E0023: dead_code

E0023 dead_code — statements that can never run.

A compile-time error of soma check, the checker of the Soma programming language (soma explain E0023).

The rule

Adjacent string literals do not concatenate in Soma: in return "a " "b" the second literal is a separate statement after return and never runs. soma check reports this case as an error (other code after a return is only a warning). Write one literal and interpolate the values into it, or join strings with +.

A program that triggers it

cell Notifications {
    on shipping_notice(order_id: String, carrier: String) {
        return "Order {order_id} has shipped " "with {carrier}."
    }
}

What soma check prints:

$ soma check wrong.cell
error: in Notifications.shipping_notice: a string literal follows `return` and is never evaluated — adjacent string literals do not concatenate. Write one literal, or interpolate: "hello {name}"
  --> wrong.cell:3:48
  |
3 |         return "Order {order_id} has shipped " "with {carrier}."
  |                                                ^
  = code: E0023
✗ 1 error(s), 0 warning(s).

The fix field of soma check --json: in Notifications.shipping_notice: a string literal follows `return` and is never evaluated — adjacent string literals do not concatenate. Write one literal, or interpolate: "hello {name}"

The fix

On line 3, return "Order {order_id} has shipped " "with {carrier}." becomes return "Order {order_id} has shipped with {carrier}.".

--- wrong.cell
+++ right.cell
@@ -1,5 +1,5 @@
 cell Notifications {
     on shipping_notice(order_id: String, carrier: String) {
-        return "Order {order_id} has shipped " "with {carrier}."
+        return "Order {order_id} has shipped with {carrier}."
     }
 }

With the fix, soma check accepts the program:

$ soma check right.cell
✓ All checks passed.