diff --git a/lib/compiler/aro/aro/Parser.zig b/lib/compiler/aro/aro/Parser.zig
index 8327469853..5ebd89ec3d 100644
--- a/lib/compiler/aro/aro/Parser.zig
+++ b/lib/compiler/aro/aro/Parser.zig
@@ -101,7 +101,7 @@ value_map: Tree.ValueMap,
 
 // buffers used during compilation
 syms: SymbolStack = .{},
-strings: std.ArrayListAligned(u8, 4),
+strings: std.ArrayListAligned(u8, .@"4"),
 labels: std.ArrayList(Label),
 list_buf: NodeList,
 decl_buf: NodeList,
@@ -693,7 +693,7 @@ pub fn parse(pp: *Preprocessor) Compilation.Error!Tree {
         .gpa = pp.comp.gpa,
         .arena = arena.allocator(),
         .tok_ids = pp.tokens.items(.id),
-        .strings = std.ArrayListAligned(u8, 4).init(pp.comp.gpa),
+        .strings = std.ArrayListAligned(u8, .@"4").init(pp.comp.gpa),
         .value_map = Tree.ValueMap.init(pp.comp.gpa),
         .data = NodeList.init(pp.comp.gpa),
         .labels = std.ArrayList(Label).init(pp.comp.gpa),
diff --git a/lib/compiler/aro/aro/Preprocessor.zig b/lib/compiler/aro/aro/Preprocessor.zig
index 9f10153d01..e45f6eabc6 100644
--- a/lib/compiler/aro/aro/Preprocessor.zig
+++ b/lib/compiler/aro/aro/Preprocessor.zig
@@ -983,7 +983,7 @@ fn expr(pp: *Preprocessor, tokenizer: *Tokenizer) MacroError!bool {
         .tok_i = @intCast(token_state.tokens_len),
         .arena = pp.arena.allocator(),
         .in_macro = true,
-        .strings = std.ArrayListAligned(u8, 4).init(pp.comp.gpa),
+        .strings = std.ArrayListAligned(u8, .@"4").init(pp.comp.gpa),
 
         .data = undefined,
         .value_map = undefined,
diff --git a/lib/compiler/objcopy.zig b/lib/compiler/objcopy.zig
index bf031bb391..bcd3a69a0c 100644
--- a/lib/compiler/objcopy.zig
+++ b/lib/compiler/objcopy.zig
@@ -841,12 +841,12 @@ fn ElfFile(comptime is_64: bool) type {
         arena: std.heap.ArenaAllocator,
 
         const SectionCategory = ElfFileHelper.SectionCategory;
-        const section_memory_align = @alignOf(Elf_Sym); // most restrictive of what we may load in memory
+        const section_memory_align: std.mem.Alignment = .of(Elf_Sym); // most restrictive of what we may load in memory
         const Section = struct {
             section: Elf_Shdr,
             name: []const u8 = "",
             segment: ?*const Elf_Phdr = null, // if the section is used by a program segment (there can be more than one)
-            payload: ?[]align(section_memory_align) const u8 = null, // if we need the data in memory
+            payload: ?[]align(section_memory_align.toByteUnits()) const u8 = null, // if we need the data in memory
             category: SectionCategory = .none, // should the section be kept in the exe or stripped to the debug database, or both.
         };
 
@@ -999,7 +999,7 @@ fn ElfFile(comptime is_64: bool) type {
                 remap_idx: u16,
 
                 // optionally overrides the payload from the source file
-                payload: ?[]align(section_memory_align) const u8 = null,
+                payload: ?[]align(section_memory_align.toByteUnits()) const u8 = null,
                 section: ?Elf_Shdr = null,
             };
             const sections_update = try allocator.alloc(Update, self.sections.len);
@@ -1219,7 +1219,7 @@ fn ElfFile(comptime is_64: bool) type {
                 if (options.debuglink) |link| {
                     const payload = payload: {
                         const crc_offset = std.mem.alignForward(usize, link.name.len + 1, 4);
-                        const buf = try allocator.alignedAlloc(u8, 4, crc_offset + 4);
+                        const buf = try allocator.alignedAlloc(u8, .@"4", crc_offset + 4);
                         @memcpy(buf[0..link.name.len], link.name);
                         @memset(buf[link.name.len..crc_offset], 0);
                         @memcpy(buf[crc_offset..], std.mem.asBytes(&link.crc32));
@@ -1498,7 +1498,7 @@ const ElfFileHelper = struct {
         var section_reader = std.io.limitedReader(in_file.reader(), size);
 
         // allocate as large as decompressed data. if the compression doesn't fit, keep the data uncompressed.
-        const compressed_data = try allocator.alignedAlloc(u8, 8, @intCast(size));
+        const compressed_data = try allocator.alignedAlloc(u8, .@"8", @intCast(size));
         var compressed_stream = std.io.fixedBufferStream(compressed_data);
 
         try compressed_stream.writer().writeAll(prefix);
diff --git a/lib/std/Build/Step/CheckObject.zig b/lib/std/Build/Step/CheckObject.zig
index 289a4ff4f8..5fee8c730b 100644
--- a/lib/std/Build/Step/CheckObject.zig
+++ b/lib/std/Build/Step/CheckObject.zig
@@ -563,7 +563,7 @@ fn make(step: *Step, make_options: Step.MakeOptions) !void {
         src_path.sub_path,
         check_object.max_bytes,
         null,
-        @alignOf(u64),
+        .of(u64),
         null,
     ) catch |err| return step.fail("unable to read '{'}': {s}", .{ src_path, @errorName(err) });
 
diff --git a/lib/std/Build/Watch.zig b/lib/std/Build/Watch.zig
index 068a50769f..13540a2b36 100644
--- a/lib/std/Build/Watch.zig
+++ b/lib/std/Build/Watch.zig
@@ -56,7 +56,7 @@ const Os = switch (builtin.os.tag) {
                 const bytes = lfh.slice();
                 const new_ptr = try gpa.alignedAlloc(
                     u8,
-                    @alignOf(std.os.linux.file_handle),
+                    .of(std.os.linux.file_handle),
                     @sizeOf(std.os.linux.file_handle) + bytes.len,
                 );
                 const new_header: *std.os.linux.file_handle = @ptrCast(new_ptr);
diff --git a/lib/std/array_hash_map.zig b/lib/std/array_hash_map.zig
index f2a4ae069f..b0b9e19169 100644
--- a/lib/std/array_hash_map.zig
+++ b/lib/std/array_hash_map.zig
@@ -2129,7 +2129,7 @@ const IndexHeader = struct {
         const len = @as(usize, 1) << @as(math.Log2Int(usize), @intCast(new_bit_index));
         const index_size = hash_map.capacityIndexSize(new_bit_index);
         const nbytes = @sizeOf(IndexHeader) + index_size * len;
-        const bytes = try gpa.alignedAlloc(u8, @alignOf(IndexHeader), nbytes);
+        const bytes = try gpa.alignedAlloc(u8, .of(IndexHeader), nbytes);
         @memset(bytes[@sizeOf(IndexHeader)..], 0xff);
         const result: *IndexHeader = @alignCast(@ptrCast(bytes.ptr));
         result.* = .{
diff --git a/lib/std/array_list.zig b/lib/std/array_list.zig
index bedba88a73..2a9159aeac 100644
--- a/lib/std/array_list.zig
+++ b/lib/std/array_list.zig
@@ -22,9 +22,9 @@ pub fn ArrayList(comptime T: type) type {
 ///
 /// This struct internally stores a `std.mem.Allocator` for memory management.
 /// To manually specify an allocator with each function call see `ArrayListAlignedUnmanaged`.
-pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
+pub fn ArrayListAligned(comptime T: type, comptime alignment: ?mem.Alignment) type {
     if (alignment) |a| {
-        if (a == @alignOf(T)) {
+        if (a.toByteUnits() == @alignOf(T)) {
             return ArrayListAligned(T, null);
         }
     }
@@ -43,10 +43,10 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
         capacity: usize,
         allocator: Allocator,
 
-        pub const Slice = if (alignment) |a| ([]align(a) T) else []T;
+        pub const Slice = if (alignment) |a| ([]align(a.toByteUnits()) T) else []T;
 
         pub fn SentinelSlice(comptime s: T) type {
-            return if (alignment) |a| ([:s]align(a) T) else [:s]T;
+            return if (alignment) |a| ([:s]align(a.toByteUnits()) T) else [:s]T;
         }
 
         /// Deinitialize with `deinit` or use `toOwnedSlice`.
@@ -611,9 +611,9 @@ pub fn ArrayListUnmanaged(comptime T: type) type {
 /// or use `toOwnedSlice`.
 ///
 /// Default initialization of this struct is deprecated; use `.empty` instead.
-pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) type {
+pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?mem.Alignment) type {
     if (alignment) |a| {
-        if (a == @alignOf(T)) {
+        if (a.toByteUnits() == @alignOf(T)) {
             return ArrayListAlignedUnmanaged(T, null);
         }
     }
@@ -637,10 +637,10 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ
             .capacity = 0,
         };
 
-        pub const Slice = if (alignment) |a| ([]align(a) T) else []T;
+        pub const Slice = if (alignment) |a| ([]align(a.toByteUnits()) T) else []T;
 
         pub fn SentinelSlice(comptime s: T) type {
-            return if (alignment) |a| ([:s]align(a) T) else [:s]T;
+            return if (alignment) |a| ([:s]align(a.toByteUnits()) T) else [:s]T;
         }
 
         /// Initialize with capacity to hold `num` elements.
@@ -1913,7 +1913,7 @@ test "ArrayList(u8) implements writer" {
         try testing.expectEqualSlices(u8, "x: 42\ny: 1234\n", buffer.items);
     }
     {
-        var list = ArrayListAligned(u8, 2).init(a);
+        var list = ArrayListAligned(u8, .@"2").init(a);
         defer list.deinit();
 
         const writer = list.writer();
@@ -1940,7 +1940,7 @@ test "ArrayListUnmanaged(u8) implements writer" {
         try testing.expectEqualSlices(u8, "x: 42\ny: 1234\n", buffer.items);
     }
     {
-        var list: ArrayListAlignedUnmanaged(u8, 2) = .empty;
+        var list: ArrayListAlignedUnmanaged(u8, .@"2") = .empty;
         defer list.deinit(a);
 
         const writer = list.writer(a);
@@ -2126,7 +2126,7 @@ test "toOwnedSliceSentinel" {
 test "accepts unaligned slices" {
     const a = testing.allocator;
     {
-        var list = std.ArrayListAligned(u8, 8).init(a);
+        var list = std.ArrayListAligned(u8, .@"8").init(a);
         defer list.deinit();
 
         try list.appendSlice(&.{ 0, 1, 2, 3 });
@@ -2136,7 +2136,7 @@ test "accepts unaligned slices" {
         try testing.expectEqualSlices(u8, list.items, &.{ 0, 8, 9, 6, 7, 2, 3 });
     }
     {
-        var list: std.ArrayListAlignedUnmanaged(u8, 8) = .empty;
+        var list: std.ArrayListAlignedUnmanaged(u8, .@"8") = .empty;
         defer list.deinit(a);
 
         try list.appendSlice(a, &.{ 0, 1, 2, 3 });
diff --git a/lib/std/bounded_array.zig b/lib/std/bounded_array.zig
index 42c77e2e77..1a4407e687 100644
--- a/lib/std/bounded_array.zig
+++ b/lib/std/bounded_array.zig
@@ -2,6 +2,7 @@ const std = @import("std.zig");
 const assert = std.debug.assert;
 const mem = std.mem;
 const testing = std.testing;
+const Alignment = std.mem.Alignment;
 
 /// A structure with an array and a length, that can be used as a slice.
 ///
@@ -16,7 +17,7 @@ const testing = std.testing;
 /// var a_clone = a; // creates a copy - the structure doesn't use any internal pointers
 /// ```
 pub fn BoundedArray(comptime T: type, comptime buffer_capacity: usize) type {
-    return BoundedArrayAligned(T, @alignOf(T), buffer_capacity);
+    return BoundedArrayAligned(T, .of(T), buffer_capacity);
 }
 
 /// A structure with an array, length and alignment, that can be used as a
@@ -34,12 +35,12 @@ pub fn BoundedArray(comptime T: type, comptime buffer_capacity: usize) type {
 /// ```
 pub fn BoundedArrayAligned(
     comptime T: type,
-    comptime alignment: u29,
+    comptime alignment: Alignment,
     comptime buffer_capacity: usize,
 ) type {
     return struct {
         const Self = @This();
-        buffer: [buffer_capacity]T align(alignment) = undefined,
+        buffer: [buffer_capacity]T align(alignment.toByteUnits()) = undefined,
         len: usize = 0,
 
         /// Set the actual length of the slice.
@@ -51,15 +52,15 @@ pub fn BoundedArrayAligned(
 
         /// View the internal array as a slice whose size was previously set.
         pub fn slice(self: anytype) switch (@TypeOf(&self.buffer)) {
-            *align(alignment) [buffer_capacity]T => []align(alignment) T,
-            *align(alignment) const [buffer_capacity]T => []align(alignment) const T,
+            *align(alignment.toByteUnits()) [buffer_capacity]T => []align(alignment.toByteUnits()) T,
+            *align(alignment.toByteUnits()) const [buffer_capacity]T => []align(alignment.toByteUnits()) const T,
             else => unreachable,
         } {
             return self.buffer[0..self.len];
         }
 
         /// View the internal array as a constant slice whose size was previously set.
-        pub fn constSlice(self: *const Self) []align(alignment) const T {
+        pub fn constSlice(self: *const Self) []align(alignment.toByteUnits()) const T {
             return self.slice();
         }
 
@@ -120,7 +121,7 @@ pub fn BoundedArrayAligned(
 
         /// Resize the slice, adding `n` new elements, which have `undefined` values.
         /// The return value is a pointer to the array of uninitialized elements.
-        pub fn addManyAsArray(self: *Self, comptime n: usize) error{Overflow}!*align(alignment) [n]T {
+        pub fn addManyAsArray(self: *Self, comptime n: usize) error{Overflow}!*align(alignment.toByteUnits()) [n]T {
             const prev_len = self.len;
             try self.resize(self.len + n);
             return self.slice()[prev_len..][0..n];
@@ -128,7 +129,7 @@ pub fn BoundedArrayAligned(
 
         /// Resize the slice, adding `n` new elements, which have `undefined` values.
         /// The return value is a slice pointing to the uninitialized elements.
-        pub fn addManyAsSlice(self: *Self, n: usize) error{Overflow}![]align(alignment) T {
+        pub fn addManyAsSlice(self: *Self, n: usize) error{Overflow}![]align(alignment.toByteUnits()) T {
             const prev_len = self.len;
             try self.resize(self.len + n);
             return self.slice()[prev_len..][0..n];
@@ -146,7 +147,7 @@ pub fn BoundedArrayAligned(
         /// This can be useful for writing directly into it.
         /// Note that such an operation must be followed up with a
         /// call to `resize()`
-        pub fn unusedCapacitySlice(self: *Self) []align(alignment) T {
+        pub fn unusedCapacitySlice(self: *Self) []align(alignment.toByteUnits()) T {
             return self.buffer[self.len..];
         }
 
@@ -399,7 +400,7 @@ test BoundedArray {
 }
 
 test "BoundedArrayAligned" {
-    var a = try BoundedArrayAligned(u8, 16, 4).init(0);
+    var a = try BoundedArrayAligned(u8, .@"16", 4).init(0);
     try a.append(0);
     try a.append(0);
     try a.append(255);
diff --git a/lib/std/crypto/argon2.zig b/lib/std/crypto/argon2.zig
index 28782e414d..77c878e779 100644
--- a/lib/std/crypto/argon2.zig
+++ b/lib/std/crypto/argon2.zig
@@ -14,7 +14,7 @@ const pwhash = crypto.pwhash;
 
 const Thread = std.Thread;
 const Blake2b512 = blake2.Blake2b512;
-const Blocks = std.ArrayListAligned([block_length]u64, 16);
+const Blocks = std.ArrayListAligned([block_length]u64, .@"16");
 const H0 = [Blake2b512.digest_length + 8]u8;
 
 const EncodingError = crypto.errors.EncodingError;
diff --git a/lib/std/crypto/scrypt.zig b/lib/std/crypto/scrypt.zig
index 7968d8736a..23202e7937 100644
--- a/lib/std/crypto/scrypt.zig
+++ b/lib/std/crypto/scrypt.zig
@@ -195,11 +195,11 @@ pub fn kdf(
         params.r > max_int / 256 or
         n > max_int / 128 / @as(u64, params.r)) return KdfError.WeakParameters;
 
-    const xy = try allocator.alignedAlloc(u32, 16, 64 * params.r);
+    const xy = try allocator.alignedAlloc(u32, .@"16", 64 * params.r);
     defer allocator.free(xy);
-    const v = try allocator.alignedAlloc(u32, 16, 32 * n * params.r);
+    const v = try allocator.alignedAlloc(u32, .@"16", 32 * n * params.r);
     defer allocator.free(v);
-    var dk = try allocator.alignedAlloc(u8, 16, params.p * 128 * params.r);
+    var dk = try allocator.alignedAlloc(u8, .@"16", params.p * 128 * params.r);
     defer allocator.free(dk);
 
     try pwhash.pbkdf2(dk, password, salt, 1, HmacSha256);
diff --git a/lib/std/fs/Dir.zig b/lib/std/fs/Dir.zig
index 3d869d9b59..8be324c0e8 100644
--- a/lib/std/fs/Dir.zig
+++ b/lib/std/fs/Dir.zig
@@ -1960,7 +1960,7 @@ pub fn readFile(self: Dir, file_path: []const u8, buffer: []u8) ![]u8 {
 /// On WASI, `file_path` should be encoded as valid UTF-8.
 /// On other platforms, `file_path` is an opaque sequence of bytes with no particular encoding.
 pub fn readFileAlloc(self: Dir, allocator: mem.Allocator, file_path: []const u8, max_bytes: usize) ![]u8 {
-    return self.readFileAllocOptions(allocator, file_path, max_bytes, null, @alignOf(u8), null);
+    return self.readFileAllocOptions(allocator, file_path, max_bytes, null, .of(u8), null);
 }
 
 /// On success, caller owns returned buffer.
@@ -1977,9 +1977,9 @@ pub fn readFileAllocOptions(
     file_path: []const u8,
     max_bytes: usize,
     size_hint: ?usize,
-    comptime alignment: u29,
+    comptime alignment: std.mem.Alignment,
     comptime optional_sentinel: ?u8,
-) !(if (optional_sentinel) |s| [:s]align(alignment) u8 else []align(alignment) u8) {
+) !(if (optional_sentinel) |s| [:s]align(alignment.toByteUnits()) u8 else []align(alignment.toByteUnits()) u8) {
     var file = try self.openFile(file_path, .{});
     defer file.close();
 
diff --git a/lib/std/fs/File.zig b/lib/std/fs/File.zig
index 9797a1b896..51745065f9 100644
--- a/lib/std/fs/File.zig
+++ b/lib/std/fs/File.zig
@@ -1133,7 +1133,7 @@ pub fn updateTimes(
 /// On success, caller owns returned buffer.
 /// If the file is larger than `max_bytes`, returns `error.FileTooBig`.
 pub fn readToEndAlloc(self: File, allocator: Allocator, max_bytes: usize) ![]u8 {
-    return self.readToEndAllocOptions(allocator, max_bytes, null, @alignOf(u8), null);
+    return self.readToEndAllocOptions(allocator, max_bytes, null, .of(u8), null);
 }
 
 /// Reads all the bytes from the current position to the end of the file.
@@ -1147,9 +1147,9 @@ pub fn readToEndAllocOptions(
     allocator: Allocator,
     max_bytes: usize,
     size_hint: ?usize,
-    comptime alignment: u29,
+    comptime alignment: Alignment,
     comptime optional_sentinel: ?u8,
-) !(if (optional_sentinel) |s| [:s]align(alignment) u8 else []align(alignment) u8) {
+) !(if (optional_sentinel) |s| [:s]align(alignment.toByteUnits()) u8 else []align(alignment.toByteUnits()) u8) {
     // If no size hint is provided fall back to the size=0 code path
     const size = size_hint orelse 0;
 
@@ -1782,3 +1782,4 @@ const windows = std.os.windows;
 const Os = std.builtin.Os;
 const maxInt = std.math.maxInt;
 const is_windows = builtin.os.tag == .windows;
+const Alignment = std.mem.Alignment;
diff --git a/lib/std/hash_map.zig b/lib/std/hash_map.zig
index 1cb4bfe010..fb9b9f269d 100644
--- a/lib/std/hash_map.zig
+++ b/lib/std/hash_map.zig
@@ -6,6 +6,7 @@ const math = std.math;
 const mem = std.mem;
 const Allocator = mem.Allocator;
 const Wyhash = std.hash.Wyhash;
+const Alignment = std.mem.Alignment;
 
 pub fn getAutoHashFn(comptime K: type, comptime Context: type) (fn (Context, K) u64) {
     comptime {
@@ -1460,7 +1461,7 @@ pub fn HashMapUnmanaged(
             const header_align = @alignOf(Header);
             const key_align = if (@sizeOf(K) == 0) 1 else @alignOf(K);
             const val_align = if (@sizeOf(V) == 0) 1 else @alignOf(V);
-            const max_align = comptime @max(header_align, key_align, val_align);
+            const max_align: Alignment = comptime .fromByteUnits(@max(header_align, key_align, val_align));
 
             const new_cap: usize = new_capacity;
             const meta_size = @sizeOf(Header) + new_cap * @sizeOf(Metadata);
@@ -1472,7 +1473,7 @@ pub fn HashMapUnmanaged(
             const vals_start = std.mem.alignForward(usize, keys_end, val_align);
             const vals_end = vals_start + new_cap * @sizeOf(V);
 
-            const total_size = std.mem.alignForward(usize, vals_end, max_align);
+            const total_size = max_align.forward(vals_end);
 
             const slice = try allocator.alignedAlloc(u8, max_align, total_size);
             const ptr: [*]u8 = @ptrCast(slice.ptr);
diff --git a/lib/std/heap.zig b/lib/std/heap.zig
index 3e7647abb6..2f5332be9f 100644
--- a/lib/std/heap.zig
+++ b/lib/std/heap.zig
@@ -7,6 +7,7 @@ const mem = std.mem;
 const c = std.c;
 const Allocator = std.mem.Allocator;
 const windows = std.os.windows;
+const Alignment = std.mem.Alignment;
 
 pub const ArenaAllocator = @import("heap/arena_allocator.zig").ArenaAllocator;
 pub const SmpAllocator = @import("heap/SmpAllocator.zig");
@@ -153,7 +154,7 @@ const CAllocator = struct {
         return @alignCast(@ptrCast(ptr - @sizeOf(usize)));
     }
 
-    fn alignedAlloc(len: usize, alignment: mem.Alignment) ?[*]u8 {
+    fn alignedAlloc(len: usize, alignment: Alignment) ?[*]u8 {
         const alignment_bytes = alignment.toByteUnits();
         if (supports_posix_memalign) {
             // The posix_memalign only accepts alignment values that are a
@@ -201,7 +202,7 @@ const CAllocator = struct {
     fn alloc(
         _: *anyopaque,
         len: usize,
-        alignment: mem.Alignment,
+        alignment: Alignment,
         return_address: usize,
     ) ?[*]u8 {
         _ = return_address;
@@ -212,7 +213,7 @@ const CAllocator = struct {
     fn resize(
         _: *anyopaque,
         buf: []u8,
-        alignment: mem.Alignment,
+        alignment: Alignment,
         new_len: usize,
         return_address: usize,
     ) bool {
@@ -233,7 +234,7 @@ const CAllocator = struct {
     fn remap(
         context: *anyopaque,
         memory: []u8,
-        alignment: mem.Alignment,
+        alignment: Alignment,
         new_len: usize,
         return_address: usize,
     ) ?[*]u8 {
@@ -245,7 +246,7 @@ const CAllocator = struct {
     fn free(
         _: *anyopaque,
         buf: []u8,
-        alignment: mem.Alignment,
+        alignment: Alignment,
         return_address: usize,
     ) void {
         _ = alignment;
@@ -281,7 +282,7 @@ const raw_c_allocator_vtable: Allocator.VTable = .{
 fn rawCAlloc(
     context: *anyopaque,
     len: usize,
-    alignment: mem.Alignment,
+    alignment: Alignment,
     return_address: usize,
 ) ?[*]u8 {
     _ = context;
@@ -299,7 +300,7 @@ fn rawCAlloc(
 fn rawCResize(
     context: *anyopaque,
     memory: []u8,
-    alignment: mem.Alignment,
+    alignment: Alignment,
     new_len: usize,
     return_address: usize,
 ) bool {
@@ -314,7 +315,7 @@ fn rawCResize(
 fn rawCRemap(
     context: *anyopaque,
     memory: []u8,
-    alignment: mem.Alignment,
+    alignment: Alignment,
     new_len: usize,
     return_address: usize,
 ) ?[*]u8 {
@@ -327,7 +328,7 @@ fn rawCRemap(
 fn rawCFree(
     context: *anyopaque,
     memory: []u8,
-    alignment: mem.Alignment,
+    alignment: Alignment,
     return_address: usize,
 ) void {
     _ = context;
@@ -425,7 +426,7 @@ pub fn StackFallbackAllocator(comptime size: usize) type {
         fn alloc(
             ctx: *anyopaque,
             len: usize,
-            alignment: mem.Alignment,
+            alignment: Alignment,
             ra: usize,
         ) ?[*]u8 {
             const self: *Self = @ptrCast(@alignCast(ctx));
@@ -436,7 +437,7 @@ pub fn StackFallbackAllocator(comptime size: usize) type {
         fn resize(
             ctx: *anyopaque,
             buf: []u8,
-            alignment: mem.Alignment,
+            alignment: Alignment,
             new_len: usize,
             ra: usize,
         ) bool {
@@ -451,7 +452,7 @@ pub fn StackFallbackAllocator(comptime size: usize) type {
         fn remap(
             context: *anyopaque,
             memory: []u8,
-            alignment: mem.Alignment,
+            alignment: Alignment,
             new_len: usize,
             return_address: usize,
         ) ?[*]u8 {
@@ -466,7 +467,7 @@ pub fn StackFallbackAllocator(comptime size: usize) type {
         fn free(
             ctx: *anyopaque,
             buf: []u8,
-            alignment: mem.Alignment,
+            alignment: Alignment,
             ra: usize,
         ) void {
             const self: *Self = @ptrCast(@alignCast(ctx));
@@ -512,7 +513,7 @@ test PageAllocator {
     }
 
     if (builtin.os.tag == .windows) {
-        const slice = try allocator.alignedAlloc(u8, page_size_min, 128);
+        const slice = try allocator.alignedAlloc(u8, .fromByteUnits(page_size_min), 128);
         slice[0] = 0x12;
         slice[127] = 0x34;
         allocator.free(slice);
@@ -609,7 +610,7 @@ pub fn testAllocatorAligned(base_allocator: mem.Allocator) !void {
     const allocator = validationAllocator.allocator();
 
     // Test a few alignment values, smaller and bigger than the type's one
-    inline for ([_]u29{ 1, 2, 4, 8, 16, 32, 64 }) |alignment| {
+    inline for ([_]Alignment{ .@"1", .@"2", .@"4", .@"8", .@"16", .@"32", .@"64" }) |alignment| {
         // initial
         var slice = try allocator.alignedAlloc(u8, alignment, 10);
         try testing.expect(slice.len == 10);
@@ -640,7 +641,7 @@ pub fn testAllocatorLargeAlignment(base_allocator: mem.Allocator) !void {
     var align_mask: usize = undefined;
     align_mask = @shlWithOverflow(~@as(usize, 0), @as(Allocator.Log2Align, @ctz(large_align)))[0];
 
-    var slice = try allocator.alignedAlloc(u8, large_align, 500);
+    var slice = try allocator.alignedAlloc(u8, .fromByteUnits(large_align), 500);
     try testing.expect(@intFromPtr(slice.ptr) & align_mask == @intFromPtr(slice.ptr));
 
     if (allocator.resize(slice, 100)) {
@@ -669,7 +670,7 @@ pub fn testAllocatorAlignedShrink(base_allocator: mem.Allocator) !void {
     const debug_allocator = fib.allocator();
 
     const alloc_size = pageSize() * 2 + 50;
-    var slice = try allocator.alignedAlloc(u8, 16, alloc_size);
+    var slice = try allocator.alignedAlloc(u8, .@"16", alloc_size);
     defer allocator.free(slice);
 
     var stuff_to_free = std.ArrayList([]align(16) u8).init(debug_allocator);
@@ -679,7 +680,7 @@ pub fn testAllocatorAlignedShrink(base_allocator: mem.Allocator) !void {
     // fail, because of this high over-alignment we want to have.
     while (@intFromPtr(slice.ptr) == mem.alignForward(usize, @intFromPtr(slice.ptr), pageSize() * 32)) {
         try stuff_to_free.append(slice);
-        slice = try allocator.alignedAlloc(u8, 16, alloc_size);
+        slice = try allocator.alignedAlloc(u8, .@"16", alloc_size);
     }
     while (stuff_to_free.pop()) |item| {
         allocator.free(item);
diff --git a/lib/std/heap/WasmAllocator.zig b/lib/std/heap/WasmAllocator.zig
index b511a216f7..2045d7c303 100644
--- a/lib/std/heap/WasmAllocator.zig
+++ b/lib/std/heap/WasmAllocator.zig
@@ -218,7 +218,7 @@ test "very large allocation" {
 }
 
 test "realloc" {
-    var slice = try test_ally.alignedAlloc(u8, @alignOf(u32), 1);
+    var slice = try test_ally.alignedAlloc(u8, .of(u32), 1);
     defer test_ally.free(slice);
     slice[0] = 0x12;
 
diff --git a/lib/std/heap/arena_allocator.zig b/lib/std/heap/arena_allocator.zig
index c472ae80c5..e3a76a06c1 100644
--- a/lib/std/heap/arena_allocator.zig
+++ b/lib/std/heap/arena_allocator.zig
@@ -2,6 +2,7 @@ const std = @import("../std.zig");
 const assert = std.debug.assert;
 const mem = std.mem;
 const Allocator = std.mem.Allocator;
+const Alignment = std.mem.Alignment;
 
 /// This allocator takes an existing allocator, wraps it, and provides an interface where
 /// you can allocate and then free it all together. Calls to free an individual item only
@@ -41,7 +42,7 @@ pub const ArenaAllocator = struct {
         data: usize,
         node: std.SinglyLinkedList.Node = .{},
     };
-    const BufNode_alignment: mem.Alignment = .fromByteUnits(@alignOf(BufNode));
+    const BufNode_alignment: Alignment = .fromByteUnits(@alignOf(BufNode));
 
     pub fn init(child_allocator: Allocator) ArenaAllocator {
         return (State{}).promote(child_allocator);
@@ -181,7 +182,7 @@ pub const ArenaAllocator = struct {
         return buf_node;
     }
 
-    fn alloc(ctx: *anyopaque, n: usize, alignment: mem.Alignment, ra: usize) ?[*]u8 {
+    fn alloc(ctx: *anyopaque, n: usize, alignment: Alignment, ra: usize) ?[*]u8 {
         const self: *ArenaAllocator = @ptrCast(@alignCast(ctx));
         _ = ra;
 
@@ -214,7 +215,7 @@ pub const ArenaAllocator = struct {
         }
     }
 
-    fn resize(ctx: *anyopaque, buf: []u8, alignment: mem.Alignment, new_len: usize, ret_addr: usize) bool {
+    fn resize(ctx: *anyopaque, buf: []u8, alignment: Alignment, new_len: usize, ret_addr: usize) bool {
         const self: *ArenaAllocator = @ptrCast(@alignCast(ctx));
         _ = alignment;
         _ = ret_addr;
@@ -242,14 +243,14 @@ pub const ArenaAllocator = struct {
     fn remap(
         context: *anyopaque,
         memory: []u8,
-        alignment: mem.Alignment,
+        alignment: Alignment,
         new_len: usize,
         return_address: usize,
     ) ?[*]u8 {
         return if (resize(context, memory, alignment, new_len, return_address)) memory.ptr else null;
     }
 
-    fn free(ctx: *anyopaque, buf: []u8, alignment: mem.Alignment, ret_addr: usize) void {
+    fn free(ctx: *anyopaque, buf: []u8, alignment: Alignment, ret_addr: usize) void {
         _ = alignment;
         _ = ret_addr;
 
@@ -279,9 +280,9 @@ test "reset with preheating" {
         const total_size: usize = random.intRangeAtMost(usize, 256, 16384);
         while (alloced_bytes < total_size) {
             const size = random.intRangeAtMost(usize, 16, 256);
-            const alignment = 32;
+            const alignment: Alignment = .@"32";
             const slice = try arena_allocator.allocator().alignedAlloc(u8, alignment, size);
-            try std.testing.expect(std.mem.isAligned(@intFromPtr(slice.ptr), alignment));
+            try std.testing.expect(alignment.check(@intFromPtr(slice.ptr)));
             try std.testing.expectEqual(size, slice.len);
             alloced_bytes += slice.len;
         }
diff --git a/lib/std/heap/debug_allocator.zig b/lib/std/heap/debug_allocator.zig
index a6b2676b1d..3243f1b1bd 100644
--- a/lib/std/heap/debug_allocator.zig
+++ b/lib/std/heap/debug_allocator.zig
@@ -1120,7 +1120,7 @@ test "realloc" {
     defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
     const allocator = gpa.allocator();
 
-    var slice = try allocator.alignedAlloc(u8, @alignOf(u32), 1);
+    var slice = try allocator.alignedAlloc(u8, .of(u32), 1);
     defer allocator.free(slice);
     slice[0] = 0x12;
 
@@ -1234,7 +1234,7 @@ test "shrink large object to large object with larger alignment" {
     const debug_allocator = fba.allocator();
 
     const alloc_size = default_page_size * 2 + 50;
-    var slice = try allocator.alignedAlloc(u8, 16, alloc_size);
+    var slice = try allocator.alignedAlloc(u8, .@"16", alloc_size);
     defer allocator.free(slice);
 
     const big_alignment: usize = default_page_size * 2;
@@ -1244,7 +1244,7 @@ test "shrink large object to large object with larger alignment" {
     var stuff_to_free = std.ArrayList([]align(16) u8).init(debug_allocator);
     while (mem.isAligned(@intFromPtr(slice.ptr), big_alignment)) {
         try stuff_to_free.append(slice);
-        slice = try allocator.alignedAlloc(u8, 16, alloc_size);
+        slice = try allocator.alignedAlloc(u8, .@"16", alloc_size);
     }
     while (stuff_to_free.pop()) |item| {
         allocator.free(item);
@@ -1308,7 +1308,7 @@ test "realloc large object to larger alignment" {
     var fba = std.heap.FixedBufferAllocator.init(&debug_buffer);
     const debug_allocator = fba.allocator();
 
-    var slice = try allocator.alignedAlloc(u8, 16, default_page_size * 2 + 50);
+    var slice = try allocator.alignedAlloc(u8, .@"16", default_page_size * 2 + 50);
     defer allocator.free(slice);
 
     const big_alignment: usize = default_page_size * 2;
@@ -1316,7 +1316,7 @@ test "realloc large object to larger alignment" {
     var stuff_to_free = std.ArrayList([]align(16) u8).init(debug_allocator);
     while (mem.isAligned(@intFromPtr(slice.ptr), big_alignment)) {
         try stuff_to_free.append(slice);
-        slice = try allocator.alignedAlloc(u8, 16, default_page_size * 2 + 50);
+        slice = try allocator.alignedAlloc(u8, .@"16", default_page_size * 2 + 50);
     }
     while (stuff_to_free.pop()) |item| {
         allocator.free(item);
@@ -1402,7 +1402,7 @@ test "large allocations count requested size not backing size" {
     var gpa: DebugAllocator(.{ .enable_memory_limit = true }) = .{};
     const allocator = gpa.allocator();
 
-    var buf = try allocator.alignedAlloc(u8, 1, default_page_size + 1);
+    var buf = try allocator.alignedAlloc(u8, .@"1", default_page_size + 1);
     try std.testing.expectEqual(default_page_size + 1, gpa.total_requested_bytes);
     buf = try allocator.realloc(buf, 1);
     try std.testing.expectEqual(1, gpa.total_requested_bytes);
diff --git a/lib/std/heap/memory_pool.zig b/lib/std/heap/memory_pool.zig
index 6b9abfd8dc..2b201f2b54 100644
--- a/lib/std/heap/memory_pool.zig
+++ b/lib/std/heap/memory_pool.zig
@@ -1,4 +1,5 @@
 const std = @import("../std.zig");
+const Alignment = std.mem.Alignment;
 
 const debug_mode = @import("builtin").mode == .Debug;
 
@@ -8,14 +9,14 @@ pub const MemoryPoolError = error{OutOfMemory};
 /// Use this when you need to allocate a lot of objects of the same type,
 /// because It outperforms general purpose allocators.
 pub fn MemoryPool(comptime Item: type) type {
-    return MemoryPoolAligned(Item, @alignOf(Item));
+    return MemoryPoolAligned(Item, .of(Item));
 }
 
 /// A memory pool that can allocate objects of a single type very quickly.
 /// Use this when you need to allocate a lot of objects of the same type,
 /// because It outperforms general purpose allocators.
-pub fn MemoryPoolAligned(comptime Item: type, comptime alignment: u29) type {
-    if (@alignOf(Item) == alignment) {
+pub fn MemoryPoolAligned(comptime Item: type, comptime alignment: Alignment) type {
+    if (@alignOf(Item) == comptime alignment.toByteUnits()) {
         return MemoryPoolExtra(Item, .{});
     } else {
         return MemoryPoolExtra(Item, .{ .alignment = alignment });
@@ -24,7 +25,7 @@ pub fn MemoryPoolAligned(comptime Item: type, comptime alignment: u29) type {
 
 pub const Options = struct {
     /// The alignment of the memory pool items. Use `null` for natural alignment.
-    alignment: ?u29 = null,
+    alignment: ?Alignment = null,
 
     /// If `true`, the memory pool can allocate additional items after a initial setup.
     /// If `false`, the memory pool will not allocate further after a call to `initPreheated`.
@@ -43,17 +44,17 @@ pub fn MemoryPoolExtra(comptime Item: type, comptime pool_options: Options) type
         pub const item_size = @max(@sizeOf(Node), @sizeOf(Item));
 
         // This needs to be kept in sync with Node.
-        const node_alignment = @alignOf(*anyopaque);
+        const node_alignment: Alignment = .of(*anyopaque);
 
         /// Alignment of the memory pool items. This is not necessarily the same
         /// as `@alignOf(Item)` as the pool also uses the items for internal means.
-        pub const item_alignment = @max(node_alignment, pool_options.alignment orelse @alignOf(Item));
+        pub const item_alignment: Alignment = node_alignment.max(pool_options.alignment orelse .of(Item));
 
         const Node = struct {
-            next: ?*align(item_alignment) @This(),
+            next: ?*align(item_alignment.toByteUnits()) @This(),
         };
-        const NodePtr = *align(item_alignment) Node;
-        const ItemPtr = *align(item_alignment) Item;
+        const NodePtr = *align(item_alignment.toByteUnits()) Node;
+        const ItemPtr = *align(item_alignment.toByteUnits()) Item;
 
         arena: std.heap.ArenaAllocator,
         free_list: ?NodePtr = null,
@@ -143,7 +144,7 @@ pub fn MemoryPoolExtra(comptime Item: type, comptime pool_options: Options) type
             pool.free_list = node;
         }
 
-        fn allocNew(pool: *Pool) MemoryPoolError!*align(item_alignment) [item_size]u8 {
+        fn allocNew(pool: *Pool) MemoryPoolError!*align(item_alignment.toByteUnits()) [item_size]u8 {
             const mem = try pool.arena.allocator().alignedAlloc(u8, item_alignment, item_size);
             return mem[0..item_size]; // coerce slice to array pointer
         }
@@ -213,7 +214,7 @@ test "greater than pointer manual alignment" {
         data: u64,
     };
 
-    var pool = MemoryPoolAligned(Foo, 16).init(std.testing.allocator);
+    var pool = MemoryPoolAligned(Foo, .@"16").init(std.testing.allocator);
     defer pool.deinit();
 
     const foo: *align(16) Foo = try pool.create();
diff --git a/lib/std/io.zig b/lib/std/io.zig
index bd9b0042b9..c70a0086c1 100644
--- a/lib/std/io.zig
+++ b/lib/std/io.zig
@@ -5,7 +5,6 @@ const c = std.c;
 const is_windows = builtin.os.tag == .windows;
 const windows = std.os.windows;
 const posix = std.posix;
-
 const math = std.math;
 const assert = std.debug.assert;
 const fs = std.fs;
@@ -13,6 +12,7 @@ const mem = std.mem;
 const meta = std.meta;
 const File = std.fs.File;
 const Allocator = std.mem.Allocator;
+const Alignment = std.mem.Alignment;
 
 fn getStdOutHandle() posix.fd_t {
     if (is_windows) {
@@ -104,7 +104,7 @@ pub fn GenericReader(
 
         pub inline fn readAllArrayListAligned(
             self: Self,
-            comptime alignment: ?u29,
+            comptime alignment: ?Alignment,
             array_list: *std.ArrayListAligned(u8, alignment),
             max_append_size: usize,
         ) (error{StreamTooLong} || Allocator.Error || Error)!void {
diff --git a/lib/std/io/Reader.zig b/lib/std/io/Reader.zig
index 33187125b8..3f2429c3ae 100644
--- a/lib/std/io/Reader.zig
+++ b/lib/std/io/Reader.zig
@@ -54,7 +54,7 @@ pub fn readAllArrayList(
 
 pub fn readAllArrayListAligned(
     self: Self,
-    comptime alignment: ?u29,
+    comptime alignment: ?Alignment,
     array_list: *std.ArrayListAligned(u8, alignment),
     max_append_size: usize,
 ) anyerror!void {
@@ -379,6 +379,7 @@ const assert = std.debug.assert;
 const mem = std.mem;
 const testing = std.testing;
 const native_endian = @import("builtin").target.cpu.arch.endian();
+const Alignment = std.mem.Alignment;
 
 test {
     _ = @import("Reader/test.zig");
diff --git a/lib/std/math.zig b/lib/std/math.zig
index 78acd4b90c..e7156ccd39 100644
--- a/lib/std/math.zig
+++ b/lib/std/math.zig
@@ -4,6 +4,7 @@ const float = @import("math/float.zig");
 const assert = std.debug.assert;
 const mem = std.mem;
 const testing = std.testing;
+const Alignment = std.mem.Alignment;
 
 /// Euler's number (e)
 pub const e = 2.71828182845904523536028747135266249775724709369995;
@@ -1084,19 +1085,16 @@ test cast {
 
 pub const AlignCastError = error{UnalignedMemory};
 
-fn AlignCastResult(comptime alignment: u29, comptime Ptr: type) type {
+fn AlignCastResult(comptime alignment: Alignment, comptime Ptr: type) type {
     var ptr_info = @typeInfo(Ptr);
-    ptr_info.pointer.alignment = alignment;
+    ptr_info.pointer.alignment = alignment.toByteUnits();
     return @Type(ptr_info);
 }
 
 /// Align cast a pointer but return an error if it's the wrong alignment
-pub fn alignCast(comptime alignment: u29, ptr: anytype) AlignCastError!AlignCastResult(alignment, @TypeOf(ptr)) {
-    const addr = @intFromPtr(ptr);
-    if (addr % alignment != 0) {
-        return error.UnalignedMemory;
-    }
-    return @alignCast(ptr);
+pub fn alignCast(comptime alignment: Alignment, ptr: anytype) AlignCastError!AlignCastResult(alignment, @TypeOf(ptr)) {
+    if (alignment.check(@intFromPtr(ptr))) return @alignCast(ptr);
+    return error.UnalignedMemory;
 }
 
 /// Asserts `int > 0`.
diff --git a/lib/std/mem.zig b/lib/std/mem.zig
index e5194ad93b..4c198408b5 100644
--- a/lib/std/mem.zig
+++ b/lib/std/mem.zig
@@ -38,6 +38,10 @@ pub const Alignment = enum(math.Log2Int(usize)) {
         return @enumFromInt(@ctz(n));
     }
 
+    pub inline fn of(comptime T: type) Alignment {
+        return comptime fromByteUnits(@alignOf(T));
+    }
+
     pub fn order(lhs: Alignment, rhs: Alignment) std.math.Order {
         return std.math.order(@intFromEnum(lhs), @intFromEnum(rhs));
     }
@@ -166,21 +170,6 @@ pub fn validationWrap(allocator: anytype) ValidationAllocator(@TypeOf(allocator)
     return ValidationAllocator(@TypeOf(allocator)).init(allocator);
 }
 
-/// An allocator helper function.  Adjusts an allocation length satisfy `len_align`.
-/// `full_len` should be the full capacity of the allocation which may be greater
-/// than the `len` that was requested.  This function should only be used by allocators
-/// that are unaffected by `len_align`.
-pub fn alignAllocLen(full_len: usize, alloc_len: usize, len_align: u29) usize {
-    assert(alloc_len > 0);
-    assert(alloc_len >= len_align);
-    assert(full_len >= alloc_len);
-    if (len_align == 0)
-        return alloc_len;
-    const adjusted = alignBackwardAnyAlign(usize, full_len, len_align);
-    assert(adjusted >= alloc_len);
-    return adjusted;
-}
-
 test "Allocator basics" {
     try testing.expectError(error.OutOfMemory, testing.failing_allocator.alloc(u8, 1));
     try testing.expectError(error.OutOfMemory, testing.failing_allocator.allocSentinel(u8, 1, 0));
diff --git a/lib/std/mem/Allocator.zig b/lib/std/mem/Allocator.zig
index c2f73096e8..dc3e3f0325 100644
--- a/lib/std/mem/Allocator.zig
+++ b/lib/std/mem/Allocator.zig
@@ -152,9 +152,9 @@ pub inline fn rawFree(a: Allocator, memory: []u8, alignment: Alignment, ret_addr
 pub fn create(a: Allocator, comptime T: type) Error!*T {
     if (@sizeOf(T) == 0) {
         const ptr = comptime std.mem.alignBackward(usize, math.maxInt(usize), @alignOf(T));
-        return @as(*T, @ptrFromInt(ptr));
+        return @ptrFromInt(ptr);
     }
-    const ptr: *T = @ptrCast(try a.allocBytesWithAlignment(@alignOf(T), @sizeOf(T), @returnAddress()));
+    const ptr: *T = @ptrCast(try a.allocBytesWithAlignment(.of(T), @sizeOf(T), @returnAddress()));
     return ptr;
 }
 
@@ -186,7 +186,7 @@ pub fn allocWithOptions(
     comptime Elem: type,
     n: usize,
     /// null means naturally aligned
-    comptime optional_alignment: ?u29,
+    comptime optional_alignment: ?Alignment,
     comptime optional_sentinel: ?Elem,
 ) Error!AllocWithOptionsPayload(Elem, optional_alignment, optional_sentinel) {
     return self.allocWithOptionsRetAddr(Elem, n, optional_alignment, optional_sentinel, @returnAddress());
@@ -197,7 +197,7 @@ pub fn allocWithOptionsRetAddr(
     comptime Elem: type,
     n: usize,
     /// null means naturally aligned
-    comptime optional_alignment: ?u29,
+    comptime optional_alignment: ?Alignment,
     comptime optional_sentinel: ?Elem,
     return_address: usize,
 ) Error!AllocWithOptionsPayload(Elem, optional_alignment, optional_sentinel) {
@@ -210,11 +210,11 @@ pub fn allocWithOptionsRetAddr(
     }
 }
 
-fn AllocWithOptionsPayload(comptime Elem: type, comptime alignment: ?u29, comptime sentinel: ?Elem) type {
+fn AllocWithOptionsPayload(comptime Elem: type, comptime alignment: ?Alignment, comptime sentinel: ?Elem) type {
     if (sentinel) |s| {
-        return [:s]align(alignment orelse @alignOf(Elem)) Elem;
+        return [:s]align(if (alignment) |a| a.toByteUnits() else @alignOf(Elem)) Elem;
     } else {
-        return []align(alignment orelse @alignOf(Elem)) Elem;
+        return []align(if (alignment) |a| a.toByteUnits() else @alignOf(Elem)) Elem;
     }
 }
 
@@ -239,9 +239,9 @@ pub fn alignedAlloc(
     self: Allocator,
     comptime T: type,
     /// null means naturally aligned
-    comptime alignment: ?u29,
+    comptime alignment: ?Alignment,
     n: usize,
-) Error![]align(alignment orelse @alignOf(T)) T {
+) Error![]align(if (alignment) |a| a.toByteUnits() else @alignOf(T)) T {
     return self.allocAdvancedWithRetAddr(T, alignment, n, @returnAddress());
 }
 
@@ -249,27 +249,38 @@ pub inline fn allocAdvancedWithRetAddr(
     self: Allocator,
     comptime T: type,
     /// null means naturally aligned
-    comptime alignment: ?u29,
+    comptime alignment: ?Alignment,
     n: usize,
     return_address: usize,
-) Error![]align(alignment orelse @alignOf(T)) T {
-    const a = alignment orelse @alignOf(T);
-    const ptr: [*]align(a) T = @ptrCast(try self.allocWithSizeAndAlignment(@sizeOf(T), a, n, return_address));
+) Error![]align(if (alignment) |a| a.toByteUnits() else @alignOf(T)) T {
+    const a = comptime (alignment orelse Alignment.fromByteUnits(@alignOf(T)));
+    const ptr: [*]align(a.toByteUnits()) T = @ptrCast(try self.allocWithSizeAndAlignment(@sizeOf(T), a, n, return_address));
     return ptr[0..n];
 }
 
-fn allocWithSizeAndAlignment(self: Allocator, comptime size: usize, comptime alignment: u29, n: usize, return_address: usize) Error![*]align(alignment) u8 {
+fn allocWithSizeAndAlignment(
+    self: Allocator,
+    comptime size: usize,
+    comptime alignment: Alignment,
+    n: usize,
+    return_address: usize,
+) Error![*]align(alignment.toByteUnits()) u8 {
     const byte_count = math.mul(usize, size, n) catch return Error.OutOfMemory;
     return self.allocBytesWithAlignment(alignment, byte_count, return_address);
 }
 
-fn allocBytesWithAlignment(self: Allocator, comptime alignment: u29, byte_count: usize, return_address: usize) Error![*]align(alignment) u8 {
+fn allocBytesWithAlignment(
+    self: Allocator,
+    comptime alignment: Alignment,
+    byte_count: usize,
+    return_address: usize,
+) Error![*]align(alignment.toByteUnits()) u8 {
     if (byte_count == 0) {
-        const ptr = comptime std.mem.alignBackward(usize, math.maxInt(usize), alignment);
-        return @as([*]align(alignment) u8, @ptrFromInt(ptr));
+        const ptr = comptime alignment.backward(math.maxInt(usize));
+        return @as([*]align(alignment.toByteUnits()) u8, @ptrFromInt(ptr));
     }
 
-    const byte_ptr = self.rawAlloc(byte_count, .fromByteUnits(alignment), return_address) orelse return Error.OutOfMemory;
+    const byte_ptr = self.rawAlloc(byte_count, alignment, return_address) orelse return Error.OutOfMemory;
     @memset(byte_ptr[0..byte_count], undefined);
     return @alignCast(byte_ptr);
 }
@@ -378,7 +389,7 @@ pub fn reallocAdvanced(
     const Slice = @typeInfo(@TypeOf(old_mem)).pointer;
     const T = Slice.child;
     if (old_mem.len == 0) {
-        return self.allocAdvancedWithRetAddr(T, Slice.alignment, new_n, return_address);
+        return self.allocAdvancedWithRetAddr(T, .fromByteUnits(Slice.alignment), new_n, return_address);
     }
     if (new_n == 0) {
         self.free(old_mem);
diff --git a/lib/std/meta/trailer_flags.zig b/lib/std/meta/trailer_flags.zig
index 186dd2be14..ddf3790c19 100644
--- a/lib/std/meta/trailer_flags.zig
+++ b/lib/std/meta/trailer_flags.zig
@@ -144,7 +144,7 @@ test TrailerFlags {
         .b = true,
         .c = true,
     });
-    const slice = try testing.allocator.alignedAlloc(u8, 8, flags.sizeInBytes());
+    const slice = try testing.allocator.alignedAlloc(u8, .@"8", flags.sizeInBytes());
     defer testing.allocator.free(slice);
 
     flags.set(slice.ptr, .b, false);
diff --git a/lib/std/multi_array_list.zig b/lib/std/multi_array_list.zig
index 9cdc4b9a3d..341ca6931e 100644
--- a/lib/std/multi_array_list.zig
+++ b/lib/std/multi_array_list.zig
@@ -350,11 +350,7 @@ pub fn MultiArrayList(comptime T: type) type {
             assert(new_len <= self.capacity);
             assert(new_len <= self.len);
 
-            const other_bytes = gpa.alignedAlloc(
-                u8,
-                @alignOf(Elem),
-                capacityInBytes(new_len),
-            ) catch {
+            const other_bytes = gpa.alignedAlloc(u8, .of(Elem), capacityInBytes(new_len)) catch {
                 const self_slice = self.slice();
                 inline for (fields, 0..) |field_info, i| {
                     if (@sizeOf(field_info.type) != 0) {
@@ -440,11 +436,7 @@ pub fn MultiArrayList(comptime T: type) type {
         /// `new_capacity` must be greater or equal to `len`.
         pub fn setCapacity(self: *Self, gpa: Allocator, new_capacity: usize) !void {
             assert(new_capacity >= self.len);
-            const new_bytes = try gpa.alignedAlloc(
-                u8,
-                @alignOf(Elem),
-                capacityInBytes(new_capacity),
-            );
+            const new_bytes = try gpa.alignedAlloc(u8, .of(Elem), capacityInBytes(new_capacity));
             if (self.len == 0) {
                 gpa.free(self.allocatedBytes());
                 self.bytes = new_bytes.ptr;
diff --git a/lib/std/process.zig b/lib/std/process.zig
index c146e95036..7751b88b14 100644
--- a/lib/std/process.zig
+++ b/lib/std/process.zig
@@ -1256,7 +1256,7 @@ pub fn argsAlloc(allocator: Allocator) ![][:0]u8 {
     const slice_sizes = slice_list.items;
     const slice_list_bytes = try math.mul(usize, @sizeOf([]u8), slice_sizes.len);
     const total_bytes = try math.add(usize, slice_list_bytes, contents_slice.len);
-    const buf = try allocator.alignedAlloc(u8, @alignOf([]u8), total_bytes);
+    const buf = try allocator.alignedAlloc(u8, .of([]u8), total_bytes);
     errdefer allocator.free(buf);
 
     const result_slice_list = mem.bytesAsSlice([:0]u8, buf[0..slice_list_bytes]);
diff --git a/lib/std/zig.zig b/lib/std/zig.zig
index da329d4885..9033164b24 100644
--- a/lib/std/zig.zig
+++ b/lib/std/zig.zig
@@ -543,7 +543,7 @@ pub fn readSourceFileToEndAlloc(gpa: Allocator, input: std.fs.File, size_hint: ?
         gpa,
         max_src_size,
         size_hint,
-        @alignOf(u8),
+        .of(u8),
         0,
     ) catch |err| switch (err) {
         error.ConnectionResetByPeer => unreachable,
diff --git a/lib/std/zon/parse.zig b/lib/std/zon/parse.zig
index 02730420e5..849aa83f86 100644
--- a/lib/std/zon/parse.zig
+++ b/lib/std/zon/parse.zig
@@ -679,7 +679,7 @@ const Parser = struct {
         const slice = try self.gpa.allocWithOptions(
             pointer.child,
             nodes.len,
-            pointer.alignment,
+            .fromByteUnits(pointer.alignment),
             pointer.sentinel(),
         );
         errdefer self.gpa.free(slice);
diff --git a/src/InternPool.zig b/src/InternPool.zig
index 752bc8adb8..195ebfedd6 100644
--- a/src/InternPool.zig
+++ b/src/InternPool.zig
@@ -255,7 +255,7 @@ pub fn trackZir(
     const new_map_capacity = map_header.capacity * 2;
     const new_map_buf = try arena.allocator().alignedAlloc(
         u8,
-        Map.alignment,
+        .fromByteUnits(Map.alignment),
         Map.entries_offset + new_map_capacity * @sizeOf(Map.Entry),
     );
     const new_map: Map = .{ .entries = @ptrCast(new_map_buf[Map.entries_offset..].ptr) };
@@ -350,7 +350,7 @@ pub fn rehashTrackedInsts(
         defer arena_state.* = arena.state;
         const new_map_buf = try arena.allocator().alignedAlloc(
             u8,
-            Map.alignment,
+            .fromByteUnits(Map.alignment),
             Map.entries_offset + want_capacity * @sizeOf(Map.Entry),
         );
         const new_map: Map = .{ .entries = @ptrCast(new_map_buf[Map.entries_offset..].ptr) };
@@ -1296,7 +1296,7 @@ const Local = struct {
                     defer mutable.arena.* = arena.state;
                     const buf = try arena.allocator().alignedAlloc(
                         u8,
-                        alignment,
+                        .fromByteUnits(alignment),
                         bytes_offset + View.capacityInBytes(capacity),
                     );
                     var new_list: ListSelf = .{ .bytes = @ptrCast(buf[bytes_offset..].ptr) };
@@ -7547,7 +7547,7 @@ fn getOrPutKeyEnsuringAdditionalCapacity(
         }
         const new_map_buf = try arena.allocator().alignedAlloc(
             u8,
-            Map.alignment,
+            .fromByteUnits(Map.alignment),
             Map.entries_offset + new_map_capacity * @sizeOf(Map.Entry),
         );
         const new_map: Map = .{ .entries = @ptrCast(new_map_buf[Map.entries_offset..].ptr) };
@@ -11666,7 +11666,7 @@ pub fn getOrPutTrailingString(
     const new_map_capacity = map_header.capacity * 2;
     const new_map_buf = try arena.allocator().alignedAlloc(
         u8,
-        Map.alignment,
+        .fromByteUnits(Map.alignment),
         Map.entries_offset + new_map_capacity * @sizeOf(Map.Entry),
     );
     const new_map: Map = .{ .entries = @ptrCast(new_map_buf[Map.entries_offset..].ptr) };
@@ -12586,7 +12586,7 @@ const GlobalErrorSet = struct {
         const new_map_capacity = map_header.capacity * 2;
         const new_map_buf = try arena.allocator().alignedAlloc(
             u8,
-            Map.alignment,
+            .fromByteUnits(Map.alignment),
             Map.entries_offset + new_map_capacity * @sizeOf(Map.Entry),
         );
         const new_map: Map = .{ .entries = @ptrCast(new_map_buf[Map.entries_offset..].ptr) };
diff --git a/src/Package/Fetch.zig b/src/Package/Fetch.zig
index 4e386be2d5..12eec6009d 100644
--- a/src/Package/Fetch.zig
+++ b/src/Package/Fetch.zig
@@ -640,7 +640,7 @@ fn loadManifest(f: *Fetch, pkg_root: Cache.Path) RunError!void {
         try fs.path.join(arena, &.{ pkg_root.sub_path, Manifest.basename }),
         Manifest.max_bytes,
         null,
-        1,
+        .@"1",
         0,
     ) catch |err| switch (err) {
         error.FileNotFound => return,
diff --git a/src/main.zig b/src/main.zig
index 28e87e78eb..2605b089eb 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -7510,7 +7510,7 @@ fn loadManifest(
             Package.Manifest.basename,
             Package.Manifest.max_bytes,
             null,
-            1,
+            .@"1",
             0,
         ) catch |err| switch (err) {
             error.FileNotFound => {
diff --git a/test/src/Cases.zig b/test/src/Cases.zig
index e69bde0904..5f0c12c2b2 100644
--- a/test/src/Cases.zig
+++ b/test/src/Cases.zig
@@ -358,7 +358,7 @@ fn addFromDirInner(
         current_file.* = filename;
 
         const max_file_size = 10 * 1024 * 1024;
-        const src = try iterable_dir.readFileAllocOptions(ctx.arena, filename, max_file_size, null, 1, 0);
+        const src = try iterable_dir.readFileAllocOptions(ctx.arena, filename, max_file_size, null, .@"1", 0);
 
         // Parse the manifest
         var manifest = try TestManifest.parse(ctx.arena, src);