Split trait_transformer back into its own crate

Cargo.toml

@@ -1,6 +1,7 @@
 [workspace]
 members = [
     "trait-variant",
+    "trait-transformer",
 ]
 
 resolver = "2"

README.md

@@ -22,7 +22,7 @@ Implementers of the trait can choose to implement the variant instead of the ori
 
 ## `trait_transformer`
 
-`trait_transformer` does the same thing as `make`, but using experimental nightly-only syntax that depends on the `return_type_notation` feature. It may be used to experiment with new kinds of trait transformations in the future.
+`trait_transformer` does the same thing as `trait_variant`, but using experimental nightly-only syntax that depends on the `return_type_notation` feature. It may be used to experiment with new kinds of trait transformations in the future.
 
 #### License and usage notes
 

trait-transformer/Cargo.toml

@@ -0,0 +1,30 @@
+# Copyright (c) 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+[package]
+name = "trait-transformer"
+version = "0.0.0"
+description = "Utilities for working with impl traits in Rust"
+categories = ["asynchronous", "no-std", "rust-patterns"]
+keywords = ["async", "trait", "impl"]
+license.workspace = true
+repository.workspace = true
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = { version = "2.0", features = ["full"] }
+
+[dev-dependencies]
+tokio = { version = "1", features = ["rt"] }

trait-variant/examples/trait_transformer.rs → trait-transformer/examples/trait_transformer.rs

@@ -11,7 +11,7 @@
 
 use std::iter;
 
-use trait_variant::trait_transformer;
+use trait_transformer::trait_transformer;
 
 #[trait_transformer(SendIntFactory: Send)]
 trait IntFactory {

trait-transformer/src/lib.rs

@@ -0,0 +1,17 @@
+// Copyright (c) 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+mod transformer;
+
+#[proc_macro_attribute]
+pub fn trait_transformer(
+    attr: proc_macro::TokenStream,
+    item: proc_macro::TokenStream,
+) -> proc_macro::TokenStream {
+    transformer::trait_transformer(attr, item)
+}

trait-variant/src/lib.rs

@@ -8,17 +8,8 @@
 
 #![doc = include_str!("../README.md")]
 
-mod transformer;
 mod variant;
 
-#[proc_macro_attribute]
-pub fn trait_transformer(
-    attr: proc_macro::TokenStream,
-    item: proc_macro::TokenStream,
-) -> proc_macro::TokenStream {
-    transformer::trait_transformer(attr, item)
-}
-
 #[proc_macro_attribute]
 pub fn make(
     attr: proc_macro::TokenStream,