Fix rlang::inject with render functions

Render functions use quoToFunction() to convert quosures to
functions; quoToFunction() was using new_function, which leads
to non-tidy evaluation, so nested quosures are not evaluated.

See rstudio#3361 (comment)

R/utils.R

@@ -538,9 +538,7 @@ installExprFunction <- function(expr, name, eval.env = parent.frame(2),
 #' @export
 quoToFunction <- function(q, label, ..stacktraceon = FALSE) {
   q <- as_quosure(q)
-  # Use new_function() instead of as_function(), because as_function() adds an
-  # extra parent environment. (This may not actually be a problem, though.)
-  func <- new_function(NULL, get_expr(q), get_env(q))
+  func <- as_function(q)
   wrapFunctionLabel(func, label, ..stacktraceon = ..stacktraceon)
 }
 

tests/testthat/test-utils.R

@@ -239,3 +239,15 @@ test_that("dateYMD works", {
     c("2019/11/05", "")
   )
 })
+
+test_that("quoToFunction handles nested quosures", {
+  quo_inner <- local({
+    x <- 1
+    rlang::quo(x)
+  })
+
+  quo_outer <- rlang::quo(!!quo_inner + 1)
+
+  func <- quoToFunction(quo_outer, "foo")
+  expect_identical(func(), 2)
+})