Constant E0011_UNBOUND_VARIABLE 

pub const E0011_UNBOUND_VARIABLE: ErrorCode;

E0010: Unbound variable

This error occurs when you try to use a variable that has not been declared in the current scope.

Example:

y = 4; // ❌ Error: `y` is unbound

// autogenerated

Here, the variable y is used as if it already exists, but it hasn’t been introduced with a let binding or passed in as a parameter.

💡 Solution:

Introduce the variable first using let:

let mut y = 2; // ✅ now `y` is declared
y = 4;

Or make sure the variable is in scope when used.

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🧠 Why this happens

Compose enforces explicit bindings to avoid mistakes like typos or accidental use of undeclared variables. This helps catch bugs early and keeps code clear and predictable.