Auto merge of #248 - emilio:union-debug-again, r=fitzgen

codegen: Always implement debug for __BindgenUnionField.

Our debug-detection code assumes so.

Fixes #246

r? @fitzgen

Author: bors-servo

src/codegen/mod.rs

@@ -1930,8 +1930,10 @@ mod utils {
     pub fn prepend_union_types(ctx: &BindgenContext,
                                result: &mut Vec<P<ast::Item>>) {
         let prefix = ctx.trait_prefix();
+
+        // TODO(emilio): The fmt::Debug impl could be way nicer with
+        // std::intrinsics::type_name, but...
         let union_field_decl = quote_item!(ctx.ext_cx(),
-            #[derive(Debug)]
             #[repr(C)]
             pub struct __BindgenUnionField<T>(
                 ::$prefix::marker::PhantomData<T>);
@@ -1983,11 +1985,22 @@ mod utils {
         )
             .unwrap();
 
+        let union_field_debug_impl = quote_item!(ctx.ext_cx(),
+            impl<T> ::std::fmt::Debug for __BindgenUnionField<T> {
+                fn fmt(&self, fmt: &mut ::std::fmt::Formatter)
+                       -> ::std::fmt::Result {
+                    fmt.write_str("__BindgenUnionField")
+                }
+            }
+        )
+            .unwrap();
+
         let items = vec![
             union_field_decl, union_field_impl,
             union_field_default_impl,
             union_field_clone_impl,
             union_field_copy_impl,
+            union_field_debug_impl,
         ];
 
         let old_items = mem::replace(result, items);

tests/expectations/tests/anon_union.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct TErrorResult<T> {

tests/expectations/tests/class.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 pub struct C {
     pub a: ::std::os::raw::c_int,

tests/expectations/tests/class_with_inner_struct.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct A {

tests/expectations/tests/jsval_layout_opaque.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 pub const JSVAL_TAG_SHIFT: ::std::os::raw::c_uint = 47;
 pub const JSVAL_PAYLOAD_MASK: ::std::os::raw::c_ulonglong = 140737488355327;
 pub const JSVAL_TAG_MASK: ::std::os::raw::c_longlong = -140737488355328;

tests/expectations/tests/struct_with_anon_union.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct foo {

tests/expectations/tests/struct_with_anon_unnamed_union.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct foo {

tests/expectations/tests/struct_with_nesting.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct foo {

tests/expectations/tests/typeref.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct nsFoo {

tests/expectations/tests/union_dtor.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug)]
 pub struct UnionWithDtor {

tests/expectations/tests/union_fields.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct _bindgen_ty_1 {

tests/expectations/tests/union_template.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct NastyStruct<T> {

tests/expectations/tests/union_with_anon_struct.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct foo {

tests/expectations/tests/union_with_anon_struct_bitfield.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct foo {

tests/expectations/tests/union_with_anon_union.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct foo {

tests/expectations/tests/union_with_anon_unnamed_struct.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct pixel {

tests/expectations/tests/union_with_anon_unnamed_union.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct foo {

tests/expectations/tests/union_with_big_member.rs

@@ -4,7 +4,6 @@
 #![allow(non_snake_case)]
 
 
-#[derive(Debug)]
 #[repr(C)]
 pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
 impl <T> __BindgenUnionField<T> {
@@ -24,6 +23,11 @@ impl <T> ::std::clone::Clone for __BindgenUnionField<T> {
     fn clone(&self) -> Self { Self::new() }
 }
 impl <T> ::std::marker::Copy for __BindgenUnionField<T> { }
+impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        fmt.write_str("__BindgenUnionField")
+    }
+}
 #[repr(C)]
 #[derive(Copy)]
 pub struct WithBigArray {
@@ -40,6 +44,21 @@ impl Clone for WithBigArray {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
+#[derive(Debug, Copy)]
+pub struct WithBigArray2 {
+    pub a: __BindgenUnionField<::std::os::raw::c_int>,
+    pub b: __BindgenUnionField<[::std::os::raw::c_char; 33usize]>,
+    pub bindgen_union_field: [u32; 9usize],
+}
+#[test]
+fn bindgen_test_layout_WithBigArray2() {
+    assert_eq!(::std::mem::size_of::<WithBigArray2>() , 36usize);
+    assert_eq!(::std::mem::align_of::<WithBigArray2>() , 4usize);
+}
+impl Clone for WithBigArray2 {
+    fn clone(&self) -> Self { *self }
+}
+#[repr(C)]
 #[derive(Copy)]
 pub struct WithBigMember {
     pub a: __BindgenUnionField<::std::os::raw::c_int>,