Do not derive Copy/Debug for some opaque types

When we treat a type as opaque, either because it is explicitly
annotated as such or because it is a template that has a non-type
parameter, we need to check if the size is larger than
RUST_DERIVE_IN_ARRAY_LIMIT.

Performing this check requires information that is up the stack, in the
`Item` rather than in the `CompInfo` or `Type`. Therefore, I introduced
two traits to encapsulate whether a thing can derive `Debug` and `Copy`
(the `CanDeriveDebug` and `CanDeriveCopy` traits, respectively) and
implemented them for ALL THE THINGS. This allowes us to perform our
various checks at the level where we have access to the necessary info,
and to let sub-levels do their own checks with their sub-info.

Fixes #372.

2 files changed, 79 insertions, 0 deletions

diff --git a/libbindgen/tests/expectations/tests/issue-372.rs b/libbindgen/tests/expectations/tests/issue-372.rs
new file mode 100644
index 00000000..c6d9209e
--- /dev/null
+++ b/libbindgen/tests/expectations/tests/issue-372.rs
@@ -0,0 +1,63 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(non_snake_case)]
+
+
+pub mod root {
+    #[allow(unused_imports)]
+    use self::super::root;
+    #[repr(C)]
+    #[derive(Debug, Copy)]
+    pub struct d {
+        pub m: root::i,
+    }
+    #[test]
+    fn bindgen_test_layout_d() {
+        assert_eq!(::std::mem::size_of::<d>() , 24usize);
+        assert_eq!(::std::mem::align_of::<d>() , 8usize);
+    }
+    impl Clone for d {
+        fn clone(&self) -> Self { *self }
+    }
+    #[repr(C)]
+    #[derive(Debug, Copy)]
+    pub struct i {
+        pub j: *mut root::i,
+        pub k: *mut root::i,
+        pub l: bool,
+    }
+    #[test]
+    fn bindgen_test_layout_i() {
+        assert_eq!(::std::mem::size_of::<i>() , 24usize);
+        assert_eq!(::std::mem::align_of::<i>() , 8usize);
+    }
+    impl Clone for i {
+        fn clone(&self) -> Self { *self }
+    }
+    #[repr(u32)]
+    #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+    pub enum n {
+        o = 0,
+        p = 1,
+        q = 2,
+        r = 3,
+        s = 4,
+        t = 5,
+        b = 6,
+        ae = 7,
+        e = 8,
+        ag = 9,
+        ah = 10,
+        ai = 11,
+    }
+    #[repr(C)]
+    pub struct F {
+        pub w: [u64; 33usize],
+    }
+    #[test]
+    fn bindgen_test_layout_F() {
+        assert_eq!(::std::mem::size_of::<F>() , 264usize);
+        assert_eq!(::std::mem::align_of::<F>() , 8usize);
+    }
+}
diff --git a/libbindgen/tests/headers/issue-372.hpp b/libbindgen/tests/headers/issue-372.hpp
new file mode 100644
index 00000000..a072f061
--- /dev/null
+++ b/libbindgen/tests/headers/issue-372.hpp
@@ -0,0 +1,16 @@
+// bindgen-flags: --enable-cxx-namespaces
+template <typename a, int b> class c { a e[b]; };
+class d;
+template <typename g, g f> class C { c<d, f> h; };
+class i {
+  i *j;
+  i *k;
+  bool l;
+};
+class d {
+  i m;
+};
+enum n { o, p, q, r, s, t, b, ae, e, ag, ah, ai };
+class F {
+  C<n, ai> w;
+};