diff --git a/doc/langref.html.in b/doc/langref.html.in
index 3a7892fd455e..7def9b42baf9 100644
--- a/doc/langref.html.in
+++ b/doc/langref.html.in
@@ -2093,8 +2093,9 @@ var foo: u8 align(4) = 100;
 test "global variable alignment" {
     assert(@TypeOf(&foo).alignment == 4);
     assert(@TypeOf(&foo) == *align(4) u8);
-    const slice = @as(*[1]u8, &foo)[0..];
-    assert(@TypeOf(slice) == []align(4) u8);
+    const as_pointer_to_array: *[1]u8 = &foo;
+    const as_slice: []u8 = as_pointer_to_array;
+    assert(@TypeOf(as_slice) == []align(4) u8);
 }
 
 fn derp() align(@sizeOf(usize) * 2) i32 { return 1234; }
@@ -2187,7 +2188,8 @@ test "basic slices" {
     // a slice is that the array's length is part of the type and known at
     // compile-time, whereas the slice's length is known at runtime.
     // Both can be accessed with the `len` field.
-    const slice = array[0..array.len];
+    var known_at_runtime_zero: usize = 0;
+    const slice = array[known_at_runtime_zero..array.len];
     assert(&slice[0] == &array[0]);
     assert(slice.len == array.len);
 
@@ -2207,13 +2209,15 @@ test "basic slices" {
       {#code_end#}
       <p>This is one reason we prefer slices to pointers.</p>
       {#code_begin|test|slices#}
-const assert = @import("std").debug.assert;
-const mem = @import("std").mem;
-const fmt = @import("std").fmt;
+const std = @import("std");
+const assert = std.debug.assert;
+const mem = std.mem;
+const fmt = std.fmt;
 
 test "using slices for strings" {
-    // Zig has no concept of strings. String literals are arrays of u8, and
-    // in general the string type is []u8 (slice of u8).
+    // Zig has no concept of strings. String literals are const pointers to
+    // arrays of u8, and by convention parameters that are "strings" are
+    // expected to be UTF-8 encoded slices of u8.
     // Here we coerce [5]u8 to []const u8
     const hello: []const u8 = "hello";
     const world: []const u8 = "世界";
@@ -2222,7 +2226,7 @@ test "using slices for strings" {
     // You can use slice syntax on an array to convert an array into a slice.
     const all_together_slice = all_together[0..];
     // String concatenation example.
-    const hello_world = try fmt.bufPrint(all_together_slice, "{} {}", .{hello, world});
+    const hello_world = try fmt.bufPrint(all_together_slice, "{} {}", .{ hello, world });
 
     // Generally, you can use UTF-8 and not worry about whether something is a
     // string. If you don't need to deal with individual characters, no need
@@ -2239,23 +2243,15 @@ test "slice pointer" {
     slice[2] = 3;
     assert(slice[2] == 3);
     // The slice is mutable because we sliced a mutable pointer.
-    assert(@TypeOf(slice) == []u8);
+    // Furthermore, it is actually a pointer to an array, since the start
+    // and end indexes were both comptime-known.
+    assert(@TypeOf(slice) == *[5]u8);
 
     // You can also slice a slice:
     const slice2 = slice[2..3];
     assert(slice2.len == 1);
     assert(slice2[0] == 3);
 }
-
-test "slice widening" {
-    // Zig supports slice widening and slice narrowing. Cast a slice of u8
-    // to a slice of anything else, and Zig will perform the length conversion.
-    const array align(@alignOf(u32)) = [_]u8{ 0x12, 0x12, 0x12, 0x12, 0x13, 0x13, 0x13, 0x13 };
-    const slice = mem.bytesAsSlice(u32, array[0..]);
-    assert(slice.len == 2);
-    assert(slice[0] == 0x12121212);
-    assert(slice[1] == 0x13131313);
-}
       {#code_end#}
       {#see_also|Pointers|for|Arrays#}
 
diff --git a/lib/std/crypto/aes.zig b/lib/std/crypto/aes.zig
index 1cc166f94301..81dc56f0b311 100644
--- a/lib/std/crypto/aes.zig
+++ b/lib/std/crypto/aes.zig
@@ -15,10 +15,10 @@ fn rotw(w: u32) u32 {
 
 // Encrypt one block from src into dst, using the expanded key xk.
 fn encryptBlock(xk: []const u32, dst: []u8, src: []const u8) void {
-    var s0 = mem.readIntSliceBig(u32, src[0..4]);
-    var s1 = mem.readIntSliceBig(u32, src[4..8]);
-    var s2 = mem.readIntSliceBig(u32, src[8..12]);
-    var s3 = mem.readIntSliceBig(u32, src[12..16]);
+    var s0 = mem.readIntBig(u32, src[0..4]);
+    var s1 = mem.readIntBig(u32, src[4..8]);
+    var s2 = mem.readIntBig(u32, src[8..12]);
+    var s3 = mem.readIntBig(u32, src[12..16]);
 
     // First round just XORs input with key.
     s0 ^= xk[0];
@@ -58,18 +58,18 @@ fn encryptBlock(xk: []const u32, dst: []u8, src: []const u8) void {
     s2 ^= xk[k + 2];
     s3 ^= xk[k + 3];
 
-    mem.writeIntSliceBig(u32, dst[0..4], s0);
-    mem.writeIntSliceBig(u32, dst[4..8], s1);
-    mem.writeIntSliceBig(u32, dst[8..12], s2);
-    mem.writeIntSliceBig(u32, dst[12..16], s3);
+    mem.writeIntBig(u32, dst[0..4], s0);
+    mem.writeIntBig(u32, dst[4..8], s1);
+    mem.writeIntBig(u32, dst[8..12], s2);
+    mem.writeIntBig(u32, dst[12..16], s3);
 }
 
 // Decrypt one block from src into dst, using the expanded key xk.
 pub fn decryptBlock(xk: []const u32, dst: []u8, src: []const u8) void {
-    var s0 = mem.readIntSliceBig(u32, src[0..4]);
-    var s1 = mem.readIntSliceBig(u32, src[4..8]);
-    var s2 = mem.readIntSliceBig(u32, src[8..12]);
-    var s3 = mem.readIntSliceBig(u32, src[12..16]);
+    var s0 = mem.readIntBig(u32, src[0..4]);
+    var s1 = mem.readIntBig(u32, src[4..8]);
+    var s2 = mem.readIntBig(u32, src[8..12]);
+    var s3 = mem.readIntBig(u32, src[12..16]);
 
     // First round just XORs input with key.
     s0 ^= xk[0];
@@ -109,10 +109,10 @@ pub fn decryptBlock(xk: []const u32, dst: []u8, src: []const u8) void {
     s2 ^= xk[k + 2];
     s3 ^= xk[k + 3];
 
-    mem.writeIntSliceBig(u32, dst[0..4], s0);
-    mem.writeIntSliceBig(u32, dst[4..8], s1);
-    mem.writeIntSliceBig(u32, dst[8..12], s2);
-    mem.writeIntSliceBig(u32, dst[12..16], s3);
+    mem.writeIntBig(u32, dst[0..4], s0);
+    mem.writeIntBig(u32, dst[4..8], s1);
+    mem.writeIntBig(u32, dst[8..12], s2);
+    mem.writeIntBig(u32, dst[12..16], s3);
 }
 
 fn xorBytes(dst: []u8, a: []const u8, b: []const u8) usize {
@@ -154,8 +154,8 @@ fn AES(comptime keysize: usize) type {
             var n: usize = 0;
             while (n < src.len) {
                 ctx.encrypt(keystream[0..], ctrbuf[0..]);
-                var ctr_i = std.mem.readIntSliceBig(u128, ctrbuf[0..]);
-                std.mem.writeIntSliceBig(u128, ctrbuf[0..], ctr_i +% 1);
+                var ctr_i = std.mem.readIntBig(u128, ctrbuf[0..]);
+                std.mem.writeIntBig(u128, ctrbuf[0..], ctr_i +% 1);
 
                 n += xorBytes(dst[n..], src[n..], &keystream);
             }
@@ -251,7 +251,7 @@ fn expandKey(key: []const u8, enc: []u32, dec: []u32) void {
     var i: usize = 0;
     var nk = key.len / 4;
     while (i < nk) : (i += 1) {
-        enc[i] = mem.readIntSliceBig(u32, key[4 * i .. 4 * i + 4]);
+        enc[i] = mem.readIntBig(u32, key[4 * i ..][0..4]);
     }
     while (i < enc.len) : (i += 1) {
         var t = enc[i - 1];
diff --git a/lib/std/crypto/blake2.zig b/lib/std/crypto/blake2.zig
index e03d8f7dab87..fc1d59290ed3 100644
--- a/lib/std/crypto/blake2.zig
+++ b/lib/std/crypto/blake2.zig
@@ -123,8 +123,7 @@ fn Blake2s(comptime out_len: usize) type {
             const rr = d.h[0 .. out_len / 32];
 
             for (rr) |s, j| {
-                // TODO https://github.com/ziglang/zig/issues/863
-                mem.writeIntSliceLittle(u32, out[4 * j .. 4 * j + 4], s);
+                mem.writeIntLittle(u32, out[4 * j ..][0..4], s);
             }
         }
 
@@ -135,8 +134,7 @@ fn Blake2s(comptime out_len: usize) type {
             var v: [16]u32 = undefined;
 
             for (m) |*r, i| {
-                // TODO https://github.com/ziglang/zig/issues/863
-                r.* = mem.readIntSliceLittle(u32, b[4 * i .. 4 * i + 4]);
+                r.* = mem.readIntLittle(u32, b[4 * i ..][0..4]);
             }
 
             var k: usize = 0;
@@ -358,8 +356,7 @@ fn Blake2b(comptime out_len: usize) type {
             const rr = d.h[0 .. out_len / 64];
 
             for (rr) |s, j| {
-                // TODO https://github.com/ziglang/zig/issues/863
-                mem.writeIntSliceLittle(u64, out[8 * j .. 8 * j + 8], s);
+                mem.writeIntLittle(u64, out[8 * j ..][0..8], s);
             }
         }
 
@@ -370,7 +367,7 @@ fn Blake2b(comptime out_len: usize) type {
             var v: [16]u64 = undefined;
 
             for (m) |*r, i| {
-                r.* = mem.readIntSliceLittle(u64, b[8 * i .. 8 * i + 8]);
+                r.* = mem.readIntLittle(u64, b[8 * i ..][0..8]);
             }
 
             var k: usize = 0;
diff --git a/lib/std/crypto/chacha20.zig b/lib/std/crypto/chacha20.zig
index d67877b05117..f6008745af7d 100644
--- a/lib/std/crypto/chacha20.zig
+++ b/lib/std/crypto/chacha20.zig
@@ -61,8 +61,7 @@ fn salsa20_wordtobyte(out: []u8, input: [16]u32) void {
     }
 
     for (x) |_, i| {
-        // TODO https://github.com/ziglang/zig/issues/863
-        mem.writeIntSliceLittle(u32, out[4 * i .. 4 * i + 4], x[i] +% input[i]);
+        mem.writeIntLittle(u32, out[4 * i ..][0..4], x[i] +% input[i]);
     }
 }
 
@@ -73,10 +72,10 @@ fn chaCha20_internal(out: []u8, in: []const u8, key: [8]u32, counter: [4]u32) vo
 
     const c = "expand 32-byte k";
     const constant_le = [_]u32{
-        mem.readIntSliceLittle(u32, c[0..4]),
-        mem.readIntSliceLittle(u32, c[4..8]),
-        mem.readIntSliceLittle(u32, c[8..12]),
-        mem.readIntSliceLittle(u32, c[12..16]),
+        mem.readIntLittle(u32, c[0..4]),
+        mem.readIntLittle(u32, c[4..8]),
+        mem.readIntLittle(u32, c[8..12]),
+        mem.readIntLittle(u32, c[12..16]),
     };
 
     mem.copy(u32, ctx[0..], constant_le[0..4]);
@@ -120,19 +119,19 @@ pub fn chaCha20IETF(out: []u8, in: []const u8, counter: u32, key: [32]u8, nonce:
     var k: [8]u32 = undefined;
     var c: [4]u32 = undefined;
 
-    k[0] = mem.readIntSliceLittle(u32, key[0..4]);
-    k[1] = mem.readIntSliceLittle(u32, key[4..8]);
-    k[2] = mem.readIntSliceLittle(u32, key[8..12]);
-    k[3] = mem.readIntSliceLittle(u32, key[12..16]);
-    k[4] = mem.readIntSliceLittle(u32, key[16..20]);
-    k[5] = mem.readIntSliceLittle(u32, key[20..24]);
-    k[6] = mem.readIntSliceLittle(u32, key[24..28]);
-    k[7] = mem.readIntSliceLittle(u32, key[28..32]);
+    k[0] = mem.readIntLittle(u32, key[0..4]);
+    k[1] = mem.readIntLittle(u32, key[4..8]);
+    k[2] = mem.readIntLittle(u32, key[8..12]);
+    k[3] = mem.readIntLittle(u32, key[12..16]);
+    k[4] = mem.readIntLittle(u32, key[16..20]);
+    k[5] = mem.readIntLittle(u32, key[20..24]);
+    k[6] = mem.readIntLittle(u32, key[24..28]);
+    k[7] = mem.readIntLittle(u32, key[28..32]);
 
     c[0] = counter;
-    c[1] = mem.readIntSliceLittle(u32, nonce[0..4]);
-    c[2] = mem.readIntSliceLittle(u32, nonce[4..8]);
-    c[3] = mem.readIntSliceLittle(u32, nonce[8..12]);
+    c[1] = mem.readIntLittle(u32, nonce[0..4]);
+    c[2] = mem.readIntLittle(u32, nonce[4..8]);
+    c[3] = mem.readIntLittle(u32, nonce[8..12]);
     chaCha20_internal(out, in, k, c);
 }
 
@@ -147,19 +146,19 @@ pub fn chaCha20With64BitNonce(out: []u8, in: []const u8, counter: u64, key: [32]
     var k: [8]u32 = undefined;
     var c: [4]u32 = undefined;
 
-    k[0] = mem.readIntSliceLittle(u32, key[0..4]);
-    k[1] = mem.readIntSliceLittle(u32, key[4..8]);
-    k[2] = mem.readIntSliceLittle(u32, key[8..12]);
-    k[3] = mem.readIntSliceLittle(u32, key[12..16]);
-    k[4] = mem.readIntSliceLittle(u32, key[16..20]);
-    k[5] = mem.readIntSliceLittle(u32, key[20..24]);
-    k[6] = mem.readIntSliceLittle(u32, key[24..28]);
-    k[7] = mem.readIntSliceLittle(u32, key[28..32]);
+    k[0] = mem.readIntLittle(u32, key[0..4]);
+    k[1] = mem.readIntLittle(u32, key[4..8]);
+    k[2] = mem.readIntLittle(u32, key[8..12]);
+    k[3] = mem.readIntLittle(u32, key[12..16]);
+    k[4] = mem.readIntLittle(u32, key[16..20]);
+    k[5] = mem.readIntLittle(u32, key[20..24]);
+    k[6] = mem.readIntLittle(u32, key[24..28]);
+    k[7] = mem.readIntLittle(u32, key[28..32]);
 
     c[0] = @truncate(u32, counter);
     c[1] = @truncate(u32, counter >> 32);
-    c[2] = mem.readIntSliceLittle(u32, nonce[0..4]);
-    c[3] = mem.readIntSliceLittle(u32, nonce[4..8]);
+    c[2] = mem.readIntLittle(u32, nonce[0..4]);
+    c[3] = mem.readIntLittle(u32, nonce[4..8]);
 
     const block_size = (1 << 6);
     // The full block size is greater than the address space on a 32bit machine
@@ -463,8 +462,8 @@ pub fn chacha20poly1305Seal(dst: []u8, plaintext: []const u8, data: []const u8,
         mac.update(zeros[0..padding]);
     }
     var lens: [16]u8 = undefined;
-    mem.writeIntSliceLittle(u64, lens[0..8], data.len);
-    mem.writeIntSliceLittle(u64, lens[8..16], plaintext.len);
+    mem.writeIntLittle(u64, lens[0..8], data.len);
+    mem.writeIntLittle(u64, lens[8..16], plaintext.len);
     mac.update(lens[0..]);
     mac.final(dst[plaintext.len..]);
 }
@@ -500,8 +499,8 @@ pub fn chacha20poly1305Open(dst: []u8, msgAndTag: []const u8, data: []const u8,
         mac.update(zeros[0..padding]);
     }
     var lens: [16]u8 = undefined;
-    mem.writeIntSliceLittle(u64, lens[0..8], data.len);
-    mem.writeIntSliceLittle(u64, lens[8..16], ciphertext.len);
+    mem.writeIntLittle(u64, lens[0..8], data.len);
+    mem.writeIntLittle(u64, lens[8..16], ciphertext.len);
     mac.update(lens[0..]);
     var computedTag: [16]u8 = undefined;
     mac.final(computedTag[0..]);
diff --git a/lib/std/crypto/md5.zig b/lib/std/crypto/md5.zig
index d9dd08c9047d..ac8948ca20a5 100644
--- a/lib/std/crypto/md5.zig
+++ b/lib/std/crypto/md5.zig
@@ -112,8 +112,7 @@ pub const Md5 = struct {
         d.round(d.buf[0..]);
 
         for (d.s) |s, j| {
-            // TODO https://github.com/ziglang/zig/issues/863
-            mem.writeIntSliceLittle(u32, out[4 * j .. 4 * j + 4], s);
+            mem.writeIntLittle(u32, out[4 * j ..][0..4], s);
         }
     }
 
diff --git a/lib/std/crypto/poly1305.zig b/lib/std/crypto/poly1305.zig
index 2395b1c7aac9..fda978307d28 100644
--- a/lib/std/crypto/poly1305.zig
+++ b/lib/std/crypto/poly1305.zig
@@ -3,11 +3,11 @@
 // https://monocypher.org/
 
 const std = @import("../std.zig");
-const builtin = @import("builtin");
+const builtin = std.builtin;
 
 const Endian = builtin.Endian;
-const readIntSliceLittle = std.mem.readIntSliceLittle;
-const writeIntSliceLittle = std.mem.writeIntSliceLittle;
+const readIntLittle = std.mem.readIntLittle;
+const writeIntLittle = std.mem.writeIntLittle;
 
 pub const Poly1305 = struct {
     const Self = @This();
@@ -59,19 +59,19 @@ pub const Poly1305 = struct {
         {
             var i: usize = 0;
             while (i < 1) : (i += 1) {
-                ctx.r[0] = readIntSliceLittle(u32, key[0..4]) & 0x0fffffff;
+                ctx.r[0] = readIntLittle(u32, key[0..4]) & 0x0fffffff;
             }
         }
         {
             var i: usize = 1;
             while (i < 4) : (i += 1) {
-                ctx.r[i] = readIntSliceLittle(u32, key[i * 4 .. i * 4 + 4]) & 0x0ffffffc;
+                ctx.r[i] = readIntLittle(u32, key[i * 4 ..][0..4]) & 0x0ffffffc;
             }
         }
         {
             var i: usize = 0;
             while (i < 4) : (i += 1) {
-                ctx.pad[i] = readIntSliceLittle(u32, key[i * 4 + 16 .. i * 4 + 16 + 4]);
+                ctx.pad[i] = readIntLittle(u32, key[i * 4 + 16 ..][0..4]);
             }
         }
 
@@ -168,10 +168,10 @@ pub const Poly1305 = struct {
         const nb_blocks = nmsg.len >> 4;
         var i: usize = 0;
         while (i < nb_blocks) : (i += 1) {
-            ctx.c[0] = readIntSliceLittle(u32, nmsg[0..4]);
-            ctx.c[1] = readIntSliceLittle(u32, nmsg[4..8]);
-            ctx.c[2] = readIntSliceLittle(u32, nmsg[8..12]);
-            ctx.c[3] = readIntSliceLittle(u32, nmsg[12..16]);
+            ctx.c[0] = readIntLittle(u32, nmsg[0..4]);
+            ctx.c[1] = readIntLittle(u32, nmsg[4..8]);
+            ctx.c[2] = readIntLittle(u32, nmsg[8..12]);
+            ctx.c[3] = readIntLittle(u32, nmsg[12..16]);
             polyBlock(ctx);
             nmsg = nmsg[16..];
         }
@@ -210,11 +210,10 @@ pub const Poly1305 = struct {
         const uu2 = (uu1 >> 32) + ctx.h[2] + ctx.pad[2]; // <= 2_00000000
         const uu3 = (uu2 >> 32) + ctx.h[3] + ctx.pad[3]; // <= 2_00000000
 
-        // TODO https://github.com/ziglang/zig/issues/863
-        writeIntSliceLittle(u32, out[0..], @truncate(u32, uu0));
-        writeIntSliceLittle(u32, out[4..], @truncate(u32, uu1));
-        writeIntSliceLittle(u32, out[8..], @truncate(u32, uu2));
-        writeIntSliceLittle(u32, out[12..], @truncate(u32, uu3));
+        writeIntLittle(u32, out[0..4], @truncate(u32, uu0));
+        writeIntLittle(u32, out[4..8], @truncate(u32, uu1));
+        writeIntLittle(u32, out[8..12], @truncate(u32, uu2));
+        writeIntLittle(u32, out[12..16], @truncate(u32, uu3));
 
         ctx.secureZero();
     }
diff --git a/lib/std/crypto/sha1.zig b/lib/std/crypto/sha1.zig
index 5be42180a16e..6edf7b745e1d 100644
--- a/lib/std/crypto/sha1.zig
+++ b/lib/std/crypto/sha1.zig
@@ -109,8 +109,7 @@ pub const Sha1 = struct {
         d.round(d.buf[0..]);
 
         for (d.s) |s, j| {
-            // TODO https://github.com/ziglang/zig/issues/863
-            mem.writeIntSliceBig(u32, out[4 * j .. 4 * j + 4], s);
+            mem.writeIntBig(u32, out[4 * j ..][0..4], s);
         }
     }
 
diff --git a/lib/std/crypto/sha2.zig b/lib/std/crypto/sha2.zig
index fd7ad532a3f7..f004bceac3bd 100644
--- a/lib/std/crypto/sha2.zig
+++ b/lib/std/crypto/sha2.zig
@@ -167,8 +167,7 @@ fn Sha2_32(comptime params: Sha2Params32) type {
             const rr = d.s[0 .. params.out_len / 32];
 
             for (rr) |s, j| {
-                // TODO https://github.com/ziglang/zig/issues/863
-                mem.writeIntSliceBig(u32, out[4 * j .. 4 * j + 4], s);
+                mem.writeIntBig(u32, out[4 * j ..][0..4], s);
             }
         }
 
@@ -509,8 +508,7 @@ fn Sha2_64(comptime params: Sha2Params64) type {
             const rr = d.s[0 .. params.out_len / 64];
 
             for (rr) |s, j| {
-                // TODO https://github.com/ziglang/zig/issues/863
-                mem.writeIntSliceBig(u64, out[8 * j .. 8 * j + 8], s);
+                mem.writeIntBig(u64, out[8 * j ..][0..8], s);
             }
         }
 
diff --git a/lib/std/crypto/sha3.zig b/lib/std/crypto/sha3.zig
index d7b2fbe2566d..7c60674d7594 100644
--- a/lib/std/crypto/sha3.zig
+++ b/lib/std/crypto/sha3.zig
@@ -120,7 +120,7 @@ fn keccak_f(comptime F: usize, d: []u8) void {
     var c = [_]u64{0} ** 5;
 
     for (s) |*r, i| {
-        r.* = mem.readIntSliceLittle(u64, d[8 * i .. 8 * i + 8]);
+        r.* = mem.readIntLittle(u64, d[8 * i ..][0..8]);
     }
 
     comptime var x: usize = 0;
@@ -167,8 +167,7 @@ fn keccak_f(comptime F: usize, d: []u8) void {
     }
 
     for (s) |r, i| {
-        // TODO https://github.com/ziglang/zig/issues/863
-        mem.writeIntSliceLittle(u64, d[8 * i .. 8 * i + 8], r);
+        mem.writeIntLittle(u64, d[8 * i ..][0..8], r);
     }
 }
 
diff --git a/lib/std/crypto/x25519.zig b/lib/std/crypto/x25519.zig
index 16e3f073f846..e2e2bf90e506 100644
--- a/lib/std/crypto/x25519.zig
+++ b/lib/std/crypto/x25519.zig
@@ -7,8 +7,8 @@ const builtin = @import("builtin");
 const fmt = std.fmt;
 
 const Endian = builtin.Endian;
-const readIntSliceLittle = std.mem.readIntSliceLittle;
-const writeIntSliceLittle = std.mem.writeIntSliceLittle;
+const readIntLittle = std.mem.readIntLittle;
+const writeIntLittle = std.mem.writeIntLittle;
 
 // Based on Supercop's ref10 implementation.
 pub const X25519 = struct {
@@ -255,16 +255,16 @@ const Fe = struct {
 
         var t: [10]i64 = undefined;
 
-        t[0] = readIntSliceLittle(u32, s[0..4]);
-        t[1] = @as(u32, readIntSliceLittle(u24, s[4..7])) << 6;
-        t[2] = @as(u32, readIntSliceLittle(u24, s[7..10])) << 5;
-        t[3] = @as(u32, readIntSliceLittle(u24, s[10..13])) << 3;
-        t[4] = @as(u32, readIntSliceLittle(u24, s[13..16])) << 2;
-        t[5] = readIntSliceLittle(u32, s[16..20]);
-        t[6] = @as(u32, readIntSliceLittle(u24, s[20..23])) << 7;
-        t[7] = @as(u32, readIntSliceLittle(u24, s[23..26])) << 5;
-        t[8] = @as(u32, readIntSliceLittle(u24, s[26..29])) << 4;
-        t[9] = (@as(u32, readIntSliceLittle(u24, s[29..32])) & 0x7fffff) << 2;
+        t[0] = readIntLittle(u32, s[0..4]);
+        t[1] = @as(u32, readIntLittle(u24, s[4..7])) << 6;
+        t[2] = @as(u32, readIntLittle(u24, s[7..10])) << 5;
+        t[3] = @as(u32, readIntLittle(u24, s[10..13])) << 3;
+        t[4] = @as(u32, readIntLittle(u24, s[13..16])) << 2;
+        t[5] = readIntLittle(u32, s[16..20]);
+        t[6] = @as(u32, readIntLittle(u24, s[20..23])) << 7;
+        t[7] = @as(u32, readIntLittle(u24, s[23..26])) << 5;
+        t[8] = @as(u32, readIntLittle(u24, s[26..29])) << 4;
+        t[9] = (@as(u32, readIntLittle(u24, s[29..32])) & 0x7fffff) << 2;
 
         carry1(h, t[0..]);
     }
@@ -544,15 +544,14 @@ const Fe = struct {
             ut[i] = @bitCast(u32, @intCast(i32, t[i]));
         }
 
-        // TODO https://github.com/ziglang/zig/issues/863
-        writeIntSliceLittle(u32, s[0..4], (ut[0] >> 0) | (ut[1] << 26));
-        writeIntSliceLittle(u32, s[4..8], (ut[1] >> 6) | (ut[2] << 19));
-        writeIntSliceLittle(u32, s[8..12], (ut[2] >> 13) | (ut[3] << 13));
-        writeIntSliceLittle(u32, s[12..16], (ut[3] >> 19) | (ut[4] << 6));
-        writeIntSliceLittle(u32, s[16..20], (ut[5] >> 0) | (ut[6] << 25));
-        writeIntSliceLittle(u32, s[20..24], (ut[6] >> 7) | (ut[7] << 19));
-        writeIntSliceLittle(u32, s[24..28], (ut[7] >> 13) | (ut[8] << 12));
-        writeIntSliceLittle(u32, s[28..], (ut[8] >> 20) | (ut[9] << 6));
+        writeIntLittle(u32, s[0..4], (ut[0] >> 0) | (ut[1] << 26));
+        writeIntLittle(u32, s[4..8], (ut[1] >> 6) | (ut[2] << 19));
+        writeIntLittle(u32, s[8..12], (ut[2] >> 13) | (ut[3] << 13));
+        writeIntLittle(u32, s[12..16], (ut[3] >> 19) | (ut[4] << 6));
+        writeIntLittle(u32, s[16..20], (ut[5] >> 0) | (ut[6] << 25));
+        writeIntLittle(u32, s[20..24], (ut[6] >> 7) | (ut[7] << 19));
+        writeIntLittle(u32, s[24..28], (ut[7] >> 13) | (ut[8] << 12));
+        writeIntLittle(u32, s[28..32], (ut[8] >> 20) | (ut[9] << 6));
 
         std.mem.secureZero(i64, t[0..]);
     }
diff --git a/lib/std/fmt.zig b/lib/std/fmt.zig
index 592fe9bb4e02..7fc996193856 100644
--- a/lib/std/fmt.zig
+++ b/lib/std/fmt.zig
@@ -1223,7 +1223,8 @@ test "slice" {
         try testFmt("slice: abc\n", "slice: {}\n", .{value});
     }
     {
-        const value = @intToPtr([*]align(1) const []const u8, 0xdeadbeef)[0..0];
+        var runtime_zero: usize = 0;
+        const value = @intToPtr([*]align(1) const []const u8, 0xdeadbeef)[runtime_zero..runtime_zero];
         try testFmt("slice: []const u8@deadbeef\n", "slice: {}\n", .{value});
     }
 
diff --git a/lib/std/fs.zig b/lib/std/fs.zig
index bc02fd0c91e9..01ed80c742f3 100644
--- a/lib/std/fs.zig
+++ b/lib/std/fs.zig
@@ -360,7 +360,7 @@ pub const Dir = struct {
                     if (self.index >= self.end_index) {
                         const rc = os.system.getdirentries(
                             self.dir.fd,
-                            self.buf[0..].ptr,
+                            &self.buf,
                             self.buf.len,
                             &self.seek,
                         );
diff --git a/lib/std/hash/auto_hash.zig b/lib/std/hash/auto_hash.zig
index 2c6b37e3db78..b5d6c528a502 100644
--- a/lib/std/hash/auto_hash.zig
+++ b/lib/std/hash/auto_hash.zig
@@ -40,7 +40,9 @@ pub fn hashPointer(hasher: var, key: var, comptime strat: HashStrategy) void {
             .DeepRecursive => hashArray(hasher, key, .DeepRecursive),
         },
 
-        .Many, .C, => switch (strat) {
+        .Many,
+        .C,
+        => switch (strat) {
             .Shallow => hash(hasher, @ptrToInt(key), .Shallow),
             else => @compileError(
                 \\ unknown-length pointers and C pointers cannot be hashed deeply.
@@ -236,9 +238,11 @@ test "hash slice shallow" {
     defer std.testing.allocator.destroy(array1);
     array1.* = [_]u32{ 1, 2, 3, 4, 5, 6 };
     const array2 = [_]u32{ 1, 2, 3, 4, 5, 6 };
-    const a = array1[0..];
-    const b = array2[0..];
-    const c = array1[0..3];
+    // TODO audit deep/shallow - maybe it has the wrong behavior with respect to array pointers and slices
+    var runtime_zero: usize = 0;
+    const a = array1[runtime_zero..];
+    const b = array2[runtime_zero..];
+    const c = array1[runtime_zero..3];
     testing.expect(testHashShallow(a) == testHashShallow(a));
     testing.expect(testHashShallow(a) != testHashShallow(array1));
     testing.expect(testHashShallow(a) != testHashShallow(b));
diff --git a/lib/std/hash/siphash.zig b/lib/std/hash/siphash.zig
index ccef47c4b2f2..ebafdd68554d 100644
--- a/lib/std/hash/siphash.zig
+++ b/lib/std/hash/siphash.zig
@@ -39,8 +39,8 @@ fn SipHashStateless(comptime T: type, comptime c_rounds: usize, comptime d_round
         pub fn init(key: []const u8) Self {
             assert(key.len >= 16);
 
-            const k0 = mem.readIntSliceLittle(u64, key[0..8]);
-            const k1 = mem.readIntSliceLittle(u64, key[8..16]);
+            const k0 = mem.readIntLittle(u64, key[0..8]);
+            const k1 = mem.readIntLittle(u64, key[8..16]);
 
             var d = Self{
                 .v0 = k0 ^ 0x736f6d6570736575,
@@ -111,7 +111,7 @@ fn SipHashStateless(comptime T: type, comptime c_rounds: usize, comptime d_round
         fn round(self: *Self, b: []const u8) void {
             assert(b.len == 8);
 
-            const m = mem.readIntSliceLittle(u64, b[0..]);
+            const m = mem.readIntLittle(u64, b[0..8]);
             self.v3 ^= m;
 
             // TODO this is a workaround, should be able to supply the value without a separate variable
diff --git a/lib/std/hash/wyhash.zig b/lib/std/hash/wyhash.zig
index 8fcbbbce4c47..8b7edd246f87 100644
--- a/lib/std/hash/wyhash.zig
+++ b/lib/std/hash/wyhash.zig
@@ -11,7 +11,7 @@ const primes = [_]u64{
 
 fn read_bytes(comptime bytes: u8, data: []const u8) u64 {
     const T = std.meta.IntType(false, 8 * bytes);
-    return mem.readIntSliceLittle(T, data[0..bytes]);
+    return mem.readIntLittle(T, data[0..bytes]);
 }
 
 fn read_8bytes_swapped(data: []const u8) u64 {
diff --git a/lib/std/json.zig b/lib/std/json.zig
index f5a72d86da23..3dd8088785cf 100644
--- a/lib/std/json.zig
+++ b/lib/std/json.zig
@@ -2249,11 +2249,16 @@ pub const StringifyOptions = struct {
     // TODO: allow picking if []u8 is string or array?
 };
 
+pub const StringifyError = error{
+    TooMuchData,
+    DifferentData,
+};
+
 pub fn stringify(
     value: var,
     options: StringifyOptions,
     out_stream: var,
-) !void {
+) StringifyError!void {
     const T = @TypeOf(value);
     switch (@typeInfo(T)) {
         .Float, .ComptimeFloat => {
@@ -2320,9 +2325,15 @@ pub fn stringify(
             return;
         },
         .Pointer => |ptr_info| switch (ptr_info.size) {
-            .One => {
-                // TODO: avoid loops?
-                return try stringify(value.*, options, out_stream);
+            .One => switch (@typeInfo(ptr_info.child)) {
+                .Array => {
+                    const Slice = []const std.meta.Elem(ptr_info.child);
+                    return stringify(@as(Slice, value), options, out_stream);
+                },
+                else => {
+                    // TODO: avoid loops?
+                    return stringify(value.*, options, out_stream);
+                },
             },
             // TODO: .Many when there is a sentinel (waiting for https://github.com/ziglang/zig/pull/3972)
             .Slice => {
@@ -2381,9 +2392,7 @@ pub fn stringify(
             },
             else => @compileError("Unable to stringify type '" ++ @typeName(T) ++ "'"),
         },
-        .Array => |info| {
-            return try stringify(value[0..], options, out_stream);
-        },
+        .Array => return stringify(&value, options, out_stream),
         else => @compileError("Unable to stringify type '" ++ @typeName(T) ++ "'"),
     }
     unreachable;
diff --git a/lib/std/mem.zig b/lib/std/mem.zig
index 438c15c2ebd6..2f7a21c6b6d2 100644
--- a/lib/std/mem.zig
+++ b/lib/std/mem.zig
@@ -560,7 +560,7 @@ pub fn span(ptr: var) Span(@TypeOf(ptr)) {
 
 test "span" {
     var array: [5]u16 = [_]u16{ 1, 2, 3, 4, 5 };
-    const ptr = array[0..2 :3].ptr;
+    const ptr = @as([*:3]u16, array[0..2 :3]);
     testing.expect(eql(u16, span(ptr), &[_]u16{ 1, 2 }));
     testing.expect(eql(u16, span(&array), &[_]u16{ 1, 2, 3, 4, 5 }));
 }
@@ -602,7 +602,7 @@ test "len" {
         testing.expect(len(&array) == 5);
         testing.expect(len(array[0..3]) == 3);
         array[2] = 0;
-        const ptr = array[0..2 :0].ptr;
+        const ptr = @as([*:0]u16, array[0..2 :0]);
         testing.expect(len(ptr) == 2);
     }
     {
@@ -824,8 +824,7 @@ pub const readIntBig = switch (builtin.endian) {
 pub fn readIntSliceNative(comptime T: type, bytes: []const u8) T {
     const n = @divExact(T.bit_count, 8);
     assert(bytes.len >= n);
-    // TODO https://github.com/ziglang/zig/issues/863
-    return readIntNative(T, @ptrCast(*const [n]u8, bytes.ptr));
+    return readIntNative(T, bytes[0..n]);
 }
 
 /// Asserts that bytes.len >= T.bit_count / 8. Reads the integer starting from index 0
@@ -863,8 +862,7 @@ pub fn readInt(comptime T: type, bytes: *const [@divExact(T.bit_count, 8)]u8, en
 pub fn readIntSlice(comptime T: type, bytes: []const u8, endian: builtin.Endian) T {
     const n = @divExact(T.bit_count, 8);
     assert(bytes.len >= n);
-    // TODO https://github.com/ziglang/zig/issues/863
-    return readInt(T, @ptrCast(*const [n]u8, bytes.ptr), endian);
+    return readInt(T, bytes[0..n], endian);
 }
 
 test "comptime read/write int" {
@@ -1586,24 +1584,24 @@ pub fn nativeToBig(comptime T: type, x: T) T {
 }
 
 fn AsBytesReturnType(comptime P: type) type {
-    if (comptime !trait.isSingleItemPtr(P))
+    if (!trait.isSingleItemPtr(P))
         @compileError("expected single item pointer, passed " ++ @typeName(P));
 
-    const size = @as(usize, @sizeOf(meta.Child(P)));
-    const alignment = comptime meta.alignment(P);
+    const size = @sizeOf(meta.Child(P));
+    const alignment = meta.alignment(P);
 
     if (alignment == 0) {
-        if (comptime trait.isConstPtr(P))
+        if (trait.isConstPtr(P))
             return *const [size]u8;
         return *[size]u8;
     }
 
-    if (comptime trait.isConstPtr(P))
+    if (trait.isConstPtr(P))
         return *align(alignment) const [size]u8;
     return *align(alignment) [size]u8;
 }
 
-///Given a pointer to a single item, returns a slice of the underlying bytes, preserving constness.
+/// Given a pointer to a single item, returns a slice of the underlying bytes, preserving constness.
 pub fn asBytes(ptr: var) AsBytesReturnType(@TypeOf(ptr)) {
     const P = @TypeOf(ptr);
     return @ptrCast(AsBytesReturnType(P), ptr);
@@ -1750,34 +1748,50 @@ fn BytesAsSliceReturnType(comptime T: type, comptime bytesType: type) type {
 }
 
 pub fn bytesAsSlice(comptime T: type, bytes: var) BytesAsSliceReturnType(T, @TypeOf(bytes)) {
-    const bytesSlice = if (comptime trait.isPtrTo(.Array)(@TypeOf(bytes))) bytes[0..] else bytes;
-
     // let's not give an undefined pointer to @ptrCast
     // it may be equal to zero and fail a null check
-    if (bytesSlice.len == 0) {
+    if (bytes.len == 0) {
         return &[0]T{};
     }
 
-    const bytesType = @TypeOf(bytesSlice);
-    const alignment = comptime meta.alignment(bytesType);
+    const Bytes = @TypeOf(bytes);
+    const alignment = comptime meta.alignment(Bytes);
 
-    const castTarget = if (comptime trait.isConstPtr(bytesType)) [*]align(alignment) const T else [*]align(alignment) T;
+    const cast_target = if (comptime trait.isConstPtr(Bytes)) [*]align(alignment) const T else [*]align(alignment) T;
 
-    return @ptrCast(castTarget, bytesSlice.ptr)[0..@divExact(bytes.len, @sizeOf(T))];
+    return @ptrCast(cast_target, bytes)[0..@divExact(bytes.len, @sizeOf(T))];
 }
 
 test "bytesAsSlice" {
-    const bytes = [_]u8{ 0xDE, 0xAD, 0xBE, 0xEF };
-    const slice = bytesAsSlice(u16, bytes[0..]);
-    testing.expect(slice.len == 2);
-    testing.expect(bigToNative(u16, slice[0]) == 0xDEAD);
-    testing.expect(bigToNative(u16, slice[1]) == 0xBEEF);
+    {
+        const bytes = [_]u8{ 0xDE, 0xAD, 0xBE, 0xEF };
+        const slice = bytesAsSlice(u16, bytes[0..]);
+        testing.expect(slice.len == 2);
+        testing.expect(bigToNative(u16, slice[0]) == 0xDEAD);
+        testing.expect(bigToNative(u16, slice[1]) == 0xBEEF);
+    }
+    {
+        const bytes = [_]u8{ 0xDE, 0xAD, 0xBE, 0xEF };
+        var runtime_zero: usize = 0;
+        const slice = bytesAsSlice(u16, bytes[runtime_zero..]);
+        testing.expect(slice.len == 2);
+        testing.expect(bigToNative(u16, slice[0]) == 0xDEAD);
+        testing.expect(bigToNative(u16, slice[1]) == 0xBEEF);
+    }
 }
 
 test "bytesAsSlice keeps pointer alignment" {
-    var bytes = [_]u8{ 0x01, 0x02, 0x03, 0x04 };
-    const numbers = bytesAsSlice(u32, bytes[0..]);
-    comptime testing.expect(@TypeOf(numbers) == []align(@alignOf(@TypeOf(bytes))) u32);
+    {
+        var bytes = [_]u8{ 0x01, 0x02, 0x03, 0x04 };
+        const numbers = bytesAsSlice(u32, bytes[0..]);
+        comptime testing.expect(@TypeOf(numbers) == []align(@alignOf(@TypeOf(bytes))) u32);
+    }
+    {
+        var bytes = [_]u8{ 0x01, 0x02, 0x03, 0x04 };
+        var runtime_zero: usize = 0;
+        const numbers = bytesAsSlice(u32, bytes[runtime_zero..]);
+        comptime testing.expect(@TypeOf(numbers) == []align(@alignOf(@TypeOf(bytes))) u32);
+    }
 }
 
 test "bytesAsSlice on a packed struct" {
@@ -1813,21 +1827,19 @@ fn SliceAsBytesReturnType(comptime sliceType: type) type {
 }
 
 pub fn sliceAsBytes(slice: var) SliceAsBytesReturnType(@TypeOf(slice)) {
-    const actualSlice = if (comptime trait.isPtrTo(.Array)(@TypeOf(slice))) slice[0..] else slice;
-    const actualSliceTypeInfo = @typeInfo(@TypeOf(actualSlice)).Pointer;
+    const Slice = @TypeOf(slice);
 
     // let's not give an undefined pointer to @ptrCast
     // it may be equal to zero and fail a null check
-    if (actualSlice.len == 0 and actualSliceTypeInfo.sentinel == null) {
+    if (slice.len == 0 and comptime meta.sentinel(Slice) == null) {
         return &[0]u8{};
     }
 
-    const sliceType = @TypeOf(actualSlice);
-    const alignment = comptime meta.alignment(sliceType);
+    const alignment = comptime meta.alignment(Slice);
 
-    const castTarget = if (comptime trait.isConstPtr(sliceType)) [*]align(alignment) const u8 else [*]align(alignment) u8;
+    const cast_target = if (comptime trait.isConstPtr(Slice)) [*]align(alignment) const u8 else [*]align(alignment) u8;
 
-    return @ptrCast(castTarget, actualSlice.ptr)[0 .. actualSlice.len * @sizeOf(comptime meta.Child(sliceType))];
+    return @ptrCast(cast_target, slice)[0 .. slice.len * @sizeOf(meta.Elem(Slice))];
 }
 
 test "sliceAsBytes" {
@@ -1897,39 +1909,6 @@ test "sliceAsBytes and bytesAsSlice back" {
     testing.expect(bytes[11] == math.maxInt(u8));
 }
 
-fn SubArrayPtrReturnType(comptime T: type, comptime length: usize) type {
-    if (trait.isConstPtr(T))
-        return *const [length]meta.Child(meta.Child(T));
-    return *[length]meta.Child(meta.Child(T));
-}
-
-/// Given a pointer to an array, returns a pointer to a portion of that array, preserving constness.
-/// TODO this will be obsoleted by https://github.com/ziglang/zig/issues/863
-pub fn subArrayPtr(
-    ptr: var,
-    comptime start: usize,
-    comptime length: usize,
-) SubArrayPtrReturnType(@TypeOf(ptr), length) {
-    assert(start + length <= ptr.*.len);
-
-    const ReturnType = SubArrayPtrReturnType(@TypeOf(ptr), length);
-    const T = meta.Child(meta.Child(@TypeOf(ptr)));
-    return @ptrCast(ReturnType, &ptr[start]);
-}
-
-test "subArrayPtr" {
-    const a1: [6]u8 = "abcdef".*;
-    const sub1 = subArrayPtr(&a1, 2, 3);
-    testing.expect(eql(u8, sub1, "cde"));
-
-    var a2: [6]u8 = "abcdef".*;
-    var sub2 = subArrayPtr(&a2, 2, 3);
-
-    testing.expect(eql(u8, sub2, "cde"));
-    sub2[1] = 'X';
-    testing.expect(eql(u8, &a2, "abcXef"));
-}
-
 /// Round an address up to the nearest aligned address
 /// The alignment must be a power of 2 and greater than 0.
 pub fn alignForward(addr: usize, alignment: usize) usize {
diff --git a/lib/std/meta.zig b/lib/std/meta.zig
index 65809abb5ca5..7343cfc51a4e 100644
--- a/lib/std/meta.zig
+++ b/lib/std/meta.zig
@@ -104,7 +104,7 @@ pub fn Child(comptime T: type) type {
         .Array => |info| info.child,
         .Pointer => |info| info.child,
         .Optional => |info| info.child,
-        else => @compileError("Expected pointer, optional, or array type, " ++ "found '" ++ @typeName(T) ++ "'"),
+        else => @compileError("Expected pointer, optional, or array type, found '" ++ @typeName(T) ++ "'"),
     };
 }
 
@@ -115,30 +115,65 @@ test "std.meta.Child" {
     testing.expect(Child(?u8) == u8);
 }
 
-/// Given a type with a sentinel e.g. `[:0]u8`, returns the sentinel
-pub fn Sentinel(comptime T: type) Child(T) {
-    // comptime asserts that ptr has a sentinel
+/// Given a "memory span" type, returns the "element type".
+pub fn Elem(comptime T: type) type {
     switch (@typeInfo(T)) {
-        .Array => |arrayInfo| {
-            return comptime arrayInfo.sentinel.?;
+        .Array => |info| return info.child,
+        .Pointer => |info| switch (info.size) {
+            .One => switch (@typeInfo(info.child)) {
+                .Array => |array_info| return array_info.child,
+                else => {},
+            },
+            .Many, .C, .Slice => return info.child,
         },
-        .Pointer => |ptrInfo| {
-            switch (ptrInfo.size) {
-                .Many, .Slice => {
-                    return comptime ptrInfo.sentinel.?;
+        else => {},
+    }
+    @compileError("Expected pointer, slice, or array, found '" ++ @typeName(T) ++ "'");
+}
+
+test "std.meta.Elem" {
+    testing.expect(Elem([1]u8) == u8);
+    testing.expect(Elem([*]u8) == u8);
+    testing.expect(Elem([]u8) == u8);
+    testing.expect(Elem(*[10]u8) == u8);
+}
+
+/// Given a type which can have a sentinel e.g. `[:0]u8`, returns the sentinel value,
+/// or `null` if there is not one.
+/// Types which cannot possibly have a sentinel will be a compile error.
+pub fn sentinel(comptime T: type) ?Elem(T) {
+    switch (@typeInfo(T)) {
+        .Array => |info| return info.sentinel,
+        .Pointer => |info| {
+            switch (info.size) {
+                .Many, .Slice => return info.sentinel,
+                .One => switch (@typeInfo(info.child)) {
+                    .Array => |array_info| return array_info.sentinel,
+                    else => {},
                 },
                 else => {},
             }
         },
         else => {},
     }
-    @compileError("not a sentinel type, found '" ++ @typeName(T) ++ "'");
+    @compileError("type '" ++ @typeName(T) ++ "' cannot possibly have a sentinel");
 }
 
-test "std.meta.Sentinel" {
-    testing.expectEqual(@as(u8, 0), Sentinel([:0]u8));
-    testing.expectEqual(@as(u8, 0), Sentinel([*:0]u8));
-    testing.expectEqual(@as(u8, 0), Sentinel([5:0]u8));
+test "std.meta.sentinel" {
+    testSentinel();
+    comptime testSentinel();
+}
+
+fn testSentinel() void {
+    testing.expectEqual(@as(u8, 0), sentinel([:0]u8).?);
+    testing.expectEqual(@as(u8, 0), sentinel([*:0]u8).?);
+    testing.expectEqual(@as(u8, 0), sentinel([5:0]u8).?);
+    testing.expectEqual(@as(u8, 0), sentinel(*const [5:0]u8).?);
+
+    testing.expect(sentinel([]u8) == null);
+    testing.expect(sentinel([*]u8) == null);
+    testing.expect(sentinel([5]u8) == null);
+    testing.expect(sentinel(*const [5]u8) == null);
 }
 
 pub fn containerLayout(comptime T: type) TypeInfo.ContainerLayout {
diff --git a/lib/std/meta/trait.zig b/lib/std/meta/trait.zig
index c0fb8c50256a..c99e1389f4b6 100644
--- a/lib/std/meta/trait.zig
+++ b/lib/std/meta/trait.zig
@@ -230,9 +230,10 @@ pub fn isSingleItemPtr(comptime T: type) bool {
 
 test "std.meta.trait.isSingleItemPtr" {
     const array = [_]u8{0} ** 10;
-    testing.expect(isSingleItemPtr(@TypeOf(&array[0])));
-    testing.expect(!isSingleItemPtr(@TypeOf(array)));
-    testing.expect(!isSingleItemPtr(@TypeOf(array[0..1])));
+    comptime testing.expect(isSingleItemPtr(@TypeOf(&array[0])));
+    comptime testing.expect(!isSingleItemPtr(@TypeOf(array)));
+    var runtime_zero: usize = 0;
+    testing.expect(!isSingleItemPtr(@TypeOf(array[runtime_zero..1])));
 }
 
 pub fn isManyItemPtr(comptime T: type) bool {
@@ -259,7 +260,8 @@ pub fn isSlice(comptime T: type) bool {
 
 test "std.meta.trait.isSlice" {
     const array = [_]u8{0} ** 10;
-    testing.expect(isSlice(@TypeOf(array[0..])));
+    var runtime_zero: usize = 0;
+    testing.expect(isSlice(@TypeOf(array[runtime_zero..])));
     testing.expect(!isSlice(@TypeOf(array)));
     testing.expect(!isSlice(@TypeOf(&array[0])));
 }
@@ -276,7 +278,7 @@ pub fn isIndexable(comptime T: type) bool {
 
 test "std.meta.trait.isIndexable" {
     const array = [_]u8{0} ** 10;
-    const slice = array[0..];
+    const slice = @as([]const u8, &array);
 
     testing.expect(isIndexable(@TypeOf(array)));
     testing.expect(isIndexable(@TypeOf(&array)));
diff --git a/lib/std/net.zig b/lib/std/net.zig
index c2328b9bd0eb..b9c1281191d2 100644
--- a/lib/std/net.zig
+++ b/lib/std/net.zig
@@ -612,8 +612,7 @@ fn linuxLookupName(
         } else {
             mem.copy(u8, &sa6.addr, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff");
             mem.copy(u8, &da6.addr, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff");
-            // TODO https://github.com/ziglang/zig/issues/863
-            mem.writeIntNative(u32, @ptrCast(*[4]u8, da6.addr[12..].ptr), addr.addr.in.addr);
+            mem.writeIntNative(u32, da6.addr[12..], addr.addr.in.addr);
             da4.addr = addr.addr.in.addr;
             da = @ptrCast(*os.sockaddr, &da4);
             dalen = @sizeOf(os.sockaddr_in);
@@ -821,7 +820,7 @@ fn linuxLookupNameFromHosts(
             // Skip to the delimiter in the stream, to fix parsing
             try stream.skipUntilDelimiterOrEof('\n');
             // Use the truncated line. A truncated comment or hostname will be handled correctly.
-            break :blk line_buf[0..];
+            break :blk @as([]u8, &line_buf); // TODO the cast should not be necessary
         },
         else => |e| return e,
     }) |line| {
@@ -958,7 +957,10 @@ fn linuxLookupNameFromDns(
         }
     }
 
-    var ap = [2][]u8{ apbuf[0][0..0], apbuf[1][0..0] };
+    var ap = [2][]u8{ apbuf[0], apbuf[1] };
+    ap[0].len = 0;
+    ap[1].len = 0;
+
     try resMSendRc(qp[0..nq], ap[0..nq], apbuf[0..nq], rc);
 
     var i: usize = 0;
@@ -1015,7 +1017,7 @@ fn getResolvConf(allocator: *mem.Allocator, rc: *ResolvConf) !void {
             // Skip to the delimiter in the stream, to fix parsing
             try stream.skipUntilDelimiterOrEof('\n');
             // Give an empty line to the while loop, which will be skipped.
-            break :blk line_buf[0..0];
+            break :blk @as([]u8, line_buf[0..0]); // TODO the cast should not be necessary
         },
         else => |e| return e,
     }) |line| {
diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
index f5acb70adb20..813a77c27586 100644
--- a/lib/std/os/windows.zig
+++ b/lib/std/os/windows.zig
@@ -1276,7 +1276,15 @@ pub fn unexpectedError(err: Win32Error) std.os.UnexpectedError {
         // 614 is the length of the longest windows error desciption
         var buf_u16: [614]u16 = undefined;
         var buf_u8: [614]u8 = undefined;
-        var len = kernel32.FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, null, err, MAKELANGID(LANG.NEUTRAL, SUBLANG.DEFAULT), buf_u16[0..].ptr, buf_u16.len / @sizeOf(TCHAR), null);
+        const len = kernel32.FormatMessageW(
+            FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+            null,
+            err,
+            MAKELANGID(LANG.NEUTRAL, SUBLANG.DEFAULT),
+            &buf_u16,
+            buf_u16.len / @sizeOf(TCHAR),
+            null,
+        );
         _ = std.unicode.utf16leToUtf8(&buf_u8, buf_u16[0..len]) catch unreachable;
         std.debug.warn("error.Unexpected: GetLastError({}): {}\n", .{ @enumToInt(err), buf_u8[0..len] });
         std.debug.dumpCurrentStackTrace(null);
diff --git a/lib/std/rand.zig b/lib/std/rand.zig
index 31891f5f0e68..ede46e306593 100644
--- a/lib/std/rand.zig
+++ b/lib/std/rand.zig
@@ -5,7 +5,7 @@
 // ```
 // var buf: [8]u8 = undefined;
 // try std.crypto.randomBytes(buf[0..]);
-// const seed = mem.readIntSliceLittle(u64, buf[0..8]);
+// const seed = mem.readIntLittle(u64, buf[0..8]);
 //
 // var r = DefaultPrng.init(seed);
 //
diff --git a/lib/std/unicode.zig b/lib/std/unicode.zig
index 8ed51fa1451c..a971a730e840 100644
--- a/lib/std/unicode.zig
+++ b/lib/std/unicode.zig
@@ -251,12 +251,12 @@ pub const Utf16LeIterator = struct {
     pub fn nextCodepoint(it: *Utf16LeIterator) !?u21 {
         assert(it.i <= it.bytes.len);
         if (it.i == it.bytes.len) return null;
-        const c0: u21 = mem.readIntSliceLittle(u16, it.bytes[it.i .. it.i + 2]);
+        const c0: u21 = mem.readIntLittle(u16, it.bytes[it.i..][0..2]);
         if (c0 & ~@as(u21, 0x03ff) == 0xd800) {
             // surrogate pair
             it.i += 2;
             if (it.i >= it.bytes.len) return error.DanglingSurrogateHalf;
-            const c1: u21 = mem.readIntSliceLittle(u16, it.bytes[it.i .. it.i + 2]);
+            const c1: u21 = mem.readIntLittle(u16, it.bytes[it.i..][0..2]);
             if (c1 & ~@as(u21, 0x03ff) != 0xdc00) return error.ExpectedSecondSurrogateHalf;
             it.i += 2;
             return 0x10000 + (((c0 & 0x03ff) << 10) | (c1 & 0x03ff));
@@ -630,11 +630,11 @@ test "utf8ToUtf16LeWithNull" {
     }
 }
 
-/// Converts a UTF-8 string literal into a UTF-16LE string literal. 
-pub fn utf8ToUtf16LeStringLiteral(comptime utf8: []const u8) *const [calcUtf16LeLen(utf8) :0] u16 {
+/// Converts a UTF-8 string literal into a UTF-16LE string literal.
+pub fn utf8ToUtf16LeStringLiteral(comptime utf8: []const u8) *const [calcUtf16LeLen(utf8):0]u16 {
     comptime {
         const len: usize = calcUtf16LeLen(utf8);
-        var utf16le: [len :0]u16 = [_ :0]u16{0} ** len;
+        var utf16le: [len:0]u16 = [_:0]u16{0} ** len;
         const utf16le_len = utf8ToUtf16Le(&utf16le, utf8[0..]) catch |err| @compileError(err);
         assert(len == utf16le_len);
         return &utf16le;
@@ -660,8 +660,8 @@ fn calcUtf16LeLen(utf8: []const u8) usize {
 }
 
 test "utf8ToUtf16LeStringLiteral" {
-{
-        const bytes = [_:0]u16{ 0x41 };
+    {
+        const bytes = [_:0]u16{0x41};
         const utf16 = utf8ToUtf16LeStringLiteral("A");
         testing.expectEqualSlices(u16, &bytes, utf16);
         testing.expect(utf16[1] == 0);
@@ -673,19 +673,19 @@ test "utf8ToUtf16LeStringLiteral" {
         testing.expect(utf16[2] == 0);
     }
     {
-        const bytes = [_:0]u16{ 0x02FF };
+        const bytes = [_:0]u16{0x02FF};
         const utf16 = utf8ToUtf16LeStringLiteral("\u{02FF}");
         testing.expectEqualSlices(u16, &bytes, utf16);
         testing.expect(utf16[1] == 0);
     }
     {
-        const bytes = [_:0]u16{ 0x7FF };
+        const bytes = [_:0]u16{0x7FF};
         const utf16 = utf8ToUtf16LeStringLiteral("\u{7FF}");
         testing.expectEqualSlices(u16, &bytes, utf16);
         testing.expect(utf16[1] == 0);
     }
     {
-        const bytes = [_:0]u16{ 0x801 };
+        const bytes = [_:0]u16{0x801};
         const utf16 = utf8ToUtf16LeStringLiteral("\u{801}");
         testing.expectEqualSlices(u16, &bytes, utf16);
         testing.expect(utf16[1] == 0);
diff --git a/src-self-hosted/stage2.zig b/src-self-hosted/stage2.zig
index 5393310f9e82..a1d741bc9b97 100644
--- a/src-self-hosted/stage2.zig
+++ b/src-self-hosted/stage2.zig
@@ -128,7 +128,7 @@ export fn stage2_translate_c(
     args_end: [*]?[*]const u8,
     resources_path: [*:0]const u8,
 ) Error {
-    var errors = @as([*]translate_c.ClangErrMsg, undefined)[0..0];
+    var errors: []translate_c.ClangErrMsg = &[0]translate_c.ClangErrMsg{};
     out_ast.* = translate_c.translate(std.heap.c_allocator, args_begin, args_end, &errors, resources_path) catch |err| switch (err) {
         error.SemanticAnalyzeFail => {
             out_errors_ptr.* = errors.ptr;
diff --git a/src-self-hosted/translate_c.zig b/src-self-hosted/translate_c.zig
index 84416ac98085..e6cf8fb149dd 100644
--- a/src-self-hosted/translate_c.zig
+++ b/src-self-hosted/translate_c.zig
@@ -1744,20 +1744,18 @@ fn writeEscapedString(buf: []u8, s: []const u8) void {
 // Returns either a string literal or a slice of `buf`.
 fn escapeChar(c: u8, char_buf: *[4]u8) []const u8 {
     return switch (c) {
-        '\"' => "\\\""[0..],
-        '\'' => "\\'"[0..],
-        '\\' => "\\\\"[0..],
-        '\n' => "\\n"[0..],
-        '\r' => "\\r"[0..],
-        '\t' => "\\t"[0..],
-        else => {
-            // Handle the remaining escapes Zig doesn't support by turning them
-            // into their respective hex representation
-            if (std.ascii.isCntrl(c))
-                return std.fmt.bufPrint(char_buf[0..], "\\x{x:0<2}", .{c}) catch unreachable
-            else
-                return std.fmt.bufPrint(char_buf[0..], "{c}", .{c}) catch unreachable;
-        },
+        '\"' => "\\\"",
+        '\'' => "\\'",
+        '\\' => "\\\\",
+        '\n' => "\\n",
+        '\r' => "\\r",
+        '\t' => "\\t",
+        // Handle the remaining escapes Zig doesn't support by turning them
+        // into their respective hex representation
+        else => if (std.ascii.isCntrl(c))
+            std.fmt.bufPrint(char_buf, "\\x{x:0<2}", .{c}) catch unreachable
+        else
+            std.fmt.bufPrint(char_buf, "{c}", .{c}) catch unreachable,
     };
 }
 
diff --git a/src/all_types.hpp b/src/all_types.hpp
index 53aae9e23647..6719d78a9245 100644
--- a/src/all_types.hpp
+++ b/src/all_types.hpp
@@ -231,6 +231,7 @@ enum ConstPtrSpecial {
     // The pointer is a reference to a single object.
     ConstPtrSpecialRef,
     // The pointer points to an element in an underlying array.
+    // Not to be confused with ConstPtrSpecialSubArray.
     ConstPtrSpecialBaseArray,
     // The pointer points to a field in an underlying struct.
     ConstPtrSpecialBaseStruct,
@@ -257,6 +258,10 @@ enum ConstPtrSpecial {
     // types to be the same, so all optionals of pointer types use x_ptr
     // instead of x_optional.
     ConstPtrSpecialNull,
+    // The pointer points to a sub-array (not an individual element).
+    // Not to be confused with ConstPtrSpecialBaseArray. However, it uses the same
+    // union payload struct (base_array).
+    ConstPtrSpecialSubArray,
 };
 
 enum ConstPtrMut {
@@ -3706,6 +3711,7 @@ struct IrInstGenSlice {
     IrInstGen *start;
     IrInstGen *end;
     IrInstGen *result_loc;
+    ZigValue *sentinel;
     bool safety_check_on;
 };
 
diff --git a/src/analyze.cpp b/src/analyze.cpp
index 9ba247012db5..77d3f333312d 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -780,6 +780,8 @@ ZigType *get_error_union_type(CodeGen *g, ZigType *err_set_type, ZigType *payloa
 }
 
 ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size, ZigValue *sentinel) {
+    Error err;
+
     TypeId type_id = {};
     type_id.id = ZigTypeIdArray;
     type_id.data.array.codegen = g;
@@ -791,7 +793,11 @@ ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size, Zi
         return existing_entry->value;
     }
 
-    assert(type_is_resolved(child_type, ResolveStatusSizeKnown));
+    size_t full_array_size = array_size + ((sentinel != nullptr) ? 1 : 0);
+
+    if (full_array_size != 0 && (err = type_resolve(g, child_type, ResolveStatusSizeKnown))) {
+        codegen_report_errors_and_exit(g);
+    }
 
     ZigType *entry = new_type_table_entry(ZigTypeIdArray);
 
@@ -803,9 +809,8 @@ ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size, Zi
     }
     buf_appendf(&entry->name, "]%s", buf_ptr(&child_type->name));
 
-    size_t full_array_size = array_size + ((sentinel != nullptr) ? 1 : 0);
     entry->size_in_bits = child_type->size_in_bits * full_array_size;
-    entry->abi_align = child_type->abi_align;
+    entry->abi_align = (full_array_size == 0) ? 0 : child_type->abi_align;
     entry->abi_size = child_type->abi_size * full_array_size;
 
     entry->data.array.child_type = child_type;
@@ -4483,7 +4488,14 @@ static uint32_t get_async_frame_align_bytes(CodeGen *g) {
 }
 
 uint32_t get_ptr_align(CodeGen *g, ZigType *type) {
-    ZigType *ptr_type = get_src_ptr_type(type);
+    ZigType *ptr_type;
+    if (type->id == ZigTypeIdStruct) {
+        assert(type->data.structure.special == StructSpecialSlice);
+        TypeStructField *ptr_field = type->data.structure.fields[slice_ptr_index];
+        ptr_type = resolve_struct_field_type(g, ptr_field);
+    } else {
+        ptr_type = get_src_ptr_type(type);
+    }
     if (ptr_type->id == ZigTypeIdPointer) {
         return (ptr_type->data.pointer.explicit_alignment == 0) ?
             get_abi_alignment(g, ptr_type->data.pointer.child_type) : ptr_type->data.pointer.explicit_alignment;
@@ -4500,8 +4512,15 @@ uint32_t get_ptr_align(CodeGen *g, ZigType *type) {
     }
 }
 
-bool get_ptr_const(ZigType *type) {
-    ZigType *ptr_type = get_src_ptr_type(type);
+bool get_ptr_const(CodeGen *g, ZigType *type) {
+    ZigType *ptr_type;
+    if (type->id == ZigTypeIdStruct) {
+        assert(type->data.structure.special == StructSpecialSlice);
+        TypeStructField *ptr_field = type->data.structure.fields[slice_ptr_index];
+        ptr_type = resolve_struct_field_type(g, ptr_field);
+    } else {
+        ptr_type = get_src_ptr_type(type);
+    }
     if (ptr_type->id == ZigTypeIdPointer) {
         return ptr_type->data.pointer.is_const;
     } else if (ptr_type->id == ZigTypeIdFn) {
@@ -5277,6 +5296,11 @@ static uint32_t hash_const_val_ptr(ZigValue *const_val) {
             hash_val += hash_ptr(const_val->data.x_ptr.data.base_array.array_val);
             hash_val += hash_size(const_val->data.x_ptr.data.base_array.elem_index);
             return hash_val;
+        case ConstPtrSpecialSubArray:
+            hash_val += (uint32_t)2643358777;
+            hash_val += hash_ptr(const_val->data.x_ptr.data.base_array.array_val);
+            hash_val += hash_size(const_val->data.x_ptr.data.base_array.elem_index);
+            return hash_val;
         case ConstPtrSpecialBaseStruct:
             hash_val += (uint32_t)3518317043;
             hash_val += hash_ptr(const_val->data.x_ptr.data.base_struct.struct_val);
@@ -6743,6 +6767,7 @@ bool const_values_equal_ptr(ZigValue *a, ZigValue *b) {
                 return false;
             return true;
         case ConstPtrSpecialBaseArray:
+        case ConstPtrSpecialSubArray:
             if (a->data.x_ptr.data.base_array.array_val != b->data.x_ptr.data.base_array.array_val) {
                 return false;
             }
@@ -7000,6 +7025,7 @@ static void render_const_val_ptr(CodeGen *g, Buf *buf, ZigValue *const_val, ZigT
             render_const_value(g, buf, const_ptr_pointee(nullptr, g, const_val, nullptr));
             return;
         case ConstPtrSpecialBaseArray:
+        case ConstPtrSpecialSubArray:
             buf_appendf(buf, "*");
             // TODO we need a source node for const_ptr_pointee because it can generate compile errors
             render_const_value(g, buf, const_ptr_pointee(nullptr, g, const_val, nullptr));
diff --git a/src/analyze.hpp b/src/analyze.hpp
index c7cbab4b8c14..b6404b1882b1 100644
--- a/src/analyze.hpp
+++ b/src/analyze.hpp
@@ -76,7 +76,7 @@ void resolve_top_level_decl(CodeGen *g, Tld *tld, AstNode *source_node, bool all
 
 ZigType *get_src_ptr_type(ZigType *type);
 uint32_t get_ptr_align(CodeGen *g, ZigType *type);
-bool get_ptr_const(ZigType *type);
+bool get_ptr_const(CodeGen *g, ZigType *type);
 ZigType *validate_var_type(CodeGen *g, AstNode *source_node, ZigType *type_entry);
 ZigType *container_ref_type(ZigType *type_entry);
 bool type_is_complete(ZigType *type_entry);
diff --git a/src/codegen.cpp b/src/codegen.cpp
index 3343807691d5..8fae16e55113 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -5418,12 +5418,16 @@ static LLVMValueRef ir_render_slice(CodeGen *g, IrExecutableGen *executable, IrI
     ZigType *array_type = array_ptr_type->data.pointer.child_type;
     LLVMValueRef array_ptr = get_handle_value(g, array_ptr_ptr, array_type, array_ptr_type);
 
-    LLVMValueRef tmp_struct_ptr = ir_llvm_value(g, instruction->result_loc);
-
     bool want_runtime_safety = instruction->safety_check_on && ir_want_runtime_safety(g, &instruction->base);
 
-    ZigType *res_slice_ptr_type = instruction->base.value->type->data.structure.fields[slice_ptr_index]->type_entry;
-    ZigValue *sentinel = res_slice_ptr_type->data.pointer.sentinel;
+    ZigType *result_type = instruction->base.value->type;
+    if (!type_has_bits(g, result_type)) {
+        return nullptr;
+    }
+
+    // This is not whether the result type has a sentinel, but whether there should be a sentinel check,
+    // e.g. if they used [a..b :s] syntax.
+    ZigValue *sentinel = instruction->sentinel;
 
     if (array_type->id == ZigTypeIdArray ||
         (array_type->id == ZigTypeIdPointer && array_type->data.pointer.ptr_len == PtrLenSingle))
@@ -5458,6 +5462,8 @@ static LLVMValueRef ir_render_slice(CodeGen *g, IrExecutableGen *executable, IrI
             }
         }
         if (!type_has_bits(g, array_type)) {
+            LLVMValueRef tmp_struct_ptr = ir_llvm_value(g, instruction->result_loc);
+
             LLVMValueRef len_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, slice_len_index, "");
 
             // TODO if runtime safety is on, store 0xaaaaaaa in ptr field
@@ -5466,20 +5472,26 @@ static LLVMValueRef ir_render_slice(CodeGen *g, IrExecutableGen *executable, IrI
             return tmp_struct_ptr;
         }
 
-
-        LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, slice_ptr_index, "");
         LLVMValueRef indices[] = {
             LLVMConstNull(g->builtin_types.entry_usize->llvm_type),
             start_val,
         };
         LLVMValueRef slice_start_ptr = LLVMBuildInBoundsGEP(g->builder, array_ptr, indices, 2, "");
-        gen_store_untyped(g, slice_start_ptr, ptr_field_ptr, 0, false);
+        if (result_type->id == ZigTypeIdPointer) {
+            ir_assert(instruction->result_loc == nullptr, &instruction->base);
+            LLVMTypeRef result_ptr_type = get_llvm_type(g, result_type);
+            return LLVMBuildBitCast(g->builder, slice_start_ptr, result_ptr_type, "");
+        } else {
+            LLVMValueRef tmp_struct_ptr = ir_llvm_value(g, instruction->result_loc);
+            LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, slice_ptr_index, "");
+            gen_store_untyped(g, slice_start_ptr, ptr_field_ptr, 0, false);
 
-        LLVMValueRef len_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, slice_len_index, "");
-        LLVMValueRef len_value = LLVMBuildNSWSub(g->builder, end_val, start_val, "");
-        gen_store_untyped(g, len_value, len_field_ptr, 0, false);
+            LLVMValueRef len_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, slice_len_index, "");
+            LLVMValueRef len_value = LLVMBuildNSWSub(g->builder, end_val, start_val, "");
+            gen_store_untyped(g, len_value, len_field_ptr, 0, false);
 
-        return tmp_struct_ptr;
+            return tmp_struct_ptr;
+        }
     } else if (array_type->id == ZigTypeIdPointer) {
         assert(array_type->data.pointer.ptr_len != PtrLenSingle);
         LLVMValueRef start_val = ir_llvm_value(g, instruction->start);
@@ -5493,24 +5505,39 @@ static LLVMValueRef ir_render_slice(CodeGen *g, IrExecutableGen *executable, IrI
             }
         }
 
-        if (type_has_bits(g, array_type)) {
-            size_t gen_ptr_index = instruction->base.value->type->data.structure.fields[slice_ptr_index]->gen_index;
-            LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, gen_ptr_index, "");
-            LLVMValueRef slice_start_ptr = LLVMBuildInBoundsGEP(g->builder, array_ptr, &start_val, 1, "");
-            gen_store_untyped(g, slice_start_ptr, ptr_field_ptr, 0, false);
+        if (!type_has_bits(g, array_type)) {
+            LLVMValueRef tmp_struct_ptr = ir_llvm_value(g, instruction->result_loc);
+            size_t gen_len_index = result_type->data.structure.fields[slice_len_index]->gen_index;
+            LLVMValueRef len_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, gen_len_index, "");
+            LLVMValueRef len_value = LLVMBuildNSWSub(g->builder, end_val, start_val, "");
+            gen_store_untyped(g, len_value, len_field_ptr, 0, false);
+            return tmp_struct_ptr;
+        }
+
+        LLVMValueRef slice_start_ptr = LLVMBuildInBoundsGEP(g->builder, array_ptr, &start_val, 1, "");
+        if (result_type->id == ZigTypeIdPointer) {
+            ir_assert(instruction->result_loc == nullptr, &instruction->base);
+            LLVMTypeRef result_ptr_type = get_llvm_type(g, result_type);
+            return LLVMBuildBitCast(g->builder, slice_start_ptr, result_ptr_type, "");
         }
 
-        size_t gen_len_index = instruction->base.value->type->data.structure.fields[slice_len_index]->gen_index;
+        LLVMValueRef tmp_struct_ptr = ir_llvm_value(g, instruction->result_loc);
+
+        size_t gen_ptr_index = result_type->data.structure.fields[slice_ptr_index]->gen_index;
+        LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, gen_ptr_index, "");
+        gen_store_untyped(g, slice_start_ptr, ptr_field_ptr, 0, false);
+
+        size_t gen_len_index = result_type->data.structure.fields[slice_len_index]->gen_index;
         LLVMValueRef len_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, gen_len_index, "");
         LLVMValueRef len_value = LLVMBuildNSWSub(g->builder, end_val, start_val, "");
         gen_store_untyped(g, len_value, len_field_ptr, 0, false);
 
         return tmp_struct_ptr;
+
     } else if (array_type->id == ZigTypeIdStruct) {
         assert(array_type->data.structure.special == StructSpecialSlice);
         assert(LLVMGetTypeKind(LLVMTypeOf(array_ptr)) == LLVMPointerTypeKind);
         assert(LLVMGetTypeKind(LLVMGetElementType(LLVMTypeOf(array_ptr))) == LLVMStructTypeKind);
-        assert(LLVMGetTypeKind(LLVMGetElementType(LLVMTypeOf(tmp_struct_ptr))) == LLVMStructTypeKind);
 
         size_t ptr_index = array_type->data.structure.fields[slice_ptr_index]->gen_index;
         assert(ptr_index != SIZE_MAX);
@@ -5547,15 +5574,22 @@ static LLVMValueRef ir_render_slice(CodeGen *g, IrExecutableGen *executable, IrI
             }
         }
 
-        LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, (unsigned)ptr_index, "");
         LLVMValueRef slice_start_ptr = LLVMBuildInBoundsGEP(g->builder, src_ptr, &start_val, 1, "");
-        gen_store_untyped(g, slice_start_ptr, ptr_field_ptr, 0, false);
+        if (result_type->id == ZigTypeIdPointer) {
+            ir_assert(instruction->result_loc == nullptr, &instruction->base);
+            LLVMTypeRef result_ptr_type = get_llvm_type(g, result_type);
+            return LLVMBuildBitCast(g->builder, slice_start_ptr, result_ptr_type, "");
+        } else {
+            LLVMValueRef tmp_struct_ptr = ir_llvm_value(g, instruction->result_loc);
+            LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, (unsigned)ptr_index, "");
+            gen_store_untyped(g, slice_start_ptr, ptr_field_ptr, 0, false);
 
-        LLVMValueRef len_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, (unsigned)len_index, "");
-        LLVMValueRef len_value = LLVMBuildNSWSub(g->builder, end_val, start_val, "");
-        gen_store_untyped(g, len_value, len_field_ptr, 0, false);
+            LLVMValueRef len_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, (unsigned)len_index, "");
+            LLVMValueRef len_value = LLVMBuildNSWSub(g->builder, end_val, start_val, "");
+            gen_store_untyped(g, len_value, len_field_ptr, 0, false);
 
-        return tmp_struct_ptr;
+            return tmp_struct_ptr;
+        }
     } else {
         zig_unreachable();
     }
@@ -6640,7 +6674,6 @@ static LLVMValueRef gen_const_ptr_array_recursive(CodeGen *g, ZigValue *array_co
         };
         return LLVMConstInBoundsGEP(base_ptr, indices, 2);
     } else {
-        assert(parent->id == ConstParentIdScalar);
         return base_ptr;
     }
 }
@@ -6868,6 +6901,7 @@ static LLVMValueRef gen_const_val_ptr(CodeGen *g, ZigValue *const_val, const cha
                 return const_val->llvm_value;
             }
         case ConstPtrSpecialBaseArray:
+        case ConstPtrSpecialSubArray:
             {
                 ZigValue *array_const_val = const_val->data.x_ptr.data.base_array.array_val;
                 assert(array_const_val->type->id == ZigTypeIdArray);
diff --git a/src/ir.cpp b/src/ir.cpp
index ef7574457613..b3b3198ce154 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -784,14 +784,32 @@ static ZigValue *const_ptr_pointee_unchecked_no_isf(CodeGen *g, ZigValue *const_
             break;
         case ConstPtrSpecialBaseArray: {
             ZigValue *array_val = const_val->data.x_ptr.data.base_array.array_val;
-            if (const_val->data.x_ptr.data.base_array.elem_index == array_val->type->data.array.len) {
+            size_t elem_index = const_val->data.x_ptr.data.base_array.elem_index;
+            if (elem_index == array_val->type->data.array.len) {
                 result = array_val->type->data.array.sentinel;
             } else {
                 expand_undef_array(g, array_val);
-                result = &array_val->data.x_array.data.s_none.elements[const_val->data.x_ptr.data.base_array.elem_index];
+                result = &array_val->data.x_array.data.s_none.elements[elem_index];
             }
             break;
         }
+        case ConstPtrSpecialSubArray: {
+            ZigValue *array_val = const_val->data.x_ptr.data.base_array.array_val;
+            size_t elem_index = const_val->data.x_ptr.data.base_array.elem_index;
+
+            // TODO handle sentinel terminated arrays
+            expand_undef_array(g, array_val);
+            result = g->pass1_arena->create<ZigValue>();
+            result->special = array_val->special;
+            result->type = get_array_type(g, array_val->type->data.array.child_type,
+                    array_val->type->data.array.len - elem_index, nullptr);
+            result->data.x_array.special = ConstArraySpecialNone;
+            result->data.x_array.data.s_none.elements = &array_val->data.x_array.data.s_none.elements[elem_index];
+            result->parent.id = ConstParentIdArray;
+            result->parent.data.p_array.array_val = array_val;
+            result->parent.data.p_array.elem_index = elem_index;
+            break;
+        }
         case ConstPtrSpecialBaseStruct: {
             ZigValue *struct_val = const_val->data.x_ptr.data.base_struct.struct_val;
             expand_undef_struct(g, struct_val);
@@ -849,11 +867,6 @@ static bool is_slice(ZigType *type) {
     return type->id == ZigTypeIdStruct && type->data.structure.special == StructSpecialSlice;
 }
 
-static bool slice_is_const(ZigType *type) {
-    assert(is_slice(type));
-    return type->data.structure.fields[slice_ptr_index]->type_entry->data.pointer.is_const;
-}
-
 // This function returns true when you can change the type of a ZigValue and the
 // value remains meaningful.
 static bool types_have_same_zig_comptime_repr(CodeGen *codegen, ZigType *expected, ZigType *actual) {
@@ -3719,7 +3732,8 @@ static IrInstSrc *ir_build_slice_src(IrBuilderSrc *irb, Scope *scope, AstNode *s
 }
 
 static IrInstGen *ir_build_slice_gen(IrAnalyze *ira, IrInst *source_instruction, ZigType *slice_type,
-    IrInstGen *ptr, IrInstGen *start, IrInstGen *end, bool safety_check_on, IrInstGen *result_loc)
+    IrInstGen *ptr, IrInstGen *start, IrInstGen *end, bool safety_check_on, IrInstGen *result_loc,
+    ZigValue *sentinel)
 {
     IrInstGenSlice *instruction = ir_build_inst_gen<IrInstGenSlice>(
             &ira->new_irb, source_instruction->scope, source_instruction->source_node);
@@ -3729,11 +3743,12 @@ static IrInstGen *ir_build_slice_gen(IrAnalyze *ira, IrInst *source_instruction,
     instruction->end = end;
     instruction->safety_check_on = safety_check_on;
     instruction->result_loc = result_loc;
+    instruction->sentinel = sentinel;
 
     ir_ref_inst_gen(ptr, ira->new_irb.current_basic_block);
     ir_ref_inst_gen(start, ira->new_irb.current_basic_block);
-    if (end) ir_ref_inst_gen(end, ira->new_irb.current_basic_block);
-    ir_ref_inst_gen(result_loc, ira->new_irb.current_basic_block);
+    if (end != nullptr) ir_ref_inst_gen(end, ira->new_irb.current_basic_block);
+    if (result_loc != nullptr) ir_ref_inst_gen(result_loc, ira->new_irb.current_basic_block);
 
     return &instruction->base;
 }
@@ -12677,41 +12692,80 @@ static IrInstGen *ir_resolve_ptr_of_array_to_slice(IrAnalyze *ira, IrInst* sourc
     Error err;
 
     assert(array_ptr->value->type->id == ZigTypeIdPointer);
+    assert(array_ptr->value->type->data.pointer.child_type->id == ZigTypeIdArray);
+
+    ZigType *array_type = array_ptr->value->type->data.pointer.child_type;
+    size_t array_len = array_type->data.array.len;
+
+    // A zero-sized array can be casted regardless of the destination alignment, or
+    // whether the pointer is undefined, and the result is always comptime known.
+    // TODO However, this is exposing a result location bug that I failed to solve on the first try.
+    // If you want to try to fix the bug, uncomment this block and get the tests passing.
+    //if (array_len == 0 && array_type->data.array.sentinel == nullptr) {
+    //    ZigValue *undef_array = ira->codegen->pass1_arena->create<ZigValue>();
+    //    undef_array->special = ConstValSpecialUndef;
+    //    undef_array->type = array_type;
+
+    //    IrInstGen *result = ir_const(ira, source_instr, wanted_type);
+    //    init_const_slice(ira->codegen, result->value, undef_array, 0, 0, false);
+    //    result->value->data.x_struct.fields[slice_ptr_index]->data.x_ptr.mut = ConstPtrMutComptimeConst;
+    //    result->value->type = wanted_type;
+    //    return result;
+    //}
 
     if ((err = type_resolve(ira->codegen, array_ptr->value->type, ResolveStatusAlignmentKnown))) {
         return ira->codegen->invalid_inst_gen;
     }
 
-    assert(array_ptr->value->type->data.pointer.child_type->id == ZigTypeIdArray);
-
-    const size_t array_len = array_ptr->value->type->data.pointer.child_type->data.array.len;
-
-    // A zero-sized array can always be casted irregardless of the destination
-    // alignment
     if (array_len != 0) {
         wanted_type = adjust_slice_align(ira->codegen, wanted_type,
             get_ptr_align(ira->codegen, array_ptr->value->type));
     }
 
     if (instr_is_comptime(array_ptr)) {
-        ZigValue *array_ptr_val = ir_resolve_const(ira, array_ptr, UndefBad);
+        UndefAllowed undef_allowed = (array_len == 0) ? UndefOk : UndefBad;
+        ZigValue *array_ptr_val = ir_resolve_const(ira, array_ptr, undef_allowed);
         if (array_ptr_val == nullptr)
             return ira->codegen->invalid_inst_gen;
-        ZigValue *pointee = const_ptr_pointee(ira, ira->codegen, array_ptr_val, source_instr->source_node);
-        if (pointee == nullptr)
-            return ira->codegen->invalid_inst_gen;
-        if (pointee->special != ConstValSpecialRuntime) {
-            assert(array_ptr_val->type->id == ZigTypeIdPointer);
-            ZigType *array_type = array_ptr_val->type->data.pointer.child_type;
-            assert(is_slice(wanted_type));
-            bool is_const = wanted_type->data.structure.fields[slice_ptr_index]->type_entry->data.pointer.is_const;
+        ir_assert(is_slice(wanted_type), source_instr);
+        if (array_ptr_val->special == ConstValSpecialUndef) {
+            ZigValue *undef_array = ira->codegen->pass1_arena->create<ZigValue>();
+            undef_array->special = ConstValSpecialUndef;
+            undef_array->type = array_type;
 
             IrInstGen *result = ir_const(ira, source_instr, wanted_type);
-            init_const_slice(ira->codegen, result->value, pointee, 0, array_type->data.array.len, is_const);
-            result->value->data.x_struct.fields[slice_ptr_index]->data.x_ptr.mut = array_ptr_val->data.x_ptr.mut;
+            init_const_slice(ira->codegen, result->value, undef_array, 0, 0, false);
+            result->value->data.x_struct.fields[slice_ptr_index]->data.x_ptr.mut = ConstPtrMutComptimeConst;
             result->value->type = wanted_type;
             return result;
         }
+        bool wanted_const = wanted_type->data.structure.fields[slice_ptr_index]->type_entry->data.pointer.is_const;
+        // Optimization to avoid creating unnecessary ZigValue in const_ptr_pointee
+        if (array_ptr_val->data.x_ptr.special == ConstPtrSpecialSubArray) {
+            ZigValue *array_val = array_ptr_val->data.x_ptr.data.base_array.array_val;
+            if (array_val->special != ConstValSpecialRuntime) {
+                IrInstGen *result = ir_const(ira, source_instr, wanted_type);
+                init_const_slice(ira->codegen, result->value, array_val,
+                        array_ptr_val->data.x_ptr.data.base_array.elem_index,
+                        array_type->data.array.len, wanted_const);
+                result->value->data.x_struct.fields[slice_ptr_index]->data.x_ptr.mut = array_ptr_val->data.x_ptr.mut;
+                result->value->type = wanted_type;
+                return result;
+            }
+        } else {
+            ZigValue *pointee = const_ptr_pointee(ira, ira->codegen, array_ptr_val, source_instr->source_node);
+            if (pointee == nullptr)
+                return ira->codegen->invalid_inst_gen;
+            if (pointee->special != ConstValSpecialRuntime) {
+                assert(array_ptr_val->type->id == ZigTypeIdPointer);
+
+                IrInstGen *result = ir_const(ira, source_instr, wanted_type);
+                init_const_slice(ira->codegen, result->value, pointee, 0, array_type->data.array.len, wanted_const);
+                result->value->data.x_struct.fields[slice_ptr_index]->data.x_ptr.mut = array_ptr_val->data.x_ptr.mut;
+                result->value->type = wanted_type;
+                return result;
+            }
+        }
     }
 
     if (result_loc == nullptr) result_loc = no_result_loc();
@@ -14581,7 +14635,7 @@ static IrInstGen *ir_analyze_cast(IrAnalyze *ira, IrInst *source_instr,
         return ir_analyze_widen_or_shorten(ira, source_instr, value, wanted_type);
     }
 
-    // *[N]T to ?[]const T
+    // *[N]T to ?[]T
     if (wanted_type->id == ZigTypeIdOptional &&
         is_slice(wanted_type->data.maybe.child_type) &&
         actual_type->id == ZigTypeIdPointer &&
@@ -19917,6 +19971,7 @@ static Error ir_read_const_ptr(IrAnalyze *ira, CodeGen *codegen, AstNode *source
         buf_write_value_bytes(codegen, (uint8_t*)buf_ptr(&buf), pointee);
         if ((err = buf_read_value_bytes(ira, codegen, source_node, (uint8_t*)buf_ptr(&buf), out_val)))
             return err;
+        buf_deinit(&buf);
         return ErrorNone;
     }
 
@@ -19936,6 +19991,31 @@ static Error ir_read_const_ptr(IrAnalyze *ira, CodeGen *codegen, AstNode *source
                 dst_size, buf_ptr(&pointee->type->name), src_size));
             return ErrorSemanticAnalyzeFail;
         }
+        case ConstPtrSpecialSubArray: {
+            ZigValue *array_val = ptr_val->data.x_ptr.data.base_array.array_val;
+            assert(array_val->type->id == ZigTypeIdArray);
+            if (array_val->data.x_array.special != ConstArraySpecialNone)
+                zig_panic("TODO");
+            if (dst_size > src_size) {
+                size_t elem_index = ptr_val->data.x_ptr.data.base_array.elem_index;
+                opt_ir_add_error_node(ira, codegen, source_node,
+                    buf_sprintf("attempt to read %" ZIG_PRI_usize " bytes from %s at index %" ZIG_PRI_usize " which is %" ZIG_PRI_usize " bytes",
+                        dst_size, buf_ptr(&array_val->type->name), elem_index, src_size));
+                return ErrorSemanticAnalyzeFail;
+            }
+            size_t elem_size = src_size;
+            size_t elem_count = (dst_size % elem_size == 0) ? (dst_size / elem_size) : (dst_size / elem_size + 1);
+            Buf buf = BUF_INIT;
+            buf_resize(&buf, elem_count * elem_size);
+            for (size_t i = 0; i < elem_count; i += 1) {
+                ZigValue *elem_val = &array_val->data.x_array.data.s_none.elements[i];
+                buf_write_value_bytes(codegen, (uint8_t*)buf_ptr(&buf) + (i * elem_size), elem_val);
+            }
+            if ((err = buf_read_value_bytes(ira, codegen, source_node, (uint8_t*)buf_ptr(&buf), out_val)))
+                return err;
+            buf_deinit(&buf);
+            return ErrorNone;
+        }
         case ConstPtrSpecialBaseArray: {
             ZigValue *array_val = ptr_val->data.x_ptr.data.base_array.array_val;
             assert(array_val->type->id == ZigTypeIdArray);
@@ -19959,6 +20039,7 @@ static Error ir_read_const_ptr(IrAnalyze *ira, CodeGen *codegen, AstNode *source
             }
             if ((err = buf_read_value_bytes(ira, codegen, source_node, (uint8_t*)buf_ptr(&buf), out_val)))
                 return err;
+            buf_deinit(&buf);
             return ErrorNone;
         }
         case ConstPtrSpecialBaseStruct:
@@ -20538,6 +20619,44 @@ static ZigType *adjust_ptr_allow_zero(CodeGen *g, ZigType *ptr_type, bool allow_
             allow_zero);
 }
 
+static Error compute_elem_align(IrAnalyze *ira, ZigType *elem_type, uint32_t base_ptr_align,
+        uint64_t elem_index, uint32_t *result)
+{
+    Error err;
+
+    if (base_ptr_align == 0) {
+        *result = 0;
+        return ErrorNone;
+    }
+
+    // figure out the largest alignment possible
+    if ((err = type_resolve(ira->codegen, elem_type, ResolveStatusSizeKnown)))
+        return err;
+
+    uint64_t elem_size = type_size(ira->codegen, elem_type);
+    uint64_t abi_align = get_abi_alignment(ira->codegen, elem_type);
+    uint64_t ptr_align = base_ptr_align;
+
+    uint64_t chosen_align = abi_align;
+    if (ptr_align >= abi_align) {
+        while (ptr_align > abi_align) {
+            if ((elem_index * elem_size) % ptr_align == 0) {
+                chosen_align = ptr_align;
+                break;
+            }
+            ptr_align >>= 1;
+        }
+    } else if (elem_size >= ptr_align && elem_size % ptr_align == 0) {
+        chosen_align = ptr_align;
+    } else {
+        // can't get here because guaranteed elem_size >= abi_align
+        zig_unreachable();
+    }
+
+    *result = chosen_align;
+    return ErrorNone;
+}
+
 static IrInstGen *ir_analyze_instruction_elem_ptr(IrAnalyze *ira, IrInstSrcElemPtr *elem_ptr_instruction) {
     Error err;
     IrInstGen *array_ptr = elem_ptr_instruction->array_ptr->child;
@@ -20676,29 +20795,11 @@ static IrInstGen *ir_analyze_instruction_elem_ptr(IrAnalyze *ira, IrInstSrcElemP
                 get_ptr_align(ira->codegen, ptr_type), 0, host_vec_len, false, (uint32_t)index,
                 nullptr, nullptr);
         } else if (return_type->data.pointer.explicit_alignment != 0) {
-            // figure out the largest alignment possible
-
-            if ((err = type_resolve(ira->codegen, return_type->data.pointer.child_type, ResolveStatusSizeKnown)))
+            uint32_t chosen_align;
+            if ((err = compute_elem_align(ira, return_type->data.pointer.child_type, 
+                return_type->data.pointer.explicit_alignment, index, &chosen_align)))
+            {
                 return ira->codegen->invalid_inst_gen;
-
-            uint64_t elem_size = type_size(ira->codegen, return_type->data.pointer.child_type);
-            uint64_t abi_align = get_abi_alignment(ira->codegen, return_type->data.pointer.child_type);
-            uint64_t ptr_align = get_ptr_align(ira->codegen, return_type);
-
-            uint64_t chosen_align = abi_align;
-            if (ptr_align >= abi_align) {
-                while (ptr_align > abi_align) {
-                    if ((index * elem_size) % ptr_align == 0) {
-                        chosen_align = ptr_align;
-                        break;
-                    }
-                    ptr_align >>= 1;
-                }
-            } else if (elem_size >= ptr_align && elem_size % ptr_align == 0) {
-                chosen_align = ptr_align;
-            } else {
-                // can't get here because guaranteed elem_size >= abi_align
-                zig_unreachable();
             }
             return_type = adjust_ptr_align(ira->codegen, return_type, chosen_align);
         }
@@ -20819,6 +20920,7 @@ static IrInstGen *ir_analyze_instruction_elem_ptr(IrAnalyze *ira, IrInstSrcElemP
                             }
                             break;
                         case ConstPtrSpecialBaseArray:
+                        case ConstPtrSpecialSubArray:
                             {
                                 size_t offset = array_ptr_val->data.x_ptr.data.base_array.elem_index;
                                 new_index = offset + index;
@@ -20889,6 +20991,7 @@ static IrInstGen *ir_analyze_instruction_elem_ptr(IrAnalyze *ira, IrInstSrcElemP
                             out_val->data.x_ptr.special = ConstPtrSpecialRef;
                             out_val->data.x_ptr.data.ref.pointee = ptr_field->data.x_ptr.data.ref.pointee;
                             break;
+                        case ConstPtrSpecialSubArray:
                         case ConstPtrSpecialBaseArray:
                             {
                                 size_t offset = ptr_field->data.x_ptr.data.base_array.elem_index;
@@ -25440,11 +25543,22 @@ static IrInstGen *ir_analyze_instruction_err_set_cast(IrAnalyze *ira, IrInstSrcE
 static Error resolve_ptr_align(IrAnalyze *ira, ZigType *ty, uint32_t *result_align) {
     Error err;
 
-    ZigType *ptr_type = get_src_ptr_type(ty);
+    ZigType *ptr_type;
+    if (is_slice(ty)) {
+        TypeStructField *ptr_field = ty->data.structure.fields[slice_ptr_index];
+        ptr_type = resolve_struct_field_type(ira->codegen, ptr_field);
+    } else {
+        ptr_type = get_src_ptr_type(ty);
+    }
     assert(ptr_type != nullptr);
     if (ptr_type->id == ZigTypeIdPointer) {
         if ((err = type_resolve(ira->codegen, ptr_type->data.pointer.child_type, ResolveStatusAlignmentKnown)))
             return err;
+    } else if (is_slice(ptr_type)) {
+        TypeStructField *ptr_field = ptr_type->data.structure.fields[slice_ptr_index];
+        ZigType *slice_ptr_type = resolve_struct_field_type(ira->codegen, ptr_field);
+        if ((err = type_resolve(ira->codegen, slice_ptr_type->data.pointer.child_type, ResolveStatusAlignmentKnown)))
+            return err;
     }
 
     *result_align = get_ptr_align(ira->codegen, ty);
@@ -25899,6 +26013,7 @@ static IrInstGen *ir_analyze_instruction_memset(IrAnalyze *ira, IrInstSrcMemset
                     start = 0;
                     bound_end = 1;
                     break;
+                case ConstPtrSpecialSubArray:
                 case ConstPtrSpecialBaseArray:
                     {
                         ZigValue *array_val = dest_ptr_val->data.x_ptr.data.base_array.array_val;
@@ -26032,6 +26147,7 @@ static IrInstGen *ir_analyze_instruction_memcpy(IrAnalyze *ira, IrInstSrcMemcpy
                     dest_start = 0;
                     dest_end = 1;
                     break;
+                case ConstPtrSpecialSubArray:
                 case ConstPtrSpecialBaseArray:
                     {
                         ZigValue *array_val = dest_ptr_val->data.x_ptr.data.base_array.array_val;
@@ -26075,6 +26191,7 @@ static IrInstGen *ir_analyze_instruction_memcpy(IrAnalyze *ira, IrInstSrcMemcpy
                     src_start = 0;
                     src_end = 1;
                     break;
+                case ConstPtrSpecialSubArray:
                 case ConstPtrSpecialBaseArray:
                     {
                         ZigValue *array_val = src_ptr_val->data.x_ptr.data.base_array.array_val;
@@ -26118,7 +26235,19 @@ static IrInstGen *ir_analyze_instruction_memcpy(IrAnalyze *ira, IrInstSrcMemcpy
     return ir_build_memcpy_gen(ira, &instruction->base.base, casted_dest_ptr, casted_src_ptr, casted_count);
 }
 
+static ZigType *get_result_loc_type(IrAnalyze *ira, ResultLoc *result_loc) {
+    if (result_loc == nullptr) return nullptr;
+
+    if (result_loc->id == ResultLocIdCast) {
+        return ir_resolve_type(ira, result_loc->source_instruction->child);
+    }
+
+    return nullptr;
+}
+
 static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *instruction) {
+    Error err;
+
     IrInstGen *ptr_ptr = instruction->ptr->child;
     if (type_is_invalid(ptr_ptr->value->type))
         return ira->codegen->invalid_inst_gen;
@@ -26148,6 +26277,7 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
         end = nullptr;
     }
 
+    ZigValue *slice_sentinel_val = nullptr;
     ZigType *non_sentinel_slice_ptr_type;
     ZigType *elem_type;
 
@@ -26198,6 +26328,7 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
         }
     } else if (is_slice(array_type)) {
         ZigType *maybe_sentineled_slice_ptr_type = array_type->data.structure.fields[slice_ptr_index]->type_entry;
+        slice_sentinel_val = maybe_sentineled_slice_ptr_type->data.pointer.sentinel;
         non_sentinel_slice_ptr_type = adjust_ptr_sentinel(ira->codegen, maybe_sentineled_slice_ptr_type, nullptr);
         elem_type = non_sentinel_slice_ptr_type->data.pointer.child_type;
     } else {
@@ -26206,7 +26337,6 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
         return ira->codegen->invalid_inst_gen;
     }
 
-    ZigType *return_type;
     ZigValue *sentinel_val = nullptr;
     if (instruction->sentinel) {
         IrInstGen *uncasted_sentinel = instruction->sentinel->child;
@@ -26218,11 +26348,76 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
         sentinel_val = ir_resolve_const(ira, sentinel, UndefBad);
         if (sentinel_val == nullptr)
             return ira->codegen->invalid_inst_gen;
-        ZigType *slice_ptr_type = adjust_ptr_sentinel(ira->codegen, non_sentinel_slice_ptr_type, sentinel_val);
+    }
+
+    ZigType *child_array_type = (array_type->id == ZigTypeIdPointer &&
+            array_type->data.pointer.ptr_len == PtrLenSingle) ? array_type->data.pointer.child_type : array_type;
+
+    ZigType *return_type;
+
+    // If start index and end index are both comptime known, then the result type is a pointer to array
+    // not a slice. However, if the start or end index is a lazy value, and the result location is a slice,
+    // then the pointer-to-array would be casted to a slice anyway. So, we preserve the laziness of these
+    // values by making the return type a slice.
+    ZigType *res_loc_type = get_result_loc_type(ira, instruction->result_loc);
+    bool result_loc_is_slice = (res_loc_type != nullptr && is_slice(res_loc_type));
+    bool end_is_known = !result_loc_is_slice &&
+        ((end != nullptr && value_is_comptime(end->value)) ||
+         (end == nullptr && child_array_type->id == ZigTypeIdArray));
+
+    ZigValue *array_sentinel = sentinel_val;
+    if (end_is_known) {
+        uint64_t end_scalar;
+        if (end != nullptr) {
+            ZigValue *end_val = ir_resolve_const(ira, end, UndefBad);
+            if (!end_val)
+                return ira->codegen->invalid_inst_gen;
+            end_scalar = bigint_as_u64(&end_val->data.x_bigint);
+        } else {
+            end_scalar = child_array_type->data.array.len;
+        }
+        array_sentinel = (child_array_type->id == ZigTypeIdArray && end_scalar == child_array_type->data.array.len)
+            ? child_array_type->data.array.sentinel : sentinel_val;
+
+        if (value_is_comptime(casted_start->value)) {
+            ZigValue *start_val = ir_resolve_const(ira, casted_start, UndefBad);
+            if (!start_val)
+                return ira->codegen->invalid_inst_gen;
+
+            uint64_t start_scalar = bigint_as_u64(&start_val->data.x_bigint);
+
+            if (start_scalar > end_scalar) {
+                ir_add_error(ira, &instruction->base.base, buf_sprintf("out of bounds slice"));
+                return ira->codegen->invalid_inst_gen;
+            }
+
+            uint32_t base_ptr_align = non_sentinel_slice_ptr_type->data.pointer.explicit_alignment;
+            uint32_t ptr_byte_alignment = 0;
+            if (end_scalar > start_scalar) {
+                if ((err = compute_elem_align(ira, elem_type, base_ptr_align, start_scalar, &ptr_byte_alignment)))
+                    return ira->codegen->invalid_inst_gen;
+            }
+
+            ZigType *return_array_type = get_array_type(ira->codegen, elem_type, end_scalar - start_scalar,
+                    array_sentinel);
+            return_type = get_pointer_to_type_extra(ira->codegen, return_array_type,
+                    non_sentinel_slice_ptr_type->data.pointer.is_const,
+                    non_sentinel_slice_ptr_type->data.pointer.is_volatile,
+                    PtrLenSingle, ptr_byte_alignment, 0, 0, false);
+            goto done_with_return_type;
+        }
+    } else if (array_sentinel == nullptr && end == nullptr) {
+        array_sentinel = slice_sentinel_val;
+    }
+    if (array_sentinel != nullptr) {
+        // TODO deal with non-abi-alignment here
+        ZigType *slice_ptr_type = adjust_ptr_sentinel(ira->codegen, non_sentinel_slice_ptr_type, array_sentinel);
         return_type = get_slice_type(ira->codegen, slice_ptr_type);
     } else {
+        // TODO deal with non-abi-alignment here
         return_type = get_slice_type(ira->codegen, non_sentinel_slice_ptr_type);
     }
+done_with_return_type:
 
     if (instr_is_comptime(ptr_ptr) &&
         value_is_comptime(casted_start->value) &&
@@ -26233,12 +26428,8 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
         size_t abs_offset;
         size_t rel_end;
         bool ptr_is_undef = false;
-        if (array_type->id == ZigTypeIdArray ||
-            (array_type->id == ZigTypeIdPointer && array_type->data.pointer.ptr_len == PtrLenSingle))
-        {
+        if (child_array_type->id == ZigTypeIdArray) {
             if (array_type->id == ZigTypeIdPointer) {
-                ZigType *child_array_type = array_type->data.pointer.child_type;
-                assert(child_array_type->id == ZigTypeIdArray);
                 parent_ptr = const_ptr_pointee(ira, ira->codegen, ptr_ptr->value, instruction->base.base.source_node);
                 if (parent_ptr == nullptr)
                     return ira->codegen->invalid_inst_gen;
@@ -26249,6 +26440,10 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
                     abs_offset = 0;
                     rel_end = SIZE_MAX;
                     ptr_is_undef = true;
+                } else if (parent_ptr->data.x_ptr.special == ConstPtrSpecialHardCodedAddr) {
+                    array_val = nullptr;
+                    abs_offset = 0;
+                    rel_end = SIZE_MAX;
                 } else {
                     array_val = const_ptr_pointee(ira, ira->codegen, parent_ptr, instruction->base.base.source_node);
                     if (array_val == nullptr)
@@ -26291,6 +26486,7 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
                         rel_end = 1;
                     }
                     break;
+                case ConstPtrSpecialSubArray:
                 case ConstPtrSpecialBaseArray:
                     array_val = parent_ptr->data.x_ptr.data.base_array.array_val;
                     abs_offset = parent_ptr->data.x_ptr.data.base_array.elem_index;
@@ -26341,6 +26537,7 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
                     abs_offset = SIZE_MAX;
                     rel_end = 1;
                     break;
+                case ConstPtrSpecialSubArray:
                 case ConstPtrSpecialBaseArray:
                     array_val = parent_ptr->data.x_ptr.data.base_array.array_val;
                     abs_offset = parent_ptr->data.x_ptr.data.base_array.elem_index;
@@ -26401,15 +26598,28 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
         }
 
         IrInstGen *result = ir_const(ira, &instruction->base.base, return_type);
-        ZigValue *out_val = result->value;
-        out_val->data.x_struct.fields = alloc_const_vals_ptrs(ira->codegen, 2);
 
-        ZigValue *ptr_val = out_val->data.x_struct.fields[slice_ptr_index];
+        ZigValue *ptr_val;
+        if (return_type->id == ZigTypeIdPointer) {
+            // pointer to array
+            ptr_val = result->value;
+        } else {
+            // slice
+            result->value->data.x_struct.fields = alloc_const_vals_ptrs(ira->codegen, 2);
+
+            ptr_val = result->value->data.x_struct.fields[slice_ptr_index];
+
+            ZigValue *len_val = result->value->data.x_struct.fields[slice_len_index];
+            init_const_usize(ira->codegen, len_val, end_scalar - start_scalar);
+        }
 
+        bool return_type_is_const = non_sentinel_slice_ptr_type->data.pointer.is_const;
         if (array_val) {
             size_t index = abs_offset + start_scalar;
-            bool is_const = slice_is_const(return_type);
-            init_const_ptr_array(ira->codegen, ptr_val, array_val, index, is_const, PtrLenUnknown);
+            init_const_ptr_array(ira->codegen, ptr_val, array_val, index, return_type_is_const, PtrLenUnknown);
+            if (return_type->id == ZigTypeIdPointer) {
+                ptr_val->data.x_ptr.special = ConstPtrSpecialSubArray;
+            }
             if (array_type->id == ZigTypeIdArray) {
                 ptr_val->data.x_ptr.mut = ptr_ptr->value->data.x_ptr.mut;
             } else if (is_slice(array_type)) {
@@ -26419,16 +26629,17 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
             }
         } else if (ptr_is_undef) {
             ptr_val->type = get_pointer_to_type(ira->codegen, parent_ptr->type->data.pointer.child_type,
-                    slice_is_const(return_type));
+                return_type_is_const);
             ptr_val->special = ConstValSpecialUndef;
         } else switch (parent_ptr->data.x_ptr.special) {
             case ConstPtrSpecialInvalid:
             case ConstPtrSpecialDiscard:
                 zig_unreachable();
             case ConstPtrSpecialRef:
-                init_const_ptr_ref(ira->codegen, ptr_val,
-                        parent_ptr->data.x_ptr.data.ref.pointee, slice_is_const(return_type));
+                init_const_ptr_ref(ira->codegen, ptr_val, parent_ptr->data.x_ptr.data.ref.pointee,
+                        return_type_is_const);
                 break;
+            case ConstPtrSpecialSubArray:
             case ConstPtrSpecialBaseArray:
                 zig_unreachable();
             case ConstPtrSpecialBaseStruct:
@@ -26443,7 +26654,7 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
                 init_const_ptr_hard_coded_addr(ira->codegen, ptr_val,
                     parent_ptr->type->data.pointer.child_type,
                     parent_ptr->data.x_ptr.data.hard_coded_addr.addr + start_scalar,
-                    slice_is_const(return_type));
+                    return_type_is_const);
                 break;
             case ConstPtrSpecialFunction:
                 zig_panic("TODO");
@@ -26451,26 +26662,11 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
                 zig_panic("TODO");
         }
 
-        ZigValue *len_val = out_val->data.x_struct.fields[slice_len_index];
-        init_const_usize(ira->codegen, len_val, end_scalar - start_scalar);
-
+        // In the case of pointer-to-array, we must restore this because above it overwrites ptr_val->type
+        result->value->type = return_type;
         return result;
     }
 
-    IrInstGen *result_loc = ir_resolve_result(ira, &instruction->base.base, instruction->result_loc,
-            return_type, nullptr, true, true);
-    if (result_loc != nullptr) {
-        if (type_is_invalid(result_loc->value->type) || result_loc->value->type->id == ZigTypeIdUnreachable) {
-            return result_loc;
-        }
-        IrInstGen *dummy_value = ir_const(ira, &instruction->base.base, return_type);
-        dummy_value->value->special = ConstValSpecialRuntime;
-        IrInstGen *dummy_result = ir_implicit_cast2(ira, &instruction->base.base,
-                dummy_value, result_loc->value->type->data.pointer.child_type);
-        if (type_is_invalid(dummy_result->value->type))
-            return ira->codegen->invalid_inst_gen;
-    }
-
     if (generate_non_null_assert) {
         IrInstGen *ptr_val = ir_get_deref(ira, &instruction->base.base, ptr_ptr, nullptr);
 
@@ -26480,8 +26676,26 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
         ir_build_assert_non_null(ira, &instruction->base.base, ptr_val);
     }
 
+    IrInstGen *result_loc = nullptr;
+
+    if (return_type->id != ZigTypeIdPointer) {
+        result_loc = ir_resolve_result(ira, &instruction->base.base, instruction->result_loc,
+                return_type, nullptr, true, true);
+        if (result_loc != nullptr) {
+            if (type_is_invalid(result_loc->value->type) || result_loc->value->type->id == ZigTypeIdUnreachable) {
+                return result_loc;
+            }
+            IrInstGen *dummy_value = ir_const(ira, &instruction->base.base, return_type);
+            dummy_value->value->special = ConstValSpecialRuntime;
+            IrInstGen *dummy_result = ir_implicit_cast2(ira, &instruction->base.base,
+                    dummy_value, result_loc->value->type->data.pointer.child_type);
+            if (type_is_invalid(dummy_result->value->type))
+                return ira->codegen->invalid_inst_gen;
+        }
+    }
+
     return ir_build_slice_gen(ira, &instruction->base.base, return_type, ptr_ptr,
-            casted_start, end, instruction->safety_check_on, result_loc);
+            casted_start, end, instruction->safety_check_on, result_loc, sentinel_val);
 }
 
 static IrInstGen *ir_analyze_instruction_has_field(IrAnalyze *ira, IrInstSrcHasField *instruction) {
@@ -27507,10 +27721,18 @@ static IrInstGen *ir_analyze_ptr_cast(IrAnalyze *ira, IrInst* source_instr, IrIn
     // We have a check for zero bits later so we use get_src_ptr_type to
     // validate src_type and dest_type.
 
-    ZigType *src_ptr_type = get_src_ptr_type(src_type);
-    if (src_ptr_type == nullptr) {
-        ir_add_error(ira, ptr_src, buf_sprintf("expected pointer, found '%s'", buf_ptr(&src_type->name)));
-        return ira->codegen->invalid_inst_gen;
+    ZigType *if_slice_ptr_type;
+    if (is_slice(src_type)) {
+        TypeStructField *ptr_field = src_type->data.structure.fields[slice_ptr_index];
+        if_slice_ptr_type = resolve_struct_field_type(ira->codegen, ptr_field);
+    } else {
+        if_slice_ptr_type = src_type;
+
+        ZigType *src_ptr_type = get_src_ptr_type(src_type);
+        if (src_ptr_type == nullptr) {
+            ir_add_error(ira, ptr_src, buf_sprintf("expected pointer, found '%s'", buf_ptr(&src_type->name)));
+            return ira->codegen->invalid_inst_gen;
+        }
     }
 
     ZigType *dest_ptr_type = get_src_ptr_type(dest_type);
@@ -27520,7 +27742,7 @@ static IrInstGen *ir_analyze_ptr_cast(IrAnalyze *ira, IrInst* source_instr, IrIn
         return ira->codegen->invalid_inst_gen;
     }
 
-    if (get_ptr_const(src_type) && !get_ptr_const(dest_type)) {
+    if (get_ptr_const(ira->codegen, src_type) && !get_ptr_const(ira->codegen, dest_type)) {
         ir_add_error(ira, source_instr, buf_sprintf("cast discards const qualifier"));
         return ira->codegen->invalid_inst_gen;
     }
@@ -27538,7 +27760,10 @@ static IrInstGen *ir_analyze_ptr_cast(IrAnalyze *ira, IrInst* source_instr, IrIn
     if ((err = type_resolve(ira->codegen, src_type, ResolveStatusZeroBitsKnown)))
         return ira->codegen->invalid_inst_gen;
 
-    if (type_has_bits(ira->codegen, dest_type) && !type_has_bits(ira->codegen, src_type) && safety_check_on) {
+    if (safety_check_on &&
+        type_has_bits(ira->codegen, dest_type) &&
+        !type_has_bits(ira->codegen, if_slice_ptr_type))
+    {
         ErrorMsg *msg = ir_add_error(ira, source_instr,
             buf_sprintf("'%s' and '%s' do not have the same in-memory representation",
                 buf_ptr(&src_type->name), buf_ptr(&dest_type->name)));
@@ -27549,6 +27774,14 @@ static IrInstGen *ir_analyze_ptr_cast(IrAnalyze *ira, IrInst* source_instr, IrIn
         return ira->codegen->invalid_inst_gen;
     }
 
+    // For slices, follow the `ptr` field.
+    if (is_slice(src_type)) {
+        TypeStructField *ptr_field = src_type->data.structure.fields[slice_ptr_index];
+        IrInstGen *ptr_ref = ir_get_ref(ira, source_instr, ptr, true, false);
+        IrInstGen *ptr_ptr = ir_analyze_struct_field_ptr(ira, source_instr, ptr_field, ptr_ref, src_type, false);
+        ptr = ir_get_deref(ira, source_instr, ptr_ptr, nullptr);
+    }
+
     if (instr_is_comptime(ptr)) {
         bool dest_allows_addr_zero = ptr_allows_addr_zero(dest_type);
         UndefAllowed is_undef_allowed = dest_allows_addr_zero ? UndefOk : UndefBad;
diff --git a/test/compare_output.zig b/test/compare_output.zig
index 1a0179c4c22d..46c475e04609 100644
--- a/test/compare_output.zig
+++ b/test/compare_output.zig
@@ -292,7 +292,7 @@ pub fn addCases(cases: *tests.CompareOutputContext) void {
         \\pub export fn main() c_int {
         \\    var array = [_]u32{ 1, 7, 3, 2, 0, 9, 4, 8, 6, 5 };
         \\
-        \\    c.qsort(@ptrCast(?*c_void, array[0..].ptr), @intCast(c_ulong, array.len), @sizeOf(i32), compare_fn);
+        \\    c.qsort(@ptrCast(?*c_void, &array), @intCast(c_ulong, array.len), @sizeOf(i32), compare_fn);
         \\
         \\    for (array) |item, i| {
         \\        if (item != i) {
diff --git a/test/compile_errors.zig b/test/compile_errors.zig
index f894a152a74b..e3e14621738c 100644
--- a/test/compile_errors.zig
+++ b/test/compile_errors.zig
@@ -103,18 +103,6 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         "tmp.zig:3:23: error: pointer to size 0 type has no address",
     });
 
-    cases.addTest("slice to pointer conversion mismatch",
-        \\pub fn bytesAsSlice(bytes: var) [*]align(1) const u16 {
-        \\    return @ptrCast([*]align(1) const u16, bytes.ptr)[0..1];
-        \\}
-        \\test "bytesAsSlice" {
-        \\    const bytes = [_]u8{ 0xDE, 0xAD, 0xBE, 0xEF };
-        \\    const slice = bytesAsSlice(bytes[0..]);
-        \\}
-    , &[_][]const u8{
-        "tmp.zig:2:54: error: expected type '[*]align(1) const u16', found '[]align(1) const u16'",
-    });
-
     cases.addTest("access invalid @typeInfo decl",
         \\const A = B;
         \\test "Crash" {
@@ -1918,8 +1906,8 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
     cases.add("reading past end of pointer casted array",
         \\comptime {
         \\    const array: [4]u8 = "aoeu".*;
-        \\    const slice = array[1..];
-        \\    const int_ptr = @ptrCast(*const u24, slice.ptr);
+        \\    const sub_array = array[1..];
+        \\    const int_ptr = @ptrCast(*const u24, sub_array);
         \\    const deref = int_ptr.*;
         \\}
     , &[_][]const u8{
diff --git a/test/runtime_safety.zig b/test/runtime_safety.zig
index 5047bfd0d0b6..b8ab47ddac99 100644
--- a/test/runtime_safety.zig
+++ b/test/runtime_safety.zig
@@ -69,7 +69,7 @@ pub fn addCases(cases: *tests.CompareOutputContext) void {
         \\}
         \\pub fn main() void {
         \\    var buf: [4]u8 = undefined;
-        \\    const ptr = buf[0..].ptr;
+        \\    const ptr: [*]u8 = &buf;
         \\    const slice = ptr[0..3 :0];
         \\}
     );
diff --git a/test/stage1/behavior/align.zig b/test/stage1/behavior/align.zig
index 5a5138d567a1..e9b7e0f1d689 100644
--- a/test/stage1/behavior/align.zig
+++ b/test/stage1/behavior/align.zig
@@ -5,10 +5,17 @@ const builtin = @import("builtin");
 var foo: u8 align(4) = 100;
 
 test "global variable alignment" {
-    expect(@TypeOf(&foo).alignment == 4);
-    expect(@TypeOf(&foo) == *align(4) u8);
-    const slice = @as(*[1]u8, &foo)[0..];
-    expect(@TypeOf(slice) == []align(4) u8);
+    comptime expect(@TypeOf(&foo).alignment == 4);
+    comptime expect(@TypeOf(&foo) == *align(4) u8);
+    {
+        const slice = @as(*[1]u8, &foo)[0..];
+        comptime expect(@TypeOf(slice) == *align(4) [1]u8);
+    }
+    {
+        var runtime_zero: usize = 0;
+        const slice = @as(*[1]u8, &foo)[runtime_zero..];
+        comptime expect(@TypeOf(slice) == []align(4) u8);
+    }
 }
 
 fn derp() align(@sizeOf(usize) * 2) i32 {
@@ -171,18 +178,19 @@ test "runtime known array index has best alignment possible" {
 
     // because pointer is align 2 and u32 align % 2 == 0 we can assume align 2
     var smaller align(2) = [_]u32{ 1, 2, 3, 4 };
-    comptime expect(@TypeOf(smaller[0..]) == []align(2) u32);
-    comptime expect(@TypeOf(smaller[0..].ptr) == [*]align(2) u32);
-    testIndex(smaller[0..].ptr, 0, *align(2) u32);
-    testIndex(smaller[0..].ptr, 1, *align(2) u32);
-    testIndex(smaller[0..].ptr, 2, *align(2) u32);
-    testIndex(smaller[0..].ptr, 3, *align(2) u32);
+    var runtime_zero: usize = 0;
+    comptime expect(@TypeOf(smaller[runtime_zero..]) == []align(2) u32);
+    comptime expect(@TypeOf(smaller[runtime_zero..].ptr) == [*]align(2) u32);
+    testIndex(smaller[runtime_zero..].ptr, 0, *align(2) u32);
+    testIndex(smaller[runtime_zero..].ptr, 1, *align(2) u32);
+    testIndex(smaller[runtime_zero..].ptr, 2, *align(2) u32);
+    testIndex(smaller[runtime_zero..].ptr, 3, *align(2) u32);
 
     // has to use ABI alignment because index known at runtime only
-    testIndex2(array[0..].ptr, 0, *u8);
-    testIndex2(array[0..].ptr, 1, *u8);
-    testIndex2(array[0..].ptr, 2, *u8);
-    testIndex2(array[0..].ptr, 3, *u8);
+    testIndex2(array[runtime_zero..].ptr, 0, *u8);
+    testIndex2(array[runtime_zero..].ptr, 1, *u8);
+    testIndex2(array[runtime_zero..].ptr, 2, *u8);
+    testIndex2(array[runtime_zero..].ptr, 3, *u8);
 }
 fn testIndex(smaller: [*]align(2) u32, index: usize, comptime T: type) void {
     comptime expect(@TypeOf(&smaller[index]) == T);
diff --git a/test/stage1/behavior/cast.zig b/test/stage1/behavior/cast.zig
index 0304ddfa9cc7..f1936069f1b8 100644
--- a/test/stage1/behavior/cast.zig
+++ b/test/stage1/behavior/cast.zig
@@ -435,7 +435,8 @@ fn incrementVoidPtrValue(value: ?*c_void) void {
 
 test "implicit cast from [*]T to ?*c_void" {
     var a = [_]u8{ 3, 2, 1 };
-    incrementVoidPtrArray(a[0..].ptr, 3);
+    var runtime_zero: usize = 0;
+    incrementVoidPtrArray(a[runtime_zero..].ptr, 3);
     expect(std.mem.eql(u8, &a, &[_]u8{ 4, 3, 2 }));
 }
 
diff --git a/test/stage1/behavior/eval.zig b/test/stage1/behavior/eval.zig
index 55ace6198cdb..2af34eaf7e10 100644
--- a/test/stage1/behavior/eval.zig
+++ b/test/stage1/behavior/eval.zig
@@ -524,7 +524,7 @@ test "comptime slice of slice preserves comptime var" {
 test "comptime slice of pointer preserves comptime var" {
     comptime {
         var buff: [10]u8 = undefined;
-        var a = buff[0..].ptr;
+        var a = @ptrCast([*]u8, &buff);
         a[0..1][0] = 1;
         expect(buff[0..][0..][0] == 1);
     }
diff --git a/test/stage1/behavior/misc.zig b/test/stage1/behavior/misc.zig
index 44a8334b5d04..51ee6f3a4f55 100644
--- a/test/stage1/behavior/misc.zig
+++ b/test/stage1/behavior/misc.zig
@@ -102,8 +102,8 @@ test "memcpy and memset intrinsics" {
     var foo: [20]u8 = undefined;
     var bar: [20]u8 = undefined;
 
-    @memset(foo[0..].ptr, 'A', foo.len);
-    @memcpy(bar[0..].ptr, foo[0..].ptr, bar.len);
+    @memset(&foo, 'A', foo.len);
+    @memcpy(&bar, &foo, bar.len);
 
     if (bar[11] != 'A') unreachable;
 }
@@ -565,12 +565,16 @@ test "volatile load and store" {
     expect(ptr.* == 1235);
 }
 
-test "slice string literal has type []const u8" {
+test "slice string literal has correct type" {
     comptime {
-        expect(@TypeOf("aoeu"[0..]) == []const u8);
+        expect(@TypeOf("aoeu"[0..]) == *const [4:0]u8);
         const array = [_]i32{ 1, 2, 3, 4 };
-        expect(@TypeOf(array[0..]) == []const i32);
+        expect(@TypeOf(array[0..]) == *const [4]i32);
     }
+    var runtime_zero: usize = 0;
+    comptime expect(@TypeOf("aoeu"[runtime_zero..]) == [:0]const u8);
+    const array = [_]i32{ 1, 2, 3, 4 };
+    comptime expect(@TypeOf(array[runtime_zero..]) == []const i32);
 }
 
 test "pointer child field" {
diff --git a/test/stage1/behavior/pointers.zig b/test/stage1/behavior/pointers.zig
index bcc1d62df36d..fbce9731f0df 100644
--- a/test/stage1/behavior/pointers.zig
+++ b/test/stage1/behavior/pointers.zig
@@ -159,12 +159,13 @@ test "allowzero pointer and slice" {
     var opt_ptr: ?[*]allowzero i32 = ptr;
     expect(opt_ptr != null);
     expect(@ptrToInt(ptr) == 0);
-    var slice = ptr[0..10];
-    expect(@TypeOf(slice) == []allowzero i32);
+    var runtime_zero: usize = 0;
+    var slice = ptr[runtime_zero..10];
+    comptime expect(@TypeOf(slice) == []allowzero i32);
     expect(@ptrToInt(&slice[5]) == 20);
 
-    expect(@typeInfo(@TypeOf(ptr)).Pointer.is_allowzero);
-    expect(@typeInfo(@TypeOf(slice)).Pointer.is_allowzero);
+    comptime expect(@typeInfo(@TypeOf(ptr)).Pointer.is_allowzero);
+    comptime expect(@typeInfo(@TypeOf(slice)).Pointer.is_allowzero);
 }
 
 test "assign null directly to C pointer and test null equality" {
diff --git a/test/stage1/behavior/ptrcast.zig b/test/stage1/behavior/ptrcast.zig
index 1c1cf251a004..3925325e619b 100644
--- a/test/stage1/behavior/ptrcast.zig
+++ b/test/stage1/behavior/ptrcast.zig
@@ -13,7 +13,7 @@ fn testReinterpretBytesAsInteger() void {
         builtin.Endian.Little => 0xab785634,
         builtin.Endian.Big => 0x345678ab,
     };
-    expect(@ptrCast(*align(1) const u32, bytes[1..5].ptr).* == expected);
+    expect(@ptrCast(*align(1) const u32, bytes[1..5]).* == expected);
 }
 
 test "reinterpret bytes of an array into an extern struct" {
diff --git a/test/stage1/behavior/slice.zig b/test/stage1/behavior/slice.zig
index 9dd57f474e67..d58132cb08a2 100644
--- a/test/stage1/behavior/slice.zig
+++ b/test/stage1/behavior/slice.zig
@@ -7,10 +7,10 @@ const mem = std.mem;
 const x = @intToPtr([*]i32, 0x1000)[0..0x500];
 const y = x[0x100..];
 test "compile time slice of pointer to hard coded address" {
-    expect(@ptrToInt(x.ptr) == 0x1000);
+    expect(@ptrToInt(x) == 0x1000);
     expect(x.len == 0x500);
 
-    expect(@ptrToInt(y.ptr) == 0x1100);
+    expect(@ptrToInt(y) == 0x1100);
     expect(y.len == 0x400);
 }
 
@@ -47,7 +47,9 @@ test "C pointer slice access" {
     var buf: [10]u32 = [1]u32{42} ** 10;
     const c_ptr = @ptrCast([*c]const u32, &buf);
 
-    comptime expectEqual([]const u32, @TypeOf(c_ptr[0..1]));
+    var runtime_zero: usize = 0;
+    comptime expectEqual([]const u32, @TypeOf(c_ptr[runtime_zero..1]));
+    comptime expectEqual(*const [1]u32, @TypeOf(c_ptr[0..1]));
 
     for (c_ptr[0..5]) |*cl| {
         expectEqual(@as(u32, 42), cl.*);
@@ -107,7 +109,9 @@ test "obtaining a null terminated slice" {
     const ptr2 = buf[0..runtime_len :0];
     // ptr2 is a null-terminated slice
     comptime expect(@TypeOf(ptr2) == [:0]u8);
-    comptime expect(@TypeOf(ptr2[0..2]) == []u8);
+    comptime expect(@TypeOf(ptr2[0..2]) == *[2]u8);
+    var runtime_zero: usize = 0;
+    comptime expect(@TypeOf(ptr2[runtime_zero..2]) == []u8);
 }
 
 test "empty array to slice" {
@@ -126,3 +130,150 @@ test "empty array to slice" {
     S.doTheTest();
     comptime S.doTheTest();
 }
+
+test "@ptrCast slice to pointer" {
+    const S = struct {
+        fn doTheTest() void {
+            var array align(@alignOf(u16)) = [5]u8{ 0xff, 0xff, 0xff, 0xff, 0xff };
+            var slice: []u8 = &array;
+            var ptr = @ptrCast(*u16, slice);
+            expect(ptr.* == 65535);
+        }
+    };
+
+    S.doTheTest();
+    comptime S.doTheTest();
+}
+
+test "slice syntax resulting in pointer-to-array" {
+    const S = struct {
+        fn doTheTest() void {
+            testArray();
+            testArrayZ();
+            testArray0();
+            testArrayAlign();
+            testPointer();
+            testPointerZ();
+            testPointer0();
+            testPointerAlign();
+            testSlice();
+            testSliceZ();
+            testSlice0();
+            testSliceAlign();
+        }
+
+        fn testArray() void {
+            var array = [5]u8{ 1, 2, 3, 4, 5 };
+            var slice = array[1..3];
+            comptime expect(@TypeOf(slice) == *[2]u8);
+            expect(slice[0] == 2);
+            expect(slice[1] == 3);
+        }
+
+        fn testArrayZ() void {
+            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
+            comptime expect(@TypeOf(array[1..3]) == *[2]u8);
+            comptime expect(@TypeOf(array[1..5]) == *[4:0]u8);
+            comptime expect(@TypeOf(array[1..]) == *[4:0]u8);
+            comptime expect(@TypeOf(array[1..3 :4]) == *[2:4]u8);
+        }
+
+        fn testArray0() void {
+            {
+                var array = [0]u8{};
+                var slice = array[0..0];
+                comptime expect(@TypeOf(slice) == *[0]u8);
+            }
+            {
+                var array = [0:0]u8{};
+                var slice = array[0..0];
+                comptime expect(@TypeOf(slice) == *[0:0]u8);
+                expect(slice[0] == 0);
+            }
+        }
+
+        fn testArrayAlign() void {
+            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
+            var slice = array[4..5];
+            comptime expect(@TypeOf(slice) == *align(4) [1]u8);
+            expect(slice[0] == 5);
+            comptime expect(@TypeOf(array[0..2]) == *align(4) [2]u8);
+        }
+
+        fn testPointer() void {
+            var array = [5]u8{ 1, 2, 3, 4, 5 };
+            var pointer: [*]u8 = &array;
+            var slice = pointer[1..3];
+            comptime expect(@TypeOf(slice) == *[2]u8);
+            expect(slice[0] == 2);
+            expect(slice[1] == 3);
+        }
+
+        fn testPointerZ() void {
+            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
+            var pointer: [*:0]u8 = &array;
+            comptime expect(@TypeOf(pointer[1..3]) == *[2]u8);
+            comptime expect(@TypeOf(pointer[1..3 :4]) == *[2:4]u8);
+        }
+
+        fn testPointer0() void {
+            var pointer: [*]u0 = &[1]u0{0};
+            var slice = pointer[0..1];
+            comptime expect(@TypeOf(slice) == *[1]u0);
+            expect(slice[0] == 0);
+        }
+
+        fn testPointerAlign() void {
+            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
+            var pointer: [*]align(4) u8 = &array;
+            var slice = pointer[4..5];
+            comptime expect(@TypeOf(slice) == *align(4) [1]u8);
+            expect(slice[0] == 5);
+            comptime expect(@TypeOf(pointer[0..2]) == *align(4) [2]u8);
+        }
+
+        fn testSlice() void {
+            var array = [5]u8{ 1, 2, 3, 4, 5 };
+            var src_slice: []u8 = &array;
+            var slice = src_slice[1..3];
+            comptime expect(@TypeOf(slice) == *[2]u8);
+            expect(slice[0] == 2);
+            expect(slice[1] == 3);
+        }
+
+        fn testSliceZ() void {
+            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
+            var slice: [:0]u8 = &array;
+            comptime expect(@TypeOf(slice[1..3]) == *[2]u8);
+            comptime expect(@TypeOf(slice[1..]) == [:0]u8);
+            comptime expect(@TypeOf(slice[1..3 :4]) == *[2:4]u8);
+        }
+
+        fn testSlice0() void {
+            {
+                var array = [0]u8{};
+                var src_slice: []u8 = &array;
+                var slice = src_slice[0..0];
+                comptime expect(@TypeOf(slice) == *[0]u8);
+            }
+            {
+                var array = [0:0]u8{};
+                var src_slice: [:0]u8 = &array;
+                var slice = src_slice[0..0];
+                comptime expect(@TypeOf(slice) == *[0]u8);
+            }
+        }
+
+        fn testSliceAlign() void {
+            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
+            var src_slice: []align(4) u8 = &array;
+            var slice = src_slice[4..5];
+            comptime expect(@TypeOf(slice) == *align(4) [1]u8);
+            expect(slice[0] == 5);
+            comptime expect(@TypeOf(src_slice[0..2]) == *align(4) [2]u8);
+        }
+    };
+
+    S.doTheTest();
+    comptime S.doTheTest();
+}
diff --git a/test/stage1/behavior/struct.zig b/test/stage1/behavior/struct.zig
index ecec7fe5d69e..0365991ed36f 100644
--- a/test/stage1/behavior/struct.zig
+++ b/test/stage1/behavior/struct.zig
@@ -409,8 +409,8 @@ const Bitfields = packed struct {
 test "native bit field understands endianness" {
     var all: u64 = 0x7765443322221111;
     var bytes: [8]u8 = undefined;
-    @memcpy(bytes[0..].ptr, @ptrCast([*]u8, &all), 8);
-    var bitfields = @ptrCast(*Bitfields, bytes[0..].ptr).*;
+    @memcpy(&bytes, @ptrCast([*]u8, &all), 8);
+    var bitfields = @ptrCast(*Bitfields, &bytes).*;
 
     expect(bitfields.f1 == 0x1111);
     expect(bitfields.f2 == 0x2222);