rlang 0.4.3

• You can now use glue syntax to unquote on the LHS of :=. This
  syntax is automatically available in all functions taking dots with
  list2() and enquos(), and thus most of the tidyverse. Note that
  if you use the glue syntax in an R package, you need to import glue.

  A single pair of braces triggers normal glue interpolation:

  df <- data.frame(x = 1:3)
  
  suffix <- "foo"
  df %>% dplyr::mutate("var_{suffix}" := x * 2)
  #>   x var_foo
  #> 1 1       2
  #> 2 2       4
  #> 3 3       6

  Using a pair of double braces is for labelling a function argument.
  Technically, this is shortcut for "{as_label(enquo(arg))}". The
  syntax is similar to the curly-curly syntax for interpolating
  function arguments:

  my_wrapper <- function(data, var, suffix = "foo") {
    data %>% dplyr::mutate("{{ var }}_{suffix}" := {{ var }} * 2)
  }
  df %>% my_wrapper(x)
  #>   x x_foo
  #> 1 1     2
  #> 2 2     4
  #> 3 3     6
  
  df %>% my_wrapper(sqrt(x))
  #>   x sqrt(x)_foo
  #> 1 1    2.000000
  #> 2 2    2.828427
  #> 3 3    3.464102

• Fixed a bug in magrittr backtraces that caused duplicate calls to
  appear in the trace.

• Fixed a bug in magrittr backtraces that caused wrong call indices.

• Empty backtraces are no longer shown when rlang_backtrace_on_error
  is set.

• The tidy eval .env pronoun is now exported for documentation
  purposes.

• warn() and abort() now check that either class or message
  was supplied. inform() allows sending empty message as it is
  occasionally useful for building user output incrementally.

• flatten() fails with a proper error when input can't be flattened (#868, #885).

• inform() now consistently appends a final newline to the message
  (#880).

• cnd_body.default() is now properly registered.

• cnd_signal() now uses the same approach as abort() to save
  unhandled errors to last_error().

• Parsable constants like NaN and NA_integer_ are now deparsed by
  expr_deparse() in their parsable form (#890).

• Infix operators now stick to their LHS when deparsed by
  expr_deparse() (#890).