Make the error messages more symmetric.

Co-authored-by: Michael Chirico <[email protected]>

Author: aitap

inst/tests/tests.Rraw

@@ -15061,7 +15061,7 @@ if (test_bit64) {
   as.i64 = bit64::as.integer64
   test(2039.01, between(1:10, as.i64(3), as.i64(6)),  error="x is not integer64 but.*Please align classes")
   test(2039.02, between(1:10, 3, as.i64(6)),          error="x is not integer64 but.*Please align classes")
-  test(2039.03, between(as.i64(1:3), "2", as.i64(4)), error="x is integer64 but lower is not")
+  test(2039.03, between(as.i64(1:3), "2", as.i64(4)), error="x is integer64 but lower is not.*Please align classes")
   old = options("datatable.verbose"=TRUE)
   x = as.i64(1:10)
   ans36 = c(FALSE,FALSE,TRUE,TRUE,TRUE,TRUE,FALSE,FALSE,FALSE,FALSE)
@@ -15091,7 +15091,7 @@ if (test_bit64) {
   # must not blindly read integer64 values as doubles when the latter fit into int32, #7164
   test(2039.22, between(42L, structure(41., class="integer64"), structure(43., class="integer64")), error="x is not integer64 but.*Please align classes")
   # must not blindly convert numeric bounds to integer64, #7164
-  test(2039.23, between(as.i64(42), 41, -2^98), error="x is integer64 but upper is not")
+  test(2039.23, between(as.i64(42), 41, -2^98), error="x is integer64 but upper is not.*Please align classes")
   options(old)
 }
 

src/between.c

@@ -32,9 +32,9 @@ SEXP between(SEXP x, SEXP lower, SEXP upper, SEXP incbounds, SEXP NAboundsArg, S
   // check before potential coercion which ignores methods, #7164
   if (INHERITS(x, char_integer64)) {
     if (!INHERITS(lower, char_integer64))
-      error(_("x is integer64 but %s is not."), "lower"); // e.g. between(int64, character, character)
+      error(_("x is integer64 but %s is not. Please align classes."), "lower"); // e.g. between(int64, character, character)
     if (!INHERITS(upper, char_integer64))
-      error(_("x is integer64 but %s is not."), "upper"); // e.g. between(int64, character, character)
+      error(_("x is integer64 but %s is not. Please align classes."), "upper"); // e.g. between(int64, character, character)
   } else {
     if (INHERITS(lower, char_integer64))
       error(_("x is not integer64 but %s is. Please align classes."), "lower");