diff --git a/options_go1.7.go b/options_go1.7.go
index 61d94aa..ca9a5ba 100644
--- a/options_go1.7.go
+++ b/options_go1.7.go
@@ -7,8 +7,9 @@
 // WithContext provided context will be used for cancellation purposes
 func WithContext(ctx context.Context) ProgressOption {
 	return func(s *pState) {
-		if ctx != nil {
-			s.cancel = ctx.Done()
+		if ctx == nil {
+			panic("ctx must not be nil")
 		}
+		s.cancel = ctx.Done()
 	}
 }