Embracing within curly braces doesn't work

[lionel-]

From @DavisVaughan in posit-dev/air#410 (comment)

Minimal reprex

func_ok <- function(var) {
  rlang::quos(if (TRUE) {{ var }})
}

func_error <- function(var) {
  rlang::quos(
    if (TRUE) {
      {{ var }}
    }
  )
}

func_ok(a)
#> <list_of<quosure>>
#> 
#> [[1]]
#> <quosure>
#> expr: ^if (TRUE) ^a
#> env:  0x11007d410

func_error(a)
#> Error in `rlang::quos()`:
#> ! `arg` must be a symbol

Super minimal

func_ok <- function(var) {
  rlang::quos(
    {{ var }}
  )
}

func_error <- function(var) {
  rlang::quos(
    {
      {{ var }}
    }
  )
}

func_ok(a)
#> <list_of<quosure>>
#> 
#> [[1]]
#> <quosure>
#> expr: ^a
#> env:  global

func_error(a)
#> Error in `rlang::quos()`:
#> ! `arg` must be a symbol