Strict language feature enablement (StrictLanguageFeatures)
Warnings for unrecognized feature names in -enable-upcoming-feature or enable-experimental-feature.
Overview
By default, if an unrecognized feature name is specified with the -enable-upcoming-feature or -enable-experimental-feature flags, the compiler will ignore it without emitting a diagnostic since some projects must be simultaneously compatible with multiple versions of the language and toolchain. This can, however, lead to misspecified features. To diagnose these cases instead, enable StrictLanguageFeatures.
See Also
@dynamicCallable implementation requirements (DynamicCallable)Add @preconcurrency import (AddPreconcurrencyImport)Always enabled availability domains (AlwaysAvailableDomain)Argument matching for trailing closures (TrailingClosureMatching)Calling a mutating async actor-isolated method (ActorIsolatedMutatingAsync)Calling an actor-isolated method from a synchronous nonisolated context (ActorIsolatedCall)Captures in a `@Sendable` closure (SendableClosureCaptures)Compilation caching (CompilationCaching)Conforming to `StringInterpolationProtocol` (StringInterpolationConformance)Conversion from `@isolated(any)` function type to synchronous function type (ConversionFromIsolatedAnyToSynchronous)Cross-isolation data race (RegionIsolationCrossIsolationDataRace)Deprecated declaration warnings (DeprecatedDeclaration)Deprecated implementation-only imports (ImplementationOnlyDeprecated)Dynamic exclusivity (DynamicExclusivity)Embedded Swift language restrictions (EmbeddedRestrictions)