UninitializedFieldError is part of the runtime API of derive_builder,
not part of its compile-time macro machinery. Exporting it from the
derive_builder_core crate caused downstream crates to unnecessarily
import all of derive_builder_core, rather than only importing it via
the proc-macro crate at compile-time.
UninitializedFieldError is part of the runtime API of derive_builder, not part of its compile-time macro machinery. Exporting it from the derive_builder_core crate caused downstream crates to unnecessarily import all of derive_builder_core, rather than only importing it via the proc-macro crate at compile-time.
Fixes #201