Why is the `prev` variable flagged as unused in the Fibonacci function?

Error in Fibonacci Function: Declared but Unused Variable

The provided code in Go attempts to calculate the Fibonacci sequence using closures. However, the compiler flags an error: "prog.go:13: prev declared and not used."

Explanation:

In the inner closure function, a variable named prev is declared using the := assignment operator. This creates a new variable in the current scope, but it is never used. To fix this issue, replace the := with = to assign the value from temp to the inherited prev variable.

Rewritten Code:

<code class="go">curr := curr + prev
prev = temp</code>

Reason for the Error:

The := operator in Go creates a new variable within the current scope, while = assigns a value to an existing variable. When using :=, a new variable is created and the old one is effectively shadowed, meaning it is not used anymore.

Note:

This issue occurs only when declaring the prev variable in the inner closure. The prev variable declared in the outer fibonacci function is used correctly.

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