0.4.0

• Pin projection has become a safe operation. In the absence of other unsafe code that you write, it is impossible to cause undefined behavior.

• #[unsafe_project] attribute has been replaced with #[pin_project] attribute. (#18, #33)

• The Unpin argument has been removed - an Unpin impl is now generated by default.

• Drop impls must be specified with #[pinned_drop] instead of via a normal Drop impl. (#18, #33, #86)

• Unpin impls must be specified with an impl of UnsafeUnpin, instead of implementing the normal Unpin trait.

• #[pin_project] attribute now determines the visibility of the projection type/method is based on the original type.

• #[pin_project] can now be used for public type with private field types.

• #[pin_project] can now interoperate with #[cfg()].

• Added project_ref method to #[pin_project] types.

• Added #[project_ref] attribute.

• Removed "project_attr" feature and always enable #[project] attribute.

• #[project] attribute can now be used for impl blocks.

• #[project] attribute can now be used for use statements.

• #[project] attribute now supports match expressions at the position of the initializer expression of let expressions.

Changes since the 0.4.0-beta.1 release:

• Fixed an issue that caused an error when using #[pin_project(UnsafeUnpin)] and not providing a manual UnsafeUnpin implementation on a type with no generics or lifetime.