E0005: duplicate_cell

E0005 duplicate_cell — two cells share a name.

A compile-time error of soma check, the checker of the Soma programming language (soma explain E0005).

The rule

Two cells in one program may not have the same name; soma check reports "defined twice — rename one; same-named cells are not merged". A second cell Orders { … } is not a continuation of the first, and a call like Orders.place(…) would be ambiguous. Rename one of the cells, or move its handlers into the other.

A program that triggers it

cell Orders {
    memory {
        orders: Map<String, Int> [persistent]
    }
    on place(id: String, total: Int) {
        orders.set(id, total)
    }
}

cell Orders {
    on summary() {
        return "orders"
    }
}

What soma check prints:

$ soma check wrong.cell
error: cell 'Orders' is defined twice — rename one; same-named cells are not merged
  --> wrong.cell:10:1
   |
10 | cell Orders {
   | ^
  = code: E0005
✗ 1 error(s), 0 warning(s).

The fix field of soma check --json: rename one; same-named cells are not merged

The fix

On line 10, cell Orders { becomes cell Reports {.

--- wrong.cell
+++ right.cell
@@ -8,5 +8,5 @@
 }
 
-cell Orders {
+cell Reports {
     on summary() {
         return "orders"

With the fix, soma check accepts the program:

$ soma check right.cell
✓ All checks passed.