swift

68b96a21 - [AutoDiff] Type-check `@differentiable` attributes during validation. (#27613)

[AutoDiff] Type-check `@differentiable` attributes during validation. (#27613) Type-check `@differentiable` attributes during `TypeChecker::validateDecl` for all relevant declaration kinds (initializers, subscripts, variables), not just function declarations. Resolves TF-888. TF-789 tracks proper request-based type-checking for `@differentiable` attribute. Exposes TF-892: `ElementaryFunctions` linker error on Linux.