From 63453f30f144791a440743abb3b0cffb2c6c456f Mon Sep 17 00:00:00 2001
From: Hadley Wickham <h.wickham@gmail.com>
Date: Fri, 2 Oct 2026 08:16:42 -0400
Subject: [PATCH] Recognise `:=` as assignment

S7's walrus operator now documents the same as `<-`, e.g. `Foo := new_class()` generates full Rd including usage.

Fixes #1916.
---
 NEWS.md                                |  1 +
 R/object-from-call.R                   |  3 ++-
 tests/testthat/test-object-from-call.R | 11 +++++++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index 7300b0609..99d93d41e 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,6 @@
 # roxygen2 (development version)
 
+* roxygen2 now recognises the walrus operator `:=` as assignment, so S7 code like `Foo := new_class()` is documented the same as `Foo <- new_class()` (#1916).
 * `@inherit` and friends once again find external topics whose name needs backticks, like ``pkg::`foo-class` `` (@taekop, #1918).
 * `@inherit foo returns` now inherits the return value, like `@inherit foo return`, instead of warning about an unknown type (@taekop, #1919).
 
diff --git a/R/object-from-call.R b/R/object-from-call.R
index e0714407e..aa4b46aff 100644
--- a/R/object-from-call.R
+++ b/R/object-from-call.R
@@ -18,7 +18,8 @@ object_from_call <- function(call, env, block, file) {
       name,
       "=" = ,
       "<-" = ,
-      "<<-" = parser_assignment(call, env, block),
+      "<<-" = ,
+      ":=" = parser_assignment(call, env, block),
       "delayedAssign" = parser_delayedAssign(call, env, block),
       "::" = parser_import(call, env, block),
 
diff --git a/tests/testthat/test-object-from-call.R b/tests/testthat/test-object-from-call.R
index 060f46657..b62b06b48 100644
--- a/tests/testthat/test-object-from-call.R
+++ b/tests/testthat/test-object-from-call.R
@@ -70,6 +70,17 @@ test_that("finds function created with assignment", {
   expect_s3_class(obj, "function")
 })
 
+test_that("finds function created with walrus assignment", {
+  obj <- call_to_object({
+    `:=` <- function(x, y) {
+      assign(deparse(substitute(x)), y, envir = parent.frame())
+    }
+    foo := function(x, y, z) {}
+  })
+  expect_s3_class(obj, "function")
+  expect_equal(obj$alias, "foo")
+})
+
 test_that("finds S3 generic created with assignment", {
   obj <- call_to_object({
     foo <- function(x, y, z) UseMethod("foo")