Migrate to Rust 2021

Cargo.toml

@@ -7,7 +7,7 @@ name = "loom"
 # - Update CHANGELOG.md
 # - Create git tag
 version = "0.7.2"
-edition = "2018"
+edition = "2021"
 license = "MIT"
 authors = ["Carl Lerche <[email protected]>"]
 description = "Permutation testing for concurrent code"

src/rt/execution.rs

@@ -2,7 +2,6 @@ use crate::rt::alloc::Allocation;
 use crate::rt::{lazy_static, object, thread, Path};
 
 use std::collections::HashMap;
-use std::convert::TryInto;
 use std::fmt;
 
 use tracing::info;