diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 5e6cec1c28..fd07b9add4 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -50,24 +50,6 @@ jobs:
         uses: actions/checkout@v4
       - name: Build and Test
         run: sh ci/aarch64-linux-release.sh
-  riscv64-linux-debug:
-    if: ${{ github.event_name == 'push' }}
-    timeout-minutes: 1020
-    runs-on: [self-hosted, Linux, riscv64]
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test
-        run: sh ci/riscv64-linux-debug.sh
-  riscv64-linux-release:
-    if: ${{ github.event_name == 'push' }}
-    timeout-minutes: 900
-    runs-on: [self-hosted, Linux, riscv64]
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Build and Test
-        run: sh ci/riscv64-linux-release.sh
   x86_64-macos-release:
     runs-on: "macos-13"
     env:
diff --git a/.github/workflows/riscv.yaml b/.github/workflows/riscv.yaml
new file mode 100644
index 0000000000..b5baf43a6d
--- /dev/null
+++ b/.github/workflows/riscv.yaml
@@ -0,0 +1,22 @@
+name: riscv
+on:
+  workflow_dispatch:
+permissions:
+  contents: read
+jobs:
+  riscv64-linux-debug:
+    timeout-minutes: 1020
+    runs-on: [self-hosted, Linux, riscv64]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Build and Test
+        run: sh ci/riscv64-linux-debug.sh
+  riscv64-linux-release:
+    timeout-minutes: 900
+    runs-on: [self-hosted, Linux, riscv64]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Build and Test
+        run: sh ci/riscv64-linux-release.sh
diff --git a/lib/std/Io/Reader.zig b/lib/std/Io/Reader.zig
index 1bf9e9bde3..e569c36773 100644
--- a/lib/std/Io/Reader.zig
+++ b/lib/std/Io/Reader.zig
@@ -1303,6 +1303,13 @@ fn takeMultipleOf7Leb128(r: *Reader, comptime Result: type) TakeLeb128Error!Resu
 }
 
 /// Left-aligns data such that `r.seek` becomes zero.
+///
+/// If `r.seek` is not already zero then `buffer` is mutated, making it illegal
+/// to call this function with a const-casted `buffer`, such as in the case of
+/// `fixed`. This issue can be avoided:
+/// * in implementations, by attempting a read before a rebase, in which
+///   case the read will return `error.EndOfStream`, preventing the rebase.
+/// * in usage, by copying into a mutable buffer before initializing `fixed`.
 pub fn rebase(r: *Reader) void {
     if (r.seek == 0) return;
     const data = r.buffer[r.seek..r.end];
@@ -1315,6 +1322,13 @@ pub fn rebase(r: *Reader) void {
 /// if necessary.
 ///
 /// Asserts `capacity` is within the buffer capacity.
+///
+/// If the rebase occurs then `buffer` is mutated, making it illegal to call
+/// this function with a const-casted `buffer`, such as in the case of `fixed`.
+/// This issue can be avoided:
+/// * in implementations, by attempting a read before a rebase, in which
+///   case the read will return `error.EndOfStream`, preventing the rebase.
+/// * in usage, by copying into a mutable buffer before initializing `fixed`.
 pub fn rebaseCapacity(r: *Reader, capacity: usize) void {
     if (r.end > r.buffer.len - capacity) rebase(r);
 }
diff --git a/lib/std/Io/Writer.zig b/lib/std/Io/Writer.zig
index 916dfbe798..036c35b9e4 100644
--- a/lib/std/Io/Writer.zig
+++ b/lib/std/Io/Writer.zig
@@ -2194,8 +2194,10 @@ pub const Discarding = struct {
         const d: *Discarding = @alignCast(@fieldParentPtr("writer", w));
         d.count += w.end;
         w.end = 0;
+        if (limit == .nothing) return 0;
         if (file_reader.getSize()) |size| {
             const n = limit.minInt64(size - file_reader.pos);
+            if (n == 0) return error.EndOfStream;
             file_reader.seekBy(@intCast(n)) catch return error.Unimplemented;
             w.end = 0;
             d.count += n;
@@ -2489,18 +2491,17 @@ pub const Allocating = struct {
 
     fn sendFile(w: *Writer, file_reader: *File.Reader, limit: std.io.Limit) FileError!usize {
         if (File.Handle == void) return error.Unimplemented;
+        if (limit == .nothing) return 0;
         const a: *Allocating = @fieldParentPtr("writer", w);
         const gpa = a.allocator;
         var list = a.toArrayList();
         defer setArrayList(a, list);
         const pos = file_reader.pos;
         const additional = if (file_reader.getSize()) |size| size - pos else |_| std.atomic.cache_line;
+        if (additional == 0) return error.EndOfStream;
         list.ensureUnusedCapacity(gpa, limit.minInt64(additional)) catch return error.WriteFailed;
         const dest = limit.slice(list.unusedCapacitySlice());
-        const n = file_reader.read(dest) catch |err| switch (err) {
-            error.ReadFailed => return error.ReadFailed,
-            error.EndOfStream => 0,
-        };
+        const n = try file_reader.read(dest);
         list.items.len += n;
         return n;
     }
@@ -2522,3 +2523,43 @@ pub const Allocating = struct {
         try testing.expectEqualSlices(u8, "x: 42\ny: 1234\n", a.getWritten());
     }
 };
+
+test "discarding sendFile" {
+    var tmp_dir = testing.tmpDir(.{});
+    defer tmp_dir.cleanup();
+
+    const file = try tmp_dir.dir.createFile("input.txt", .{ .read = true });
+    defer file.close();
+    var r_buffer: [256]u8 = undefined;
+    var file_writer: std.fs.File.Writer = .init(file, &r_buffer);
+    try file_writer.interface.writeByte('h');
+    try file_writer.interface.flush();
+
+    var file_reader = file_writer.moveToReader();
+    try file_reader.seekTo(0);
+
+    var w_buffer: [256]u8 = undefined;
+    var discarding: std.io.Writer.Discarding = .init(&w_buffer);
+
+    _ = try file_reader.interface.streamRemaining(&discarding.writer);
+}
+
+test "allocating sendFile" {
+    var tmp_dir = testing.tmpDir(.{});
+    defer tmp_dir.cleanup();
+
+    const file = try tmp_dir.dir.createFile("input.txt", .{ .read = true });
+    defer file.close();
+    var r_buffer: [256]u8 = undefined;
+    var file_writer: std.fs.File.Writer = .init(file, &r_buffer);
+    try file_writer.interface.writeByte('h');
+    try file_writer.interface.flush();
+
+    var file_reader = file_writer.moveToReader();
+    try file_reader.seekTo(0);
+
+    var allocating: std.io.Writer.Allocating = .init(std.testing.allocator);
+    defer allocating.deinit();
+
+    _ = try file_reader.interface.streamRemaining(&allocating.writer);
+}
diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
index 52a227df28..829a8c37cc 100644
--- a/lib/std/os/windows.zig
+++ b/lib/std/os/windows.zig
@@ -1690,6 +1690,40 @@ pub fn getpeername(s: ws2_32.SOCKET, name: *ws2_32.sockaddr, namelen: *ws2_32.so
     return ws2_32.getpeername(s, name, @as(*i32, @ptrCast(namelen)));
 }
 
+pub fn sendmsg(
+    s: ws2_32.SOCKET,
+    msg: *ws2_32.WSAMSG_const,
+    flags: u32,
+) i32 {
+    var bytes_send: DWORD = undefined;
+    if (ws2_32.WSASendMsg(s, msg, flags, &bytes_send, null, null) == ws2_32.SOCKET_ERROR) {
+        return ws2_32.SOCKET_ERROR;
+    } else {
+        return @as(i32, @as(u31, @intCast(bytes_send)));
+    }
+}
+
+pub fn sendto(s: ws2_32.SOCKET, buf: [*]const u8, len: usize, flags: u32, to: ?*const ws2_32.sockaddr, to_len: ws2_32.socklen_t) i32 {
+    var buffer = ws2_32.WSABUF{ .len = @as(u31, @truncate(len)), .buf = @constCast(buf) };
+    var bytes_send: DWORD = undefined;
+    if (ws2_32.WSASendTo(s, @as([*]ws2_32.WSABUF, @ptrCast(&buffer)), 1, &bytes_send, flags, to, @as(i32, @intCast(to_len)), null, null) == ws2_32.SOCKET_ERROR) {
+        return ws2_32.SOCKET_ERROR;
+    } else {
+        return @as(i32, @as(u31, @intCast(bytes_send)));
+    }
+}
+
+pub fn recvfrom(s: ws2_32.SOCKET, buf: [*]u8, len: usize, flags: u32, from: ?*ws2_32.sockaddr, from_len: ?*ws2_32.socklen_t) i32 {
+    var buffer = ws2_32.WSABUF{ .len = @as(u31, @truncate(len)), .buf = buf };
+    var bytes_received: DWORD = undefined;
+    var flags_inout = flags;
+    if (ws2_32.WSARecvFrom(s, @as([*]ws2_32.WSABUF, @ptrCast(&buffer)), 1, &bytes_received, &flags_inout, from, @as(?*i32, @ptrCast(from_len)), null, null) == ws2_32.SOCKET_ERROR) {
+        return ws2_32.SOCKET_ERROR;
+    } else {
+        return @as(i32, @as(u31, @intCast(bytes_received)));
+    }
+}
+
 pub fn poll(fds: [*]ws2_32.pollfd, n: c_ulong, timeout: i32) i32 {
     return ws2_32.WSAPoll(fds, n, timeout);
 }
diff --git a/test/standalone/build.zig b/test/standalone/build.zig
index bae4497419..48956d01f2 100644
--- a/test/standalone/build.zig
+++ b/test/standalone/build.zig
@@ -31,6 +31,7 @@ pub fn build(b: *std.Build) void {
     const tools_target = b.resolveTargetQuery(.{});
     for ([_][]const u8{
         // Alphabetically sorted. No need to build `tools/spirv/grammar.zig`.
+        "../../tools/dump-cov.zig",
         "../../tools/fetch_them_macos_headers.zig",
         "../../tools/gen_macos_headers_c.zig",
         "../../tools/gen_outline_atomics.zig",
diff --git a/test/standalone/build.zig.zon b/test/standalone/build.zig.zon
index a62ba23c5a..8cf899477f 100644
--- a/test/standalone/build.zig.zon
+++ b/test/standalone/build.zig.zon
@@ -1,5 +1,6 @@
 .{
-    .name = "standalone_test_cases",
+    .name = .standalone_test_cases,
+    .fingerprint = 0xc0dbdf9c818957be,
     .version = "0.0.0",
     .dependencies = .{
         .simple = .{
diff --git a/tools/dump-cov.zig b/tools/dump-cov.zig
index 7699ac702b..16df7e3479 100644
--- a/tools/dump-cov.zig
+++ b/tools/dump-cov.zig
@@ -33,7 +33,7 @@ pub fn main() !void {
     defer coverage.deinit(gpa);
 
     var debug_info = std.debug.Info.load(gpa, exe_path, &coverage) catch |err| {
-        fatal("failed to load debug info for {}: {s}", .{ exe_path, @errorName(err) });
+        fatal("failed to load debug info for {f}: {s}", .{ exe_path, @errorName(err) });
     };
     defer debug_info.deinit(gpa);
 
@@ -42,10 +42,10 @@ pub fn main() !void {
         cov_path.sub_path,
         1 << 30,
         null,
-        @alignOf(SeenPcsHeader),
+        .of(SeenPcsHeader),
         null,
     ) catch |err| {
-        fatal("failed to load coverage file {}: {s}", .{ cov_path, @errorName(err) });
+        fatal("failed to load coverage file {f}: {s}", .{ cov_path, @errorName(err) });
     };
 
     var stdout_buffer: [4000]u8 = undefined;