Stricter linting rule (#582)

Cargo.toml

@@ -28,3 +28,7 @@ dbg_macro = "deny"
 missing_const_for_fn = "deny"
 std_instead_of_alloc = "deny"
 std_instead_of_core = "deny"
+
+[lints.rust]
+missing_docs = "deny"
+warnings = "deny"

build.rs

@@ -1,8 +1,37 @@
+//! A build script.
+
 const LIB_ATOMIC_OPS_DIR: &str = "vendor/libatomic_ops";
 const LIB_GC_DIR: &str = "vendor/bdwgc";
 
-#[cfg(feature = "autotools")]
+cfg_select! {
-fn main() {
+    feature = "cmake" => {
+        fn main() {
+            use cmake::Config;
+            use std::path::Path;
+
+            let libatomic_include_path = Path::new(LIB_ATOMIC_OPS_DIR)
+                .join("src")
+                .canonicalize()
+                .unwrap()
+                .display()
+                .to_string()
+                .replace(r"\\?\", "");
+
+            let dst = Config::new(LIB_GC_DIR)
+                .profile("Release")
+                .define("GC_BUILD_SHARED_LIBS", "FALSE")
+                .cflag(format!("-I{}", libatomic_include_path))
+                .build();
+
+            println!(
+                "cargo:rustc-link-search=native={}",
+                dst.join("lib").display()
+            );
+            println!("cargo:rustc-link-lib=static=gc");
+        }
+    }
+    feature = "autotools" => {
+        fn main() {
             for dir in &[LIB_ATOMIC_OPS_DIR, LIB_GC_DIR] {
                 std::process::Command::new("sh")
                     .arg("-c")
@@ -42,30 +71,6 @@ fn main() {
                     .output()
                     .unwrap();
             }
-}
+        }
-
+    }
-#[cfg(feature = "cmake")]
-fn main() {
-    use cmake::Config;
-    use std::path::Path;
-
-    let libatomic_include_path = Path::new(LIB_ATOMIC_OPS_DIR)
-        .join("src")
-        .canonicalize()
-        .unwrap()
-        .display()
-        .to_string()
-        .replace(r"\\?\", "");
-
-    let dst = Config::new(LIB_GC_DIR)
-        .profile("Release")
-        .define("GC_BUILD_SHARED_LIBS", "FALSE")
-        .cflag(format!("-I{}", libatomic_include_path))
-        .build();
-
-    println!(
-        "cargo:rustc-link-search=native={}",
-        dst.join("lib").display()
-    );
-    println!("cargo:rustc-link-lib=static=gc");
 }

src/lib.rs

@@ -3,8 +3,10 @@
 
 mod error;
 
-use core::alloc::{GlobalAlloc, Layout};
+use core::{
-use core::ptr::null;
+    alloc::{GlobalAlloc, Layout},
+    ptr::null,
+};
 use libc::{c_int, c_void, size_t};
 
 const GC_SUCCESS: c_int = 0;
@@ -38,6 +40,7 @@ unsafe extern "C" {
     ) -> *mut c_void;
 }
 
+/// An allocator.
 pub struct Allocator;
 
 impl Allocator {