Add support for no_std compilation (updated)

.github/workflows/rust.yml

@@ -25,6 +25,20 @@ jobs:
       run: cargo test --verbose --all-features --all
     - name: Build Examples
       run: cargo build --examples --all-features --all
+  no_std_build:
+    name: no_std Build
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - run: rustup update
+    - name: Build
+      run: cargo build --verbose --no-default-features
+    - name: Build
+      run: cargo build --verbose --no-default-features --features=alloc
+    - name: Run tests
+      run: cargo test --verbose --no-default-features
+    - name: Run tests as no_std with alloc
+      run: cargo test --verbose --no-default-features --features=alloc
   clippy:
     name: Clippy
     runs-on: ubuntu-latest

Cargo.toml

@@ -23,8 +23,15 @@ rust-version = "1.63.0"
 derive_arbitrary = { version = "1.3.2", path = "./derive", optional = true }
 
 [features]
+# Provide support for std types by default.
+default = ["std"]
 # Turn this feature on to enable support for `#[derive(Arbitrary)]`.
 derive = ["derive_arbitrary"]
+# Whether or not to require the standard library. Turning off this feature
+# makes Arbitrary work with no_std crates.
+std = ["alloc"]
+# Provide support for alloc types.
+alloc = []
 
 [[example]]
 name = "derive_enum"

src/error.rs

@@ -1,4 +1,4 @@
-use std::{error, fmt};
+use core::fmt;
 
 /// An enumeration of buffer creation errors
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -32,12 +32,13 @@ impl fmt::Display for Error {
     }
 }
 
-impl error::Error for Error {}
+#[cfg(feature = "std")]
+impl std::error::Error for Error {}
 
 /// A `Result` with the error type fixed as `arbitrary::Error`.
 ///
 /// Either an `Ok(T)` or `Err(arbitrary::Error)`.
-pub type Result<T, E = Error> = std::result::Result<T, E>;
+pub type Result<T, E = Error> = core::result::Result<T, E>;
 
 #[cfg(test)]
 mod tests {