diff --git a/lib/std/array_list.zig b/lib/std/array_list.zig
index 87bf3c51df..523d1c810f 100644
--- a/lib/std/array_list.zig
+++ b/lib/std/array_list.zig
@@ -189,32 +189,30 @@ pub fn AlignedArrayList(comptime T: type, comptime alignment: ?u29) type {
             self.len += items.len;
         }
 
-        pub usingnamespace if (T == u8)
-            struct {
-                /// Same as `append` except it returns the number of bytes written, which is always the same
-                /// as `m.len`. The purpose of this function existing is to match `std.io.OutStream` API.
-                fn appendWrite(self: *Self, m: []const u8) !usize {
-                    try self.appendSlice(m);
-                    return m.len;
-                }
+        /// Same as `append` except it returns the number of bytes written, which is always the same
+        /// as `m.len`. The purpose of this function existing is to match `std.io.OutStream` API.
+        /// This function may be called only when `T` is `u8`.
+        fn appendWrite(self: *Self, m: []const u8) !usize {
+            try self.appendSlice(m);
+            return m.len;
+        }
 
-                pub fn outStream(self: *Self) std.io.OutStream(*Self, error{OutOfMemory}, appendWrite) {
-                    return .{ .context = self };
-                }
-            }
-        else
-            struct {};
+        /// Initializes an OutStream which will append to the list.
+        /// This function may be called only when `T` is `u8`.
+        pub fn outStream(self: *Self) std.io.OutStream(*Self, error{OutOfMemory}, appendWrite) {
+            return .{ .context = self };
+        }
 
-        /// Append a value to the list `n` times. Allocates more memory
-        /// as necessary.
+        /// Append a value to the list `n` times.
+        /// Allocates more memory as necessary.
         pub fn appendNTimes(self: *Self, value: T, n: usize) !void {
             const old_len = self.len;
             try self.resize(self.len + n);
             mem.set(T, self.items[old_len..self.len], value);
         }
 
-        /// Adjust the list's length to `new_len`. Doesn't initialize
-        /// added items if any.
+        /// Adjust the list's length to `new_len`.
+        /// Does not initialize added items if any.
         pub fn resize(self: *Self, new_len: usize) !void {
             try self.ensureCapacity(new_len);
             self.len = new_len;
diff --git a/lib/std/build.zig b/lib/std/build.zig
index 626638647e..ccd0ebaf8a 100644
--- a/lib/std/build.zig
+++ b/lib/std/build.zig
@@ -1961,7 +1961,6 @@ pub const LibExeObjStep = struct {
                 }
             } else {
                 var mcpu_buffer = std.ArrayList(u8).init(builder.allocator);
-                errdefer mcpu_buffer.deinit();
 
                 try mcpu_buffer.outStream().print("-mcpu={}", .{cross.cpu.model.name});
 
diff --git a/lib/std/child_process.zig b/lib/std/child_process.zig
index 8e341a07b8..0c24af2d85 100644
--- a/lib/std/child_process.zig
+++ b/lib/std/child_process.zig
@@ -757,7 +757,6 @@ fn windowsCreateProcess(app_name: [*:0]u16, cmd_line: [*:0]u16, envp_ptr: ?[*]u1
 }
 
 /// Caller must dealloc.
-/// Guarantees a null byte at result[result.len].
 fn windowsCreateCommandLine(allocator: *mem.Allocator, argv: []const []const u8) ![:0]u8 {
     var buf = try Buffer.initSize(allocator, 0);
     defer buf.deinit();
diff --git a/lib/std/zig/cross_target.zig b/lib/std/zig/cross_target.zig
index 9099519274..4d19ecee8c 100644
--- a/lib/std/zig/cross_target.zig
+++ b/lib/std/zig/cross_target.zig
@@ -504,7 +504,7 @@ pub const CrossTarget = struct {
         const os_name = if (self.os_tag) |os_tag| @tagName(os_tag) else "native";
 
         var result = std.ArrayList(u8).init(allocator);
-        errdefer result.deinit();
+        defer result.deinit();
 
         try result.outStream().print("{}-{}", .{ arch_name, os_name });
 
diff --git a/src-self-hosted/libc_installation.zig b/src-self-hosted/libc_installation.zig
index f802cbd606..11708e2a31 100644
--- a/src-self-hosted/libc_installation.zig
+++ b/src-self-hosted/libc_installation.zig
@@ -327,20 +327,14 @@ pub const LibCInstallation = struct {
         var search_buf: [2]Search = undefined;
         const searches = fillSearch(&search_buf, sdk);
 
-        for (searches) |search| {
-            const dir_path = try fs.path.join(
-                allocator,
-                &[_][]const u8{
-                    search.path,
-                    "Include",
-                    search.version,
-                    "ucrt",
-                },
-            );
-            var found = false;
-            defer if (!found) allocator.free(dir_path);
+        var result_buf = std.ArrayList([]const u8).init(allocator);
+        defer result_buf.deinit();
 
-            var dir = fs.cwd().openDir(dir_path, .{}) catch |err| switch (err) {
+        for (searches) |search| {
+            result_buf.shrink(0);
+            try result_buf.outStream().print("{}\\Include\\{}\\ucrt", .{ search.path, search.version });
+
+            var dir = fs.cwd().openDir(result_buf.span(), .{}) catch |err| switch (err) {
                 error.FileNotFound,
                 error.NotDir,
                 error.NoDevice,
@@ -355,8 +349,7 @@ pub const LibCInstallation = struct {
                 else => return error.FileSystem,
             };
 
-            found = true;
-            self.include_dir = dir_path;
+            self.include_dir = result_buf.toOwnedSlice();
             return;
         }
 
@@ -373,6 +366,9 @@ pub const LibCInstallation = struct {
         var search_buf: [2]Search = undefined;
         const searches = fillSearch(&search_buf, sdk);
 
+        var result_buf = try std.ArrayList([]const u8).init(allocator);
+        defer result_buf.deinit();
+
         const arch_sub_dir = switch (builtin.arch) {
             .i386 => "x86",
             .x86_64 => "x64",
@@ -381,20 +377,10 @@ pub const LibCInstallation = struct {
         };
 
         for (searches) |search| {
-            const dir_path = try fs.path.join(
-                allocator,
-                &[_][]const u8{
-                    search.path,
-                    "Lib",
-                    search.version,
-                    "ucrt",
-                    arch_sub_dir,
-                },
-            );
-            var found = false;
-            defer if (!found) allocator.free(dir_path);
+            result_buf.shrink(0);
+            try result_buf.outStream().print("{}\\Lib\\{}\\ucrt\\{}", .{ search.path, search.version, arch_sub_dir });
 
-            var dir = fs.cwd().openDir(dir_path, .{}) catch |err| switch (err) {
+            var dir = fs.cwd().openDir(result_buf.span(), .{}) catch |err| switch (err) {
                 error.FileNotFound,
                 error.NotDir,
                 error.NoDevice,
@@ -409,8 +395,7 @@ pub const LibCInstallation = struct {
                 else => return error.FileSystem,
             };
 
-            found = true;
-            self.crt_dir = dir_path;
+            self.crt_dir = result_buf.toOwnedSlice();
             return;
         }
         return error.LibCRuntimeNotFound;
@@ -434,6 +419,10 @@ pub const LibCInstallation = struct {
 
         var search_buf: [2]Search = undefined;
         const searches = fillSearch(&search_buf, sdk);
+
+        var result_buf = try std.ArrayList([]const u8).init(allocator);
+        defer result_buf.deinit();
+
         const arch_sub_dir = switch (builtin.arch) {
             .i386 => "x86",
             .x86_64 => "x64",
@@ -442,20 +431,11 @@ pub const LibCInstallation = struct {
         };
 
         for (searches) |search| {
-            const dir_path = try fs.path.join(
-                allocator,
-                &[_][]const u8{
-                    search.path,
-                    "Lib",
-                    search.version,
-                    "um",
-                    arch_sub_dir,
-                },
-            );
-            var found = false;
-            defer if (!found) allocator.free(dir_path);
+            result_buf.shrink(0);
+            const stream = result_buf.outStream();
+            try stream.print("{}\\Lib\\{}\\um\\{}", .{ search.path, search.version, arch_sub_dir });
 
-            var dir = fs.cwd().openDir(dir_path, .{}) catch |err| switch (err) {
+            var dir = fs.cwd().openDir(result_buf.span(), .{}) catch |err| switch (err) {
                 error.FileNotFound,
                 error.NotDir,
                 error.NoDevice,
@@ -470,8 +450,7 @@ pub const LibCInstallation = struct {
                 else => return error.FileSystem,
             };
 
-            found = true;
-            self.kernel32_lib_dir = dir_path;
+            self.kernel32_lib_dir = result_buf.toOwnedSlice();
             return;
         }
         return error.LibCKernel32LibNotFound;
@@ -489,13 +468,7 @@ pub const LibCInstallation = struct {
         const up1 = fs.path.dirname(msvc_lib_dir) orelse return error.LibCStdLibHeaderNotFound;
         const up2 = fs.path.dirname(up1) orelse return error.LibCStdLibHeaderNotFound;
 
-        const dir_path = try fs.path.join(
-            allocator,
-            &[_][]const u8{
-                up2,
-                "include",
-            },
-        );
+        const dir_path = try fs.path.join(allocator, &[_][]const u8{ up2, "include" });
         errdefer allocator.free(dir_path);
 
         var dir = fs.cwd().openDir(dir_path, .{}) catch |err| switch (err) {
diff --git a/src-self-hosted/stage2.zig b/src-self-hosted/stage2.zig
index 771765bee6..02213464e6 100644
--- a/src-self-hosted/stage2.zig
+++ b/src-self-hosted/stage2.zig
@@ -413,11 +413,11 @@ fn printErrMsgToFile(
 
     var text_buf = std.ArrayList(u8).init(allocator);
     defer text_buf.deinit();
-    const out_stream = &text_buf.outStream();
+    const out_stream = text_buf.outStream();
     try parse_error.render(&tree.tokens, out_stream);
     const text = text_buf.span();
 
-    const stream = &file.outStream();
+    const stream = file.outStream();
     try stream.print("{}:{}:{}: error: {}\n", .{ path, start_loc.line + 1, start_loc.column + 1, text });
 
     if (!color_on) return;
diff --git a/src-self-hosted/translate_c.zig b/src-self-hosted/translate_c.zig
index 62318a40aa..854037ec57 100644
--- a/src-self-hosted/translate_c.zig
+++ b/src-self-hosted/translate_c.zig
@@ -297,7 +297,6 @@ pub fn translate(
     };
 
     var source_buffer = std.ArrayList(u8).init(arena);
-    errdefer source_buffer.deinit();
 
     var context = Context{
         .tree = tree,
diff --git a/src/codegen.cpp b/src/codegen.cpp
index 2c2bf7c36b..24e77e8689 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -9123,17 +9123,20 @@ static void detect_libc(CodeGen *g) {
         g->libc_include_dir_len = 0;
         g->libc_include_dir_list = heap::c_allocator.allocate<const char *>(dir_count);
 
-        g->libc_include_dir_list[g->libc_include_dir_len] = buf_ptr(buf_create_from_mem(g->libc->include_dir, g->libc->include_dir_len));
+        g->libc_include_dir_list[g->libc_include_dir_len] = buf_ptr(buf_create_from_mem(
+                    g->libc->include_dir, g->libc->include_dir_len));
         g->libc_include_dir_len += 1;
 
         if (want_sys_dir) {
-            g->libc_include_dir_list[g->libc_include_dir_len] = buf_ptr(buf_create_from_mem(g->libc->sys_include_dir, g->libc->sys_include_dir_len));
+            g->libc_include_dir_list[g->libc_include_dir_len] = buf_ptr(buf_create_from_mem(
+                        g->libc->sys_include_dir, g->libc->sys_include_dir_len));
             g->libc_include_dir_len += 1;
         }
 
         if (want_um_and_shared_dirs != 0) {
             Buf *include_dir_parent = buf_alloc();
-            os_path_join(buf_create_from_mem(g->libc->include_dir, g->libc->include_dir_len), buf_create_from_str(".."), include_dir_parent);
+            os_path_join(buf_create_from_mem(g->libc->include_dir, g->libc->include_dir_len),
+                    buf_create_from_str(".."), include_dir_parent);
 
             Buf *buff1 = buf_alloc();
             os_path_join(include_dir_parent, buf_create_from_str("um"), buff1);
diff --git a/src/link.cpp b/src/link.cpp
index 49bbb7c1a5..fba572de98 100644
--- a/src/link.cpp
+++ b/src/link.cpp
@@ -1595,7 +1595,8 @@ static const char *get_libc_crt_file(CodeGen *parent, const char *file, Stage2Pr
     } else {
         assert(parent->libc != nullptr);
         Buf *out_buf = buf_alloc();
-        os_path_join(buf_create_from_mem(parent->libc->crt_dir, parent->libc->crt_dir_len), buf_create_from_str(file), out_buf);
+        os_path_join(buf_create_from_mem(parent->libc->crt_dir, parent->libc->crt_dir_len),
+                buf_create_from_str(file), out_buf);
         return buf_ptr(out_buf);
     }
 }