == .Packed) 1 else extendedMaskSize(Operand, operand),
+            .Struct => |info| if (info.layout == .@"packed") 1 else extendedMaskSize(Operand, operand),
             .Union => extendedUnionSize(Operand, operand),
             else => unreachable,
         },
src/codegen/c.zig
@@ -890,7 +890,7 @@ pub const DeclGen = struct {
                     return writer.writeAll(" }");
                 },
                 .Struct => switch (ty.containerLayout(mod)) {
-                    .Auto, .Extern => {
+                    .auto, .@"extern" => {
                         if (!location.isInitializer()) {
                             try writer.writeByte('(');
                             try dg.renderType(writer, ty);
@@ -912,7 +912,7 @@ pub const DeclGen = struct {
 
                         return writer.writeByte('}');
                     },
-                    .Packed => return writer.print("{x}", .{try dg.fmtIntLiteral(ty, Value.undef, .Other)}),
+                    .@"packed" => return writer.print("{x}", .{try dg.fmtIntLiteral(ty, Value.undef, .Other)}),
                 },
                 .Union => {
                     if (!location.isInitializer()) {
@@ -1379,7 +1379,7 @@ pub const DeclGen = struct {
                 .struct_type => {
                     const struct_type = ip.loadStructType(ty.toIntern());
                     switch (struct_type.layout) {
-                        .Auto, .Extern => {
+                        .auto, .@"extern" => {
                             if (!location.isInitializer()) {
                                 try writer.writeByte('(');
                                 try dg.renderType(writer, ty);
@@ -1408,7 +1408,7 @@ pub const DeclGen = struct {
                             }
                             try writer.writeByte('}');
                         },
-                        .Packed => {
+                        .@"packed" => {
                             const int_info = ty.intInfo(mod);
 
                             const bits = Type.smallestUnsignedBits(int_info.bits - 1);
@@ -1517,7 +1517,7 @@ pub const DeclGen = struct {
                 if (un.tag == .none) {
                     const backing_ty = try ty.unionBackingType(mod);
                     switch (union_obj.getLayout(ip)) {
-                        .Packed => {
+                        .@"packed" => {
                             if (!location.isInitializer()) {
                                 try writer.writeByte('(');
                                 try dg.renderType(writer, backing_ty);
@@ -1525,7 +1525,7 @@ pub const DeclGen = struct {
                             }
                             try dg.renderValue(writer, backing_ty, Value.fromInterned(un.val), initializer_type);
                         },
-                        .Extern => {
+                        .@"extern" => {
                             if (location == .StaticInitializer) {
                                 return dg.fail("TODO: C backend: implement extern union backing type rendering in static initializers", .{});
                             }
@@ -1551,7 +1551,7 @@ pub const DeclGen = struct {
                     const field_index = mod.unionTagFieldIndex(union_obj, Value.fromInterned(un.tag)).?;
                     const field_ty = Type.fromInterned(union_obj.field_types.get(ip)[field_index]);
                     const field_name = union_obj.loadTagType(ip).names.get(ip)[field_index];
-                    if (union_obj.getLayout(ip) == .Packed) {
+                    if (union_obj.getLayout(ip) == .@"packed") {
                         if (field_ty.hasRuntimeBits(mod)) {
                             if (field_ty.isPtrAtRuntime(mod)) {
                                 try writer.writeByte('(');
@@ -5497,7 +5497,7 @@ fn fieldLocation(
         .Union => {
             const union_obj = mod.typeToUnion(container_ty).?;
             return switch (union_obj.getLayout(ip)) {
-                .Auto, .Extern => {
+                .auto, .@"extern" => {
                     const field_ty = Type.fromInterned(union_obj.field_types.get(ip)[field_index]);
                     if (!field_ty.hasRuntimeBitsIgnoreComptime(mod))
                         return if (container_ty.unionTagTypeSafety(mod) != null and
@@ -5511,7 +5511,7 @@ fn fieldLocation(
                     else
                         .{ .identifier = ip.stringToSlice(field_name) } };
                 },
-                .Packed => .begin,
+                .@"packed" => .begin,
             };
         },
         .Pointer => switch (container_ty.ptrSize(mod)) {
@@ -5671,11 +5671,11 @@ fn airStructFieldVal(f: *Function, inst: Air.Inst.Index) !CValue {
 
     const field_name: CValue = switch (mod.intern_pool.indexToKey(struct_ty.ip_index)) {
         .struct_type => switch (struct_ty.containerLayout(mod)) {
-            .Auto, .Extern => if (struct_ty.isSimpleTuple(mod))
+            .auto, .@"extern" => if (struct_ty.isSimpleTuple(mod))
                 .{ .field = extra.field_index }
             else
                 .{ .identifier = ip.stringToSlice(struct_ty.legacyStructFieldName(extra.field_index, mod)) },
-            .Packed => {
+            .@"packed" => {
                 const struct_type = mod.typeToStruct(struct_ty).?;
                 const int_info = struct_ty.intInfo(mod);
 
@@ -5740,7 +5740,7 @@ fn airStructFieldVal(f: *Function, inst: Air.Inst.Index) !CValue {
 
         .union_type => field_name: {
             const union_obj = ip.loadUnionType(struct_ty.toIntern());
-            if (union_obj.flagsPtr(ip).layout == .Packed) {
+            if (union_obj.flagsPtr(ip).layout == .@"packed") {
                 const operand_lval = if (struct_byval == .constant) blk: {
                     const operand_local = try f.allocLocal(inst, struct_ty);
                     try f.writeCValue(writer, operand_local, .Other);
@@ -7081,7 +7081,7 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {
             }
         },
         .Struct => switch (inst_ty.containerLayout(mod)) {
-            .Auto, .Extern => for (resolved_elements, 0..) |element, field_index| {
+            .auto, .@"extern" => for (resolved_elements, 0..) |element, field_index| {
                 if (inst_ty.structFieldIsComptime(field_index, mod)) continue;
                 const field_ty = inst_ty.structFieldType(field_index, mod);
                 if (!field_ty.hasRuntimeBitsIgnoreComptime(mod)) continue;
@@ -7095,7 +7095,7 @@ fn airAggregateInit(f: *Function, inst: Air.Inst.Index) !CValue {
                 try f.writeCValue(writer, element, .Other);
                 try a.end(f, writer);
             },
-            .Packed => {
+            .@"packed" => {
                 try f.writeCValue(writer, local, .Other);
                 try writer.writeAll(" = ");
                 const int_info = inst_ty.intInfo(mod);
@@ -7181,7 +7181,7 @@ fn airUnionInit(f: *Function, inst: Air.Inst.Index) !CValue {
 
     const writer = f.object.writer();
     const local = try f.allocLocal(inst, union_ty);
-    if (union_obj.getLayout(ip) == .Packed) {
+    if (union_obj.getLayout(ip) == .@"packed") {
         try f.writeCValue(writer, local, .Other);
         try writer.writeAll(" = ");
         try f.writeCValue(writer, payload, .Initializer);
src/codegen/llvm.zig
@@ -3327,7 +3327,7 @@ pub const Object = struct {
 
                     const struct_type = ip.loadStructType(t.toIntern());
 
-                    if (struct_type.layout == .Packed) {
+                    if (struct_type.layout == .@"packed") {
                         const int_ty = try o.lowerType(Type.fromInterned(struct_type.backingIntType(ip).*));
                         try o.type_map.put(o.gpa, t.toIntern(), int_ty);
                         return int_ty;
@@ -3477,7 +3477,7 @@ pub const Object = struct {
                     const union_obj = ip.loadUnionType(t.toIntern());
                     const layout = mod.getUnionLayout(union_obj);
 
-                    if (union_obj.flagsPtr(ip).layout == .Packed) {
+                    if (union_obj.flagsPtr(ip).layout == .@"packed") {
                         const int_ty = try o.builder.intType(@intCast(t.bitSize(mod)));
                         try o.type_map.put(o.gpa, t.toIntern(), int_ty);
                         return int_ty;
@@ -4038,7 +4038,7 @@ pub const Object = struct {
                     const struct_type = ip.loadStructType(ty.toIntern());
                     assert(struct_type.haveLayout(ip));
                     const struct_ty = try o.lowerType(ty);
-                    if (struct_type.layout == .Packed) {
+                    if (struct_type.layout == .@"packed") {
                         comptime assert(Type.packed_struct_layout_version == 2);
                         var running_int = try o.builder.intConst(struct_ty, 0);
                         var running_bits: u16 = 0;
@@ -4154,7 +4154,7 @@ pub const Object = struct {
                 const payload = if (un.tag != .none) p: {
                     const field_index = mod.unionTagFieldIndex(union_obj, Value.fromInterned(un.tag)).?;
                     const field_ty = Type.fromInterned(union_obj.field_types.get(ip)[field_index]);
-                    if (container_layout == .Packed) {
+                    if (container_layout == .@"packed") {
                         if (!field_ty.hasRuntimeBits(mod)) return o.builder.intConst(union_ty, 0);
                         const small_int_val = try o.builder.castConst(
                             if (field_ty.isPtrAtRuntime(mod)) .ptrtoint else .bitcast,
@@ -4190,7 +4190,7 @@ pub const Object = struct {
                 } else p: {
                     assert(layout.tag_size == 0);
                     const union_val = try o.lowerValue(un.val);
-                    if (container_layout == .Packed) {
+                    if (container_layout == .@"packed") {
                         const bitcast_val = try o.builder.castConst(
                             .bitcast,
                             union_val,
@@ -4324,7 +4324,7 @@ pub const Object = struct {
                 const field_index: u32 = @intCast(field_ptr.index);
                 switch (parent_ty.zigTypeTag(mod)) {
                     .Union => {
-                        if (parent_ty.containerLayout(mod) == .Packed) {
+                        if (parent_ty.containerLayout(mod) == .@"packed") {
                             return parent_ptr;
                         }
 
@@ -6531,7 +6531,7 @@ pub const FuncGen = struct {
             assert(!isByRef(field_ty, mod));
             switch (struct_ty.zigTypeTag(mod)) {
                 .Struct => switch (struct_ty.containerLayout(mod)) {
-                    .Packed => {
+                    .@"packed" => {
                         const struct_type = mod.typeToStruct(struct_ty).?;
                         const bit_offset = mod.structPackedFieldBitOffset(struct_type, field_index);
                         const containing_int = struct_llvm_val;
@@ -6558,7 +6558,7 @@ pub const FuncGen = struct {
                     },
                 },
                 .Union => {
-                    assert(struct_ty.containerLayout(mod) == .Packed);
+                    assert(struct_ty.containerLayout(mod) == .@"packed");
                     const containing_int = struct_llvm_val;
                     const elem_llvm_ty = try o.lowerType(field_ty);
                     if (field_ty.zigTypeTag(mod) == .Float or field_ty.zigTypeTag(mod) == .Vector) {
@@ -6581,7 +6581,7 @@ pub const FuncGen = struct {
         switch (struct_ty.zigTypeTag(mod)) {
             .Struct => {
                 const layout = struct_ty.containerLayout(mod);
-                assert(layout != .Packed);
+                assert(layout != .@"packed");
                 const struct_llvm_ty = try o.lowerType(struct_ty);
                 const llvm_field_index = o.llvmFieldIndex(struct_ty, field_index).?;
                 const field_ptr =
@@ -9995,7 +9995,7 @@ pub const FuncGen = struct {
                     return running_int;
                 }
 
-                assert(result_ty.containerLayout(mod) != .Packed);
+                assert(result_ty.containerLayout(mod) != .@"packed");
 
                 if (isByRef(result_ty, mod)) {
                     // TODO in debug builds init to undef so that the padding will be 0xaa
@@ -10080,7 +10080,7 @@ pub const FuncGen = struct {
         const layout = union_ty.unionGetLayout(mod);
         const union_obj = mod.typeToUnion(union_ty).?;
 
-        if (union_obj.getLayout(ip) == .Packed) {
+        if (union_obj.getLayout(ip) == .@"packed") {
             const big_bits = union_ty.bitSize(mod);
             const int_llvm_ty = try o.builder.intType(@intCast(big_bits));
             const field_ty = Type.fromInterned(union_obj.field_types.get(ip)[extra.field_index]);
@@ -10420,7 +10420,7 @@ pub const FuncGen = struct {
         const struct_ty = struct_ptr_ty.childType(mod);
         switch (struct_ty.zigTypeTag(mod)) {
             .Struct => switch (struct_ty.containerLayout(mod)) {
-                .Packed => {
+                .@"packed" => {
                     const result_ty = self.typeOfIndex(inst);
                     const result_ty_info = result_ty.ptrInfo(mod);
                     const struct_ptr_ty_info = struct_ptr_ty.ptrInfo(mod);
@@ -10462,7 +10462,7 @@ pub const FuncGen = struct {
             },
             .Union => {
                 const layout = struct_ty.unionGetLayout(mod);
-                if (layout.payload_size == 0 or struct_ty.containerLayout(mod) == .Packed) return struct_ptr;
+                if (layout.payload_size == 0 or struct_ty.containerLayout(mod) == .@"packed") return struct_ptr;
                 const payload_index = @intFromBool(layout.tag_align.compare(.gte, layout.payload_align));
                 const union_llvm_ty = try o.lowerType(struct_ty);
                 return self.wip.gepStruct(union_llvm_ty, struct_ptr, payload_index, "");
@@ -11572,7 +11572,7 @@ fn isByRef(ty: Type, mod: *Module) bool {
             };
 
             // Packed structs are represented to LLVM as integers.
-            if (struct_type.layout == .Packed) return false;
+            if (struct_type.layout == .@"packed") return false;
 
             const field_types = struct_type.field_types.get(ip);
             var it = struct_type.iterateRuntimeOrder(ip);
@@ -11586,7 +11586,7 @@ fn isByRef(ty: Type, mod: *Module) bool {
             return false;
         },
         .Union => switch (ty.containerLayout(mod)) {
-            .Packed => return false,
+            .@"packed" => return false,
             else => return ty.hasRuntimeBits(mod),
         },
         .ErrorUnion => {
@@ -11624,8 +11624,8 @@ fn isScalar(mod: *Module, ty: Type) bool {
         .Vector,
         => true,
 
-        .Struct => ty.containerLayout(mod) == .Packed,
-        .Union => ty.containerLayout(mod) == .Packed,
+        .Struct => ty.containerLayout(mod) == .@"packed",
+        .Union => ty.containerLayout(mod) == .@"packed",
         else => false,
     };
 }
src/codegen/spirv.zig
@@ -979,7 +979,7 @@ const DeclGen = struct {
                 },
                 .struct_type => {
                     const struct_type = mod.typeToStruct(ty).?;
-                    if (struct_type.layout == .Packed) {
+                    if (struct_type.layout == .@"packed") {
                         return self.todo("packed struct constants", .{});
                     }
 
@@ -1275,7 +1275,7 @@ const DeclGen = struct {
         const ip = &mod.intern_pool;
         const union_obj = mod.typeToUnion(ty).?;
 
-        if (union_obj.getLayout(ip) == .Packed) {
+        if (union_obj.getLayout(ip) == .@"packed") {
             return self.todo("packed union types", .{});
         }
 
@@ -1532,7 +1532,7 @@ const DeclGen = struct {
                     else => unreachable,
                 };
 
-                if (struct_type.layout == .Packed) {
+                if (struct_type.layout == .@"packed") {
                     return try self.resolveType(Type.fromInterned(struct_type.backingIntType(ip).*), .direct);
                 }
 
@@ -3904,7 +3904,7 @@ const DeclGen = struct {
         const union_ty = mod.typeToUnion(ty).?;
         const tag_ty = Type.fromInterned(union_ty.enum_tag_ty);
 
-        if (union_ty.getLayout(ip) == .Packed) {
+        if (union_ty.getLayout(ip) == .@"packed") {
             unreachable; // TODO
         }
 
@@ -3984,11 +3984,11 @@ const DeclGen = struct {
 
         switch (object_ty.zigTypeTag(mod)) {
             .Struct => switch (object_ty.containerLayout(mod)) {
-                .Packed => unreachable, // TODO
+                .@"packed" => unreachable, // TODO
                 else => return try self.extractField(field_ty, object_id, field_index),
             },
             .Union => switch (object_ty.containerLayout(mod)) {
-                .Packed => unreachable, // TODO
+                .@"packed" => unreachable, // TODO
                 else => {
                     // Store, ptr-elem-ptr, pointer-cast, load
                     const layout = self.unionLayout(object_ty);
@@ -4058,13 +4058,13 @@ const DeclGen = struct {
         const object_ty = object_ptr_ty.childType(mod);
         switch (object_ty.zigTypeTag(mod)) {
             .Struct => switch (object_ty.containerLayout(mod)) {
-                .Packed => unreachable, // TODO
+                .@"packed" => unreachable, // TODO
                 else => {
                     return try self.accessChain(result_ty_ref, object_ptr, &.{field_index});
                 },
             },
             .Union => switch (object_ty.containerLayout(mod)) {
-                .Packed => unreachable, // TODO
+                .@"packed" => unreachable, // TODO
                 else => {
                     const layout = self.unionLayout(object_ty);
                     if (!layout.has_payload) {
src/link/Dwarf.zig
@@ -317,7 +317,7 @@ pub const DeclState = struct {
                             try ty.print(dbg_info_buffer.writer(), mod);
                             try dbg_info_buffer.append(0);
 
-                            if (struct_type.layout == .Packed) {
+                            if (struct_type.layout == .@"packed") {
                                 log.debug("TODO implement .debug_info for packed structs", .{});
                                 break :blk;
                             }
src/codegen.zig
@@ -513,7 +513,7 @@ pub fn generateSymbol(
             .struct_type => {
                 const struct_type = ip.loadStructType(typed_value.ty.toIntern());
                 switch (struct_type.layout) {
-                    .Packed => {
+                    .@"packed" => {
                         const abi_size = math.cast(usize, typed_value.ty.abiSize(mod)) orelse
                             return error.Overflow;
                         const current_pos = code.items.len;
@@ -550,7 +550,7 @@ pub fn generateSymbol(
                             bits += @as(u16, @intCast(Type.fromInterned(field_ty).bitSize(mod)));
                         }
                     },
-                    .Auto, .Extern => {
+                    .auto, .@"extern" => {
                         const struct_begin = code.items.len;
                         const field_types = struct_type.field_types.get(ip);
                         const offsets = struct_type.offsets.get(ip);
@@ -736,11 +736,11 @@ fn lowerParentPtr(
                     .anon_struct_type,
                     .union_type,
                     => switch (Type.fromInterned(base_ty).containerLayout(mod)) {
-                        .Auto, .Extern => @intCast(Type.fromInterned(base_ty).structFieldOffset(
+                        .auto, .@"extern" => @intCast(Type.fromInterned(base_ty).structFieldOffset(
                             @intCast(field.index),
                             mod,
                         )),
-                        .Packed => if (mod.typeToStruct(Type.fromInterned(base_ty))) |struct_obj|
+                        .@"packed" => if (mod.typeToStruct(Type.fromInterned(base_ty))) |struct_obj|
                             if (Type.fromInterned(ptr.ty).ptrInfo(mod).packed_offset.host_size == 0)
                                 @divExact(Type.fromInterned(base_ptr_ty).ptrInfo(mod)
                                     .packed_offset.bit_offset + mod.structPackedFieldBitOffset(
src/InternPool.zig
@@ -2025,15 +2025,15 @@ pub const LoadedStructType = struct {
     /// complicated logic.
     pub fn knownNonOpv(s: @This(), ip: *InternPool) bool {
         return switch (s.layout) {
-            .Packed => false,
-            .Auto, .Extern => s.flagsPtr(ip).known_non_opv,
+            .@"packed" => false,
+            .auto, .@"extern" => s.flagsPtr(ip).known_non_opv,
         };
     }
 
     /// The returned pointer expires with any addition to the `InternPool`.
     /// Asserts the struct is not packed.
     pub fn flagsPtr(self: @This(), ip: *const InternPool) *Tag.TypeStruct.Flags {
-        assert(self.layout != .Packed);
+        assert(self.layout != .@"packed");
         const flags_field_index = std.meta.fieldIndex(Tag.TypeStruct, "flags").?;
         return @ptrCast(&ip.extra.items[self.extra_index + flags_field_index]);
     }
@@ -2041,13 +2041,13 @@ pub const LoadedStructType = struct {
     /// The returned pointer expires with any addition to the `InternPool`.
     /// Asserts that the struct is packed.
     pub fn packedFlagsPtr(self: @This(), ip: *const InternPool) *Tag.TypeStructPacked.Flags {
-        assert(self.layout == .Packed);
+        assert(self.layout == .@"packed");
         const flags_field_index = std.meta.fieldIndex(Tag.TypeStructPacked, "flags").?;
         return @ptrCast(&ip.extra.items[self.extra_index + flags_field_index]);
     }
 
     pub fn assumeRuntimeBitsIfFieldTypesWip(s: @This(), ip: *InternPool) bool {
-        if (s.layout == .Packed) return false;
+        if (s.layout == .@"packed") return false;
         const flags_ptr = s.flagsPtr(ip);
         if (flags_ptr.field_types_wip) {
             flags_ptr.assumed_runtime_bits = true;
@@ -2057,7 +2057,7 @@ pub const LoadedStructType = struct {
     }
 
     pub fn setTypesWip(s: @This(), ip: *InternPool) bool {
-        if (s.layout == .Packed) return false;
+        if (s.layout == .@"packed") return false;
         const flags_ptr = s.flagsPtr(ip);
         if (flags_ptr.field_types_wip) return true;
         flags_ptr.field_types_wip = true;
@@ -2065,12 +2065,12 @@ pub const LoadedStructType = struct {
     }
 
     pub fn clearTypesWip(s: @This(), ip: *InternPool) void {
-        if (s.layout == .Packed) return;
+        if (s.layout == .@"packed") return;
         s.flagsPtr(ip).field_types_wip = false;
     }
 
     pub fn setLayoutWip(s: @This(), ip: *InternPool) bool {
-        if (s.layout == .Packed) return false;
+        if (s.layout == .@"packed") return false;
         const flags_ptr = s.flagsPtr(ip);
         if (flags_ptr.layout_wip) return true;
         flags_ptr.layout_wip = true;
@@ -2078,12 +2078,12 @@ pub const LoadedStructType = struct {
     }
 
     pub fn clearLayoutWip(s: @This(), ip: *InternPool) void {
-        if (s.layout == .Packed) return;
+        if (s.layout == .@"packed") return;
         s.flagsPtr(ip).layout_wip = false;
     }
 
     pub fn setAlignmentWip(s: @This(), ip: *InternPool) bool {
-        if (s.layout == .Packed) return false;
+        if (s.layout == .@"packed") return false;
         const flags_ptr = s.flagsPtr(ip);
         if (flags_ptr.alignment_wip) return true;
         flags_ptr.alignment_wip = true;
@@ -2091,19 +2091,19 @@ pub const LoadedStructType = struct {
     }
 
     pub fn clearAlignmentWip(s: @This(), ip: *InternPool) void {
-        if (s.layout == .Packed) return;
+        if (s.layout == .@"packed") return;
         s.flagsPtr(ip).alignment_wip = false;
     }
 
     pub fn setInitsWip(s: @This(), ip: *InternPool) bool {
         switch (s.layout) {
-            .Packed => {
+            .@"packed" => {
                 const flag = &s.packedFlagsPtr(ip).field_inits_wip;
                 if (flag.*) return true;
                 flag.* = true;
                 return false;
             },
-            .Auto, .Extern => {
+            .auto, .@"extern" => {
                 const flag = &s.flagsPtr(ip).field_inits_wip;
                 if (flag.*) return true;
                 flag.* = true;
@@ -2114,13 +2114,13 @@ pub const LoadedStructType = struct {
 
     pub fn clearInitsWip(s: @This(), ip: *InternPool) void {
         switch (s.layout) {
-            .Packed => s.packedFlagsPtr(ip).field_inits_wip = false,
-            .Auto, .Extern => s.flagsPtr(ip).field_inits_wip = false,
+            .@"packed" => s.packedFlagsPtr(ip).field_inits_wip = false,
+            .auto, .@"extern" => s.flagsPtr(ip).field_inits_wip = false,
         }
     }
 
     pub fn setFullyResolved(s: @This(), ip: *InternPool) bool {
-        if (s.layout == .Packed) return true;
+        if (s.layout == .@"packed") return true;
         const flags_ptr = s.flagsPtr(ip);
         if (flags_ptr.fully_resolved) return true;
         flags_ptr.fully_resolved = true;
@@ -2134,7 +2134,7 @@ pub const LoadedStructType = struct {
     /// The returned pointer expires with any addition to the `InternPool`.
     /// Asserts the struct is not packed.
     pub fn size(self: @This(), ip: *InternPool) *u32 {
-        assert(self.layout != .Packed);
+        assert(self.layout != .@"packed");
         const size_field_index = std.meta.fieldIndex(Tag.TypeStruct, "size").?;
         return @ptrCast(&ip.extra.items[self.extra_index + size_field_index]);
     }
@@ -2144,14 +2144,14 @@ pub const LoadedStructType = struct {
     /// set to `none` until the layout is resolved.
     /// Asserts the struct is packed.
     pub fn backingIntType(s: @This(), ip: *const InternPool) *Index {
-        assert(s.layout == .Packed);
+        assert(s.layout == .@"packed");
         const field_index = std.meta.fieldIndex(Tag.TypeStructPacked, "backing_int_ty").?;
         return @ptrCast(&ip.extra.items[s.extra_index + field_index]);
     }
 
     /// Asserts the struct is not packed.
     pub fn setZirIndex(s: @This(), ip: *InternPool, new_zir_index: TrackedInst.Index.Optional) void {
-        assert(s.layout != .Packed);
+        assert(s.layout != .@"packed");
         const field_index = std.meta.fieldIndex(Tag.TypeStruct, "zir_index").?;
         ip.extra.items[s.extra_index + field_index] = @intFromEnum(new_zir_index);
     }
@@ -2163,31 +2163,31 @@ pub const LoadedStructType = struct {
 
     pub fn haveFieldInits(s: @This(), ip: *const InternPool) bool {
         return switch (s.layout) {
-            .Packed => s.packedFlagsPtr(ip).inits_resolved,
-            .Auto, .Extern => s.flagsPtr(ip).inits_resolved,
+            .@"packed" => s.packedFlagsPtr(ip).inits_resolved,
+            .auto, .@"extern" => s.flagsPtr(ip).inits_resolved,
         };
     }
 
     pub fn setHaveFieldInits(s: @This(), ip: *InternPool) void {
         switch (s.layout) {
-            .Packed => s.packedFlagsPtr(ip).inits_resolved = true,
-            .Auto, .Extern => s.flagsPtr(ip).inits_resolved = true,
+            .@"packed" => s.packedFlagsPtr(ip).inits_resolved = true,
+            .auto, .@"extern" => s.flagsPtr(ip).inits_resolved = true,
         }
     }
 
     pub fn haveLayout(s: @This(), ip: *InternPool) bool {
         return switch (s.layout) {
-            .Packed => s.backingIntType(ip).* != .none,
-            .Auto, .Extern => s.flagsPtr(ip).layout_resolved,
+            .@"packed" => s.backingIntType(ip).* != .none,
+            .auto, .@"extern" => s.flagsPtr(ip).layout_resolved,
         };
     }
 
     pub fn isTuple(s: @This(), ip: *InternPool) bool {
-        return s.layout != .Packed and s.flagsPtr(ip).is_tuple;
+        return s.layout != .@"packed" and s.flagsPtr(ip).is_tuple;
     }
 
     pub fn hasReorderedFields(s: @This()) bool {
-        return s.layout == .Auto;
+        return s.layout == .auto;
     }
 
     pub const RuntimeOrderIterator = struct {
@@ -2221,7 +2221,7 @@ pub const LoadedStructType = struct {
     /// May or may not include zero-bit fields.
     /// Asserts the struct is not packed.
     pub fn iterateRuntimeOrder(s: @This(), ip: *InternPool) RuntimeOrderIterator {
-        assert(s.layout != .Packed);
+        assert(s.layout != .@"packed");
         return .{
             .ip = ip,
             .field_index = 0,
@@ -2239,7 +2239,7 @@ pub fn loadStructType(ip: *const InternPool, index: Index) LoadedStructType {
                 .decl = .none,
                 .namespace = .none,
                 .zir_index = .none,
-                .layout = .Auto,
+                .layout = .auto,
                 .field_names = .{ .start = 0, .len = 0 },
                 .field_types = .{ .start = 0, .len = 0 },
                 .field_inits = .{ .start = 0, .len = 0 },
@@ -2314,7 +2314,7 @@ pub fn loadStructType(ip: *const InternPool, index: Index) LoadedStructType {
                 .decl = extra.data.decl.toOptional(),
                 .namespace = namespace,
                 .zir_index = extra.data.zir_index.toOptional(),
-                .layout = if (extra.data.flags.is_extern) .Extern else .Auto,
+                .layout = if (extra.data.flags.is_extern) .@"extern" else .auto,
                 .field_names = names,
                 .field_types = field_types,
                 .field_inits = inits,
@@ -2367,7 +2367,7 @@ pub fn loadStructType(ip: *const InternPool, index: Index) LoadedStructType {
                 .decl = extra.data.decl.toOptional(),
                 .namespace = extra.data.namespace,
                 .zir_index = extra.data.zir_index.toOptional(),
-                .layout = .Packed,
+                .layout = .@"packed",
                 .field_names = field_names,
                 .field_types = field_types,
                 .field_inits = field_inits,
@@ -4455,7 +4455,6 @@ pub fn indexToKey(ip: *const InternPool, index: Index) Key {
                 } else .{ .start = 0, .len = 0 } },
             } };
         } },
-
         .type_struct_anon => .{ .anon_struct_type = extraTypeStructAnon(ip, data) },
         .type_tuple_anon => .{ .anon_struct_type = extraTypeTupleAnon(ip, data) },
         .type_union => .{ .union_type = ns: {
@@ -6009,9 +6008,9 @@ pub fn getStructType(
     };
 
     const is_extern = switch (ini.layout) {
-        .Auto => false,
-        .Extern => true,
-        .Packed => {
+        .auto => false,
+        .@"extern" => true,
+        .@"packed" => {
             try ip.extra.ensureUnusedCapacity(gpa, @typeInfo(Tag.TypeStructPacked).Struct.fields.len +
                 // TODO: fmt bug
                 // zig fmt: off
@@ -6140,7 +6139,7 @@ pub fn getStructType(
     if (ini.any_comptime_fields) {
         ip.extra.appendNTimesAssumeCapacity(0, comptime_elements_len);
     }
-    if (ini.layout == .Auto) {
+    if (ini.layout == .auto) {
         ip.extra.appendNTimesAssumeCapacity(@intFromEnum(LoadedStructType.RuntimeOrder.unresolved), ini.fields_len);
     }
     ip.extra.appendNTimesAssumeCapacity(std.math.maxInt(u32), ini.fields_len);
src/Module.zig
@@ -3310,7 +3310,7 @@ fn getFileRootStruct(zcu: *Zcu, decl_index: Decl.Index, namespace_index: Namespa
     const small: Zir.Inst.StructDecl.Small = @bitCast(extended.small);
     assert(!small.has_captures_len);
     assert(!small.has_backing_int);
-    assert(small.layout == .Auto);
+    assert(small.layout == .auto);
     var extra_index: usize = extended.operand + @typeInfo(Zir.Inst.StructDecl).Struct.fields.len;
     const fields_len = if (small.has_fields_len) blk: {
         const fields_len = file.zir.extra[extra_index];
@@ -3327,7 +3327,7 @@ fn getFileRootStruct(zcu: *Zcu, decl_index: Decl.Index, namespace_index: Namespa
 
     const tracked_inst = try ip.trackZir(gpa, file, .main_struct_inst);
     const wip_ty = switch (try ip.getStructType(gpa, .{
-        .layout = .Auto,
+        .layout = .auto,
         .fields_len = fields_len,
         .known_non_opv = small.known_non_opv,
         .requires_comptime = if (small.known_comptime_only) .yes else .unknown,
@@ -5969,7 +5969,7 @@ pub fn typeToStruct(mod: *Module, ty: Type) ?InternPool.LoadedStructType {
 
 pub fn typeToPackedStruct(mod: *Module, ty: Type) ?InternPool.LoadedStructType {
     const s = mod.typeToStruct(ty) orelse return null;
-    if (s.layout != .Packed) return null;
+    if (s.layout != .@"packed") return null;
     return s;
 }
 
@@ -6185,18 +6185,18 @@ pub fn structFieldAlignment(
     field_ty: Type,
     layout: std.builtin.Type.ContainerLayout,
 ) Alignment {
-    assert(layout != .Packed);
+    assert(layout != .@"packed");
     if (explicit_alignment != .none) return explicit_alignment;
     switch (layout) {
-        .Packed => unreachable,
-        .Auto => {
+        .@"packed" => unreachable,
+        .auto => {
             if (mod.getTarget().ofmt == .c) {
                 return structFieldAlignmentExtern(mod, field_ty);
             } else {
                 return field_ty.abiAlignment(mod);
             }
         },
-        .Extern => return structFieldAlignmentExtern(mod, field_ty),
+        .@"extern" => return structFieldAlignmentExtern(mod, field_ty),
     }
 }
 
@@ -6224,7 +6224,7 @@ pub fn structPackedFieldBitOffset(
     field_index: u32,
 ) u16 {
     const ip = &mod.intern_pool;
-    assert(struct_type.layout == .Packed);
+    assert(struct_type.layout == .@"packed");
     assert(struct_type.haveLayout(ip));
     var bit_sum: u64 = 0;
     for (0..struct_type.field_types.len) |i| {
src/print_zir.zig
@@ -1440,7 +1440,7 @@ const Writer = struct {
         if (small.has_backing_int) {
             const backing_int_body_len = self.code.extra[extra_index];
             extra_index += 1;
-            try stream.writeAll("Packed(");
+            try stream.writeAll("packed(");
             if (backing_int_body_len == 0) {
                 const backing_int_ref: Zir.Inst.Ref = @enumFromInt(self.code.extra[extra_index]);
                 extra_index += 1;
src/Sema.zig
@@ -3236,7 +3236,7 @@ fn zirUnionDecl(
             .status = .none,
             .runtime_tag = if (small.has_tag_type or small.auto_enum_tag)
                 .tagged
-            else if (small.layout != .Auto)
+            else if (small.layout != .auto)
                 .none
             else switch (block.wantSafety()) {
                 true => .safety,
@@ -10380,7 +10380,7 @@ fn zirBitcast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
             };
             return sema.failWithOwnedErrorMsg(block, msg);
         },
-        .Struct, .Union => if (dest_ty.containerLayout(mod) == .Auto) {
+        .Struct, .Union => if (dest_ty.containerLayout(mod) == .auto) {
             const container = switch (dest_ty.zigTypeTag(mod)) {
                 .Struct => "struct",
                 .Union => "union",
@@ -10443,7 +10443,7 @@ fn zirBitcast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
             };
             return sema.failWithOwnedErrorMsg(block, msg);
         },
-        .Struct, .Union => if (operand_ty.containerLayout(mod) == .Auto) {
+        .Struct, .Union => if (operand_ty.containerLayout(mod) == .auto) {
             const container = switch (operand_ty.zigTypeTag(mod)) {
                 .Struct => "struct",
                 .Union => "union",
@@ -18131,8 +18131,8 @@ fn zirTypeInfo(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
                 };
 
                 const alignment = switch (layout) {
-                    .Auto, .Extern => try sema.unionFieldAlignment(union_obj, @intCast(i)),
-                    .Packed => .none,
+                    .auto, .@"extern" => try sema.unionFieldAlignment(union_obj, @intCast(i)),
+                    .@"packed" => .none,
                 };
 
                 const field_ty = union_obj.field_types.get(ip)[i];
@@ -18350,7 +18350,7 @@ fn zirTypeInfo(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
                     const opt_default_val = if (field_init == .none) null else Value.fromInterned(field_init);
                     const default_val_ptr = try sema.optRefValue(opt_default_val);
                     const alignment = switch (struct_type.layout) {
-                        .Packed => .none,
+                        .@"packed" => .none,
                         else => try sema.structFieldAlignment(
                             struct_type.fieldAlign(ip, i),
                             field_ty,
@@ -19906,7 +19906,7 @@ fn zirStructInit(
         var field_i: u32 = 0;
         var extra_index = extra.end;
 
-        const is_packed = resolved_ty.containerLayout(mod) == .Packed;
+        const is_packed = resolved_ty.containerLayout(mod) == .@"packed";
         while (field_i < extra.data.fields_len) : (field_i += 1) {
             const item = sema.code.extraData(Zir.Inst.StructInit.Item, extra_index);
             extra_index = item.end;
@@ -21302,7 +21302,7 @@ fn zirReify(
                 return sema.fail(block, src, "reified structs must have no decls", .{});
             }
 
-            if (layout != .Packed and !backing_integer_val.isNull(mod)) {
+            if (layout != .@"packed" and !backing_integer_val.isNull(mod)) {
                 return sema.fail(block, src, "non-packed struct does not support backing integer type", .{});
             }
 
@@ -21665,7 +21665,7 @@ fn reifyUnion(
             .status = .none,
             .runtime_tag = if (opt_tag_type_val.optionalValue(mod) != null)
                 .tagged
-            else if (layout != .Auto)
+            else if (layout != .auto)
                 .none
             else switch (block.wantSafety()) {
                 true => .safety,
@@ -21804,7 +21804,7 @@ fn reifyUnion(
                 break :msg msg;
             });
         }
-        if (layout == .Extern and !try sema.validateExternType(field_ty, .union_field)) {
+        if (layout == .@"extern" and !try sema.validateExternType(field_ty, .union_field)) {
             return sema.failWithOwnedErrorMsg(block, msg: {
                 const msg = try sema.errMsg(block, src, "extern unions cannot contain fields of type '{}'", .{field_ty.fmt(mod)});
                 errdefer msg.destroy(gpa);
@@ -21815,7 +21815,7 @@ fn reifyUnion(
                 try sema.addDeclaredHereNote(msg, field_ty);
                 break :msg msg;
             });
-        } else if (layout == .Packed and !try sema.validatePackedType(field_ty)) {
+        } else if (layout == .@"packed" and !try sema.validatePackedType(field_ty)) {
             return sema.failWithOwnedErrorMsg(block, msg: {
                 const msg = try sema.errMsg(block, src, "packed unions cannot contain fields of type '{}'", .{field_ty.fmt(mod)});
                 errdefer msg.destroy(gpa);
@@ -21938,9 +21938,9 @@ fn reifyStruct(
     errdefer wip_ty.cancel(ip);
 
     if (is_tuple) switch (layout) {
-        .Extern => return sema.fail(block, src, "extern tuples are not supported", .{}),
-        .Packed => return sema.fail(block, src, "packed tuples are not supported", .{}),
-        .Auto => {},
+        .@"extern" => return sema.fail(block, src, "extern tuples are not supported", .{}),
+        .@"packed" => return sema.fail(block, src, "packed tuples are not supported", .{}),
+        .auto => {},
     };
 
     const new_decl_index = try sema.createAnonymousDeclTypeNamed(block, src, .{
@@ -21990,11 +21990,11 @@ fn reifyStruct(
 
             const byte_align = try field_alignment_val.toUnsignedIntAdvanced(sema);
             if (byte_align == 0) {
-                if (layout != .Packed) {
+                if (layout != .@"packed") {
                     struct_type.field_aligns.get(ip)[field_idx] = .none;
                 }
             } else {
-                if (layout == .Packed) return sema.fail(block, src, "alignment in a packed struct field must be set to 0", .{});
+                if (layout == .@"packed") return sema.fail(block, src, "alignment in a packed struct field must be set to 0", .{});
                 if (!math.isPowerOfTwo(byte_align)) return sema.fail(block, src, "alignment value '{d}' is not a power of two or zero", .{byte_align});
                 struct_type.field_aligns.get(ip)[field_idx] = Alignment.fromNonzeroByteUnits(byte_align);
             }
@@ -22004,9 +22004,9 @@ fn reifyStruct(
         if (field_is_comptime) {
             assert(any_comptime_fields);
             switch (layout) {
-                .Extern => return sema.fail(block, src, "extern struct fields cannot be marked comptime", .{}),
-                .Packed => return sema.fail(block, src, "packed struct fields cannot be marked comptime", .{}),
-                .Auto => struct_type.setFieldComptime(ip, field_idx),
+                .@"extern" => return sema.fail(block, src, "extern struct fields cannot be marked comptime", .{}),
+                .@"packed" => return sema.fail(block, src, "packed struct fields cannot be marked comptime", .{}),
+                .auto => struct_type.setFieldComptime(ip, field_idx),
             }
         }
 
@@ -22047,7 +22047,7 @@ fn reifyStruct(
                 break :msg msg;
             });
         }
-        if (layout == .Extern and !try sema.validateExternType(field_ty, .struct_field)) {
+        if (layout == .@"extern" and !try sema.validateExternType(field_ty, .struct_field)) {
             return sema.failWithOwnedErrorMsg(block, msg: {
                 const msg = try sema.errMsg(block, src, "extern structs cannot contain fields of type '{}'", .{field_ty.fmt(sema.mod)});
                 errdefer msg.destroy(gpa);
@@ -22058,7 +22058,7 @@ fn reifyStruct(
                 try sema.addDeclaredHereNote(msg, field_ty);
                 break :msg msg;
             });
-        } else if (layout == .Packed and !try sema.validatePackedType(field_ty)) {
+        } else if (layout == .@"packed" and !try sema.validatePackedType(field_ty)) {
             return sema.failWithOwnedErrorMsg(block, msg: {
                 const msg = try sema.errMsg(block, src, "packed structs cannot contain fields of type '{}'", .{field_ty.fmt(sema.mod)});
                 errdefer msg.destroy(gpa);
@@ -22072,7 +22072,7 @@ fn reifyStruct(
         }
     }
 
-    if (layout == .Packed) {
+    if (layout == .@"packed") {
         var fields_bit_sum: u64 = 0;
         for (0..struct_type.field_types.len) |field_idx| {
             const field_ty = Type.fromInterned(struct_type.field_types.get(ip)[field_idx]);
@@ -23311,7 +23311,7 @@ fn bitOffsetOf(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!u6
     }
 
     switch (ty.containerLayout(mod)) {
-        .Packed => {
+        .@"packed" => {
             var bit_sum: u64 = 0;
             const struct_type = ip.loadStructType(ty.toIntern());
             for (0..struct_type.field_types.len) |i| {
@@ -24710,7 +24710,7 @@ fn zirFieldParentPtr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileEr
         },
     };
 
-    if (parent_ty.containerLayout(mod) == .Packed) {
+    if (parent_ty.containerLayout(mod) == .@"packed") {
         return sema.fail(block, src, "TODO handle packed structs/unions with @fieldParentPtr", .{});
     } else {
         ptr_ty_data.flags.alignment = blk: {
@@ -26328,15 +26328,15 @@ fn validateExternType(
             return sema.validateExternType(ty.intTagType(mod), position);
         },
         .Struct, .Union => switch (ty.containerLayout(mod)) {
-            .Extern => return true,
-            .Packed => {
+            .@"extern" => return true,
+            .@"packed" => {
                 const bit_size = try ty.bitSizeAdvanced(mod, sema);
                 switch (bit_size) {
                     0, 8, 16, 32, 64, 128 => return true,
                     else => return false,
                 }
             },
-            .Auto => return !(try sema.typeHasRuntimeBits(ty)),
+            .auto => return !(try sema.typeHasRuntimeBits(ty)),
         },
         .Array => {
             if (position == .ret_ty or position == .param_ty) return false;
@@ -26456,7 +26456,7 @@ fn validatePackedType(sema: *Sema, ty: Type) !bool {
         .Enum,
         => return true,
         .Pointer => return !ty.isSlice(mod) and !try sema.typeRequiresComptime(ty),
-        .Struct, .Union => return ty.containerLayout(mod) == .Packed,
+        .Struct, .Union => return ty.containerLayout(mod) == .@"packed",
     }
 }
 
@@ -27596,7 +27596,7 @@ fn structFieldPtrByIndex(
     else
         try sema.typeAbiAlignment(Type.fromInterned(struct_ptr_ty_info.child));
 
-    if (struct_type.layout == .Packed) {
+    if (struct_type.layout == .@"packed") {
         comptime assert(Type.packed_struct_layout_version == 2);
 
         var running_bits: u16 = 0;
@@ -27641,7 +27641,7 @@ fn structFieldPtrByIndex(
                 ptr_ty_data.packed_offset = .{ .host_size = 0, .bit_offset = 0 };
             }
         }
-    } else if (struct_type.layout == .Extern) {
+    } else if (struct_type.layout == .@"extern") {
         // For extern structs, field alignment might be bigger than type's
         // natural alignment. Eg, in `extern struct { x: u32, y: u16 }` the
         // second field is aligned as u32.
@@ -27846,7 +27846,7 @@ fn unionFieldPtr(
             .is_const = union_ptr_info.flags.is_const,
             .is_volatile = union_ptr_info.flags.is_volatile,
             .address_space = union_ptr_info.flags.address_space,
-            .alignment = if (union_obj.getLayout(ip) == .Auto) blk: {
+            .alignment = if (union_obj.getLayout(ip) == .auto) blk: {
                 const union_align = if (union_ptr_info.flags.alignment != .none)
                     union_ptr_info.flags.alignment
                 else
@@ -27875,7 +27875,7 @@ fn unionFieldPtr(
 
     if (try sema.resolveDefinedValue(block, src, union_ptr)) |union_ptr_val| ct: {
         switch (union_obj.getLayout(ip)) {
-            .Auto => if (!initializing) {
+            .auto => if (!initializing) {
                 const union_val = (try sema.pointerDeref(block, src, union_ptr_val, union_ptr_ty)) orelse
                     break :ct;
                 if (union_val.isUndef(mod)) {
@@ -27899,7 +27899,7 @@ fn unionFieldPtr(
                     return sema.failWithOwnedErrorMsg(block, msg);
                 }
             },
-            .Packed, .Extern => {},
+            .@"packed", .@"extern" => {},
         }
         return Air.internedToRef((try mod.intern(.{ .ptr = .{
             .ty = ptr_field_ty.toIntern(),
@@ -27911,7 +27911,7 @@ fn unionFieldPtr(
     }
 
     try sema.requireRuntimeBlock(block, src, null);
-    if (!initializing and union_obj.getLayout(ip) == .Auto and block.wantSafety() and
+    if (!initializing and union_obj.getLayout(ip) == .auto and block.wantSafety() and
         union_ty.unionTagTypeSafety(mod) != null and union_obj.field_types.len > 1)
     {
         const wanted_tag_val = try mod.enumValueFieldIndex(Type.fromInterned(union_obj.enum_tag_ty), enum_field_index);
@@ -27954,7 +27954,7 @@ fn unionFieldVal(
         const field_tag = try mod.enumValueFieldIndex(Type.fromInterned(union_obj.enum_tag_ty), enum_field_index);
         const tag_matches = un.tag == field_tag.toIntern();
         switch (union_obj.getLayout(ip)) {
-            .Auto => {
+            .auto => {
                 if (tag_matches) {
                     return Air.internedToRef(un.val);
                 } else {
@@ -27971,7 +27971,7 @@ fn unionFieldVal(
                     return sema.failWithOwnedErrorMsg(block, msg);
                 }
             },
-            .Packed, .Extern => |layout| {
+            .@"packed", .@"extern" => |layout| {
                 if (tag_matches) {
                     return Air.internedToRef(un.val);
                 } else {
@@ -27989,7 +27989,7 @@ fn unionFieldVal(
     }
 
     try sema.requireRuntimeBlock(block, src, null);
-    if (union_obj.getLayout(ip) == .Auto and block.wantSafety() and
+    if (union_obj.getLayout(ip) == .auto and block.wantSafety() and
         union_ty.unionTagTypeSafety(mod) != null and union_obj.field_types.len > 1)
     {
         const wanted_tag_val = try mod.enumValueFieldIndex(Type.fromInterned(union_obj.enum_tag_ty), enum_field_index);
@@ -30961,7 +30961,7 @@ fn beginComptimePtrMutation(
 
                             const tag_type = base_child_ty.unionTagTypeHypothetical(mod);
                             const hypothetical_tag = try mod.enumValueFieldIndex(tag_type, field_index);
-                            if (layout == .Auto or (payload.tag != null and hypothetical_tag.eql(payload.tag.?, tag_type, mod))) {
+                            if (layout == .auto or (payload.tag != null and hypothetical_tag.eql(payload.tag.?, tag_type, mod))) {
                                 // We need to set the active field of the union.
                                 payload.tag = hypothetical_tag;
 
@@ -30988,7 +30988,7 @@ fn beginComptimePtrMutation(
                                     .pointee = .{ .reinterpret = .{
                                         .val_ptr = val_ptr,
                                         .byte_offset = 0,
-                                        .write_packed = layout == .Packed,
+                                        .write_packed = layout == .@"packed",
                                     } },
                                     .ty = parent.ty,
                                 };
@@ -31395,7 +31395,7 @@ fn beginComptimePtrLoad(
 
                 if (container_ty.hasWellDefinedLayout(mod)) {
                     const struct_obj = mod.typeToStruct(container_ty);
-                    if (struct_obj != null and struct_obj.?.layout == .Packed) {
+                    if (struct_obj != null and struct_obj.?.layout == .@"packed") {
                         // packed structs are not byte addressable
                         deref.parent = null;
                     } else if (deref.parent) |*parent| {
@@ -31551,7 +31551,7 @@ fn bitCastUnionFieldVal(
 
     // Reading a larger value means we need to reinterpret from undefined bytes.
     const offset = switch (layout) {
-        .Extern => offset: {
+        .@"extern" => offset: {
             if (field_size > old_size) @memset(buffer[old_size..], 0xaa);
             val.writeToMemory(old_ty, mod, buffer) catch |err| switch (err) {
                 error.OutOfMemory => return error.OutOfMemory,
@@ -31561,7 +31561,7 @@ fn bitCastUnionFieldVal(
             };
             break :offset 0;
         },
-        .Packed => offset: {
+        .@"packed" => offset: {
             if (field_size > old_size) {
                 const min_size = @max(old_size, 1);
                 switch (endian) {
@@ -31577,7 +31577,7 @@ fn bitCastUnionFieldVal(
 
             break :offset if (endian == .big) buffer.len - field_size else 0;
         },
-        .Auto => unreachable,
+        .auto => unreachable,
     };
 
     return Value.readFromMemory(field_ty, mod, buffer[offset..], sema.arena) catch |err| switch (err) {
@@ -35608,7 +35608,7 @@ pub fn resolveStructAlignment(
     const target = mod.getTarget();
 
     assert(struct_type.flagsPtr(ip).alignment == .none);
-    assert(struct_type.layout != .Packed);
+    assert(struct_type.layout != .@"packed");
 
     if (struct_type.flagsPtr(ip).field_types_wip) {
         // We'll guess "pointer-aligned", if the struct has an
@@ -35661,7 +35661,7 @@ fn resolveStructLayout(sema: *Sema, ty: Type) CompileError!void {
 
     try sema.resolveTypeFields(ty);
 
-    if (struct_type.layout == .Packed) {
+    if (struct_type.layout == .@"packed") {
         try semaBackingIntType(mod, struct_type);
         return;
     }
@@ -36625,11 +36625,11 @@ fn semaStructFields(
     const fields_len, const small, var extra_index = structZirInfo(zir, zir_index);
 
     if (fields_len == 0) switch (struct_type.layout) {
-        .Packed => {
+        .@"packed" => {
             try semaBackingIntType(mod, struct_type);
             return;
         },
-        .Auto, .Extern => {
+        .auto, .@"extern" => {
             struct_type.size(ip).* = 0;
             struct_type.flagsPtr(ip).layout_resolved = true;
             return;
@@ -36810,7 +36810,7 @@ fn semaStructFields(
             return sema.failWithOwnedErrorMsg(&block_scope, msg);
         }
         switch (struct_type.layout) {
-            .Extern => if (!try sema.validateExternType(field_ty, .struct_field)) {
+            .@"extern" => if (!try sema.validateExternType(field_ty, .struct_field)) {
                 const msg = msg: {
                     const ty_src = mod.fieldSrcLoc(decl_index, .{
                         .index = field_i,
@@ -36826,7 +36826,7 @@ fn semaStructFields(
                 };
                 return sema.failWithOwnedErrorMsg(&block_scope, msg);
             },
-            .Packed => if (!try sema.validatePackedType(field_ty)) {
+            .@"packed" => if (!try sema.validatePackedType(field_ty)) {
                 const msg = msg: {
                     const ty_src = mod.fieldSrcLoc(decl_index, .{
                         .index = field_i,
@@ -37350,7 +37350,7 @@ fn semaUnionFields(mod: *Module, arena: Allocator, union_type: InternPool.Loaded
             return sema.failWithOwnedErrorMsg(&block_scope, msg);
         }
         const layout = union_type.getLayout(ip);
-        if (layout == .Extern and
+        if (layout == .@"extern" and
             !try sema.validateExternType(field_ty, .union_field))
         {
             const msg = msg: {
@@ -37367,7 +37367,7 @@ fn semaUnionFields(mod: *Module, arena: Allocator, union_type: InternPool.Loaded
                 break :msg msg;
             };
             return sema.failWithOwnedErrorMsg(&block_scope, msg);
-        } else if (layout == .Packed and !try sema.validatePackedType(field_ty)) {
+        } else if (layout == .@"packed" and !try sema.validatePackedType(field_ty)) {
             const msg = msg: {
                 const ty_src = mod.fieldSrcLoc(union_type.decl, .{
                     .index = field_i,
@@ -38286,9 +38286,9 @@ fn structFieldAlignment(
         return explicit_alignment;
     const mod = sema.mod;
     switch (layout) {
-        .Packed => return .none,
-        .Auto => if (mod.getTarget().ofmt != .c) return sema.typeAbiAlignment(field_ty),
-        .Extern => {},
+        .@"packed" => return .none,
+        .auto => if (mod.getTarget().ofmt != .c) return sema.typeAbiAlignment(field_ty),
+        .@"extern" => {},
     }
     // extern
     const ty_abi_align = try sema.typeAbiAlignment(field_ty);
src/type.zig
@@ -741,12 +741,12 @@ pub const Type = struct {
             .struct_type => {
                 const struct_type = ip.loadStructType(ty.toIntern());
                 // Struct with no fields have a well-defined layout of no bits.
-                return struct_type.layout != .Auto or struct_type.field_types.len == 0;
+                return struct_type.layout != .auto or struct_type.field_types.len == 0;
             },
             .union_type => {
                 const union_type = ip.loadUnionType(ty.toIntern());
                 return switch (union_type.flagsPtr(ip).runtime_tag) {
-                    .none, .safety => union_type.flagsPtr(ip).layout != .Auto,
+                    .none, .safety => union_type.flagsPtr(ip).layout != .auto,
                     .tagged => false,
                 };
             },
@@ -1027,7 +1027,7 @@ pub const Type = struct {
                 },
                 .struct_type => {
                     const struct_type = ip.loadStructType(ty.toIntern());
-                    if (struct_type.layout == .Packed) {
+                    if (struct_type.layout == .@"packed") {
                         switch (strat) {
                             .sema => |sema| try sema.resolveTypeLayout(ty),
                             .lazy => if (struct_type.backingIntType(ip).* == .none) return .{
@@ -1407,7 +1407,7 @@ pub const Type = struct {
                     switch (strat) {
                         .sema => |sema| try sema.resolveTypeLayout(ty),
                         .lazy => switch (struct_type.layout) {
-                            .Packed => {
+                            .@"packed" => {
                                 if (struct_type.backingIntType(ip).* == .none) return .{
                                     .val = Value.fromInterned((try mod.intern(.{ .int = .{
                                         .ty = .comptime_int_type,
@@ -1415,7 +1415,7 @@ pub const Type = struct {
                                     } }))),
                                 };
                             },
-                            .Auto, .Extern => {
+                            .auto, .@"extern" => {
                                 if (!struct_type.haveLayout(ip)) return .{
                                     .val = Value.fromInterned((try mod.intern(.{ .int = .{
                                         .ty = .comptime_int_type,
@@ -1427,10 +1427,10 @@ pub const Type = struct {
                         .eager => {},
                     }
                     switch (struct_type.layout) {
-                        .Packed => return .{
+                        .@"packed" => return .{
                             .scalar = Type.fromInterned(struct_type.backingIntType(ip).*).abiSize(mod),
                         },
-                        .Auto, .Extern => {
+                        .auto, .@"extern" => {
                             assert(struct_type.haveLayout(ip));
                             return .{ .scalar = struct_type.size(ip).* };
                         },
@@ -1656,7 +1656,7 @@ pub const Type = struct {
             },
             .struct_type => {
                 const struct_type = ip.loadStructType(ty.toIntern());
-                const is_packed = struct_type.layout == .Packed;
+                const is_packed = struct_type.layout == .@"packed";
                 if (opt_sema) |sema| {
                     try sema.resolveTypeFields(ty);
                     if (is_packed) try sema.resolveTypeLayout(ty);
@@ -1674,7 +1674,7 @@ pub const Type = struct {
 
             .union_type => {
                 const union_type = ip.loadUnionType(ty.toIntern());
-                const is_packed = ty.containerLayout(mod) == .Packed;
+                const is_packed = ty.containerLayout(mod) == .@"packed";
                 if (opt_sema) |sema| {
                     try sema.resolveTypeFields(ty);
                     if (is_packed) try sema.resolveTypeLayout(ty);
@@ -1987,9 +1987,9 @@ pub const Type = struct {
     /// Asserts the type is either an extern or packed union.
     pub fn unionBackingType(ty: Type, mod: *Module) !Type {
         return switch (ty.containerLayout(mod)) {
-            .Extern => try mod.arrayType(.{ .len = ty.abiSize(mod), .child = .u8_type }),
-            .Packed => try mod.intType(.unsigned, @intCast(ty.bitSize(mod))),
-            .Auto => unreachable,
+            .@"extern" => try mod.arrayType(.{ .len = ty.abiSize(mod), .child = .u8_type }),
+            .@"packed" => try mod.intType(.unsigned, @intCast(ty.bitSize(mod))),
+            .auto => unreachable,
         };
     }
 
@@ -2003,7 +2003,7 @@ pub const Type = struct {
         const ip = &mod.intern_pool;
         return switch (ip.indexToKey(ty.toIntern())) {
             .struct_type => ip.loadStructType(ty.toIntern()).layout,
-            .anon_struct_type => .Auto,
+            .anon_struct_type => .auto,
             .union_type => ip.loadUnionType(ty.toIntern()).flagsPtr(ip).layout,
             else => unreachable,
         };
@@ -2177,7 +2177,7 @@ pub const Type = struct {
     pub fn isAbiInt(ty: Type, mod: *Module) bool {
         return switch (ty.zigTypeTag(mod)) {
             .Int, .Enum, .ErrorSet => true,
-            .Struct => ty.containerLayout(mod) == .Packed,
+            .Struct => ty.containerLayout(mod) == .@"packed",
             else => false,
         };
     }
@@ -2690,7 +2690,7 @@ pub const Type = struct {
                     const struct_type = ip.loadStructType(ty.toIntern());
                     // packed structs cannot be comptime-only because they have a well-defined
                     // memory layout and every field has a well-defined bit pattern.
-                    if (struct_type.layout == .Packed)
+                    if (struct_type.layout == .@"packed")
                         return false;
 
                     // A struct with no fields is not comptime-only.
@@ -3051,7 +3051,7 @@ pub const Type = struct {
         switch (ip.indexToKey(ty.toIntern())) {
             .struct_type => {
                 const struct_type = ip.loadStructType(ty.toIntern());
-                assert(struct_type.layout != .Packed);
+                assert(struct_type.layout != .@"packed");
                 const explicit_align = struct_type.fieldAlign(ip, index);
                 const field_ty = Type.fromInterned(struct_type.field_types.get(ip)[index]);
                 return mod.structFieldAlignment(explicit_align, field_ty, struct_type.layout);
@@ -3132,7 +3132,7 @@ pub const Type = struct {
             .struct_type => {
                 const struct_type = ip.loadStructType(ty.toIntern());
                 assert(struct_type.haveLayout(ip));
-                assert(struct_type.layout != .Packed);
+                assert(struct_type.layout != .@"packed");
                 return struct_type.offsets.get(ip)[index];
             },
 
@@ -3208,7 +3208,7 @@ pub const Type = struct {
         return switch (ip.indexToKey(ty.toIntern())) {
             .struct_type => {
                 const struct_type = ip.loadStructType(ty.toIntern());
-                if (struct_type.layout == .Packed) return false;
+                if (struct_type.layout == .@"packed") return false;
                 if (struct_type.decl == .none) return false;
                 return struct_type.flagsPtr(ip).is_tuple;
             },
@@ -3230,7 +3230,7 @@ pub const Type = struct {
         return switch (ip.indexToKey(ty.toIntern())) {
             .struct_type => {
                 const struct_type = ip.loadStructType(ty.toIntern());
-                if (struct_type.layout == .Packed) return false;
+                if (struct_type.layout == .@"packed") return false;
                 if (struct_type.decl == .none) return false;
                 return struct_type.flagsPtr(ip).is_tuple;
             },
src/Value.zig
@@ -676,8 +676,8 @@ pub fn writeToMemory(val: Value, ty: Type, mod: *Module, buffer: []u8) error{
         .Struct => {
             const struct_type = mod.typeToStruct(ty) orelse return error.IllDefinedMemoryLayout;
             switch (struct_type.layout) {
-                .Auto => return error.IllDefinedMemoryLayout,
-                .Extern => for (0..struct_type.field_types.len) |i| {
+                .auto => return error.IllDefinedMemoryLayout,
+                .@"extern" => for (0..struct_type.field_types.len) |i| {
                     const off: usize = @intCast(ty.structFieldOffset(i, mod));
                     const field_val = switch (val.ip_index) {
                         .none => switch (val.tag()) {
@@ -701,7 +701,7 @@ pub fn writeToMemory(val: Value, ty: Type, mod: *Module, buffer: []u8) error{
                     const field_ty = Type.fromInterned(struct_type.field_types.get(ip)[i]);
                     try writeToMemory(field_val, field_ty, mod, buffer[off..]);
                 },
-                .Packed => {
+                .@"packed" => {
                     const byte_count = (@as(usize, @intCast(ty.bitSize(mod))) + 7) / 8;
                     return writeToPackedMemory(val, ty, mod, buffer[0..byte_count], 0);
                 },
@@ -724,8 +724,8 @@ pub fn writeToMemory(val: Value, ty: Type, mod: *Module, buffer: []u8) error{
             bigint.writeTwosComplement(buffer[0..byte_count], endian);
         },
         .Union => switch (ty.containerLayout(mod)) {
-            .Auto => return error.IllDefinedMemoryLayout, // Sema is supposed to have emitted a compile error already
-            .Extern => {
+            .auto => return error.IllDefinedMemoryLayout, // Sema is supposed to have emitted a compile error already
+            .@"extern" => {
                 if (val.unionTag(mod)) |union_tag| {
                     const union_obj = mod.typeToUnion(ty).?;
                     const field_index = mod.unionTagFieldIndex(union_obj, union_tag).?;
@@ -739,7 +739,7 @@ pub fn writeToMemory(val: Value, ty: Type, mod: *Module, buffer: []u8) error{
                     return writeToMemory(val.unionValue(mod), backing_ty, mod, buffer[0..byte_count]);
                 }
             },
-            .Packed => {
+            .@"packed" => {
                 const backing_ty = try ty.unionBackingType(mod);
                 const byte_count: usize = @intCast(backing_ty.abiSize(mod));
                 return writeToPackedMemory(val, ty, mod, buffer[0..byte_count], 0);
@@ -841,7 +841,7 @@ pub fn writeToPackedMemory(
             const struct_type = ip.loadStructType(ty.toIntern());
             // Sema is supposed to have emitted a compile error already in the case of Auto,
             // and Extern is handled in non-packed writeToMemory.
-            assert(struct_type.layout == .Packed);
+            assert(struct_type.layout == .@"packed");
             var bits: u16 = 0;
             for (0..struct_type.field_types.len) |i| {
                 const field_val = switch (val.ip_index) {
@@ -866,8 +866,8 @@ pub fn writeToPackedMemory(
         .Union => {
             const union_obj = mod.typeToUnion(ty).?;
             switch (union_obj.getLayout(ip)) {
-                .Auto, .Extern => unreachable, // Handled in non-packed writeToMemory
-                .Packed => {
+                .auto, .@"extern" => unreachable, // Handled in non-packed writeToMemory
+                .@"packed" => {
                     if (val.unionTag(mod)) |union_tag| {
                         const field_index = mod.unionTagFieldIndex(union_obj, union_tag).?;
                         const field_type = Type.fromInterned(union_obj.field_types.get(ip)[field_index]);
@@ -991,8 +991,8 @@ pub fn readFromMemory(
         .Struct => {
             const struct_type = mod.typeToStruct(ty).?;
             switch (struct_type.layout) {
-                .Auto => unreachable, // Sema is supposed to have emitted a compile error already
-                .Extern => {
+                .auto => unreachable, // Sema is supposed to have emitted a compile error already
+                .@"extern" => {
                     const field_types = struct_type.field_types;
                     const field_vals = try arena.alloc(InternPool.Index, field_types.len);
                     for (field_vals, 0..) |*field_val, i| {
@@ -1006,7 +1006,7 @@ pub fn readFromMemory(
                         .storage = .{ .elems = field_vals },
                     } })));
                 },
-                .Packed => {
+                .@"packed" => {
                     const byte_count = (@as(usize, @intCast(ty.bitSize(mod))) + 7) / 8;
                     return readFromPackedMemory(ty, mod, buffer[0..byte_count], 0, arena);
                 },
@@ -1025,8 +1025,8 @@ pub fn readFromMemory(
             } })));
         },
         .Union => switch (ty.containerLayout(mod)) {
-            .Auto => return error.IllDefinedMemoryLayout,
-            .Extern => {
+            .auto => return error.IllDefinedMemoryLayout,
+            .@"extern" => {
                 const union_size = ty.abiSize(mod);
                 const array_ty = try mod.arrayType(.{ .len = union_size, .child = .u8_type });
                 const val = try (try readFromMemory(array_ty, mod, buffer, arena)).intern(array_ty, mod);
@@ -1036,7 +1036,7 @@ pub fn readFromMemory(
                     .val = val,
                 } })));
             },
-            .Packed => {
+            .@"packed" => {
                 const byte_count = (@as(usize, @intCast(ty.bitSize(mod))) + 7) / 8;
                 return readFromPackedMemory(ty, mod, buffer[0..byte_count], 0, arena);
             },
@@ -1177,8 +1177,8 @@ pub fn readFromPackedMemory(
             } })));
         },
         .Union => switch (ty.containerLayout(mod)) {
-            .Auto, .Extern => unreachable, // Handled by non-packed readFromMemory
-            .Packed => {
+            .auto, .@"extern" => unreachable, // Handled by non-packed readFromMemory
+            .@"packed" => {
                 const backing_ty = try ty.unionBackingType(mod);
                 const val = (try readFromPackedMemory(backing_ty, mod, buffer, bit_offset, arena)).toIntern();
                 return Value.fromInterned((try mod.intern(.{ .un = .{
@@ -4064,7 +4064,7 @@ fn dbHelper(self: *Value, tag_to_payload_map: *map: {
         .alignment = 0,
     };
     break :map @Type(.{ .Struct = .{
-        .layout = .Extern,
+        .layout = .@"extern",
         .fields = &fields,
         .decls = &.{},
         .is_tuple = false,
test/behavior/tuple.zig
@@ -135,7 +135,7 @@ test "array-like initializer for tuple types" {
     const T = @Type(.{
         .Struct = .{
             .is_tuple = true,
-            .layout = .Auto,
+            .layout = .auto,
             .decls = &.{},
             .fields = &.{
                 .{
@@ -323,7 +323,7 @@ test "zero sized struct in tuple handled correctly" {
         data: @Type(.{
             .Struct = .{
                 .is_tuple = true,
-                .layout = .Auto,
+                .layout = .auto,
                 .decls = &.{},
                 .fields = &.{.{
                     .name = "0",
@@ -471,7 +471,7 @@ test "coerce anon tuple to tuple" {
 
 test "empty tuple type" {
     const S = @Type(.{ .Struct = .{
-        .layout = .Auto,
+        .layout = .auto,
         .fields = &.{},
         .decls = &.{},
         .is_tuple = true,
test/behavior/tuple_declarations.zig
@@ -12,7 +12,7 @@ test "tuple declaration type info" {
         const T = struct { comptime u32 align(2) = 1, []const u8 };
         const info = @typeInfo(T).Struct;
 
-        try expect(info.layout == .Auto);
+        try expect(info.layout == .auto);
         try expect(info.backing_integer == null);
         try expect(info.fields.len == 2);
         try expect(info.decls.len == 0);
test/behavior/type.zig
@@ -263,7 +263,7 @@ test "Type.Struct" {
 
     const A = @Type(@typeInfo(struct { x: u8, y: u32 }));
     const infoA = @typeInfo(A).Struct;
-    try testing.expectEqual(Type.ContainerLayout.Auto, infoA.layout);
+    try testing.expectEqual(Type.ContainerLayout.auto, infoA.layout);
     try testing.expectEqualSlices(u8, "x", infoA.fields[0].name);
     try testing.expectEqual(u8, infoA.fields[0].type);
     try testing.expectEqual(@as(?*const anyopaque, null), infoA.fields[0].default_value);
@@ -281,7 +281,7 @@ test "Type.Struct" {
 
     const B = @Type(@typeInfo(extern struct { x: u8, y: u32 = 5 }));
     const infoB = @typeInfo(B).Struct;
-    try testing.expectEqual(Type.ContainerLayout.Extern, infoB.layout);
+    try testing.expectEqual(Type.ContainerLayout.@"extern", infoB.layout);
     try testing.expectEqualSlices(u8, "x", infoB.fields[0].name);
     try testing.expectEqual(u8, infoB.fields[0].type);
     try testing.expectEqual(@as(?*const anyopaque, null), infoB.fields[0].default_value);
@@ -293,7 +293,7 @@ test "Type.Struct" {
 
     const C = @Type(@typeInfo(packed struct { x: u8 = 3, y: u32 = 5 }));
     const infoC = @typeInfo(C).Struct;
-    try testing.expectEqual(Type.ContainerLayout.Packed, infoC.layout);
+    try testing.expectEqual(Type.ContainerLayout.@"packed", infoC.layout);
     try testing.expectEqualSlices(u8, "x", infoC.fields[0].name);
     try testing.expectEqual(u8, infoC.fields[0].type);
     try testing.expectEqual(@as(u8, 3), @as(*const u8, @ptrCast(infoC.fields[0].default_value.?)).*);
@@ -306,7 +306,7 @@ test "Type.Struct" {
     // anon structs
     const D = @Type(@typeInfo(@TypeOf(.{ .x = 3, .y = 5 })));
     const infoD = @typeInfo(D).Struct;
-    try testing.expectEqual(Type.ContainerLayout.Auto, infoD.layout);
+    try testing.expectEqual(Type.ContainerLayout.auto, infoD.layout);
     try testing.expectEqualSlices(u8, "x", infoD.fields[0].name);
     try testing.expectEqual(comptime_int, infoD.fields[0].type);
     try testing.expectEqual(@as(comptime_int, 3), @as(*const comptime_int, @ptrCast(infoD.fields[0].default_value.?)).*);
@@ -319,7 +319,7 @@ test "Type.Struct" {
     // tuples
     const E = @Type(@typeInfo(@TypeOf(.{ 1, 2 })));
     const infoE = @typeInfo(E).Struct;
-    try testing.expectEqual(Type.ContainerLayout.Auto, infoE.layout);
+    try testing.expectEqual(Type.ContainerLayout.auto, infoE.layout);
     try testing.expectEqualSlices(u8, "0", infoE.fields[0].name);
     try testing.expectEqual(comptime_int, infoE.fields[0].type);
     try testing.expectEqual(@as(comptime_int, 1), @as(*const comptime_int, @ptrCast(infoE.fields[0].default_value.?)).*);
@@ -332,14 +332,14 @@ test "Type.Struct" {
     // empty struct
     const F = @Type(@typeInfo(struct {}));
     const infoF = @typeInfo(F).Struct;
-    try testing.expectEqual(Type.ContainerLayout.Auto, infoF.layout);
+    try testing.expectEqual(Type.ContainerLayout.auto, infoF.layout);
     try testing.expect(infoF.fields.len == 0);
     try testing.expectEqual(@as(bool, false), infoF.is_tuple);
 
     // empty tuple
     const G = @Type(@typeInfo(@TypeOf(.{})));
     const infoG = @typeInfo(G).Struct;
-    try testing.expectEqual(Type.ContainerLayout.Auto, infoG.layout);
+    try testing.expectEqual(Type.ContainerLayout.auto, infoG.layout);
     try testing.expect(infoG.fields.len == 0);
     try testing.expectEqual(@as(bool, true), infoG.is_tuple);
 }
@@ -386,7 +386,7 @@ test "Type.Union" {
 
     const Untagged = @Type(.{
         .Union = .{
-            .layout = .Extern,
+            .layout = .@"extern",
             .tag_type = null,
             .fields = &.{
                 .{ .name = "int", .type = i32, .alignment = @alignOf(f32) },
@@ -402,7 +402,7 @@ test "Type.Union" {
 
     const PackedUntagged = @Type(.{
         .Union = .{
-            .layout = .Packed,
+            .layout = .@"packed",
             .tag_type = null,
             .fields = &.{
                 .{ .name = "signed", .type = i32, .alignment = @alignOf(i32) },
@@ -429,7 +429,7 @@ test "Type.Union" {
     });
     const Tagged = @Type(.{
         .Union = .{
-            .layout = .Auto,
+            .layout = .auto,
             .tag_type = Tag,
             .fields = &.{
                 .{ .name = "signed", .type = i32, .alignment = @alignOf(i32) },
@@ -457,7 +457,7 @@ test "Type.Union from Type.Enum" {
     });
     const T = @Type(.{
         .Union = .{
-            .layout = .Auto,
+            .layout = .auto,
             .tag_type = Tag,
             .fields = &.{
                 .{ .name = "working_as_expected", .type = u32, .alignment = @alignOf(u32) },
@@ -472,7 +472,7 @@ test "Type.Union from regular enum" {
     const E = enum { working_as_expected };
     const T = @Type(.{
         .Union = .{
-            .layout = .Auto,
+            .layout = .auto,
             .tag_type = E,
             .fields = &.{
                 .{ .name = "working_as_expected", .type = u32, .alignment = @alignOf(u32) },
@@ -487,7 +487,7 @@ test "Type.Union from empty regular enum" {
     const E = enum {};
     const U = @Type(.{
         .Union = .{
-            .layout = .Auto,
+            .layout = .auto,
             .tag_type = E,
             .fields = &.{},
             .decls = &.{},
@@ -507,7 +507,7 @@ test "Type.Union from empty Type.Enum" {
     });
     const U = @Type(.{
         .Union = .{
-            .layout = .Auto,
+            .layout = .auto,
             .tag_type = E,
             .fields = &.{},
             .decls = &.{},
@@ -553,7 +553,7 @@ test "reified struct field name from optional payload" {
         const m_name: ?[1:0]u8 = "a".*;
         if (m_name) |*name| {
             const T = @Type(.{ .Struct = .{
-                .layout = .Auto,
+                .layout = .auto,
                 .fields = &.{.{
                     .name = name,
                     .type = u8,
@@ -575,7 +575,7 @@ test "reified union uses @alignOf" {
         fn CreateUnion(comptime T: type) type {
             return @Type(.{
                 .Union = .{
-                    .layout = .Auto,
+                    .layout = .auto,
                     .tag_type = null,
                     .fields = &[_]std.builtin.Type.UnionField{
                         .{
@@ -597,7 +597,7 @@ test "reified struct uses @alignOf" {
         fn NamespacedGlobals(comptime modules: anytype) type {
             return @Type(.{
                 .Struct = .{
-                    .layout = .Auto,
+                    .layout = .auto,
                     .is_tuple = false,
                     .fields = &.{
                         .{
@@ -659,7 +659,7 @@ test "empty struct assigned to reified struct field" {
         fn NamespacedComponents(comptime modules: anytype) type {
             return @Type(.{
                 .Struct = .{
-                    .layout = .Auto,
+                    .layout = .auto,
                     .is_tuple = false,
                     .fields = &.{.{
                         .name = "components",
@@ -721,7 +721,7 @@ test "struct field names sliced at comptime from larger string" {
 
         const T = @Type(.{
             .Struct = .{
-                .layout = .Auto,
+                .layout = .auto,
                 .is_tuple = false,
                 .fields = fields,
                 .decls = &.{},
test/behavior/type_info.zig
@@ -250,7 +250,7 @@ test "type info: union info" {
 fn testUnion() !void {
     const typeinfo_info = @typeInfo(Type);
     try expect(typeinfo_info == .Union);
-    try expect(typeinfo_info.Union.layout == .Auto);
+    try expect(typeinfo_info.Union.layout == .auto);
     try expect(typeinfo_info.Union.tag_type.? == TypeId);
     try expect(typeinfo_info.Union.fields.len == 24);
     try expect(typeinfo_info.Union.fields[4].type == @TypeOf(@typeInfo(u8).Int));
@@ -264,7 +264,7 @@ fn testUnion() !void {
     const notag_union_info = @typeInfo(TestNoTagUnion);
     try expect(notag_union_info == .Union);
     try expect(notag_union_info.Union.tag_type == null);
-    try expect(notag_union_info.Union.layout == .Auto);
+    try expect(notag_union_info.Union.layout == .auto);
     try expect(notag_union_info.Union.fields.len == 2);
     try expect(notag_union_info.Union.fields[0].alignment == @alignOf(void));
     try expect(notag_union_info.Union.fields[1].type == u32);
@@ -275,7 +275,7 @@ fn testUnion() !void {
     };
 
     const extern_union_info = @typeInfo(TestExternUnion);
-    try expect(extern_union_info.Union.layout == .Extern);
+    try expect(extern_union_info.Union.layout == .@"extern");
     try expect(extern_union_info.Union.tag_type == null);
     try expect(extern_union_info.Union.fields[0].type == *anyopaque);
 }
@@ -310,7 +310,7 @@ fn testPackedStruct() !void {
     const struct_info = @typeInfo(TestPackedStruct);
     try expect(struct_info == .Struct);
     try expect(struct_info.Struct.is_tuple == false);
-    try expect(struct_info.Struct.layout == .Packed);
+    try expect(struct_info.Struct.layout == .@"packed");
     try expect(struct_info.Struct.backing_integer == u128);
     try expect(struct_info.Struct.fields.len == 4);
     try expect(struct_info.Struct.fields[0].alignment == 0);
test/cases/compile_errors/packed_struct_field_alignment_unavailable_for_reify_type.zig
@@ -1,5 +1,5 @@
 export fn entry() void {
-    _ = @Type(.{ .Struct = .{ .layout = .Packed, .fields = &.{
+    _ = @Type(.{ .Struct = .{ .layout = .@"packed", .fields = &.{
         .{ .name = "one", .type = u4, .default_value = null, .is_comptime = false, .alignment = 2 },
     }, .decls = &.{}, .is_tuple = false } });
 }
test/cases/compile_errors/reify_struct.zig
@@ -1,6 +1,6 @@
 comptime {
     @Type(.{ .Struct = .{
-        .layout = .Auto,
+        .layout = .auto,
         .fields = &.{.{
             .name = "foo",
             .type = u32,
@@ -14,7 +14,7 @@ comptime {
 }
 comptime {
     @Type(.{ .Struct = .{
-        .layout = .Auto,
+        .layout = .auto,
         .fields = &.{.{
             .name = "3",
             .type = u32,
@@ -28,7 +28,7 @@ comptime {
 }
 comptime {
     @Type(.{ .Struct = .{
-        .layout = .Auto,
+        .layout = .auto,
         .fields = &.{.{
             .name = "0",
             .type = u32,
@@ -42,7 +42,7 @@ comptime {
 }
 comptime {
     @Type(.{ .Struct = .{
-        .layout = .Extern,
+        .layout = .@"extern",
         .fields = &.{.{
             .name = "0",
             .type = u32,
@@ -56,7 +56,7 @@ comptime {
 }
 comptime {
     @Type(.{ .Struct = .{
-        .layout = .Packed,
+        .layout = .@"packed",
         .fields = &.{.{
             .name = "0",
             .type = u32,
test/cases/compile_errors/reify_type_for_tagged_union_with_extra_enum_field.zig
@@ -12,7 +12,7 @@ const Tag = @Type(.{
 });
 const Tagged = @Type(.{
     .Union = .{
-        .layout = .Auto,
+        .layout = .auto,
         .tag_type = Tag,
         .fields = &.{
             .{ .name = "signed", .type = i32, .alignment = @alignOf(i32) },
test/cases/compile_errors/reify_type_for_tagged_union_with_extra_union_field.zig
@@ -11,7 +11,7 @@ const Tag = @Type(.{
 });
 const Tagged = @Type(.{
     .Union = .{
-        .layout = .Auto,
+        .layout = .auto,
         .tag_type = Tag,
         .fields = &.{
             .{ .name = "signed", .type = i32, .alignment = @alignOf(i32) },
test/cases/compile_errors/reify_type_for_tagged_union_with_no_enum_fields.zig
@@ -8,7 +8,7 @@ const Tag = @Type(.{
 });
 const Tagged = @Type(.{
     .Union = .{
-        .layout = .Auto,
+        .layout = .auto,
         .tag_type = Tag,
         .fields = &.{
             .{ .name = "signed", .type = i32, .alignment = @alignOf(i32) },
test/cases/compile_errors/reify_type_for_tagged_union_with_no_union_fields.zig
@@ -11,7 +11,7 @@ const Tag = @Type(.{
 });
 const Tagged = @Type(.{
     .Union = .{
-        .layout = .Auto,
+        .layout = .auto,
         .tag_type = Tag,
         .fields = &.{},
         .decls = &.{},
test/cases/compile_errors/reify_type_for_union_with_opaque_field.zig
@@ -1,6 +1,6 @@
 const Untagged = @Type(.{
     .Union = .{
-        .layout = .Auto,
+        .layout = .auto,
         .tag_type = null,
         .fields = &.{
             .{ .name = "foo", .type = opaque {}, .alignment = 1 },
test/cases/compile_errors/reify_type_with_invalid_field_alignment.zig
@@ -1,7 +1,7 @@
 comptime {
     _ = @Type(.{
         .Union = .{
-            .layout = .Auto,
+            .layout = .auto,
             .tag_type = null,
             .fields = &.{
                 .{ .name = "foo", .type = usize, .alignment = 3 },
@@ -13,7 +13,7 @@ comptime {
 comptime {
     _ = @Type(.{
         .Struct = .{
-            .layout = .Auto,
+            .layout = .auto,
             .fields = &.{.{
                 .name = "0",
                 .type = u32,
test/cases/compile_errors/reify_type_with_undefined.zig
@@ -7,7 +7,7 @@ comptime {
             .fields = undefined,
             .decls = undefined,
             .is_tuple = false,
-            .layout = .Auto,
+            .layout = .auto,
         },
     });
 }
@@ -16,7 +16,7 @@ comptime {
     const fields: [1]std.builtin.Type.StructField = undefined;
     _ = @Type(.{
         .Struct = .{
-            .layout = .Auto,
+            .layout = .auto,
             .fields = &fields,
             .decls = &.{},
             .is_tuple = false,