std: add missing error to windows.WriteFile

I encountered this error today when testing the self-hosted compiler on
Windows.

2 files changed, 8 insertions, 0 deletions

diff --git a/lib/std/os.zig b/lib/std/os.zig
index 1192c72629..2836ddf9c9 100644
--- a/lib/std/os.zig
+++ b/lib/std/os.zig
@@ -953,6 +953,10 @@ pub const WriteError = error{
     OperationAborted,
     NotOpenForWriting,
 
+    /// The process cannot access the file because another process has locked
+    /// a portion of the file. Windows-only.
+    LockViolation,
+
     /// This error occurs when no global event loop is configured,
     /// and reading from the file descriptor would block.
     WouldBlock,
diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
index 3e42ee5f2d..c79ccb5113 100644
--- a/lib/std/os/windows.zig
+++ b/lib/std/os/windows.zig
@@ -517,6 +517,9 @@ pub const WriteFileError = error{
     OperationAborted,
     BrokenPipe,
     NotOpenForWriting,
+    /// The process cannot access the file because another process has locked
+    /// a portion of the file.
+    LockViolation,
     Unexpected,
 };
 
@@ -597,6 +600,7 @@ pub fn WriteFile(
                 .IO_PENDING => unreachable,
                 .BROKEN_PIPE => return error.BrokenPipe,
                 .INVALID_HANDLE => return error.NotOpenForWriting,
+                .LOCK_VIOLATION => return error.LockViolation,
                 else => |err| return unexpectedError(err),
             }
         }