E0119: flesh

E0119 flesh — a flesh body that cannot go into a skeleton: no skeleton of that name, a second body for one signal, parameters that differ from the signal's, or a helper with an untyped parameter.

A compile-time error of soma check, the checker of the Soma programming language (soma explain E0119).

The rule

A flesh block holds the bodies of a skeleton of the same name, and each body must fit its signal: same parameter names in the same order, with the types taken from the signal. soma check reports E0119 for a flesh whose parameters differ from the signal's (here amount instead of cents), a flesh with no skeleton of that name, a second body for one signal, or a private helper with an untyped parameter. Write the parameters exactly as the signal names them, on deposit(owner, cents); soma skeleton app.cell Wallet.deposit prints the brief with the signature to copy.

A program that triggers it

skeleton Wallet {
    memory {
        balances: Map<String, Int> [persistent]
        invariant balances >= 0
    }
    face {
        signal balance(owner: String) -> Int               reads balances
        signal deposit(owner: String, cents: Int) -> Int   writes balances
    }
}

flesh Wallet {
    on balance(owner) { return balances.get(owner) ?? 0 }
    on deposit(owner, amount) {
        let total = (balances.get(owner) ?? 0) + amount
        balances.set(owner, total)
        return total
    }
}

What soma check prints:

$ soma check wrong.cell
error: flesh `on deposit(owner, amount)` does not match the skeleton's `signal deposit(owner: String, cents: Int)` — write `on deposit(owner, cents)`
  --> wrong.cell:14:5
   |
14 |     on deposit(owner, amount) {
   |     ^
  = code: E0119
✗ 1 error(s), 0 warning(s).

The fix field of soma check --json: write `on deposit(owner, cents)`

The fix

Lines 14–15 are rewritten.

--- wrong.cell
+++ right.cell
@@ -12,6 +12,6 @@
 flesh Wallet {
     on balance(owner) { return balances.get(owner) ?? 0 }
-    on deposit(owner, amount) {
-        let total = (balances.get(owner) ?? 0) + amount
+    on deposit(owner, cents) {
+        let total = (balances.get(owner) ?? 0) + cents
         balances.set(owner, total)
         return total

With the fix, soma check accepts the program:

$ soma check right.cell
✓ All checks passed.