Bump MSRV to 1.56 and Rust edition to 2021

Cargo.toml

@@ -5,9 +5,10 @@ authors = ["Manuel Woelker <[email protected]>"]
 description = "A virtual filesystem for Rust"
 repository = "https://github.com/manuel-woelker/rust-vfs"
 readme = "README.md"
+edition = "2021"
+rust-version = "1.56"
 keywords = ["vfs", "virtual", "filesystem", "async"]
 license = "Apache-2.0"
-edition = "2021"
 
 [badges]
 travis-ci = { repository = "manuel-woelker/rust-vfs", branch = "master" }

src/error.rs

@@ -26,9 +26,7 @@ impl From<VfsErrorKind> for VfsError {
         let kind = match kind {
             VfsErrorKind::IoError(io) => match io.kind() {
                 io::ErrorKind::NotFound => VfsErrorKind::FileNotFound,
-                // TODO: If MSRV changes to 1.53, enable this. Alternatively,
-                //      if it's possible to #[cfg] just this line, try that
-                // io::ErrorKind::Unsupported => VfsErrorKind::NotSupported,
+                io::ErrorKind::Unsupported => VfsErrorKind::NotSupported,
                 _ => VfsErrorKind::IoError(io),
             },
             // Remaining kinda are passed through as-is

src/impls/altroot.rs

@@ -25,13 +25,12 @@ impl AltrootFS {
 }
 
 impl AltrootFS {
-    #[allow(clippy::manual_strip)] // strip prefix manually for MSRV 1.32
     fn path(&self, path: &str) -> VfsResult<VfsPath> {
         if path.is_empty() {
             return Ok(self.root.clone());
         }
-        if path.starts_with('/') {
-            return self.root.join(&path[1..]);
+        if let Some(path) = path.strip_prefix('/') {
+            return self.root.join(path);
         }
         self.root.join(path)
     }

src/test_macros.rs

@@ -696,7 +696,7 @@ use super::*;
             fn read_to_string_nonutf8() -> VfsResult<()> {
                 let root = create_root();
                 let path = root.join("foobar.txt")?;
-                path.create_file()?.write_all(&vec![0, 159, 146, 150])?;
+                path.create_file()?.write_all(&[0, 159, 146, 150])?;
                 let error_message = path.read_to_string().expect_err("read_to_string").to_string();
                 assert_eq!(
                     &error_message,