1 files changed, 2 insertions, 0 deletions
diff --git a/src/builtins.zig b/src/builtins.zig
index 9a49df16..8788e65f 100644
--- a/src/builtins.zig
+++ b/src/builtins.zig
@@ -1827,6 +1827,7 @@ const Board = struct {
         writeWord(addr, value);
         const back = readWord(addr);
         var buf: [96]u8 = undefined;
+        // unreachable below: three 8-digit hex words and 18 bytes fit 96
         p.setMessage(id, std.fmt.bufPrint(
             &buf,
             "{x:0>8}: wrote {x:0>8}, reads {x:0>8}",
@@ -1849,6 +1850,7 @@ const Board = struct {
         if (!toggle(p.host.ctx, pin, &was, &now)) return Error.BadPin;
 
         var buf: [48]u8 = undefined;
+        // unreachable: three small numbers and 10 bytes fit 48
         p.setMessage(id, std.fmt.bufPrint(&buf, "GPIO {d}: {d}->{d}", .{ pin, was, now }) catch unreachable);
     }