update macro_magic to 0.4.1

frame/examples/default-config/src/lib.rs

@@ -106,12 +106,6 @@ pub mod pallet {
 #[cfg(any(test, doc))]
 pub mod tests {
 	use super::*;
-
-	use frame_support::macro_magic::use_attr;
-	// Because `derive_impl` is a [macro_magic](https://crates.io/crates/macro_magic) attribute
-	// macro, [`#[use_attr]`](`frame_support::macro_magic::use_attr`) must be attached to any use
-	// statement that brings it into scope.
-	#[use_attr]
 	use frame_support::derive_impl;
 
 	use super::pallet as pallet_default_config_example;
@@ -168,7 +162,7 @@ pub mod tests {
 	}
 
 	// Similarly, we use the defaults provided by own crate as well.
-	use pallet::config_preludes::TestDefaultConfig;
+	use pallet::config_preludes::*;
 	#[derive_impl(TestDefaultConfig as pallet::DefaultConfig)]
 	impl crate::pallet::Config for Test {
 		// These two both cannot have defaults.

frame/examples/kitchensink/src/tests.rs

@@ -18,9 +18,7 @@
 //! Tests for pallet-example-kitchensink.
 
 use crate::*;
-#[use_attr]
-use frame_support::derive_impl;
-use frame_support::{macro_magic::use_attr, parameter_types, traits::ConstU64};
+use frame_support::{derive_impl, parameter_types, traits::ConstU64};
 use sp_runtime::BuildStorage;
 // Reexport crate as its pallet name for construct_runtime.
 use crate as pallet_example_kitchensink;

frame/support/Cargo.toml

@@ -29,7 +29,7 @@ sp-staking = { version = "4.0.0-dev", default-features = false, path = "../../pr
 sp-weights = { version = "20.0.0", default-features = false, path = "../../primitives/weights" }
 sp-debug-derive = { default-features = false, path = "../../primitives/debug-derive" }
 tt-call = "1.0.8"
-macro_magic = "0.3.5"
+macro_magic = "0.4.1"
 frame-support-procedural = { version = "4.0.0-dev", default-features = false, path = "./procedural" }
 paste = "1.0"
 once_cell = { version = "1", default-features = false, optional = true }

frame/support/procedural/Cargo.toml

@@ -24,7 +24,7 @@ quote = "1.0.28"
 syn = { version = "2.0.16", features = ["full"] }
 frame-support-procedural-tools = { version = "4.0.0-dev", path = "./tools" }
 proc-macro-warning = { version = "0.4.1", default-features = false }
-macro_magic = { version = "0.3.5", features = ["proc_support"] }
+macro_magic = { version = "0.4.1", features = ["proc_support"] }
 expander = "2.0.0"
 
 [features]

frame/support/procedural/src/lib.rs

@@ -37,6 +37,7 @@ mod storage_alias;
 mod transactional;
 mod tt_macro;
 
+use frame_support_procedural_tools::generate_crate_access_2018;
 use macro_magic::import_tokens_attr;
 use proc_macro::TokenStream;
 use quote::{quote, ToTokens};
@@ -952,28 +953,6 @@ pub fn storage_alias(_: TokenStream, input: TokenStream) -> TokenStream {
 ///
 /// # Advanced Usage
 ///
-/// ## Importing & Re-Exporting
-///
-/// Since `#[derive_impl(..)]` is a
-/// [`macro_magic`](https://docs.rs/macro_magic/latest/macro_magic/)-based attribute macro, special
-/// care must be taken when importing and re-exporting it. Glob imports will work properly, such as
-/// `use frame_support::*` to bring `derive_impl` into scope, however any other use statements
-/// involving `derive_impl` should have
-/// [`#[macro_magic::use_attr]`](https://docs.rs/macro_magic/latest/macro_magic/attr.use_attr.html)
-/// attached or your use statement will fail to fully bring the macro into scope.
-///
-/// This brings `derive_impl` into scope in the current context:
-/// ```ignore
-/// #[use_attr]
-/// use frame_support::derive_impl;
-/// ```
-///
-/// This brings `derive_impl` into scope and publicly re-exports it from the current context:
-/// ```ignore
-/// #[use_attr]
-/// pub use frame_support::derive_impl;
-/// ```
-///
 /// ## Expansion
 ///
 /// The `#[derive_impl(default_impl_path as disambiguation_path)]` attribute will expand to the
@@ -987,7 +966,18 @@ pub fn storage_alias(_: TokenStream, input: TokenStream) -> TokenStream {
 /// Items that lack a `syn::Ident` for whatever reason are first checked to see if they exist,
 /// verbatim, in the local/destination trait before they are copied over, so you should not need to
 /// worry about collisions between identical unnamed items.
-#[import_tokens_attr(frame_support::macro_magic)]
+#[import_tokens_attr {
+    format!(
+        "{}::macro_magic",
+        match generate_crate_access_2018("frame-support") {
+            Ok(path) => Ok(path),
+            Err(_) => generate_crate_access_2018("frame"),
+        }
+        .expect("Failed to find either `frame-support` or `frame` in `Cargo.toml` dependencies.")
+        .to_token_stream()
+        .to_string()
+    )
+}]
 #[with_custom_parsing(derive_impl::DeriveImplAttrArgs)]
 #[proc_macro_attribute]
 pub fn derive_impl(attrs: TokenStream, input: TokenStream) -> TokenStream {
@@ -1034,8 +1024,41 @@ pub fn no_default(_: TokenStream, _: TokenStream) -> TokenStream {
 /// 	type MaxConsumers = frame_support::traits::ConstU32<16>;
 /// }
 /// ```
+///
+/// ## Advanced Usage
+///
 /// This macro acts as a thin wrapper around macro_magic's `#[export_tokens]`. See the docs
-/// [here](https://docs.rs/macro_magic/latest/macro_magic/attr.export_tokens.html) for more info.
+/// [here](https://docs.rs/macro_magic/latest/macro_magic/attr.export_tokens.html) for more
+/// info.
+///
+/// There are some caveats when applying a `use` statement to bring a
+/// `#[register_default_impl]` item into scope. If you have a `#[register_default_impl]`
+/// defined in `my_crate::submodule::MyItem`, it is currently not sufficient to do something
+/// like:
+///
+/// ```ignore
+/// use my_crate::submodule::MyItem;
+/// #[derive_impl(MyItem as Whatever)]
+/// ```
+///
+/// This will fail with a mysterious message about `__export_tokens_tt_my_item` not being
+/// defined.
+///
+/// You can, however, do any of the following:
+/// ```ignore
+/// // partial path works
+/// use my_crate::submodule;
+/// #[derive_impl(submodule::MyItem as Whatever)]
+/// ```
+/// ```ignore
+/// // full path works
+/// #[derive_impl(my_crate::submodule::MyItem as Whatever)]
+/// ```
+/// ```ignore
+/// // wild-cards work
+/// use my_crate::submodule::*;
+/// #[derive_impl(MyItem as Whatever)]
+/// ```
 #[proc_macro_attribute]
 pub fn register_default_impl(attrs: TokenStream, tokens: TokenStream) -> TokenStream {
 	// ensure this is a impl statement

frame/support/src/lib.rs

@@ -210,7 +210,6 @@ impl TypeId for PalletId {
 /// ```
 pub use frame_support_procedural::storage_alias;
 
-#[macro_magic::use_attr]
 pub use frame_support_procedural::derive_impl;
 
 /// Create new implementations of the [`Get`](crate::traits::Get) trait.

frame/support/test/tests/derive_impl_ui/attached_to_non_impl.stderr

@@ -1,15 +1,5 @@
 error: expected `impl`
-  --> tests/derive_impl_ui/attached_to_non_impl.rs:24:1
+  --> tests/derive_impl_ui/attached_to_non_impl.rs:39:1
    |
-24 | / #[register_default_impl(FourLeggedAnimal)]
-25 | | impl Animal for FourLeggedAnimal {
-26 | |     type Locomotion = RunsOnFourLegs;
-27 | |     type Diet = Omnivore;
-...  |
-37 | |
-38 | | #[derive_impl(FourLeggedAnimal as Animal)]
-   | |_-----------------------------------------^
-   |   |
-   |   in this procedural macro expansion
-   |
-   = note: this error originates in the macro `__import_tokens_attr_derive_impl_inner` which comes from the expansion of the attribute macro `derive_impl` (in Nightly builds, run with -Z macro-backtrace for more info)
+39 | struct Something {}
+   | ^^^^^^

frame/support/test/tests/derive_impl_ui/bad_disambiguation_path.stderr

@@ -1,16 +1,5 @@
 error[E0433]: failed to resolve: use of undeclared type `Insect`
-  --> tests/derive_impl_ui/bad_disambiguation_path.rs:24:1
+  --> tests/derive_impl_ui/bad_disambiguation_path.rs:38:35
    |
-24 | / #[register_default_impl(FourLeggedAnimal)]
-25 | | impl Animal for FourLeggedAnimal {
-26 | |     type Locomotion = RunsOnFourLegs;
-27 | |     type Diet = Omnivore;
-...  |
-37 | |
-38 | | #[derive_impl(FourLeggedAnimal as Insect)]
-   | | -----------------------------------------^
-   | |_|________________________________________|
-   |   |                                        use of undeclared type `Insect`
-   |   in this procedural macro expansion
-   |
-   = note: this error originates in the macro `__import_tokens_attr_derive_impl_inner` which comes from the expansion of the attribute macro `derive_impl` (in Nightly builds, run with -Z macro-backtrace for more info)
+38 | #[derive_impl(FourLeggedAnimal as Insect)]
+   |                                   ^^^^^^ use of undeclared type `Insect`