Inline Temp Variable Refactoring

TL;DR

Explanation

A temporary variable assigned once and used once can often be inlined if the expression is already self-explanatory. Especially common in boolean checks: $isEligible = $user->age >= 18; return $isEligible; → return $user->age >= 18; But: keep the temp if it (1) clarifies a complex expression with a meaningful name, (2) is used more than once, (3) makes a slow operation happen once. Inline Temp is the inverse of Extract Variable. It reduces line count but should only be done when clarity is preserved or improved.

Common Misconception

Why It Matters

Common Mistakes

• Inlining complex expressions that need a name to be understandable.
• Inlining variables used in multiple places — creates duplication.
• Not inlining obvious single-use variables that add no information.

Code Examples

$result = calculateTotal($items);
return $result; // $result adds nothing

return calculateTotal($items); // Direct, no noise

// But KEEP the temp when it adds meaning:
$isEligibleForDiscount = $user->isPremium() && $order->total > 100;
return $isEligibleForDiscount; // Name clarifies the condition

References

• ↗ https://refactoring.guru/inline-temp

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