Diagnostic groups

Detailed explanations for various compiler diagnostics.

Overview

Diagnostic groups collect some number of diagnostics together under a common group name. This allows for extra documentation to help explain relevant language concepts, as well as the ability to control the behavior of warnings in a more precise manner (when that group contains warnings):

• -Werror <group> - upgrades warnings in the specified group to errors
• -Wwarning <group> - indicates that warnings in the specified group should remain warnings, even if they were previously upgraded to errors

As a concrete example, to upgrade deprecated declaration warnings to errors:

-Werror DeprecatedDeclaration

Or upgrade all warnings except deprecated declaration to errors:

-warnings-as-errors -Wwarning DeprecatedDeclaration

Groups with warnings

• doc:always-available-domain
• doc:trailing-closure-matching
• doc:compilation-caching
• doc:string-interpolation-conformance
• doc:deprecated-declaration
• doc:implementation-only-deprecated
• doc:dynamic-exclusivity
• doc:embedded-restrictions
• doc:explicit-sendable-annotations
• doc:preconcurrency-import
• doc:foreign-reference-type
• doc:return-type-implicit-copy
• doc:implicit-strong-capture
• doc:clang-declaration-import
• doc:isolated-conformances
• doc:error-in-future-swift-version
• doc:module-version-missing
• doc:oslog
• doc:result-builder-methods
• doc:semantic-copies
• doc:strict-language-features
• doc:strict-memory-safety
• doc:unknown-warning-group
• doc:untyped-throws

Topics

• doc:dynamic-callable-requirements
• doc:always-available-domain
• doc:trailing-closure-matching
• doc:actor-isolated-mutating-async
• doc:actor-isolated-call
• doc:sendable-closure-captures
• doc:compilation-caching
• doc:string-interpolation-conformance
• doc:deprecated-declaration
• doc:implementation-only-deprecated
• doc:dynamic-exclusivity
• doc:embedded-restrictions
• doc:explicit-sendable-annotations
• doc:preconcurrency-import
• doc:foreign-reference-type
• doc:return-type-implicit-copy
• doc:implicit-strong-capture
• doc:clang-declaration-import
• doc:isolated-conformances
• doc:error-in-future-swift-version
• doc:missing-module-on-known-paths
• doc:module-version-missing
• doc:module-not-testable
• doc:multiple-inheritance
• doc:nominal-types
• doc:oslog
• doc:exclusivity-violation
• doc:performance-hints
• doc:property-wrapper-requirements
• doc:conformance-isolation
• doc:protocol-type-non-conformance
• doc:result-builder-methods
• doc:semantic-copies
• doc:sendable-metatypes
• doc:sending-closure-risks-data-race
• doc:sending-risks-data-race
• doc:strict-language-features
• doc:strict-memory-safety
• doc:temporary-pointers
• doc:opaque-type-inference
• doc:unknown-warning-group
• doc:availability-unrecognized-name
• doc:mutable-global-variable
• doc:untyped-throws
• doc:existential-member-access-limitations