ValueTypesByDefault [rule] v0.1.0

Value types — struct, enum, tuples — give Swift its data-race safety, predictable equality, and copy-on-write performance. The standard library is built on them: Array, Dictionary, String, Set, Date, all URL-derived types. Use them as the default for any new type that represents data, configuration, or a record. Reach for class only when identity, deinit cleanup, or shared mutable state through references is genuinely required.

Checks

• New domain types are declared struct (records, configurations, DTOs, view-state, model values).
• Closed sets of named cases are declared enum, often with associated values for case-specific data.
• Equatable / Hashable conformance for value types is synthesised by the compiler — declared but not hand-written.
• Copy-on-write is relied on for performance: large struct payloads use COW under the hood (Array, Dictionary, custom COW box) rather than being prematurely converted to class.

Label

Model new types as struct or enum unless reference semantics are required

ValueTypesByDefault [rule] v0.1.0

Value types — struct, enum, tuples — give Swift its data-race safety, predictable equality, and copy-on-write performance. The standard library is built on them: Array, Dictionary, String, Set, Date, all URL-derived types. Use them as the default for any new type that represents data, configuration, or a record. Reach for class only when identity, deinit cleanup, or shared mutable state through references is genuinely required.

Checks

• New domain types are declared struct (records, configurations, DTOs, view-state, model values).
• Closed sets of named cases are declared enum, often with associated values for case-specific data.
• Equatable / Hashable conformance for value types is synthesised by the compiler — declared but not hand-written.
• Copy-on-write is relied on for performance: large struct payloads use COW under the hood (Array, Dictionary, custom COW box) rather than being prematurely converted to class.

Label

Model new types as struct or enum unless reference semantics are required

Label

Model new types as struct or enum unless reference semantics are required