Constant E0002_INVALID_ASSIGNMENT 

pub const E0002_INVALID_ASSIGNMENT: ErrorCode;

E0002: Assignments are not allowed in expression contexts

Assignments like x = y are statements, not expressions. They cannot be used in places where an expression is expected.

• ✅ If you meant to compare, use x == y.
• ✅ If you meant to assign, wrap it in a block: { x = y }.

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Example of erroneous code

let f = (x, a) => (x = a);

// autogenerated

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Explanation

Assignment (x = a) evaluates to the unit type () and cannot be used where a value is expected. This includes:

• return values in closures or functions,
• if and while conditions,
• or anywhere an actual value is needed.

This helps avoid common mistakes, such as confusing assignment with comparison:

if a = b {  } // probably meant `a == b`

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Fixes

✅ If you meant to compare:

let f = (x, a) => (x == a);

✅ If you meant to assign a value:

let f = (x, a) => { x = a; };

✅ Or use let for rebinding the variable:

let f = (x, a) => { let x = a; x; };