diff --git a/R/highlight.r b/R/highlight.r
index afc2f73b6..0026ff662 100644
--- a/R/highlight.r
+++ b/R/highlight.r
@@ -10,8 +10,8 @@ highlight_text <- function(text) {
     error = function(e) NULL
   )
 
-  # Failed to parse
-  if (is.null(expr)) {
+  # Failed to parse, or yielded empty expression
+  if (length(expr) == 0) {
     return(escape_html(text))
   }
 
diff --git a/tests/testthat/test-highlight.R b/tests/testthat/test-highlight.R
index ad7f8b0dc..342778d95 100644
--- a/tests/testthat/test-highlight.R
+++ b/tests/testthat/test-highlight.R
@@ -59,9 +59,3 @@ test_that("unparsed code is still escaped", {
   expect_equal(highlight_text("<"), "&lt;")
 })
 
-test_that("code consisting of comments only is not stripped of tags", {
-  scoped_package_context("test")
-
-  expect_equal(highlight_text("#"), "<span class='co'>#</span>")
-})
-