avoid structure()

Author: MichaelChirico

R/bmerge.R

@@ -85,17 +85,15 @@ bmerge = function(i, x, icols, xcols, roll, rollends, nomatch, mult, ops, verbos
         }
       }
       condition_message = gettextf("Incompatible join types: %s (%s) and %s (%s). Factor columns must join to factor or character columns.", xname, x_merge_type, iname, i_merge_type)
-      condition = structure(
-        list(
-          message = condition_message,
-          call = sys.call(sys.nframe()-1L),
-          bmerge_x_arg_col_name      = names(x)[xcol],
-          bmerge_x_arg_type          = x_merge_type,
-          bmerge_i_arg_col_name      = names(i)[icol],
-          bmerge_i_arg_type          = i_merge_type
-        ),
-        class = c("dt_bmerge_incompatible_type_error", "error", "condition")
+      condition = list(
+        message = condition_message,
+        call = sys.call(sys.nframe() - 1L),
+        bmerge_x_arg_col_name      = names(x)[xcol],
+        bmerge_x_arg_type          = x_merge_type,
+        bmerge_i_arg_col_name      = names(i)[icol],
+        bmerge_i_arg_type          = i_merge_type
       )
+      class(condition) = c("dt_bmerge_incompatible_type_error", "error", "condition")
       stop(condition)
     }
     # we check factors first to cater for the case when trying to do rolling joins on factors