From fa1d33313cec8161f5b7846d364df3d900558f8f Mon Sep 17 00:00:00 2001
From: Michael Chirico <michaelchirico4@gmail.com>
Date: Wed, 17 Apr 2024 19:29:45 -0700
Subject: [PATCH] add a test

---
 src/library/stats/tests/offsets.R | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/library/stats/tests/offsets.R b/src/library/stats/tests/offsets.R
index ac018cefd2d..7cac39079bc 100644
--- a/src/library/stats/tests/offsets.R
+++ b/src/library/stats/tests/offsets.R
@@ -37,3 +37,9 @@ stopifnot(exprs = {
     is.null(model.weights(model.frame(fit5)))
 })
 ## these were all (even the model fit!) wrong in R <= 4.2.1
+
+## via formula, with stats:: namespace-qualification (#18706)
+fit6 <- lm(Postwt ~ Prewt + Treat + stats::offset(Prewt), data = anorexia)
+summary(fit6)
+pred <- fitted(fit6)
+stopifnot(all.equal(predict(fit6, anorexia), pred))