Merge pull request #22 from alecmocatta/borrowck-fix

Borrowck fix

Cargo.toml

@@ -2,7 +2,7 @@
 
 [package]
 name = "serde_closure"
-version = "0.2.7"
+version = "0.2.8"
 license = "MIT OR Apache-2.0"
 authors = ["Alec Mocatta <[email protected]>"]
 categories = ["development-tools","encoding","rust-patterns","network-programming"]
@@ -14,7 +14,7 @@ This library provides macros that wrap closures to make them serializable and de
 """
 repository = "https://github.com/alecmocatta/serde_closure"
 homepage = "https://github.com/alecmocatta/serde_closure"
-documentation = "https://docs.rs/serde_closure/0.2.7"
+documentation = "https://docs.rs/serde_closure/0.2.8"
 readme = "README.md"
 edition = "2018"
 
@@ -23,7 +23,7 @@ azure-devops = { project = "alecmocatta/serde_closure", pipeline = "tests" }
 maintenance = { status = "actively-developed" }
 
 [dependencies]
-serde_closure_derive = { version = "=0.2.7", path = "serde_closure_derive" }
+serde_closure_derive = { version = "=0.2.8", path = "serde_closure_derive" }
 serde = { version = "1.0", features = ["derive"] }
 proc-macro-hack = "0.5"
 

README.md

@@ -4,7 +4,7 @@
 [![MIT / Apache 2.0 licensed](https://img.shields.io/crates/l/serde_closure.svg?maxAge=2592000)](#License)
 [![Build Status](https://dev.azure.com/alecmocatta/serde_closure/_apis/build/status/tests?branchName=master)](https://dev.azure.com/alecmocatta/serde_closure/_build/latest?branchName=master)
 
-[Docs](https://docs.rs/serde_closure/0.2.7)
+[Docs](https://docs.rs/serde_closure/0.2.8)
 
 Serializable and debuggable closures.
 
@@ -30,9 +30,9 @@ requires nightly Rust for the `unboxed_closures` and `fn_traits` features (rust
 issue [#29625](https://github.com/rust-lang/rust/issues/29625)).
 
  * There are three macros,
-   [`FnOnce`](https://docs.rs/serde_closure/0.2.7/serde_closure/macro.FnOnce.html),
-   [`FnMut`](https://docs.rs/serde_closure/0.2.7/serde_closure/macro.FnMut.html)
-   and [`Fn`](https://docs.rs/serde_closure/0.2.7/serde_closure/macro.Fn.html),
+   [`FnOnce`](https://docs.rs/serde_closure/0.2.8/serde_closure/macro.FnOnce.html),
+   [`FnMut`](https://docs.rs/serde_closure/0.2.8/serde_closure/macro.FnMut.html)
+   and [`Fn`](https://docs.rs/serde_closure/0.2.8/serde_closure/macro.Fn.html),
    corresponding to the three types of Rust closure.
  * Wrap your closure with one of the macros and it will now implement `Copy`,
    `Clone`, `PartialEq`, `Eq`, `Hash`, `PartialOrd`, `Ord`, `Serialize`,

serde_closure_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_closure_derive"
-version = "0.2.7"
+version = "0.2.8"
 license = "MIT OR Apache-2.0"
 authors = ["Alec Mocatta <[email protected]>"]
 categories = ["development-tools","encoding","rust-patterns","network-programming"]
@@ -14,7 +14,7 @@ See https://crates.io/crates/serde_closure for documentation.
 """
 repository = "https://github.com/alecmocatta/serde_closure"
 homepage = "https://github.com/alecmocatta/serde_closure"
-documentation = "https://docs.rs/serde_closure/0.2.7"
+documentation = "https://docs.rs/serde_closure/0.2.8"
 edition = "2018"
 
 [badges]

serde_closure_derive/src/lib.rs

@@ -9,7 +9,7 @@
 //! See [`serde_closure`](https://docs.rs/serde_closure/) for
 //! documentation.
 
-#![doc(html_root_url = "https://docs.rs/serde_closure_derive/0.2.7")]
+#![doc(html_root_url = "https://docs.rs/serde_closure_derive/0.2.8")]
 #![feature(proc_macro_diagnostic)]
 #![allow(non_snake_case)] // due to proc-macro-hack can't apply this directly
 
@@ -404,15 +404,23 @@ fn impl_fn_once(closure: Closure, kind: Kind) -> Result<TokenStream, Error> {
 				#fn_impl
 			}
 
+			// This asserts that inferred env variables aren't nameable types.
 			{
 				#(let #env_variables = ::serde_closure::internal::a_variable;)*
 			}
-			#[allow(unreachable_code)]
-			{
-				if false {
-					#(#env_variables = loop {};)*
-				}
-			}
+			// This asserts that inferred env variables aren't types with >=1 type parameters.
+			if false {
+				#(&#env_variables::<>;)*
+			}
+			// TODO: Work out how to assert env variables aren't unnameable types with 0 type parameters.
+			// This might work in the future, but today it causes borrowck issues:
+			// https://users.rust-lang.org/t/statically-asserting-an-ident-is-a-variable-not-a-type/34619
+			// #[allow(unreachable_code)]
+			// {
+			// 	if false {
+			// 		#(#env_variables = loop {};)*
+			// 	}
+			// }
 
 			let mut #ret_name = #impls_name::#name::new(#env_capture);
 			let #env_types_name = ::serde_closure::internal::to_phantom(&#ret_name);

src/lib.rs

@@ -164,7 +164,7 @@
 //! automatically serializable and deserializable with
 //! [`serde`](https://github.com/serde-rs/serde).
 
-#![doc(html_root_url = "https://docs.rs/serde_closure/0.2.7")]
+#![doc(html_root_url = "https://docs.rs/serde_closure/0.2.8")]
 #![feature(unboxed_closures, fn_traits)]
 #![warn(
 	missing_copy_implementations,

tests/test.rs

@@ -442,6 +442,23 @@ fn capturing() {
 	fn serialize<T: Serialize>(_t: &T) {}
 }
 
+#[test]
+fn multiple_async() {
+	let x = 10usize;
+
+	let _left = async {
+		FnOnce!(move || {
+			let _ = x;
+		})
+	};
+
+	let _right = async {
+		FnOnce!(move || {
+			let _ = x;
+		})
+	};
+}
+
 mod no_prelude {
 	#![no_implicit_prelude]