updated message

Author: venom1204

R/data.table.R

@@ -311,9 +311,9 @@ replace_dot_alias = function(e) {
         jsub = jsub[[2L]]  # to allow {} wrapping of := e.g. [,{`:=`(...)},] [#376]
         root = root_name(jsub)
       } else if (length(jsub) > 2L && jsub[[2L]] %iscall% ":=") {
-        #2142 -- j can be {} and have length 1
-        stopf("You have wrapped `:=` with `{}` which is ok, but then `:=` must be the only thing inside `{}` and must be used only once. You have other statements inside the `{}`. Consider placing `{}` on the RHS of `:=` instead, e.g., DT[, someCol := { tmpVar <- ...; tmpVar*2 }].")
-      }
+          #2142 -- j can be {} and have length 1
+          stopf("Invalid use of `:=` inside `{}`. `:=` must be the only expression inside `{}` when used in `j`. Instead of: DT[{tmp1 <- ...; tmp2 <- ...; someCol := tmp1 * tmp2}], Use: DT[, someCol := {tmp1 <- ...; tmp2 <- ...; tmp1 * tmp2}]")
+        }
     }
     if (root=="eval" && !any(all.vars(jsub[[2L]]) %chin% names_x)) {
       # TODO: this && !any depends on data. Can we remove it?