GuardLetEarlyReturn [rule] v0.1.0

When the rest of a function does not make sense without a particular optional being non-nil, write guard let x = optionalX else { return ... }. The bound name is in scope for the entire remainder of the function, and the failure case sits at the top where it is easy to read. Use if let only when both branches do real work; do not use if let to bind a precondition and then put the entire function body inside the if.

Checks

• Functions with multiple optional preconditions chain guard let statements at the top, each handling its own failure case.
• The else branch of every guard exits the current scope (return, throw, break, continue, fatalError for compile-time-impossible cases).
• Pyramid-of-doom if let { if let { if let ... } } is rewritten as a flat list of guard let statements.
• When the failure case has nothing useful to log or report, the else branch may still log a one-liner so the absence is observable in production.

Label

Use guard let to bind preconditions and exit early; reserve if let for branching logic

GuardLetEarlyReturn [rule] v0.1.0

When the rest of a function does not make sense without a particular optional being non-nil, write guard let x = optionalX else { return ... }. The bound name is in scope for the entire remainder of the function, and the failure case sits at the top where it is easy to read. Use if let only when both branches do real work; do not use if let to bind a precondition and then put the entire function body inside the if.

Checks

• Functions with multiple optional preconditions chain guard let statements at the top, each handling its own failure case.
• The else branch of every guard exits the current scope (return, throw, break, continue, fatalError for compile-time-impossible cases).
• Pyramid-of-doom if let { if let { if let ... } } is rewritten as a flat list of guard let statements.
• When the failure case has nothing useful to log or report, the else branch may still log a one-liner so the absence is observable in production.

Label

Use guard let to bind preconditions and exit early; reserve if let for branching logic

Label

Use guard let to bind preconditions and exit early; reserve if let for branching logic