diff --git a/src/internal/syscall/unix/net_darwin.go b/src/internal/syscall/unix/net_darwin.go
index 8b908ae600..5601b49750 100644
--- a/src/internal/syscall/unix/net_darwin.go
+++ b/src/internal/syscall/unix/net_darwin.go
@@ -119,7 +119,7 @@ func syscall_syscall6X(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err
 func syscall_syscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno)
 
 type ResState struct {
-	unexported [70]uintptr
+	unexported [69]uintptr
 }
 
 //go:cgo_import_dynamic libresolv_res_9_ninit res_9_ninit "/usr/lib/libresolv.9.dylib"
diff --git a/src/net/cgo_unix_cgo_darwin.go b/src/net/cgo_unix_cgo_darwin.go
index d1ae625039..fa21265c8c 100644
--- a/src/net/cgo_unix_cgo_darwin.go
+++ b/src/net/cgo_unix_cgo_darwin.go
@@ -17,10 +17,10 @@ import (
 )
 
 func init() {
-	const expected_size = int(unsafe.Sizeof(C.struct___res_state{}))
-	const got_size = int(unsafe.Sizeof(unix.ResState{}))
+	const expected_size = unsafe.Sizeof(C.struct___res_state{})
+	const got_size = unsafe.Sizeof(unix.ResState{})
 
-	// This will cause a compile error when the size differs in any way.
-	var _ [expected_size - got_size]byte
+	// This will cause a compile error when the size of
+	// unix.ResState is too small.
 	var _ [got_size - expected_size]byte
 }