implement Default trait

161 files changed, 968 insertions, 204 deletions

diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index 0fdfaad0..5ee43173 100644
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -8,7 +8,7 @@ use aster;
 use ir::annotations::FieldAccessorKind;
 use ir::comp::{Base, CompInfo, CompKind, Field, Method, MethodKind};
 use ir::context::{BindgenContext, ItemId};
-use ir::derive::{CanDeriveCopy, CanDeriveDebug};
+use ir::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault};
 use ir::enum_ty::{Enum, EnumVariant, EnumVariantValue};
 use ir::function::{Function, FunctionSig};
 use ir::int::IntKind;
@@ -688,10 +688,16 @@ impl<'a> CodeGenerator for Vtable<'a> {
         assert_eq!(item.id(), self.item_id);
         // For now, generate an empty struct, later we should generate function
         // pointers and whatnot.
+        let mut attributes = vec![attributes::repr("C")];
+
+        if ctx.options().derive_default {
+            attributes.push(attributes::derives(&["Default"]))
+        }
+
         let vtable = aster::AstBuilder::new()
             .item()
             .pub_()
-            .with_attr(attributes::repr("C"))
+            .with_attrs(attributes)
             .struct_(self.canonical_name(ctx))
             .build();
         result.push(vtable);
@@ -879,6 +885,7 @@ impl CodeGenerator for CompInfo {
 
         let mut attributes = vec![];
         let mut needs_clone_impl = false;
+        let mut needs_default_impl = false;
         if ctx.options().generate_comments {
             if let Some(comment) = item.comment() {
                 attributes.push(attributes::doc(comment));
@@ -896,6 +903,12 @@ impl CodeGenerator for CompInfo {
             derives.push("Debug");
         }
 
+        if item.can_derive_default(ctx, ()) {
+            derives.push("Default");
+        } else {
+            needs_default_impl = ctx.options().derive_default;
+        }
+
         if item.can_derive_copy(ctx, ()) &&
            !item.annotations().disallow_copy() {
             derives.push("Copy");
@@ -1440,8 +1453,14 @@ impl CodeGenerator for CompInfo {
 
         // NB: We can't use to_rust_ty here since for opaque types this tries to
         // use the specialization knowledge to generate a blob field.
-        let ty_for_impl =
-            aster::AstBuilder::new().ty().path().id(&canonical_name).build();
+        let ty_for_impl = aster::AstBuilder::new()
+            .ty()
+            .path()
+            .segment(&canonical_name)
+            .with_generics(generics.clone())
+            .build()
+            .build();
+
         if needs_clone_impl {
             let impl_ = quote_item!(ctx.ext_cx(),
                 impl X {
@@ -1467,6 +1486,32 @@ impl CodeGenerator for CompInfo {
             result.push(clone_impl);
         }
 
+        if needs_default_impl {
+            let prefix = ctx.trait_prefix();
+            let impl_ = quote_item!(ctx.ext_cx(),
+                impl X {
+                    fn default() -> Self { unsafe { ::$prefix::mem::zeroed() } }
+                }
+            );
+
+            let impl_ = match impl_.unwrap().node {
+                ast::ItemKind::Impl(_, _, _, _, _, ref items) => items.clone(),
+                _ => unreachable!(),
+            };
+
+            let default_impl = aster::AstBuilder::new()
+                .item()
+                .impl_()
+                .trait_()
+                .id("Default")
+                .build()
+                .with_generics(generics.clone())
+                .with_items(impl_)
+                .build_ty(ty_for_impl.clone());
+
+            result.push(default_impl);
+        }
+
         if !methods.is_empty() {
             let methods = aster::AstBuilder::new()
                 .item()
@@ -2582,6 +2627,7 @@ mod utils {
 
         let incomplete_array_decl = quote_item!(ctx.ext_cx(),
             #[repr(C)]
+            #[derive(Default)]
             pub struct __IncompleteArrayField<T>(
                 ::$prefix::marker::PhantomData<T>);
         )
diff --git a/src/ir/comp.rs b/src/ir/comp.rs
index 53efd278..1ca39559 100644
--- a/src/ir/comp.rs
+++ b/src/ir/comp.rs
@@ -2,7 +2,7 @@
 
 use super::annotations::Annotations;
 use super::context::{BindgenContext, ItemId};
-use super::derive::{CanDeriveCopy, CanDeriveDebug};
+use super::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault};
 use super::item::Item;
 use super::layout::Layout;
 use super::ty::Type;
@@ -171,6 +171,14 @@ impl CanDeriveDebug for Field {
     }
 }
 
+impl CanDeriveDefault for Field {
+    type Extra = ();
+
+    fn can_derive_default(&self, ctx: &BindgenContext, _: ()) -> bool {
+        self.ty.can_derive_default(ctx, ())
+    }
+}
+
 impl<'a> CanDeriveCopy<'a> for Field {
     type Extra = ();
 
@@ -296,6 +304,10 @@ pub struct CompInfo {
     /// around the template arguments.
     detect_derive_debug_cycle: Cell<bool>,
 
+    /// Used to detect if we've run in a can_derive_default cycle while cycling
+    /// around the template arguments.
+    detect_derive_default_cycle: Cell<bool>,
+
     /// Used to detect if we've run in a has_destructor cycle while cycling
     /// around the template arguments.
     detect_has_destructor_cycle: Cell<bool>,
@@ -326,6 +338,7 @@ impl CompInfo {
             is_anonymous: false,
             found_unknown_attr: false,
             detect_derive_debug_cycle: Cell::new(false),
+            detect_derive_default_cycle: Cell::new(false),
             detect_has_destructor_cycle: Cell::new(false),
             is_forward_declaration: false,
         }
@@ -952,6 +965,52 @@ impl CanDeriveDebug for CompInfo {
     }
 }
 
+impl CanDeriveDefault for CompInfo {
+    type Extra = Option<Layout>;
+
+    fn can_derive_default(&self,
+                          ctx: &BindgenContext,
+                          layout: Option<Layout>)
+                          -> bool {
+        // We can reach here recursively via template parameters of a member,
+        // for example.
+        if self.detect_derive_default_cycle.get() {
+            warn!("Derive default cycle detected!");
+            return true;
+        }
+
+        if self.kind == CompKind::Union {
+            if ctx.options().unstable_rust {
+                return false;
+            }
+
+            return layout.unwrap_or_else(Layout::zero)
+                .opaque()
+                .can_derive_debug(ctx, ());
+        }
+
+        self.detect_derive_default_cycle.set(true);
+
+        let can_derive_default = !self.has_vtable(ctx) &&
+                                 !self.needs_explicit_vtable(ctx) &&
+                                 self.base_members
+            .iter()
+            .all(|base| base.ty.can_derive_default(ctx, ())) &&
+                                 self.template_args
+            .iter()
+            .all(|id| id.can_derive_default(ctx, ())) &&
+                                 self.fields
+            .iter()
+            .all(|f| f.can_derive_default(ctx, ())) &&
+                                 self.ref_template
+            .map_or(true, |id| id.can_derive_default(ctx, ()));
+
+        self.detect_derive_default_cycle.set(false);
+
+        can_derive_default
+    }
+}
+
 impl<'a> CanDeriveCopy<'a> for CompInfo {
     type Extra = (&'a Item, Option<Layout>);
 
diff --git a/src/ir/context.rs b/src/ir/context.rs
index 38ecdf17..a7482394 100644
--- a/src/ir/context.rs
+++ b/src/ir/context.rs
@@ -1,6 +1,6 @@
 //! Common context that is passed around during parsing and codegen.
 
-use super::derive::{CanDeriveCopy, CanDeriveDebug};
+use super::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault};
 use super::int::IntKind;
 use super::item::{Item, ItemCanonicalPath};
 use super::item_kind::ItemKind;
@@ -42,6 +42,14 @@ impl CanDeriveDebug for ItemId {
     }
 }
 
+impl CanDeriveDefault for ItemId {
+    type Extra = ();
+
+    fn can_derive_default(&self, ctx: &BindgenContext, _: ()) -> bool {
+        ctx.resolve_item(*self).can_derive_default(ctx, ())
+    }
+}
+
 impl<'a> CanDeriveCopy<'a> for ItemId {
     type Extra = ();
 
diff --git a/src/ir/derive.rs b/src/ir/derive.rs
index d13a8117..6d9f368b 100644
--- a/src/ir/derive.rs
+++ b/src/ir/derive.rs
@@ -65,3 +65,24 @@ pub trait CanDeriveCopy<'a> {
                                 extra: Self::Extra)
                                 -> bool;
 }
+
+/// A trait that encapsulates the logic for whether or not we can derive `Default`
+/// for a given thing.
+///
+/// This should ideally be a no-op that just returns `true`, but instead needs
+/// to be a recursive method that checks whether all the proper members can
+/// derive default or not, because of the limit rust has on 32 items as max in the
+/// array.
+pub trait CanDeriveDefault {
+    /// Implementations can define this type to get access to any extra
+    /// information required to determine whether they can derive `Default`. If
+    /// extra information is unneeded, then this should simply be the unit type.
+    type Extra;
+
+    /// Return `true` if `Default` can be derived for this thing, `false`
+    /// otherwise.
+    fn can_derive_default(&self,
+                          ctx: &BindgenContext,
+                          extra: Self::Extra)
+                          -> bool;
+}
\ No newline at end of file
diff --git a/src/ir/item.rs b/src/ir/item.rs
index a5d10e41..c8de95c0 100644
--- a/src/ir/item.rs
+++ b/src/ir/item.rs
@@ -2,7 +2,7 @@
 
 use super::annotations::Annotations;
 use super::context::{BindgenContext, ItemId};
-use super::derive::{CanDeriveCopy, CanDeriveDebug};
+use super::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault};
 use super::function::Function;
 use super::item_kind::ItemKind;
 use super::module::Module;
@@ -235,6 +235,26 @@ impl CanDeriveDebug for Item {
     }
 }
 
+impl CanDeriveDefault for Item {
+    type Extra = ();
+
+    fn can_derive_default(&self, ctx: &BindgenContext, _: ()) -> bool {
+        ctx.options().derive_default &&
+        match self.kind {
+            ItemKind::Type(ref ty) => {
+                if self.is_opaque(ctx) {
+                    ty.layout(ctx)
+                        .map_or(false,
+                                |l| l.opaque().can_derive_default(ctx, ()))
+                } else {
+                    ty.can_derive_default(ctx, ())
+                }
+            }
+            _ => false,
+        }
+    }
+}
+
 impl<'a> CanDeriveCopy<'a> for Item {
     type Extra = ();
 
diff --git a/src/ir/layout.rs b/src/ir/layout.rs
index e8c6c32b..03d43b51 100644
--- a/src/ir/layout.rs
+++ b/src/ir/layout.rs
@@ -1,7 +1,7 @@
 //! Intermediate representation for the physical layout of some type.
 
 use super::context::BindgenContext;
-use super::derive::{CanDeriveCopy, CanDeriveDebug};
+use super::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault};
 use super::ty::RUST_DERIVE_IN_ARRAY_LIMIT;
 use std::cmp;
 
@@ -79,6 +79,15 @@ impl CanDeriveDebug for Opaque {
     }
 }
 
+impl CanDeriveDefault for Opaque {
+    type Extra = ();
+
+    fn can_derive_default(&self, _: &BindgenContext, _: ()) -> bool {
+        self.array_size()
+            .map_or(false, |size| size <= RUST_DERIVE_IN_ARRAY_LIMIT)
+    }
+}
+
 impl<'a> CanDeriveCopy<'a> for Opaque {
     type Extra = ();
 
diff --git a/src/ir/ty.rs b/src/ir/ty.rs
index 5903430c..c3a35f0f 100644
--- a/src/ir/ty.rs
+++ b/src/ir/ty.rs
@@ -2,7 +2,7 @@
 
 use super::comp::CompInfo;
 use super::context::{BindgenContext, ItemId};
-use super::derive::{CanDeriveCopy, CanDeriveDebug};
+use super::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault};
 use super::enum_ty::Enum;
 use super::function::FunctionSig;
 use super::int::IntKind;
@@ -412,6 +412,39 @@ impl CanDeriveDebug for Type {
     }
 }
 
+impl CanDeriveDefault for Type {
+    type Extra = ();
+
+    fn can_derive_default(&self, ctx: &BindgenContext, _: ()) -> bool {
+        match self.kind {
+            TypeKind::Array(t, len) => {
+                len <= RUST_DERIVE_IN_ARRAY_LIMIT &&
+                t.can_derive_default(ctx, ())
+            }
+            TypeKind::ResolvedTypeRef(t) |
+            TypeKind::TemplateAlias(t, _) |
+            TypeKind::Alias(t) => t.can_derive_default(ctx, ()),
+            TypeKind::Comp(ref info) => {
+                info.can_derive_default(ctx, self.layout(ctx))
+            }
+            TypeKind::Void |
+            TypeKind::Named |
+            TypeKind::TemplateRef(..) |
+            TypeKind::Reference(..) |
+            TypeKind::NullPtr |
+            TypeKind::Pointer(..) |
+            TypeKind::BlockPointer |
+            TypeKind::ObjCInterface(..) |
+            TypeKind::Enum(..) => false,
+            TypeKind::Function(..) |
+            TypeKind::Int(..) |
+            TypeKind::Float(..) |
+            TypeKind::Complex(..) => true,
+            TypeKind::UnresolvedTypeRef(..) => unreachable!(),
+        }
+    }
+}
+
 impl<'a> CanDeriveCopy<'a> for Type {
     type Extra = &'a Item;
 
diff --git a/src/lib.rs b/src/lib.rs
index 84a2ee67..38ff3619 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -320,6 +320,12 @@ impl Builder {
         self
     }
 
+    /// Set whether `Default` should be derived by default.
+    pub fn derive_default(mut self, doit: bool) -> Self {
+        self.options.derive_default = doit;
+        self
+    }
+
     /// Emit Clang AST.
     pub fn emit_clang_ast(mut self) -> Builder {
         self.options.emit_ast = true;
@@ -496,6 +502,10 @@ pub struct BindgenOptions {
     /// and types.
     pub derive_debug: bool,
 
+    /// True if we shold derive Default trait implementations for C/C++ structures
+    /// and types.
+    pub derive_default: bool,
+
     /// True if we can use unstable Rust code in the bindings, false if we
     /// cannot.
     pub unstable_rust: bool,
@@ -581,6 +591,7 @@ impl Default for BindgenOptions {
             emit_ast: false,
             emit_ir: false,
             derive_debug: true,
+            derive_default: false,
             enable_cxx_namespaces: false,
             disable_name_namespacing: false,
             unstable_rust: true,
diff --git a/src/options.rs b/src/options.rs
index 8d11be2d..cc5f4845 100644
--- a/src/options.rs
+++ b/src/options.rs
@@ -42,6 +42,13 @@ pub fn builder_from_flags<I>(args: I)
             Arg::with_name("no-derive-debug")
                 .long("no-derive-debug")
                 .help("Avoid deriving Debug on any type."),
+            Arg::with_name("no-derive-default")
+                .long("no-derive-default")
+                .hidden(true)
+                .help("Avoid deriving Default on any type."),
+            Arg::with_name("with-derive-default")
+                .long("with-derive-default")
+                .help("Deriving Default on any type."),
             Arg::with_name("no-doc-comments")
                 .long("no-doc-comments")
                 .help("Avoid including doc comments in the output, see: \
@@ -212,6 +219,14 @@ pub fn builder_from_flags<I>(args: I)
         builder = builder.derive_debug(false);
     }
 
+    if matches.is_present("with-derive-default") {
+        builder = builder.derive_default(true);
+    }
+
+    if matches.is_present("no-derive-default") {
+        builder = builder.derive_default(false);
+    }
+
     if let Some(prefix) = matches.value_of("ctypes-prefix") {
         builder = builder.ctypes_prefix(prefix);
     }
diff --git a/tests/expectations/tests/16-byte-alignment.rs b/tests/expectations/tests/16-byte-alignment.rs
index b9dd74e3..2ab00679 100644
--- a/tests/expectations/tests/16-byte-alignment.rs
+++ b/tests/expectations/tests/16-byte-alignment.rs
@@ -29,21 +29,21 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_ipv4_tuple {
     pub src_addr: u32,
     pub dst_addr: u32,
     pub __bindgen_anon_1: rte_ipv4_tuple__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_ipv4_tuple__bindgen_ty_1 {
     pub __bindgen_anon_1: __BindgenUnionField<rte_ipv4_tuple__bindgen_ty_1__bindgen_ty_1>,
     pub sctp_tag: __BindgenUnionField<u32>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_ipv4_tuple__bindgen_ty_1__bindgen_ty_1 {
     pub dport: u16,
     pub sport: u16,
@@ -116,21 +116,21 @@ impl Clone for rte_ipv4_tuple {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_ipv6_tuple {
     pub src_addr: [u8; 16usize],
     pub dst_addr: [u8; 16usize],
     pub __bindgen_anon_1: rte_ipv6_tuple__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_ipv6_tuple__bindgen_ty_1 {
     pub __bindgen_anon_1: __BindgenUnionField<rte_ipv6_tuple__bindgen_ty_1__bindgen_ty_1>,
     pub sctp_tag: __BindgenUnionField<u32>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_ipv6_tuple__bindgen_ty_1__bindgen_ty_1 {
     pub dport: u16,
     pub sport: u16,
@@ -227,3 +227,6 @@ fn bindgen_test_layout_rte_thash_tuple() {
 impl Clone for rte_thash_tuple {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_thash_tuple {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/381-decltype-alias.rs b/tests/expectations/tests/381-decltype-alias.rs
index 766be3bc..45b0cfdd 100644
--- a/tests/expectations/tests/381-decltype-alias.rs
+++ b/tests/expectations/tests/381-decltype-alias.rs
@@ -10,3 +10,6 @@ pub struct std_allocator_traits<_Alloc> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<_Alloc>,
 }
+impl <_Alloc> Default for std_allocator_traits<_Alloc> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/accessors.rs b/tests/expectations/tests/accessors.rs
index c0d95bfb..753188bd 100644
--- a/tests/expectations/tests/accessors.rs
+++ b/tests/expectations/tests/accessors.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct SomeAccessors {
     pub mNoAccessor: ::std::os::raw::c_int,
     /** <div rustbindgen accessor></div> */
@@ -70,7 +70,7 @@ impl SomeAccessors {
 }
 /** <div rustbindgen accessor></div> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct AllAccessors {
     pub mBothAccessors: ::std::os::raw::c_int,
     pub mAlsoBothAccessors: ::std::os::raw::c_int,
@@ -116,7 +116,7 @@ impl AllAccessors {
 }
 /** <div rustbindgen accessor="unsafe"></div> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct AllUnsafeAccessors {
     pub mBothAccessors: ::std::os::raw::c_int,
     pub mAlsoBothAccessors: ::std::os::raw::c_int,
@@ -164,7 +164,7 @@ impl AllUnsafeAccessors {
 }
 /** <div rustbindgen accessor></div> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct ContradictAccessors {
     pub mBothAccessors: ::std::os::raw::c_int,
     /** <div rustbindgen accessor="false"></div> */
@@ -231,7 +231,7 @@ impl ContradictAccessors {
 }
 /** <div rustbindgen accessor replaces="Replaced"></div> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Replaced {
     pub mAccessor: ::std::os::raw::c_int,
 }
@@ -260,7 +260,7 @@ impl Replaced {
 }
 /** <div rustbindgen accessor></div> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Wrapper {
     pub mReplaced: Replaced,
 }
diff --git a/tests/expectations/tests/annotation_hide.rs b/tests/expectations/tests/annotation_hide.rs
index 62840b13..1ad8fd83 100644
--- a/tests/expectations/tests/annotation_hide.rs
+++ b/tests/expectations/tests/annotation_hide.rs
@@ -8,7 +8,7 @@
  * <div rustbindgen opaque></div>
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct D {
     pub _bindgen_opaque_blob: u32,
 }
@@ -23,7 +23,7 @@ impl Clone for D {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct NotAnnotated {
     pub f: ::std::os::raw::c_int,
 }
diff --git a/tests/expectations/tests/anon_enum.rs b/tests/expectations/tests/anon_enum.rs
index b2c7f5fc..07ea4810 100644
--- a/tests/expectations/tests/anon_enum.rs
+++ b/tests/expectations/tests/anon_enum.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Test {
     pub foo: ::std::os::raw::c_int,
     pub bar: f32,
diff --git a/tests/expectations/tests/anon_enum_trait.rs b/tests/expectations/tests/anon_enum_trait.rs
index c258f7d6..31eaca83 100644
--- a/tests/expectations/tests/anon_enum_trait.rs
+++ b/tests/expectations/tests/anon_enum_trait.rs
@@ -27,8 +27,11 @@ pub const DataType_type_: DataType__bindgen_ty_1 =
 #[repr(i32)]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum DataType__bindgen_ty_1 { generic_type = 0, }
+impl <_Tp> Default for DataType<_Tp> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/anon_union.rs b/tests/expectations/tests/anon_union.rs
index 6ded1e57..4418bc77 100644
--- a/tests/expectations/tests/anon_union.rs
+++ b/tests/expectations/tests/anon_union.rs
@@ -43,25 +43,28 @@ pub const TErrorResult_UnionState_HasException: TErrorResult_UnionState =
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum TErrorResult_UnionState { HasMessage = 0, }
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct TErrorResult_Message<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct TErrorResult_DOMExceptionInfo<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct TErrorResult__bindgen_ty_1<T> {
     pub mMessage: __BindgenUnionField<*mut TErrorResult_Message<T>>,
     pub mDOMExceptionInfo: __BindgenUnionField<*mut TErrorResult_DOMExceptionInfo<T>>,
     pub bindgen_union_field: u64,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for TErrorResult<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct ErrorResult {
@@ -77,6 +80,9 @@ fn bindgen_test_layout_ErrorResult() {
 impl Clone for ErrorResult {
     fn clone(&self) -> Self { *self }
 }
+impl Default for ErrorResult {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[test]
 fn __bindgen_test_layout_template_1() {
     assert_eq!(::std::mem::size_of::<TErrorResult<::std::os::raw::c_int>>() ,
diff --git a/tests/expectations/tests/auto.rs b/tests/expectations/tests/auto.rs
index 554546af..4551f703 100644
--- a/tests/expectations/tests/auto.rs
+++ b/tests/expectations/tests/auto.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub _address: u8,
 }
@@ -26,6 +26,9 @@ pub struct Bar<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Bar<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 extern "C" {
     #[link_name = "_Z5Test2v"]
     pub fn Test2() -> ::std::os::raw::c_uint;
diff --git a/tests/expectations/tests/bad-namespace-parenthood-inheritance.rs b/tests/expectations/tests/bad-namespace-parenthood-inheritance.rs
index 553879b7..b0c91e8c 100644
--- a/tests/expectations/tests/bad-namespace-parenthood-inheritance.rs
+++ b/tests/expectations/tests/bad-namespace-parenthood-inheritance.rs
@@ -10,8 +10,11 @@ pub struct std_char_traits<_CharT> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<_CharT>,
 }
+impl <_CharT> Default for std_char_traits<_CharT> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct __gnu_cxx_char_traits {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/base-to-derived.rs b/tests/expectations/tests/base-to-derived.rs
index 4749096b..6ff4ce9a 100644
--- a/tests/expectations/tests/base-to-derived.rs
+++ b/tests/expectations/tests/base-to-derived.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct false_type {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/bitfield-enum-basic.rs b/tests/expectations/tests/bitfield-enum-basic.rs
index a8d3ecc5..362cf280 100644
--- a/tests/expectations/tests/bitfield-enum-basic.rs
+++ b/tests/expectations/tests/bitfield-enum-basic.rs
@@ -48,7 +48,7 @@ impl ::std::ops::BitOr<_bindgen_ty_1> for _bindgen_ty_1 {
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct _bindgen_ty_1(pub ::std::os::raw::c_uint);
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Dummy {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/bitfield_method_mangling.rs b/tests/expectations/tests/bitfield_method_mangling.rs
index 94f0aa8e..0ab5fce5 100644
--- a/tests/expectations/tests/bitfield_method_mangling.rs
+++ b/tests/expectations/tests/bitfield_method_mangling.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct _bindgen_ty_1 {
     pub _bitfield_1: u32,
 }
diff --git a/tests/expectations/tests/canonical_path_without_namespacing.rs b/tests/expectations/tests/canonical_path_without_namespacing.rs
index dff6b707..43bec38d 100644
--- a/tests/expectations/tests/canonical_path_without_namespacing.rs
+++ b/tests/expectations/tests/canonical_path_without_namespacing.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Bar {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/class.rs b/tests/expectations/tests/class.rs
index 46adbc29..92389cbe 100644
--- a/tests/expectations/tests/class.rs
+++ b/tests/expectations/tests/class.rs
@@ -5,6 +5,7 @@
 
 
 #[repr(C)]
+#[derive(Default)]
 pub struct __IncompleteArrayField<T>(::std::marker::PhantomData<T>);
 impl <T> __IncompleteArrayField<T> {
     #[inline]
@@ -81,6 +82,9 @@ fn bindgen_test_layout_C() {
                 "Alignment of field: " , stringify ! ( C ) , "::" , stringify
                 ! ( big_array ) ));
 }
+impl Default for C {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 pub struct C_with_zero_length_array {
     pub a: ::std::os::raw::c_int,
@@ -114,6 +118,9 @@ fn bindgen_test_layout_C_with_zero_length_array() {
                 C_with_zero_length_array ) , "::" , stringify ! (
                 zero_length_array ) ));
 }
+impl Default for C_with_zero_length_array {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 pub struct C_with_incomplete_array {
     pub a: ::std::os::raw::c_int,
@@ -129,6 +136,9 @@ fn bindgen_test_layout_C_with_incomplete_array() {
                 concat ! (
                 "Alignment of " , stringify ! ( C_with_incomplete_array ) ));
 }
+impl Default for C_with_incomplete_array {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 pub struct C_with_zero_length_array_and_incomplete_array {
     pub a: ::std::os::raw::c_int,
@@ -147,8 +157,11 @@ fn bindgen_test_layout_C_with_zero_length_array_and_incomplete_array() {
                 "Alignment of " , stringify ! (
                 C_with_zero_length_array_and_incomplete_array ) ));
 }
+impl Default for C_with_zero_length_array_and_incomplete_array {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct WithDtor {
     pub b: ::std::os::raw::c_int,
 }
@@ -179,8 +192,11 @@ fn bindgen_test_layout_IncompleteArrayNonCopiable() {
                 "Alignment of " , stringify ! ( IncompleteArrayNonCopiable )
                 ));
 }
+impl Default for IncompleteArrayNonCopiable {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Union {
     pub d: __BindgenUnionField<f32>,
     pub i: __BindgenUnionField<::std::os::raw::c_int>,
@@ -207,7 +223,7 @@ impl Clone for Union {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct WithUnion {
     pub data: Union,
 }
@@ -227,7 +243,7 @@ impl Clone for WithUnion {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct RealAbstractionWithTonsOfMethods {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/class_nested.rs b/tests/expectations/tests/class_nested.rs
index 8a4125c9..19d70e50 100644
--- a/tests/expectations/tests/class_nested.rs
+++ b/tests/expectations/tests/class_nested.rs
@@ -5,12 +5,12 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A {
     pub member_a: ::std::os::raw::c_int,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A_B {
     pub member_b: ::std::os::raw::c_int,
 }
@@ -49,7 +49,7 @@ extern "C" {
     pub static mut var: A_B;
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct D {
     pub member: A_B,
 }
@@ -78,3 +78,9 @@ pub struct Templated<T> {
 pub struct Templated_Templated_inner<T> {
     pub member_ptr: *mut T,
 }
+impl <T> Default for Templated_Templated_inner<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
+impl <T> Default for Templated<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/class_no_members.rs b/tests/expectations/tests/class_no_members.rs
index e41e3ffc..ad532100 100644
--- a/tests/expectations/tests/class_no_members.rs
+++ b/tests/expectations/tests/class_no_members.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct whatever {
     pub _address: u8,
 }
@@ -20,7 +20,7 @@ impl Clone for whatever {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct whatever_child {
     pub _address: u8,
 }
@@ -35,7 +35,7 @@ impl Clone for whatever_child {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct whatever_child_with_member {
     pub m_member: ::std::os::raw::c_int,
 }
diff --git a/tests/expectations/tests/class_static.rs b/tests/expectations/tests/class_static.rs
index 207295b6..521621a7 100644
--- a/tests/expectations/tests/class_static.rs
+++ b/tests/expectations/tests/class_static.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct MyClass {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/class_static_const.rs b/tests/expectations/tests/class_static_const.rs
index 5e59485b..4b0108a1 100644
--- a/tests/expectations/tests/class_static_const.rs
+++ b/tests/expectations/tests/class_static_const.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/class_use_as.rs b/tests/expectations/tests/class_use_as.rs
index 9184c9c8..f4db9013 100644
--- a/tests/expectations/tests/class_use_as.rs
+++ b/tests/expectations/tests/class_use_as.rs
@@ -8,7 +8,7 @@
  * <div rustbindgen="true" replaces="whatever"></div>
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct whatever {
     pub replacement: ::std::os::raw::c_int,
 }
@@ -28,7 +28,7 @@ impl Clone for whatever {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct container {
     pub c: whatever,
 }
diff --git a/tests/expectations/tests/class_with_dtor.rs b/tests/expectations/tests/class_with_dtor.rs
index 1d8e6b4d..4c1d2718 100644
--- a/tests/expectations/tests/class_with_dtor.rs
+++ b/tests/expectations/tests/class_with_dtor.rs
@@ -9,6 +9,9 @@
 pub struct HandleWithDtor<T> {
     pub ptr: *mut T,
 }
+impl <T> Default for HandleWithDtor<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type HandleValue = HandleWithDtor<::std::os::raw::c_int>;
 #[repr(C)]
 #[derive(Debug)]
@@ -27,6 +30,9 @@ fn bindgen_test_layout_WithoutDtor() {
                 "Alignment of field: " , stringify ! ( WithoutDtor ) , "::" ,
                 stringify ! ( shouldBeWithDtor ) ));
 }
+impl Default for WithoutDtor {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[test]
 fn __bindgen_test_layout_template_1() {
     assert_eq!(::std::mem::size_of::<HandleWithDtor<::std::os::raw::c_int>>()
diff --git a/tests/expectations/tests/class_with_inner_struct.rs b/tests/expectations/tests/class_with_inner_struct.rs
index 1056fd69..a99aada5 100644
--- a/tests/expectations/tests/class_with_inner_struct.rs
+++ b/tests/expectations/tests/class_with_inner_struct.rs
@@ -29,14 +29,14 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A {
     pub c: ::std::os::raw::c_uint,
     pub named_union: A__bindgen_ty_1,
     pub __bindgen_anon_1: A__bindgen_ty_2,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A_Segment {
     pub begin: ::std::os::raw::c_int,
     pub end: ::std::os::raw::c_int,
@@ -62,7 +62,7 @@ impl Clone for A_Segment {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A__bindgen_ty_1 {
     pub f: __BindgenUnionField<::std::os::raw::c_int>,
     pub bindgen_union_field: u32,
@@ -83,7 +83,7 @@ impl Clone for A__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A__bindgen_ty_2 {
     pub d: __BindgenUnionField<::std::os::raw::c_int>,
     pub bindgen_union_field: u32,
@@ -123,12 +123,12 @@ impl Clone for A {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct B {
     pub d: ::std::os::raw::c_uint,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct B_Segment {
     pub begin: ::std::os::raw::c_int,
     pub end: ::std::os::raw::c_int,
@@ -176,20 +176,20 @@ pub enum StepSyntax {
     FunctionalWithEndKeyword = 3,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct C {
     pub d: ::std::os::raw::c_uint,
     pub __bindgen_anon_1: C__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct C__bindgen_ty_1 {
     pub mFunc: __BindgenUnionField<C__bindgen_ty_1__bindgen_ty_1>,
     pub __bindgen_anon_1: __BindgenUnionField<C__bindgen_ty_1__bindgen_ty_2>,
     pub bindgen_union_field: [u32; 4usize],
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct C__bindgen_ty_1__bindgen_ty_1 {
     pub mX1: f32,
     pub mY1: f32,
@@ -264,6 +264,9 @@ fn bindgen_test_layout_C__bindgen_ty_1__bindgen_ty_2() {
 impl Clone for C__bindgen_ty_1__bindgen_ty_2 {
     fn clone(&self) -> Self { *self }
 }
+impl Default for C__bindgen_ty_1__bindgen_ty_2 {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[test]
 fn bindgen_test_layout_C__bindgen_ty_1() {
     assert_eq!(::std::mem::size_of::<C__bindgen_ty_1>() , 16usize , concat ! (
@@ -280,7 +283,7 @@ impl Clone for C__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct C_Segment {
     pub begin: ::std::os::raw::c_int,
     pub end: ::std::os::raw::c_int,
diff --git a/tests/expectations/tests/class_with_typedef.rs b/tests/expectations/tests/class_with_typedef.rs
index d3141fd9..1a92b986 100644
--- a/tests/expectations/tests/class_with_typedef.rs
+++ b/tests/expectations/tests/class_with_typedef.rs
@@ -65,6 +65,9 @@ extern "C" {
 impl Clone for C {
     fn clone(&self) -> Self { *self }
 }
+impl Default for C {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 impl C {
     #[inline]
     pub unsafe fn method(&mut self, c: C_MyInt) { C_method(&mut *self, c) }
@@ -102,3 +105,6 @@ fn bindgen_test_layout_D() {
 impl Clone for D {
     fn clone(&self) -> Self { *self }
 }
+impl Default for D {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/complex.rs b/tests/expectations/tests/complex.rs
index 1048138e..d250f6b1 100644
--- a/tests/expectations/tests/complex.rs
+++ b/tests/expectations/tests/complex.rs
@@ -11,7 +11,7 @@ pub struct __BindgenComplex<T> {
     pub im: T,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct TestDouble {
     pub mMember: __BindgenComplex<f64>,
 }
@@ -50,8 +50,11 @@ fn bindgen_test_layout_TestDoublePtr() {
 impl Clone for TestDoublePtr {
     fn clone(&self) -> Self { *self }
 }
+impl Default for TestDoublePtr {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct TestFloat {
     pub mMember: __BindgenComplex<f32>,
 }
@@ -90,3 +93,6 @@ fn bindgen_test_layout_TestFloatPtr() {
 impl Clone for TestFloatPtr {
     fn clone(&self) -> Self { *self }
 }
+impl Default for TestFloatPtr {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/const_bool.rs b/tests/expectations/tests/const_bool.rs
index 2c8ba788..de9e81b0 100644
--- a/tests/expectations/tests/const_bool.rs
+++ b/tests/expectations/tests/const_bool.rs
@@ -6,7 +6,7 @@
 
 pub const k: bool = true;
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/const_enum_unnamed.rs b/tests/expectations/tests/const_enum_unnamed.rs
index 8a5f0f23..b6f61b35 100644
--- a/tests/expectations/tests/const_enum_unnamed.rs
+++ b/tests/expectations/tests/const_enum_unnamed.rs
@@ -10,7 +10,7 @@ pub const FOO_BAZ: _bindgen_ty_1 = _bindgen_ty_1::FOO_BAZ;
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum _bindgen_ty_1 { FOO_BAR = 0, FOO_BAZ = 1, }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/const_tparam.rs b/tests/expectations/tests/const_tparam.rs
index 3ed10d28..f47ca082 100644
--- a/tests/expectations/tests/const_tparam.rs
+++ b/tests/expectations/tests/const_tparam.rs
@@ -10,3 +10,6 @@ pub struct C<T> {
     pub foo: *const T,
     pub bar: *mut T,
 }
+impl <T> Default for C<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/constant-non-specialized-tp.rs b/tests/expectations/tests/constant-non-specialized-tp.rs
index bbadf8a2..f2aa5a75 100644
--- a/tests/expectations/tests/constant-non-specialized-tp.rs
+++ b/tests/expectations/tests/constant-non-specialized-tp.rs
@@ -10,6 +10,9 @@ pub struct Test<Args> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<Args>,
 }
+impl <Args> Default for Test<Args> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct Outer<T> {
@@ -17,8 +20,11 @@ pub struct Outer<T> {
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct Outer_Inner<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Outer<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/constify-all-enums.rs b/tests/expectations/tests/constify-all-enums.rs
index ae89a9b7..e1210d9a 100644
--- a/tests/expectations/tests/constify-all-enums.rs
+++ b/tests/expectations/tests/constify-all-enums.rs
@@ -28,3 +28,6 @@ fn bindgen_test_layout_bar() {
 impl Clone for bar {
     fn clone(&self) -> Self { *self }
 }
+impl Default for bar {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/constructor-tp.rs b/tests/expectations/tests/constructor-tp.rs
index 0f53317b..ee04d3c5 100644
--- a/tests/expectations/tests/constructor-tp.rs
+++ b/tests/expectations/tests/constructor-tp.rs
@@ -10,8 +10,11 @@ pub struct Foo<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Foo<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Bar {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/constructors.rs b/tests/expectations/tests/constructors.rs
index 3abb2da7..13a4dcf8 100644
--- a/tests/expectations/tests/constructors.rs
+++ b/tests/expectations/tests/constructors.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct TestOverload {
     pub _address: u8,
 }
@@ -43,7 +43,7 @@ impl TestOverload {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct TestPublicNoArgs {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/convert-floats.rs b/tests/expectations/tests/convert-floats.rs
index 5971db06..ba35da33 100644
--- a/tests/expectations/tests/convert-floats.rs
+++ b/tests/expectations/tests/convert-floats.rs
@@ -60,3 +60,6 @@ fn bindgen_test_layout_foo() {
 impl Clone for foo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for foo {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/crtp.rs b/tests/expectations/tests/crtp.rs
index 8fe0a5ae..7143f50e 100644
--- a/tests/expectations/tests/crtp.rs
+++ b/tests/expectations/tests/crtp.rs
@@ -10,6 +10,9 @@ pub struct Base<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Base<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct Derived {
@@ -25,12 +28,18 @@ fn bindgen_test_layout_Derived() {
 impl Clone for Derived {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Derived {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug)]
 pub struct BaseWithDestructor<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for BaseWithDestructor<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug)]
 pub struct DerivedFromBaseWithDestructor {
@@ -46,6 +55,9 @@ fn bindgen_test_layout_DerivedFromBaseWithDestructor() {
                 "Alignment of " , stringify ! ( DerivedFromBaseWithDestructor
                 ) ));
 }
+impl Default for DerivedFromBaseWithDestructor {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[test]
 fn __bindgen_test_layout_template_1() {
     assert_eq!(::std::mem::size_of::<Base<Derived>>() , 1usize , concat ! (
diff --git a/tests/expectations/tests/dash_language.rs b/tests/expectations/tests/dash_language.rs
index 148f9c32..24df1014 100644
--- a/tests/expectations/tests/dash_language.rs
+++ b/tests/expectations/tests/dash_language.rs
@@ -10,3 +10,6 @@ pub struct Foo<T> {
     pub bar: ::std::os::raw::c_int,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Foo<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/duplicated-namespaces-definitions.rs b/tests/expectations/tests/duplicated-namespaces-definitions.rs
index 1b785fd7..196cfc46 100644
--- a/tests/expectations/tests/duplicated-namespaces-definitions.rs
+++ b/tests/expectations/tests/duplicated-namespaces-definitions.rs
@@ -11,7 +11,7 @@ pub mod root {
         #[allow(unused_imports)]
         use self::super::super::root;
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct Bar {
             pub foo: ::std::os::raw::c_int,
             pub baz: bool,
@@ -60,5 +60,8 @@ pub mod root {
         impl Clone for Foo {
             fn clone(&self) -> Self { *self }
         }
+        impl Default for Foo {
+            fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+        }
     }
 }
diff --git a/tests/expectations/tests/empty_template_param_name.rs b/tests/expectations/tests/empty_template_param_name.rs
index e10b56db..6ee8fce3 100644
--- a/tests/expectations/tests/empty_template_param_name.rs
+++ b/tests/expectations/tests/empty_template_param_name.rs
@@ -11,3 +11,6 @@ pub struct __iterator_traits<_Iterator> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<_Iterator>,
 }
+impl <_Iterator> Default for __iterator_traits<_Iterator> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/enum_and_vtable_mangling.rs b/tests/expectations/tests/enum_and_vtable_mangling.rs
index e372d98b..300edd39 100644
--- a/tests/expectations/tests/enum_and_vtable_mangling.rs
+++ b/tests/expectations/tests/enum_and_vtable_mangling.rs
@@ -10,6 +10,7 @@ pub const whatever_else: _bindgen_ty_1 = _bindgen_ty_1::whatever_else;
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum _bindgen_ty_1 { match_ = 0, whatever_else = 1, }
 #[repr(C)]
+#[derive(Default)]
 pub struct C__bindgen_vtable {
 }
 #[repr(C)]
@@ -32,3 +33,6 @@ fn bindgen_test_layout_C() {
 impl Clone for C {
     fn clone(&self) -> Self { *self }
 }
+impl Default for C {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/enum_in_template_with_typedef.rs b/tests/expectations/tests/enum_in_template_with_typedef.rs
index 66a304aa..e4725b83 100644
--- a/tests/expectations/tests/enum_in_template_with_typedef.rs
+++ b/tests/expectations/tests/enum_in_template_with_typedef.rs
@@ -16,3 +16,6 @@ pub const std_fbstring_core_Category_Bar: std_fbstring_core_Category =
 #[repr(u8)]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum std_fbstring_core_Category { Foo = 0, }
+impl <Char> Default for std_fbstring_core<Char> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/eval-variadic-template-parameter.rs b/tests/expectations/tests/eval-variadic-template-parameter.rs
index f8c937e2..acc6f34c 100644
--- a/tests/expectations/tests/eval-variadic-template-parameter.rs
+++ b/tests/expectations/tests/eval-variadic-template-parameter.rs
@@ -10,3 +10,6 @@ pub struct B<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for B<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/forward-declaration-autoptr.rs b/tests/expectations/tests/forward-declaration-autoptr.rs
index ffe5b7b6..b05984c8 100644
--- a/tests/expectations/tests/forward-declaration-autoptr.rs
+++ b/tests/expectations/tests/forward-declaration-autoptr.rs
@@ -12,6 +12,9 @@ pub struct Foo([u8; 0]);
 pub struct RefPtr<T> {
     pub m_inner: *mut T,
 }
+impl <T> Default for RefPtr<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct Bar {
@@ -32,3 +35,6 @@ fn bindgen_test_layout_Bar() {
 impl Clone for Bar {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Bar {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/forward-inherit-struct-with-fields.rs b/tests/expectations/tests/forward-inherit-struct-with-fields.rs
index e377b3ad..ce61a545 100644
--- a/tests/expectations/tests/forward-inherit-struct-with-fields.rs
+++ b/tests/expectations/tests/forward-inherit-struct-with-fields.rs
@@ -9,9 +9,15 @@
 pub struct Rooted<T> {
     pub _base: js_RootedBase<T>,
 }
+impl <T> Default for Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct js_RootedBase<T> {
     pub foo: *mut T,
     pub next: *mut Rooted<T>,
 }
+impl <T> Default for js_RootedBase<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/forward-inherit-struct.rs b/tests/expectations/tests/forward-inherit-struct.rs
index 5de70fa9..1057e70c 100644
--- a/tests/expectations/tests/forward-inherit-struct.rs
+++ b/tests/expectations/tests/forward-inherit-struct.rs
@@ -10,9 +10,15 @@ pub struct Rooted<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct js_RootedBase<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for js_RootedBase<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/forward_declared_complex_types.rs b/tests/expectations/tests/forward_declared_complex_types.rs
index 0637fea3..a6e67f7b 100644
--- a/tests/expectations/tests/forward_declared_complex_types.rs
+++ b/tests/expectations/tests/forward_declared_complex_types.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo_empty {
     pub _address: u8,
 }
@@ -42,6 +42,9 @@ fn bindgen_test_layout_Bar() {
 impl Clone for Bar {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Bar {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 extern "C" {
     #[link_name = "_Z10baz_structP3Foo"]
     pub fn baz_struct(f: *mut Foo);
diff --git a/tests/expectations/tests/forward_declared_struct.rs b/tests/expectations/tests/forward_declared_struct.rs
index 51c61cdf..ec8b15d1 100644
--- a/tests/expectations/tests/forward_declared_struct.rs
+++ b/tests/expectations/tests/forward_declared_struct.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct a {
     pub b: ::std::os::raw::c_int,
 }
@@ -24,7 +24,7 @@ impl Clone for a {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct c {
     pub d: ::std::os::raw::c_int,
 }
diff --git a/tests/expectations/tests/func_ptr_in_struct.rs b/tests/expectations/tests/func_ptr_in_struct.rs
index eba6c7e2..ce145866 100644
--- a/tests/expectations/tests/func_ptr_in_struct.rs
+++ b/tests/expectations/tests/func_ptr_in_struct.rs
@@ -30,3 +30,6 @@ fn bindgen_test_layout_Foo() {
 impl Clone for Foo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Foo {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/in_class_typedef.rs b/tests/expectations/tests/in_class_typedef.rs
index 4e95ca8c..3634a631 100644
--- a/tests/expectations/tests/in_class_typedef.rs
+++ b/tests/expectations/tests/in_class_typedef.rs
@@ -13,9 +13,12 @@ pub struct Foo<T> {
 pub type Foo_elem_type<T> = T;
 pub type Foo_ptr_type<T> = *mut T;
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct Foo_Bar<T> {
     pub x: ::std::os::raw::c_int,
     pub y: ::std::os::raw::c_int,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Foo<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/inherit-namespaced.rs b/tests/expectations/tests/inherit-namespaced.rs
index c0d2e5a6..e5d5f875 100644
--- a/tests/expectations/tests/inherit-namespaced.rs
+++ b/tests/expectations/tests/inherit-namespaced.rs
@@ -10,9 +10,15 @@ pub struct js_RootedBase<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for js_RootedBase<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct Rooted<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/inherit_named.rs b/tests/expectations/tests/inherit_named.rs
index 8081c649..31c4bee9 100644
--- a/tests/expectations/tests/inherit_named.rs
+++ b/tests/expectations/tests/inherit_named.rs
@@ -10,8 +10,14 @@ pub struct Wohoo<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Wohoo<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct Weeee<T> {
     pub _base: T,
 }
+impl <T> Default for Weeee<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/inherit_typedef.rs b/tests/expectations/tests/inherit_typedef.rs
index ff6a62d3..76d7c35f 100644
--- a/tests/expectations/tests/inherit_typedef.rs
+++ b/tests/expectations/tests/inherit_typedef.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub _address: u8,
 }
@@ -21,7 +21,7 @@ impl Clone for Foo {
 }
 pub type TypedefedFoo = Foo;
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Bar {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/inline_namespace.rs b/tests/expectations/tests/inline_namespace.rs
index 6b2c4f80..8f2243ba 100644
--- a/tests/expectations/tests/inline_namespace.rs
+++ b/tests/expectations/tests/inline_namespace.rs
@@ -13,7 +13,7 @@ pub mod root {
         pub type Ty = ::std::os::raw::c_int;
     }
     #[repr(C)]
-    #[derive(Debug, Copy)]
+    #[derive(Debug, Default, Copy)]
     pub struct Bar {
         pub baz: root::foo::Ty,
     }
diff --git a/tests/expectations/tests/inline_namespace_conservative.rs b/tests/expectations/tests/inline_namespace_conservative.rs
index 5b74a5f6..7cf7c264 100644
--- a/tests/expectations/tests/inline_namespace_conservative.rs
+++ b/tests/expectations/tests/inline_namespace_conservative.rs
@@ -18,7 +18,7 @@ pub mod root {
         pub type Ty = ::std::os::raw::c_longlong;
     }
     #[repr(C)]
-    #[derive(Debug, Copy)]
+    #[derive(Debug, Default, Copy)]
     pub struct Bar {
         pub baz: root::foo::bar::Ty,
     }
diff --git a/tests/expectations/tests/inner_const.rs b/tests/expectations/tests/inner_const.rs
index 3422f168..fd2793a4 100644
--- a/tests/expectations/tests/inner_const.rs
+++ b/tests/expectations/tests/inner_const.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub bar: ::std::os::raw::c_int,
 }
diff --git a/tests/expectations/tests/inner_template_self.rs b/tests/expectations/tests/inner_template_self.rs
index 4345e422..3510fa7c 100644
--- a/tests/expectations/tests/inner_template_self.rs
+++ b/tests/expectations/tests/inner_template_self.rs
@@ -10,6 +10,9 @@ pub struct LinkedList<T> {
     pub next: *mut LinkedList<T>,
     pub prev: *mut LinkedList<T>,
 }
+impl <T> Default for LinkedList<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct InstantiateIt {
@@ -30,3 +33,6 @@ fn bindgen_test_layout_InstantiateIt() {
 impl Clone for InstantiateIt {
     fn clone(&self) -> Self { *self }
 }
+impl Default for InstantiateIt {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/issue-358.rs b/tests/expectations/tests/issue-358.rs
index 1b933d34..d3be3c43 100644
--- a/tests/expectations/tests/issue-358.rs
+++ b/tests/expectations/tests/issue-358.rs
@@ -10,6 +10,9 @@ pub struct JS_PersistentRooted<c> {
     pub _base: a,
     pub _phantom_0: ::std::marker::PhantomData<c>,
 }
+impl <c> Default for JS_PersistentRooted<c> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct a {
@@ -18,3 +21,6 @@ pub struct a {
 impl Clone for a {
     fn clone(&self) -> Self { *self }
 }
+impl Default for a {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/issue-372.rs b/tests/expectations/tests/issue-372.rs
index 8fcfd33d..1693f46a 100644
--- a/tests/expectations/tests/issue-372.rs
+++ b/tests/expectations/tests/issue-372.rs
@@ -27,6 +27,9 @@ pub mod root {
     impl Clone for d {
         fn clone(&self) -> Self { *self }
     }
+    impl Default for d {
+        fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+    }
     #[repr(C)]
     #[derive(Debug, Copy)]
     pub struct i {
@@ -59,6 +62,9 @@ pub mod root {
     impl Clone for i {
         fn clone(&self) -> Self { *self }
     }
+    impl Default for i {
+        fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+    }
     #[repr(u32)]
     #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
     pub enum n {
@@ -91,4 +97,7 @@ pub mod root {
                     "Alignment of field: " , stringify ! ( F ) , "::" ,
                     stringify ! ( w ) ));
     }
+    impl Default for F {
+        fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+    }
 }
diff --git a/tests/expectations/tests/issue-410.rs b/tests/expectations/tests/issue-410.rs
index a8e0d8d4..2fe0f99b 100644
--- a/tests/expectations/tests/issue-410.rs
+++ b/tests/expectations/tests/issue-410.rs
@@ -11,7 +11,7 @@ pub mod root {
         #[allow(unused_imports)]
         use self::super::super::root;
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct Value {
             pub _address: u8,
         }
diff --git a/tests/expectations/tests/issue-447.rs b/tests/expectations/tests/issue-447.rs
index 0582f412..7ac9d714 100644
--- a/tests/expectations/tests/issue-447.rs
+++ b/tests/expectations/tests/issue-447.rs
@@ -14,7 +14,7 @@ pub mod root {
             #[allow(unused_imports)]
             use self::super::super::super::root;
             #[repr(C)]
-            #[derive(Debug, Copy)]
+            #[derive(Debug, Default, Copy)]
             pub struct GuardObjectNotifier {
                 pub _address: u8,
             }
@@ -35,7 +35,7 @@ pub mod root {
         }
     }
     #[repr(C)]
-    #[derive(Debug, Copy)]
+    #[derive(Debug, Default, Copy)]
     pub struct JSAutoCompartment {
         pub _address: u8,
     }
diff --git a/tests/expectations/tests/issue_311.rs b/tests/expectations/tests/issue_311.rs
index debc893d..6576b8b5 100644
--- a/tests/expectations/tests/issue_311.rs
+++ b/tests/expectations/tests/issue_311.rs
@@ -8,12 +8,12 @@ pub mod root {
     #[allow(unused_imports)]
     use self::super::root;
     #[repr(C)]
-    #[derive(Debug, Copy)]
+    #[derive(Debug, Default, Copy)]
     pub struct jsval_layout {
         pub __bindgen_anon_1: root::jsval_layout__bindgen_ty_1,
     }
     #[repr(C)]
-    #[derive(Debug, Copy)]
+    #[derive(Debug, Default, Copy)]
     pub struct jsval_layout__bindgen_ty_1 {
         pub _address: u8,
     }
diff --git a/tests/expectations/tests/jsval_layout_opaque.rs b/tests/expectations/tests/jsval_layout_opaque.rs
index ac092587..848286e7 100644
--- a/tests/expectations/tests/jsval_layout_opaque.rs
+++ b/tests/expectations/tests/jsval_layout_opaque.rs
@@ -96,7 +96,7 @@ pub enum JSWhyMagic {
     JS_WHY_MAGIC_COUNT = 18,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct jsval_layout {
     pub asBits: __BindgenUnionField<u64>,
     pub debugView: __BindgenUnionField<jsval_layout__bindgen_ty_1>,
@@ -125,6 +125,9 @@ fn bindgen_test_layout_jsval_layout__bindgen_ty_1() {
 impl Clone for jsval_layout__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
+impl Default for jsval_layout__bindgen_ty_1 {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 impl jsval_layout__bindgen_ty_1 {
     #[inline]
     pub fn payload47(&self) -> u64 {
@@ -157,12 +160,12 @@ impl jsval_layout__bindgen_ty_1 {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct jsval_layout__bindgen_ty_2 {
     pub payload: jsval_layout__bindgen_ty_2__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct jsval_layout__bindgen_ty_2__bindgen_ty_1 {
     pub i32: __BindgenUnionField<i32>,
     pub u32: __BindgenUnionField<u32>,
@@ -269,7 +272,7 @@ impl Clone for jsval_layout {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Value {
     pub data: jsval_layout,
 }
diff --git a/tests/expectations/tests/layout.rs b/tests/expectations/tests/layout.rs
index 5fae570c..115a108a 100644
--- a/tests/expectations/tests/layout.rs
+++ b/tests/expectations/tests/layout.rs
@@ -5,6 +5,7 @@
 
 
 #[repr(C)]
+#[derive(Default)]
 pub struct __IncompleteArrayField<T>(::std::marker::PhantomData<T>);
 impl <T> __IncompleteArrayField<T> {
     #[inline]
@@ -37,7 +38,7 @@ impl <T> ::std::clone::Clone for __IncompleteArrayField<T> {
 }
 impl <T> ::std::marker::Copy for __IncompleteArrayField<T> { }
 #[repr(C, packed)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct header {
     pub proto: ::std::os::raw::c_char,
     pub size: ::std::os::raw::c_uint,
diff --git a/tests/expectations/tests/layout_align.rs b/tests/expectations/tests/layout_align.rs
index 0479521c..a21fa4d6 100644
--- a/tests/expectations/tests/layout_align.rs
+++ b/tests/expectations/tests/layout_align.rs
@@ -5,6 +5,7 @@
 
 
 #[repr(C)]
+#[derive(Default)]
 pub struct __IncompleteArrayField<T>(::std::marker::PhantomData<T>);
 impl <T> __IncompleteArrayField<T> {
     #[inline]
@@ -61,8 +62,11 @@ fn bindgen_test_layout_rte_kni_fifo() {
 impl Clone for rte_kni_fifo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_kni_fifo {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_link {
     /**< ETH_SPEED_NUM_ */
     pub link_speed: u32,
diff --git a/tests/expectations/tests/layout_arp.rs b/tests/expectations/tests/layout_arp.rs
index c868f627..f3c59eb4 100644
--- a/tests/expectations/tests/layout_arp.rs
+++ b/tests/expectations/tests/layout_arp.rs
@@ -24,7 +24,7 @@ pub const ARP_OP_INVREPLY: ::std::os::raw::c_uint = 9;
  * See http://standards.ieee.org/regauth/groupmac/tutorial.html
  */
 #[repr(C, packed)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct ether_addr {
     /**< Addr bytes in tx order */
     pub addr_bytes: [u8; 6usize],
@@ -48,7 +48,7 @@ impl Clone for ether_addr {
  * ARP header IPv4 payload.
  */
 #[repr(C, packed)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct arp_ipv4 {
     /**< sender hardware address */
     pub arp_sha: ether_addr,
@@ -93,7 +93,7 @@ impl Clone for arp_ipv4 {
  * ARP header.
  */
 #[repr(C, packed)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct arp_hdr {
     pub arp_hrd: u16,
     pub arp_pro: u16,
diff --git a/tests/expectations/tests/layout_array.rs b/tests/expectations/tests/layout_array.rs
index bc690fb6..3f86cda9 100644
--- a/tests/expectations/tests/layout_array.rs
+++ b/tests/expectations/tests/layout_array.rs
@@ -109,11 +109,14 @@ fn bindgen_test_layout_rte_mempool_ops() {
 impl Clone for rte_mempool_ops {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_mempool_ops {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /**
  * The rte_spinlock_t type.
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct _bindgen_ty_1 {
     /**< lock status 0 = unlocked, 1 = locked */
     pub locked: ::std::os::raw::c_int,
@@ -180,6 +183,9 @@ fn bindgen_test_layout_rte_mempool_ops_table() {
 impl Clone for rte_mempool_ops_table {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_mempool_ops_table {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /**
  * Structure to hold malloc heap
  */
@@ -218,6 +224,9 @@ fn bindgen_test_layout_malloc_heap__bindgen_ty_1() {
 impl Clone for malloc_heap__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
+impl Default for malloc_heap__bindgen_ty_1 {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[test]
 fn bindgen_test_layout_malloc_heap() {
     assert_eq!(::std::mem::size_of::<malloc_heap>() , 128usize , concat ! (
@@ -246,3 +255,6 @@ fn bindgen_test_layout_malloc_heap() {
 impl Clone for malloc_heap {
     fn clone(&self) -> Self { *self }
 }
+impl Default for malloc_heap {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/layout_cmdline_token.rs b/tests/expectations/tests/layout_cmdline_token.rs
index be4944bb..35127399 100644
--- a/tests/expectations/tests/layout_cmdline_token.rs
+++ b/tests/expectations/tests/layout_cmdline_token.rs
@@ -108,6 +108,9 @@ fn bindgen_test_layout_cmdline_token_hdr_cmdline_token_ops() {
 impl Clone for cmdline_token_hdr_cmdline_token_ops {
     fn clone(&self) -> Self { *self }
 }
+impl Default for cmdline_token_hdr_cmdline_token_ops {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[test]
 fn bindgen_test_layout_cmdline_token_hdr() {
     assert_eq!(::std::mem::size_of::<cmdline_token_hdr>() , 16usize , concat !
@@ -128,6 +131,9 @@ fn bindgen_test_layout_cmdline_token_hdr() {
 impl Clone for cmdline_token_hdr {
     fn clone(&self) -> Self { *self }
 }
+impl Default for cmdline_token_hdr {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type cmdline_parse_token_hdr_t = cmdline_token_hdr;
 #[repr(u32)]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -163,6 +169,9 @@ fn bindgen_test_layout_cmdline_token_num_data() {
 impl Clone for cmdline_token_num_data {
     fn clone(&self) -> Self { *self }
 }
+impl Default for cmdline_token_num_data {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct cmdline_token_num {
@@ -189,4 +198,7 @@ fn bindgen_test_layout_cmdline_token_num() {
 impl Clone for cmdline_token_num {
     fn clone(&self) -> Self { *self }
 }
+impl Default for cmdline_token_num {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type cmdline_parse_token_num_t = cmdline_token_num;
diff --git a/tests/expectations/tests/layout_eth_conf.rs b/tests/expectations/tests/layout_eth_conf.rs
index 0034e707..16788d06 100644
--- a/tests/expectations/tests/layout_eth_conf.rs
+++ b/tests/expectations/tests/layout_eth_conf.rs
@@ -115,6 +115,9 @@ fn bindgen_test_layout_rte_eth_rxmode() {
 impl Clone for rte_eth_rxmode {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_rxmode {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 impl rte_eth_rxmode {
     #[inline]
     pub fn header_split(&self) -> u16 {
@@ -268,6 +271,9 @@ fn bindgen_test_layout_rte_eth_txmode() {
 impl Clone for rte_eth_txmode {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_txmode {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 impl rte_eth_txmode {
     #[inline]
     pub fn hw_vlan_reject_tagged(&self) -> u8 {
@@ -358,6 +364,9 @@ fn bindgen_test_layout_rte_eth_rss_conf() {
 impl Clone for rte_eth_rss_conf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_rss_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(u32)]
 /**
  * This enum indicates the possible number of traffic classes
@@ -403,7 +412,7 @@ pub struct rte_eth_vmdq_dcb_conf {
     pub dcb_tc: [u8; 8usize],
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_vmdq_dcb_conf__bindgen_ty_1 {
     /**< The vlan id of the received frame */
     pub vlan_id: u16,
@@ -476,6 +485,9 @@ fn bindgen_test_layout_rte_eth_vmdq_dcb_conf() {
                 "Alignment of field: " , stringify ! ( rte_eth_vmdq_dcb_conf )
                 , "::" , stringify ! ( dcb_tc ) ));
 }
+impl Default for rte_eth_vmdq_dcb_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct rte_eth_dcb_rx_conf {
@@ -505,6 +517,9 @@ fn bindgen_test_layout_rte_eth_dcb_rx_conf() {
 impl Clone for rte_eth_dcb_rx_conf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_dcb_rx_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct rte_eth_vmdq_dcb_tx_conf {
@@ -536,6 +551,9 @@ fn bindgen_test_layout_rte_eth_vmdq_dcb_tx_conf() {
 impl Clone for rte_eth_vmdq_dcb_tx_conf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_vmdq_dcb_tx_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct rte_eth_dcb_tx_conf {
@@ -565,6 +583,9 @@ fn bindgen_test_layout_rte_eth_dcb_tx_conf() {
 impl Clone for rte_eth_dcb_tx_conf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_dcb_tx_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct rte_eth_vmdq_tx_conf {
@@ -587,6 +608,9 @@ fn bindgen_test_layout_rte_eth_vmdq_tx_conf() {
 impl Clone for rte_eth_vmdq_tx_conf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_vmdq_tx_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 pub struct rte_eth_vmdq_rx_conf {
     /**< VMDq only mode, 8 or 64 pools */
@@ -605,7 +629,7 @@ pub struct rte_eth_vmdq_rx_conf {
     pub pool_map: [rte_eth_vmdq_rx_conf__bindgen_ty_1; 64usize],
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_vmdq_rx_conf__bindgen_ty_1 {
     /**< The vlan id of the received frame */
     pub vlan_id: u16,
@@ -683,6 +707,9 @@ fn bindgen_test_layout_rte_eth_vmdq_rx_conf() {
                 "Alignment of field: " , stringify ! ( rte_eth_vmdq_rx_conf )
                 , "::" , stringify ! ( pool_map ) ));
 }
+impl Default for rte_eth_vmdq_rx_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(u32)]
 /**
  *  Flow Director setting modes: none, signature or perfect.
@@ -720,7 +747,7 @@ pub enum rte_fdir_status_mode {
  * A structure used to define the input for IPV4 flow
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_ipv4_flow {
     /**< IPv4 source address in big endian. */
     pub src_ip: u32,
@@ -772,7 +799,7 @@ impl Clone for rte_eth_ipv4_flow {
  * A structure used to define the input for IPV6 flow
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_ipv6_flow {
     /**< IPv6 source address in big endian. */
     pub src_ip: [u32; 4usize],
@@ -825,7 +852,7 @@ impl Clone for rte_eth_ipv6_flow {
  *  to match the various fields of RX packet headers.
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_fdir_masks {
     /**< Bit mask for vlan_tci in big endian */
     pub vlan_tci_mask: u16,
@@ -944,12 +971,15 @@ fn bindgen_test_layout_rte_eth_flex_payload_cfg() {
 impl Clone for rte_eth_flex_payload_cfg {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_flex_payload_cfg {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /**
  * A structure used to define FDIR masks for flexible payload
  * for each flow type
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_fdir_flex_mask {
     pub flow_type: u16,
     pub mask: [u8; 16usize],
@@ -1022,6 +1052,9 @@ fn bindgen_test_layout_rte_eth_fdir_flex_conf() {
 impl Clone for rte_eth_fdir_flex_conf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_eth_fdir_flex_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /**
  * A structure used to configure the Flow Director (FDIR) feature
  * of an Ethernet port.
@@ -1082,11 +1115,14 @@ fn bindgen_test_layout_rte_fdir_conf() {
 impl Clone for rte_fdir_conf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_fdir_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /**
  * A structure used to enable/disable specific device interrupts.
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_intr_conf {
     /** enable/disable lsc interrupt. 0 (default) - disable, 1 enable */
     pub lsc: u16,
@@ -1192,8 +1228,11 @@ fn bindgen_test_layout_rte_eth_conf__bindgen_ty_1() {
                 rte_eth_conf__bindgen_ty_1 ) , "::" , stringify ! (
                 vmdq_rx_conf ) ));
 }
+impl Default for rte_eth_conf__bindgen_ty_1 {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_eth_conf__bindgen_ty_2 {
     pub vmdq_dcb_tx_conf: __BindgenUnionField<rte_eth_vmdq_dcb_tx_conf>,
     pub dcb_tx_conf: __BindgenUnionField<rte_eth_dcb_tx_conf>,
@@ -1283,3 +1322,6 @@ fn bindgen_test_layout_rte_eth_conf() {
                 "Alignment of field: " , stringify ! ( rte_eth_conf ) , "::" ,
                 stringify ! ( intr_conf ) ));
 }
+impl Default for rte_eth_conf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/layout_kni_mbuf.rs b/tests/expectations/tests/layout_kni_mbuf.rs
index e0e3579a..d704267d 100644
--- a/tests/expectations/tests/layout_kni_mbuf.rs
+++ b/tests/expectations/tests/layout_kni_mbuf.rs
@@ -109,3 +109,6 @@ fn bindgen_test_layout_rte_kni_mbuf() {
 impl Clone for rte_kni_mbuf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_kni_mbuf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/layout_mbuf.rs b/tests/expectations/tests/layout_mbuf.rs
index f1702673..c0c2cce2 100644
--- a/tests/expectations/tests/layout_mbuf.rs
+++ b/tests/expectations/tests/layout_mbuf.rs
@@ -38,7 +38,7 @@ pub type MARKER64 = [u64; 0usize];
  * The atomic counter structure.
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct _bindgen_ty_1 {
     /**< An internal counter value. */
     pub cnt: i16,
@@ -118,7 +118,7 @@ pub struct rte_mbuf {
 	 * config option.
 	 */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_1 {
     /**< Atomically accessed refcnt */
     pub refcnt_atomic: __BindgenUnionField<rte_atomic16_t>,
@@ -149,7 +149,7 @@ impl Clone for rte_mbuf__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_2 {
     /**< L2/L3/L4 and tunnel information. */
     pub packet_type: __BindgenUnionField<u32>,
@@ -157,7 +157,7 @@ pub struct rte_mbuf__bindgen_ty_2 {
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_2__bindgen_ty_1 {
     pub _bitfield_1: u32,
 }
@@ -285,7 +285,7 @@ impl Clone for rte_mbuf__bindgen_ty_2 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_3 {
     /**< RSS hash result if RSS enabled */
     pub rss: __BindgenUnionField<u32>,
@@ -298,20 +298,20 @@ pub struct rte_mbuf__bindgen_ty_3 {
     pub bindgen_union_field: [u32; 2usize],
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_3__bindgen_ty_1 {
     pub __bindgen_anon_1: rte_mbuf__bindgen_ty_3__bindgen_ty_1__bindgen_ty_1,
     pub hi: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_3__bindgen_ty_1__bindgen_ty_1 {
     pub __bindgen_anon_1: __BindgenUnionField<rte_mbuf__bindgen_ty_3__bindgen_ty_1__bindgen_ty_1__bindgen_ty_1>,
     pub lo: __BindgenUnionField<u32>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_3__bindgen_ty_1__bindgen_ty_1__bindgen_ty_1 {
     pub hash: u16,
     pub id: u16,
@@ -395,7 +395,7 @@ impl Clone for rte_mbuf__bindgen_ty_3__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_3__bindgen_ty_2 {
     pub lo: u32,
     pub hi: u32,
@@ -459,7 +459,7 @@ impl Clone for rte_mbuf__bindgen_ty_3 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_4 {
     /**< Can be used for external metadata */
     pub userdata: __BindgenUnionField<*mut ::std::os::raw::c_void>,
@@ -493,7 +493,7 @@ impl Clone for rte_mbuf__bindgen_ty_4 {
 #[derive(Debug, Copy, Clone)]
 pub struct rte_mbuf_rte_mempool([u8; 0]);
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_5 {
     /**< combined for easy fetch */
     pub tx_offload: __BindgenUnionField<u64>,
@@ -501,7 +501,7 @@ pub struct rte_mbuf__bindgen_ty_5 {
     pub bindgen_union_field: u64,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct rte_mbuf__bindgen_ty_5__bindgen_ty_1 {
     pub _bitfield_1: u64,
 }
@@ -731,3 +731,6 @@ fn bindgen_test_layout_rte_mbuf() {
 impl Clone for rte_mbuf {
     fn clone(&self) -> Self { *self }
 }
+impl Default for rte_mbuf {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/maddness-is-avoidable.rs b/tests/expectations/tests/maddness-is-avoidable.rs
index d31345ba..2fb5e540 100644
--- a/tests/expectations/tests/maddness-is-avoidable.rs
+++ b/tests/expectations/tests/maddness-is-avoidable.rs
@@ -18,3 +18,9 @@ pub struct RefPtr_Proxy<T, R, Args> {
     pub _phantom_1: ::std::marker::PhantomData<R>,
     pub _phantom_2: ::std::marker::PhantomData<Args>,
 }
+impl <T, R, Args> Default for RefPtr_Proxy<T, R, Args> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
+impl <T> Default for RefPtr<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/method-mangling.rs b/tests/expectations/tests/method-mangling.rs
index 94877dca..23f12280 100644
--- a/tests/expectations/tests/method-mangling.rs
+++ b/tests/expectations/tests/method-mangling.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/module-whitelisted.rs b/tests/expectations/tests/module-whitelisted.rs
index cee91305..cb6dd6a6 100644
--- a/tests/expectations/tests/module-whitelisted.rs
+++ b/tests/expectations/tests/module-whitelisted.rs
@@ -8,7 +8,7 @@ pub mod root {
     #[allow(unused_imports)]
     use self::super::root;
     #[repr(C)]
-    #[derive(Debug, Copy)]
+    #[derive(Debug, Default, Copy)]
     pub struct Test {
         pub _address: u8,
     }
diff --git a/tests/expectations/tests/msvc-no-usr.rs b/tests/expectations/tests/msvc-no-usr.rs
index 842ca1f3..7ea253b6 100644
--- a/tests/expectations/tests/msvc-no-usr.rs
+++ b/tests/expectations/tests/msvc-no-usr.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A {
     pub foo: usize,
 }
diff --git a/tests/expectations/tests/multiple-inherit-empty-correct-layout.rs b/tests/expectations/tests/multiple-inherit-empty-correct-layout.rs
index 008ed565..253d5843 100644
--- a/tests/expectations/tests/multiple-inherit-empty-correct-layout.rs
+++ b/tests/expectations/tests/multiple-inherit-empty-correct-layout.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub _address: u8,
 }
@@ -20,7 +20,7 @@ impl Clone for Foo {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Bar {
     pub _address: u8,
 }
@@ -35,7 +35,7 @@ impl Clone for Bar {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Baz {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/mutable.rs b/tests/expectations/tests/mutable.rs
index 82689ce1..cde3dac1 100644
--- a/tests/expectations/tests/mutable.rs
+++ b/tests/expectations/tests/mutable.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct C {
     pub m_member: ::std::os::raw::c_int,
     pub m_other: ::std::os::raw::c_int,
@@ -31,7 +31,7 @@ impl Clone for C {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct NonCopiable {
     pub m_member: ::std::os::raw::c_int,
 }
@@ -48,7 +48,7 @@ fn bindgen_test_layout_NonCopiable() {
                 stringify ! ( m_member ) ));
 }
 #[repr(C)]
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct NonCopiableWithNonCopiableMutableMember {
     pub m_member: NonCopiable,
 }
diff --git a/tests/expectations/tests/namespace.rs b/tests/expectations/tests/namespace.rs
index 4d27385d..dda4cd26 100644
--- a/tests/expectations/tests/namespace.rs
+++ b/tests/expectations/tests/namespace.rs
@@ -28,7 +28,7 @@ pub mod root {
             pub fn foo();
         }
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct A {
             pub b: root::whatever::whatever_int_t,
         }
@@ -69,6 +69,9 @@ pub mod root {
         pub m_c_ptr: *mut T,
         pub m_c_arr: [T; 10usize],
     }
+    impl <T> Default for C<T> {
+        fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+    }
     pub mod w {
         #[allow(unused_imports)]
         use self::super::super::root;
@@ -78,6 +81,9 @@ pub mod root {
         pub struct D<T> {
             pub m_c: root::C<T>,
         }
+        impl <T> Default for D<T> {
+            fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+        }
         extern "C" {
             #[link_name = "_ZN1w3hehEv"]
             pub fn heh() -> root::w::whatever_int_t;
diff --git a/tests/expectations/tests/nested.rs b/tests/expectations/tests/nested.rs
index 4c119bc7..d50f8e17 100644
--- a/tests/expectations/tests/nested.rs
+++ b/tests/expectations/tests/nested.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Calc {
     pub w: ::std::os::raw::c_int,
 }
@@ -25,18 +25,18 @@ impl Clone for Calc {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Test {
     pub _address: u8,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Test_Size {
     pub mWidth: Test_Size_Dimension,
     pub mHeight: Test_Size_Dimension,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Test_Size_Dimension {
     pub _base: Calc,
 }
diff --git a/tests/expectations/tests/nested_vtable.rs b/tests/expectations/tests/nested_vtable.rs
index 7cc30423..e16a23d7 100644
--- a/tests/expectations/tests/nested_vtable.rs
+++ b/tests/expectations/tests/nested_vtable.rs
@@ -5,6 +5,7 @@
 
 
 #[repr(C)]
+#[derive(Default)]
 pub struct nsISupports__bindgen_vtable {
 }
 #[repr(C)]
@@ -22,6 +23,9 @@ fn bindgen_test_layout_nsISupports() {
 impl Clone for nsISupports {
     fn clone(&self) -> Self { *self }
 }
+impl Default for nsISupports {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct nsIRunnable {
@@ -37,6 +41,9 @@ fn bindgen_test_layout_nsIRunnable() {
 impl Clone for nsIRunnable {
     fn clone(&self) -> Self { *self }
 }
+impl Default for nsIRunnable {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct Runnable {
@@ -52,3 +59,6 @@ fn bindgen_test_layout_Runnable() {
 impl Clone for Runnable {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Runnable {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/nested_within_namespace.rs b/tests/expectations/tests/nested_within_namespace.rs
index db4e0493..cb6eead3 100644
--- a/tests/expectations/tests/nested_within_namespace.rs
+++ b/tests/expectations/tests/nested_within_namespace.rs
@@ -11,12 +11,12 @@ pub mod root {
         #[allow(unused_imports)]
         use self::super::super::root;
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct Bar {
             pub foo: ::std::os::raw::c_int,
         }
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct Bar_Baz {
             pub foo: ::std::os::raw::c_int,
         }
@@ -51,7 +51,7 @@ pub mod root {
             fn clone(&self) -> Self { *self }
         }
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct Baz {
             pub baz: ::std::os::raw::c_int,
         }
diff --git a/tests/expectations/tests/no-comments.rs b/tests/expectations/tests/no-comments.rs
index c3bb13c4..058f2045 100644
--- a/tests/expectations/tests/no-comments.rs
+++ b/tests/expectations/tests/no-comments.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Foo {
     pub s: ::std::os::raw::c_int,
 }
diff --git a/tests/expectations/tests/no-derive-debug.rs b/tests/expectations/tests/no-derive-debug.rs
index 4de75797..07e6ae82 100644
--- a/tests/expectations/tests/no-derive-debug.rs
+++ b/tests/expectations/tests/no-derive-debug.rs
@@ -3,7 +3,7 @@
 
 #![allow(non_snake_case)]
 
-#[repr(C)] #[derive(Copy, Clone)] pub struct foo { bar: ::std::os::raw::c_int, }
+#[repr(C)] #[derive(Copy, Clone, Default)] pub struct foo { bar: ::std::os::raw::c_int, }
 
 /**
  * bar should compile. It will normally derive debug, but our blacklist of foo
@@ -11,7 +11,7 @@
  * from building if --no-derive-debug didn't work.
  */
 #[repr(C)]
-#[derive(Copy)]
+#[derive(Default, Copy)]
 pub struct bar {
     pub foo: foo,
     pub baz: ::std::os::raw::c_int,
diff --git a/tests/expectations/tests/no-derive-default.rs b/tests/expectations/tests/no-derive-default.rs
new file mode 100644
index 00000000..2cec9d19
--- /dev/null
+++ b/tests/expectations/tests/no-derive-default.rs
@@ -0,0 +1,38 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(non_snake_case)]
+
+#[repr(C)] #[derive(Copy, Clone, Debug)] pub struct foo { bar: ::std::os::raw::c_int, }
+
+/**
+ * bar should compile. It will normally derive default, but our blacklist of foo
+ * and replacement for another type that doesn't implement it would prevent it
+ * from building if --no-derive-default didn't work.
+ */
+#[repr(C)]
+#[derive(Debug, Copy)]
+pub struct bar {
+    pub foo: foo,
+    pub baz: ::std::os::raw::c_int,
+}
+#[test]
+fn bindgen_test_layout_bar() {
+    assert_eq!(::std::mem::size_of::<bar>() , 8usize , concat ! (
+               "Size of: " , stringify ! ( bar ) ));
+    assert_eq! (::std::mem::align_of::<bar>() , 4usize , concat ! (
+                "Alignment of " , stringify ! ( bar ) ));
+    assert_eq! (unsafe {
+                & ( * ( 0 as * const bar ) ) . foo as * const _ as usize } ,
+                0usize , concat ! (
+                "Alignment of field: " , stringify ! ( bar ) , "::" ,
+                stringify ! ( foo ) ));
+    assert_eq! (unsafe {
+                & ( * ( 0 as * const bar ) ) . baz as * const _ as usize } ,
+                4usize , concat ! (
+                "Alignment of field: " , stringify ! ( bar ) , "::" ,
+                stringify ! ( baz ) ));
+}
+impl Clone for bar {
+    fn clone(&self) -> Self { *self }
+}
diff --git a/tests/expectations/tests/no-recursive-whitelisting.rs b/tests/expectations/tests/no-recursive-whitelisting.rs
index c8341990..7cc3d89e 100644
--- a/tests/expectations/tests/no-recursive-whitelisting.rs
+++ b/tests/expectations/tests/no-recursive-whitelisting.rs
@@ -25,3 +25,6 @@ fn bindgen_test_layout_Foo() {
 impl Clone for Foo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Foo {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/no-std.rs b/tests/expectations/tests/no-std.rs
index 21cfda00..998ac2a8 100644
--- a/tests/expectations/tests/no-std.rs
+++ b/tests/expectations/tests/no-std.rs
@@ -38,3 +38,6 @@ fn bindgen_test_layout_foo() {
 impl Clone for foo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for foo {
+    fn default() -> Self { unsafe { ::core::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/no_copy.rs b/tests/expectations/tests/no_copy.rs
index 53ab9677..3590241f 100644
--- a/tests/expectations/tests/no_copy.rs
+++ b/tests/expectations/tests/no_copy.rs
@@ -11,3 +11,6 @@ pub struct CopiableButWait<T> {
     pub whatever: ::std::os::raw::c_int,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for CopiableButWait<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/nsStyleAutoArray.rs b/tests/expectations/tests/nsStyleAutoArray.rs
index c150ec46..bc5f5184 100644
--- a/tests/expectations/tests/nsStyleAutoArray.rs
+++ b/tests/expectations/tests/nsStyleAutoArray.rs
@@ -9,6 +9,9 @@
 pub struct nsTArray<T> {
     pub mBuff: *mut T,
 }
+impl <T> Default for nsTArray<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct nsStyleAutoArray<T> {
@@ -20,3 +23,6 @@ pub struct nsStyleAutoArray<T> {
 pub enum nsStyleAutoArray_WithSingleInitialElement {
     WITH_SINGLE_INITIAL_ELEMENT = 0,
 }
+impl <T> Default for nsStyleAutoArray<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/objc_interface_type.rs b/tests/expectations/tests/objc_interface_type.rs
index 544ced07..edf551d3 100644
--- a/tests/expectations/tests/objc_interface_type.rs
+++ b/tests/expectations/tests/objc_interface_type.rs
@@ -31,6 +31,9 @@ fn bindgen_test_layout_FooStruct() {
 impl Clone for FooStruct {
     fn clone(&self) -> Self { *self }
 }
+impl Default for FooStruct {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 extern "C" {
     pub fn fooFunc(foo: id);
 }
diff --git a/tests/expectations/tests/only_bitfields.rs b/tests/expectations/tests/only_bitfields.rs
index 7811584b..9252097d 100644
--- a/tests/expectations/tests/only_bitfields.rs
+++ b/tests/expectations/tests/only_bitfields.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct C {
     pub _bitfield_1: u8,
 }
diff --git a/tests/expectations/tests/opaque-tracing.rs b/tests/expectations/tests/opaque-tracing.rs
index b19a1e68..c7534d97 100644
--- a/tests/expectations/tests/opaque-tracing.rs
+++ b/tests/expectations/tests/opaque-tracing.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Container {
     pub _bindgen_opaque_blob: [u32; 2usize],
 }
diff --git a/tests/expectations/tests/opaque_in_struct.rs b/tests/expectations/tests/opaque_in_struct.rs
index cba5952e..f689b02b 100644
--- a/tests/expectations/tests/opaque_in_struct.rs
+++ b/tests/expectations/tests/opaque_in_struct.rs
@@ -6,7 +6,7 @@
 
 /** <div rustbindgen opaque> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct opaque {
     pub _bindgen_opaque_blob: u32,
 }
@@ -21,7 +21,7 @@ impl Clone for opaque {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct container {
     pub contained: opaque,
 }
diff --git a/tests/expectations/tests/opaque_pointer.rs b/tests/expectations/tests/opaque_pointer.rs
index 3cfa6d87..15b01db4 100644
--- a/tests/expectations/tests/opaque_pointer.rs
+++ b/tests/expectations/tests/opaque_pointer.rs
@@ -8,7 +8,7 @@
  * <div rustbindgen opaque></div>
  */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct OtherOpaque {
     pub _bindgen_opaque_blob: u32,
 }
@@ -30,6 +30,9 @@ impl Clone for OtherOpaque {
 pub struct Opaque<T> {
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Opaque<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct WithOpaquePtr {
@@ -62,3 +65,6 @@ fn bindgen_test_layout_WithOpaquePtr() {
 impl Clone for WithOpaquePtr {
     fn clone(&self) -> Self { *self }
 }
+impl Default for WithOpaquePtr {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/opaque_typedef.rs b/tests/expectations/tests/opaque_typedef.rs
index c45cbc6f..d6d5ac5d 100644
--- a/tests/expectations/tests/opaque_typedef.rs
+++ b/tests/expectations/tests/opaque_typedef.rs
@@ -10,6 +10,9 @@ pub struct RandomTemplate<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for RandomTemplate<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /** <div rustbindgen opaque></div> */
 pub type ShouldBeOpaque = [u8; 0usize];
 pub type ShouldNotBeOpaque = RandomTemplate<f32>;
diff --git a/tests/expectations/tests/private.rs b/tests/expectations/tests/private.rs
index 809e224a..a9fbef9f 100644
--- a/tests/expectations/tests/private.rs
+++ b/tests/expectations/tests/private.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct HasPrivate {
     pub mNotPrivate: ::std::os::raw::c_int,
     /** <div rustbindgen private></div> */
@@ -33,7 +33,7 @@ impl Clone for HasPrivate {
 }
 /** <div rustbindgen private></div> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct VeryPrivate {
     mIsPrivate: ::std::os::raw::c_int,
     mIsAlsoPrivate: ::std::os::raw::c_int,
@@ -60,7 +60,7 @@ impl Clone for VeryPrivate {
 }
 /** <div rustbindgen private></div> */
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct ContradictPrivate {
     /** <div rustbindgen private="false"></div> */
     pub mNotPrivate: ::std::os::raw::c_int,
diff --git a/tests/expectations/tests/public-dtor.rs b/tests/expectations/tests/public-dtor.rs
index d4c18c6b..1accf49c 100644
--- a/tests/expectations/tests/public-dtor.rs
+++ b/tests/expectations/tests/public-dtor.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct cv_String {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/ref_argument_array.rs b/tests/expectations/tests/ref_argument_array.rs
index 675bbbca..714467f6 100644
--- a/tests/expectations/tests/ref_argument_array.rs
+++ b/tests/expectations/tests/ref_argument_array.rs
@@ -6,6 +6,7 @@
 
 pub const NSID_LENGTH: ::std::os::raw::c_uint = 10;
 #[repr(C)]
+#[derive(Default)]
 pub struct nsID__bindgen_vtable {
 }
 #[repr(C)]
@@ -23,3 +24,6 @@ fn bindgen_test_layout_nsID() {
 impl Clone for nsID {
     fn clone(&self) -> Self { *self }
 }
+impl Default for nsID {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/reparented_replacement.rs b/tests/expectations/tests/reparented_replacement.rs
index baeab03e..6965f767 100644
--- a/tests/expectations/tests/reparented_replacement.rs
+++ b/tests/expectations/tests/reparented_replacement.rs
@@ -12,7 +12,7 @@ pub mod root {
         use self::super::super::root;
         /// <div rustbindgen replaces="foo::Bar"></div>
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct Bar {
             pub bazz: ::std::os::raw::c_int,
         }
diff --git a/tests/expectations/tests/replace_template_alias.rs b/tests/expectations/tests/replace_template_alias.rs
index f922ac77..dbd0d283 100644
--- a/tests/expectations/tests/replace_template_alias.rs
+++ b/tests/expectations/tests/replace_template_alias.rs
@@ -13,3 +13,6 @@ pub type JS_detail_MaybeWrapped<T> = T;
 pub struct JS_Rooted<T> {
     pub ptr: JS_detail_MaybeWrapped<T>,
 }
+impl <T> Default for JS_Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/replace_use.rs b/tests/expectations/tests/replace_use.rs
index ed55080a..d93121d3 100644
--- a/tests/expectations/tests/replace_use.rs
+++ b/tests/expectations/tests/replace_use.rs
@@ -13,6 +13,9 @@ pub struct nsTArray<T> {
     pub y: ::std::os::raw::c_uint,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for nsTArray<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct Test {
@@ -33,3 +36,6 @@ fn bindgen_test_layout_Test() {
 impl Clone for Test {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Test {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/replaces_double.rs b/tests/expectations/tests/replaces_double.rs
index 50dafd42..99b812db 100644
--- a/tests/expectations/tests/replaces_double.rs
+++ b/tests/expectations/tests/replaces_double.rs
@@ -13,3 +13,6 @@ pub struct Rooted<T> {
      * <div rustbindgen replaces="Rooted_MaybeWrapped"></div>
      */
 pub type Rooted_MaybeWrapped<T> = T;
+impl <T> Default for Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/same_struct_name_in_different_namespaces.rs b/tests/expectations/tests/same_struct_name_in_different_namespaces.rs
index 4dde8266..820b5e71 100644
--- a/tests/expectations/tests/same_struct_name_in_different_namespaces.rs
+++ b/tests/expectations/tests/same_struct_name_in_different_namespaces.rs
@@ -8,7 +8,7 @@
 #[derive(Debug, Copy, Clone)]
 pub struct JS_Zone([u8; 0]);
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct JS_shadow_Zone {
     pub x: ::std::os::raw::c_int,
     pub y: ::std::os::raw::c_int,
diff --git a/tests/expectations/tests/size_t_template.rs b/tests/expectations/tests/size_t_template.rs
index 87df768d..4d81651e 100644
--- a/tests/expectations/tests/size_t_template.rs
+++ b/tests/expectations/tests/size_t_template.rs
@@ -24,3 +24,6 @@ fn bindgen_test_layout_C() {
 impl Clone for C {
     fn clone(&self) -> Self { *self }
 }
+impl Default for C {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/struct_containing_forward_declared_struct.rs b/tests/expectations/tests/struct_containing_forward_declared_struct.rs
index 60f12262..ff16490a 100644
--- a/tests/expectations/tests/struct_containing_forward_declared_struct.rs
+++ b/tests/expectations/tests/struct_containing_forward_declared_struct.rs
@@ -10,7 +10,7 @@ pub struct a {
     pub val_a: *mut a_b,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct a_b {
     pub val_b: ::std::os::raw::c_int,
 }
@@ -44,3 +44,6 @@ fn bindgen_test_layout_a() {
 impl Clone for a {
     fn clone(&self) -> Self { *self }
 }
+impl Default for a {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/struct_with_anon_struct.rs b/tests/expectations/tests/struct_with_anon_struct.rs
index 75baf354..b02fdd0e 100644
--- a/tests/expectations/tests/struct_with_anon_struct.rs
+++ b/tests/expectations/tests/struct_with_anon_struct.rs
@@ -5,12 +5,12 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub bar: foo__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: ::std::os::raw::c_int,
     pub b: ::std::os::raw::c_int,
diff --git a/tests/expectations/tests/struct_with_anon_struct_array.rs b/tests/expectations/tests/struct_with_anon_struct_array.rs
index f20f03d8..a19c957b 100644
--- a/tests/expectations/tests/struct_with_anon_struct_array.rs
+++ b/tests/expectations/tests/struct_with_anon_struct_array.rs
@@ -5,13 +5,13 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub bar: [foo__bindgen_ty_1; 2usize],
     pub baz: [[[foo__bindgen_ty_2; 4usize]; 3usize]; 2usize],
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: ::std::os::raw::c_int,
     pub b: ::std::os::raw::c_int,
@@ -37,7 +37,7 @@ impl Clone for foo__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_2 {
     pub a: ::std::os::raw::c_int,
     pub b: ::std::os::raw::c_int,
diff --git a/tests/expectations/tests/struct_with_anon_struct_pointer.rs b/tests/expectations/tests/struct_with_anon_struct_pointer.rs
index 087ff3d8..e0b06f76 100644
--- a/tests/expectations/tests/struct_with_anon_struct_pointer.rs
+++ b/tests/expectations/tests/struct_with_anon_struct_pointer.rs
@@ -10,7 +10,7 @@ pub struct foo {
     pub bar: *mut foo__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: ::std::os::raw::c_int,
     pub b: ::std::os::raw::c_int,
@@ -50,3 +50,6 @@ fn bindgen_test_layout_foo() {
 impl Clone for foo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for foo {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/struct_with_anon_union.rs b/tests/expectations/tests/struct_with_anon_union.rs
index ac4b6f75..aff61c45 100644
--- a/tests/expectations/tests/struct_with_anon_union.rs
+++ b/tests/expectations/tests/struct_with_anon_union.rs
@@ -29,12 +29,12 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub bar: foo__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: __BindgenUnionField<::std::os::raw::c_uint>,
     pub b: __BindgenUnionField<::std::os::raw::c_ushort>,
diff --git a/tests/expectations/tests/struct_with_anon_unnamed_struct.rs b/tests/expectations/tests/struct_with_anon_unnamed_struct.rs
index 982b3bdc..80039415 100644
--- a/tests/expectations/tests/struct_with_anon_unnamed_struct.rs
+++ b/tests/expectations/tests/struct_with_anon_unnamed_struct.rs
@@ -5,12 +5,12 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub __bindgen_anon_1: foo__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: ::std::os::raw::c_uint,
     pub b: ::std::os::raw::c_uint,
diff --git a/tests/expectations/tests/struct_with_anon_unnamed_union.rs b/tests/expectations/tests/struct_with_anon_unnamed_union.rs
index 26edbceb..f55d8e38 100644
--- a/tests/expectations/tests/struct_with_anon_unnamed_union.rs
+++ b/tests/expectations/tests/struct_with_anon_unnamed_union.rs
@@ -29,12 +29,12 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub __bindgen_anon_1: foo__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: __BindgenUnionField<::std::os::raw::c_uint>,
     pub b: __BindgenUnionField<::std::os::raw::c_ushort>,
diff --git a/tests/expectations/tests/struct_with_bitfields.rs b/tests/expectations/tests/struct_with_bitfields.rs
index 90f2fba2..861ad662 100644
--- a/tests/expectations/tests/struct_with_bitfields.rs
+++ b/tests/expectations/tests/struct_with_bitfields.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct bitfield {
     pub _bitfield_1: u8,
     pub e: ::std::os::raw::c_int,
diff --git a/tests/expectations/tests/struct_with_derive_debug.rs b/tests/expectations/tests/struct_with_derive_debug.rs
index b81baa00..58a94853 100644
--- a/tests/expectations/tests/struct_with_derive_debug.rs
+++ b/tests/expectations/tests/struct_with_derive_debug.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct LittleArray {
     pub a: [::std::os::raw::c_int; 32usize],
 }
@@ -40,8 +40,11 @@ fn bindgen_test_layout_BigArray() {
                 "Alignment of field: " , stringify ! ( BigArray ) , "::" ,
                 stringify ! ( a ) ));
 }
+impl Default for BigArray {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct WithLittleArray {
     pub a: LittleArray,
 }
@@ -76,3 +79,6 @@ fn bindgen_test_layout_WithBigArray() {
                 "Alignment of field: " , stringify ! ( WithBigArray ) , "::" ,
                 stringify ! ( a ) ));
 }
+impl Default for WithBigArray {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/struct_with_nesting.rs b/tests/expectations/tests/struct_with_nesting.rs
index 4bd5586b..30ba124b 100644
--- a/tests/expectations/tests/struct_with_nesting.rs
+++ b/tests/expectations/tests/struct_with_nesting.rs
@@ -29,13 +29,13 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub a: ::std::os::raw::c_uint,
     pub __bindgen_anon_1: foo__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub b: __BindgenUnionField<::std::os::raw::c_uint>,
     pub __bindgen_anon_1: __BindgenUnionField<foo__bindgen_ty_1__bindgen_ty_1>,
@@ -43,7 +43,7 @@ pub struct foo__bindgen_ty_1 {
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1__bindgen_ty_1 {
     pub c1: ::std::os::raw::c_ushort,
     pub c2: ::std::os::raw::c_ushort,
@@ -75,7 +75,7 @@ impl Clone for foo__bindgen_ty_1__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1__bindgen_ty_2 {
     pub d1: ::std::os::raw::c_uchar,
     pub d2: ::std::os::raw::c_uchar,
diff --git a/tests/expectations/tests/struct_with_packing.rs b/tests/expectations/tests/struct_with_packing.rs
index b7afdafe..cba3d475 100644
--- a/tests/expectations/tests/struct_with_packing.rs
+++ b/tests/expectations/tests/struct_with_packing.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C, packed)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct a {
     pub b: ::std::os::raw::c_char,
     pub c: ::std::os::raw::c_short,
diff --git a/tests/expectations/tests/struct_with_struct.rs b/tests/expectations/tests/struct_with_struct.rs
index d28806c4..bcdaada2 100644
--- a/tests/expectations/tests/struct_with_struct.rs
+++ b/tests/expectations/tests/struct_with_struct.rs
@@ -5,12 +5,12 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub bar: foo__bindgen_ty_1,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub x: ::std::os::raw::c_uint,
     pub y: ::std::os::raw::c_uint,
diff --git a/tests/expectations/tests/struct_with_typedef_template_arg.rs b/tests/expectations/tests/struct_with_typedef_template_arg.rs
index 6f8d71f1..f882c65d 100644
--- a/tests/expectations/tests/struct_with_typedef_template_arg.rs
+++ b/tests/expectations/tests/struct_with_typedef_template_arg.rs
@@ -13,3 +13,6 @@ pub struct Proxy<T, Args> {
 }
 pub type Proxy_foo<T> =
     ::std::option::Option<unsafe extern "C" fn(bar: *mut T)>;
+impl <T, Args> Default for Proxy<T, Args> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/template-fun-ty.rs b/tests/expectations/tests/template-fun-ty.rs
index c2a8a028..b894920f 100644
--- a/tests/expectations/tests/template-fun-ty.rs
+++ b/tests/expectations/tests/template-fun-ty.rs
@@ -12,6 +12,9 @@ pub struct Foo<T> {
 }
 pub type Foo_FunctionPtr<T> =
     ::std::option::Option<unsafe extern "C" fn() -> T>;
+impl <T> Default for Foo<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct RefPtr<T> {
@@ -28,4 +31,10 @@ pub struct RefPtr_Proxy<T, R, Args> {
 }
 pub type RefPtr_Proxy_member_function<R, Args> =
     ::std::option::Option<unsafe extern "C" fn(arg1: Args) -> R>;
+impl <T, R, Args> Default for RefPtr_Proxy<T, R, Args> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
+impl <T> Default for RefPtr<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type Returner<T> = ::std::option::Option<unsafe extern "C" fn() -> T>;
diff --git a/tests/expectations/tests/template.rs b/tests/expectations/tests/template.rs
index 844dc6c2..131a54fd 100644
--- a/tests/expectations/tests/template.rs
+++ b/tests/expectations/tests/template.rs
@@ -12,6 +12,9 @@ pub struct Foo<T, U> {
     pub m_member_arr: [T; 1usize],
     pub _phantom_1: ::std::marker::PhantomData<U>,
 }
+impl <T, U> Default for Foo<T, U> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 extern "C" {
     #[link_name = "_Z3bar3FooIiiE"]
     pub fn bar(foo: Foo<::std::os::raw::c_int, ::std::os::raw::c_int>);
@@ -30,6 +33,12 @@ pub struct D_U<T, Z> {
     pub m_baz: Z,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T, Z> Default for D_U<T, Z> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
+impl <T> Default for D<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct Rooted<T> {
@@ -37,6 +46,9 @@ pub struct Rooted<T> {
     pub next: *mut Rooted<*mut ::std::os::raw::c_void>,
     pub ptr: T,
 }
+impl <T> Default for Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct RootedContainer {
@@ -57,11 +69,17 @@ fn bindgen_test_layout_RootedContainer() {
 impl Clone for RootedContainer {
     fn clone(&self) -> Self { *self }
 }
+impl Default for RootedContainer {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug)]
 pub struct WithDtor<T> {
     pub member: T,
 }
+impl <T> Default for WithDtor<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type WithDtorIntFwd = WithDtor<::std::os::raw::c_int>;
 #[repr(C)]
 #[derive(Debug)]
@@ -80,14 +98,20 @@ fn bindgen_test_layout_PODButContainsDtor() {
                 "Alignment of field: " , stringify ! ( PODButContainsDtor ) ,
                 "::" , stringify ! ( member ) ));
 }
+impl Default for PODButContainsDtor {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /** <div rustbindgen opaque> */
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct Opaque<T> {
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Opaque<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct POD {
     pub opaque_member: u32,
 }
@@ -114,17 +138,26 @@ impl Clone for POD {
 pub struct NestedReplaced<T> {
     pub buff: *mut T,
 }
+impl <T> Default for NestedReplaced<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct NestedBase<T, U> {
     pub buff: *mut T,
     pub _phantom_1: ::std::marker::PhantomData<U>,
 }
+impl <T, U> Default for NestedBase<T, U> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct Incomplete<T> {
     pub d: T,
 }
+impl <T> Default for Incomplete<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct NestedContainer<T> {
@@ -132,8 +165,11 @@ pub struct NestedContainer<T> {
     pub nested: NestedReplaced<T>,
     pub inc: Incomplete<T>,
 }
+impl <T> Default for NestedContainer<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Untemplated {
     pub _address: u8,
 }
@@ -153,6 +189,9 @@ pub struct Templated<T> {
     pub m_untemplated: Untemplated,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for Templated<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /**
  * If the replacement doesn't happen at the parse level the container would be
  * copy and the replacement wouldn't, so this wouldn't compile.
@@ -164,16 +203,25 @@ pub struct Templated<T> {
 pub struct ReplacedWithoutDestructor<T> {
     pub buff: *mut T,
 }
+impl <T> Default for ReplacedWithoutDestructor<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug)]
 pub struct ShouldNotBeCopiable<T> {
     pub m_member: ReplacedWithoutDestructor<T>,
 }
+impl <T> Default for ShouldNotBeCopiable<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug)]
 pub struct ShouldNotBeCopiableAsWell<U> {
     pub m_member: ReplacedWithoutDestructorFwd<U>,
 }
+impl <U> Default for ShouldNotBeCopiableAsWell<U> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 /**
  * If the replacement doesn't happen at the parse level the container would be
  * copy and the replacement wouldn't, so this wouldn't compile.
@@ -185,12 +233,18 @@ pub struct ShouldNotBeCopiableAsWell<U> {
 pub struct ReplacedWithoutDestructorFwd<T> {
     pub buff: *mut T,
 }
+impl <T> Default for ReplacedWithoutDestructorFwd<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct TemplateWithVar<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for TemplateWithVar<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[test]
 fn __bindgen_test_layout_template_1() {
     assert_eq!(::std::mem::size_of::<Foo<::std::os::raw::c_int, ::std::os::raw::c_int>>()
diff --git a/tests/expectations/tests/template_alias.rs b/tests/expectations/tests/template_alias.rs
index d301a11c..44f7830f 100644
--- a/tests/expectations/tests/template_alias.rs
+++ b/tests/expectations/tests/template_alias.rs
@@ -10,3 +10,6 @@ pub type JS_detail_Wrapped<T> = T;
 pub struct JS_Rooted<T> {
     pub ptr: JS_detail_Wrapped<T>,
 }
+impl <T> Default for JS_Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/template_alias_namespace.rs b/tests/expectations/tests/template_alias_namespace.rs
index cf4a079c..dd4add40 100644
--- a/tests/expectations/tests/template_alias_namespace.rs
+++ b/tests/expectations/tests/template_alias_namespace.rs
@@ -20,5 +20,8 @@ pub mod root {
         pub struct Rooted<T> {
             pub ptr: root::JS::detail::Wrapped<T>,
         }
+        impl <T> Default for Rooted<T> {
+            fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+        }
     }
 }
diff --git a/tests/expectations/tests/template_typedef_transitive_param.rs b/tests/expectations/tests/template_typedef_transitive_param.rs
index 166ddc3c..cc801f35 100644
--- a/tests/expectations/tests/template_typedef_transitive_param.rs
+++ b/tests/expectations/tests/template_typedef_transitive_param.rs
@@ -15,4 +15,10 @@ pub struct Wrapper<T> {
 pub struct Wrapper_Wrapped<T> {
     pub t: T,
 }
+impl <T> Default for Wrapper_Wrapped<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type Wrapper_Type<T> = Wrapper_Wrapped<T>;
+impl <T> Default for Wrapper<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/template_typedefs.rs b/tests/expectations/tests/template_typedefs.rs
index 5f0d80b9..9213c0d2 100644
--- a/tests/expectations/tests/template_typedefs.rs
+++ b/tests/expectations/tests/template_typedefs.rs
@@ -20,3 +20,6 @@ pub type Foo_nsCOMArrayEnumFunc<T> =
                                                aData:
                                                    *mut ::std::os::raw::c_void)
                               -> bool>;
+impl <T, U> Default for Foo<T, U> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/templateref_opaque.rs b/tests/expectations/tests/templateref_opaque.rs
index d69254c8..dfe941af 100644
--- a/tests/expectations/tests/templateref_opaque.rs
+++ b/tests/expectations/tests/templateref_opaque.rs
@@ -11,6 +11,9 @@ pub struct detail_PointerType<T> {
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
 pub type detail_PointerType_Type<T> = *mut T;
+impl <T> Default for detail_PointerType<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy, Clone)]
 pub struct UniquePtr<T> {
@@ -18,3 +21,6 @@ pub struct UniquePtr<T> {
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
 pub type UniquePtr_Pointer<T> = detail_PointerType<T>;
+impl <T> Default for UniquePtr<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/type-referenced-by-whitelisted-function.rs b/tests/expectations/tests/type-referenced-by-whitelisted-function.rs
index f4201a56..67381d41 100644
--- a/tests/expectations/tests/type-referenced-by-whitelisted-function.rs
+++ b/tests/expectations/tests/type-referenced-by-whitelisted-function.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct dl_phdr_info {
     pub x: ::std::os::raw::c_int,
 }
diff --git a/tests/expectations/tests/type_alias_partial_template_especialization.rs b/tests/expectations/tests/type_alias_partial_template_especialization.rs
index 70b5f66c..2e0f2f4d 100644
--- a/tests/expectations/tests/type_alias_partial_template_especialization.rs
+++ b/tests/expectations/tests/type_alias_partial_template_especialization.rs
@@ -10,3 +10,6 @@ pub type MaybeWrapped<A> = A;
 pub struct Rooted<T> {
     pub ptr: MaybeWrapped<T>,
 }
+impl <T> Default for Rooted<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/type_alias_template_specialized.rs b/tests/expectations/tests/type_alias_template_specialized.rs
index 5dd2038f..20665af6 100644
--- a/tests/expectations/tests/type_alias_template_specialized.rs
+++ b/tests/expectations/tests/type_alias_template_specialized.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Rooted {
     pub ptr: ::std::os::raw::c_int,
 }
diff --git a/tests/expectations/tests/typeref.rs b/tests/expectations/tests/typeref.rs
index c199b7ab..47b7a66a 100644
--- a/tests/expectations/tests/typeref.rs
+++ b/tests/expectations/tests/typeref.rs
@@ -48,8 +48,11 @@ fn bindgen_test_layout_nsFoo() {
 impl Clone for nsFoo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for nsFoo {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct mozilla_FragmentOrURL {
     pub mIsLocalRef: bool,
 }
@@ -71,7 +74,7 @@ impl Clone for mozilla_FragmentOrURL {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct mozilla_Position {
     pub _address: u8,
 }
@@ -92,13 +95,16 @@ pub struct mozilla_StyleShapeSource<ReferenceBox> {
     pub _phantom_0: ::std::marker::PhantomData<ReferenceBox>,
 }
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct mozilla_StyleShapeSource__bindgen_ty_1<ReferenceBox> {
     pub mPosition: __BindgenUnionField<*mut mozilla_Position>,
     pub mFragmentOrURL: __BindgenUnionField<*mut mozilla_FragmentOrURL>,
     pub bindgen_union_field: u64,
     pub _phantom_0: ::std::marker::PhantomData<ReferenceBox>,
 }
+impl <ReferenceBox> Default for mozilla_StyleShapeSource<ReferenceBox> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct Bar {
@@ -119,3 +125,6 @@ fn bindgen_test_layout_Bar() {
 impl Clone for Bar {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Bar {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/union-in-ns.rs b/tests/expectations/tests/union-in-ns.rs
index cb69d603..208b6283 100644
--- a/tests/expectations/tests/union-in-ns.rs
+++ b/tests/expectations/tests/union-in-ns.rs
@@ -36,7 +36,7 @@ pub mod root {
     #[allow(unused_imports)]
     use self::super::root;
     #[repr(C)]
-    #[derive(Debug, Copy)]
+    #[derive(Debug, Default, Copy)]
     pub struct bar {
         pub baz: root::__BindgenUnionField<::std::os::raw::c_int>,
         pub bindgen_union_field: u32,
diff --git a/tests/expectations/tests/union_dtor.rs b/tests/expectations/tests/union_dtor.rs
index ad707b63..bfd573e0 100644
--- a/tests/expectations/tests/union_dtor.rs
+++ b/tests/expectations/tests/union_dtor.rs
@@ -29,7 +29,7 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct UnionWithDtor {
     pub mFoo: __BindgenUnionField<::std::os::raw::c_int>,
     pub mBar: __BindgenUnionField<*mut ::std::os::raw::c_void>,
diff --git a/tests/expectations/tests/union_fields.rs b/tests/expectations/tests/union_fields.rs
index 64eb3fe4..823a0b8b 100644
--- a/tests/expectations/tests/union_fields.rs
+++ b/tests/expectations/tests/union_fields.rs
@@ -29,7 +29,7 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct _bindgen_ty_1 {
     pub mInt: __BindgenUnionField<::std::os::raw::c_int>,
     pub mFloat: __BindgenUnionField<f32>,
diff --git a/tests/expectations/tests/union_template.rs b/tests/expectations/tests/union_template.rs
index fc92afb8..2eba0f0a 100644
--- a/tests/expectations/tests/union_template.rs
+++ b/tests/expectations/tests/union_template.rs
@@ -37,7 +37,7 @@ pub struct NastyStruct<T> {
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct NastyStruct__bindgen_ty_1<T> {
     pub mFoo: __BindgenUnionField<*mut ::std::os::raw::c_void>,
     pub mDummy: __BindgenUnionField<::std::os::raw::c_ulong>,
@@ -45,15 +45,18 @@ pub struct NastyStruct__bindgen_ty_1<T> {
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct NastyStruct__bindgen_ty_2<T> {
     pub wat: __BindgenUnionField<::std::os::raw::c_short>,
     pub wut: __BindgenUnionField<*mut ::std::os::raw::c_int>,
     pub bindgen_union_field: u64,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for NastyStruct<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct Whatever<T> {
     pub mTPtr: __BindgenUnionField<*mut ::std::os::raw::c_void>,
     pub mInt: __BindgenUnionField<::std::os::raw::c_int>,
diff --git a/tests/expectations/tests/union_with_anon_struct.rs b/tests/expectations/tests/union_with_anon_struct.rs
index 4b9c635f..59f8fcab 100644
--- a/tests/expectations/tests/union_with_anon_struct.rs
+++ b/tests/expectations/tests/union_with_anon_struct.rs
@@ -29,13 +29,13 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub bar: __BindgenUnionField<foo__bindgen_ty_1>,
     pub bindgen_union_field: [u32; 2usize],
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: ::std::os::raw::c_uint,
     pub b: ::std::os::raw::c_uint,
diff --git a/tests/expectations/tests/union_with_anon_struct_bitfield.rs b/tests/expectations/tests/union_with_anon_struct_bitfield.rs
index 449fd440..d14a38bb 100644
--- a/tests/expectations/tests/union_with_anon_struct_bitfield.rs
+++ b/tests/expectations/tests/union_with_anon_struct_bitfield.rs
@@ -29,14 +29,14 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub a: __BindgenUnionField<::std::os::raw::c_int>,
     pub __bindgen_anon_1: __BindgenUnionField<foo__bindgen_ty_1>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub _bitfield_1: u32,
 }
diff --git a/tests/expectations/tests/union_with_anon_union.rs b/tests/expectations/tests/union_with_anon_union.rs
index 16b33551..9e182d21 100644
--- a/tests/expectations/tests/union_with_anon_union.rs
+++ b/tests/expectations/tests/union_with_anon_union.rs
@@ -29,13 +29,13 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub bar: __BindgenUnionField<foo__bindgen_ty_1>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub a: __BindgenUnionField<::std::os::raw::c_uint>,
     pub b: __BindgenUnionField<::std::os::raw::c_ushort>,
diff --git a/tests/expectations/tests/union_with_anon_unnamed_struct.rs b/tests/expectations/tests/union_with_anon_unnamed_struct.rs
index 7982728a..4d0b639f 100644
--- a/tests/expectations/tests/union_with_anon_unnamed_struct.rs
+++ b/tests/expectations/tests/union_with_anon_unnamed_struct.rs
@@ -29,14 +29,14 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct pixel {
     pub rgba: __BindgenUnionField<::std::os::raw::c_uint>,
     pub __bindgen_anon_1: __BindgenUnionField<pixel__bindgen_ty_1>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct pixel__bindgen_ty_1 {
     pub r: ::std::os::raw::c_uchar,
     pub g: ::std::os::raw::c_uchar,
diff --git a/tests/expectations/tests/union_with_anon_unnamed_union.rs b/tests/expectations/tests/union_with_anon_unnamed_union.rs
index 1e7f918c..fd6f82fc 100644
--- a/tests/expectations/tests/union_with_anon_unnamed_union.rs
+++ b/tests/expectations/tests/union_with_anon_unnamed_union.rs
@@ -29,14 +29,14 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub a: __BindgenUnionField<::std::os::raw::c_uint>,
     pub __bindgen_anon_1: __BindgenUnionField<foo__bindgen_ty_1>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub b: __BindgenUnionField<::std::os::raw::c_ushort>,
     pub c: __BindgenUnionField<::std::os::raw::c_uchar>,
diff --git a/tests/expectations/tests/union_with_big_member.rs b/tests/expectations/tests/union_with_big_member.rs
index 58407cdb..2b7a8eef 100644
--- a/tests/expectations/tests/union_with_big_member.rs
+++ b/tests/expectations/tests/union_with_big_member.rs
@@ -55,8 +55,11 @@ fn bindgen_test_layout_WithBigArray() {
 impl Clone for WithBigArray {
     fn clone(&self) -> Self { *self }
 }
+impl Default for WithBigArray {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct WithBigArray2 {
     pub a: __BindgenUnionField<::std::os::raw::c_int>,
     pub b: __BindgenUnionField<[::std::os::raw::c_char; 33usize]>,
@@ -109,3 +112,6 @@ fn bindgen_test_layout_WithBigMember() {
 impl Clone for WithBigMember {
     fn clone(&self) -> Self { *self }
 }
+impl Default for WithBigMember {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/union_with_nesting.rs b/tests/expectations/tests/union_with_nesting.rs
index 17c3c8f0..d92e8efa 100644
--- a/tests/expectations/tests/union_with_nesting.rs
+++ b/tests/expectations/tests/union_with_nesting.rs
@@ -29,20 +29,20 @@ impl <T> ::std::fmt::Debug for __BindgenUnionField<T> {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub a: __BindgenUnionField<::std::os::raw::c_uint>,
     pub __bindgen_anon_1: __BindgenUnionField<foo__bindgen_ty_1>,
     pub bindgen_union_field: u32,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1 {
     pub __bindgen_anon_1: foo__bindgen_ty_1__bindgen_ty_1,
     pub __bindgen_anon_2: foo__bindgen_ty_1__bindgen_ty_2,
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1__bindgen_ty_1 {
     pub b1: __BindgenUnionField<::std::os::raw::c_ushort>,
     pub b2: __BindgenUnionField<::std::os::raw::c_ushort>,
@@ -75,7 +75,7 @@ impl Clone for foo__bindgen_ty_1__bindgen_ty_1 {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo__bindgen_ty_1__bindgen_ty_2 {
     pub c1: __BindgenUnionField<::std::os::raw::c_ushort>,
     pub c2: __BindgenUnionField<::std::os::raw::c_ushort>,
diff --git a/tests/expectations/tests/unknown_attr.rs b/tests/expectations/tests/unknown_attr.rs
index 12a35760..efb86102 100644
--- a/tests/expectations/tests/unknown_attr.rs
+++ b/tests/expectations/tests/unknown_attr.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct _bindgen_ty_1 {
     pub __clang_max_align_nonce1: ::std::os::raw::c_longlong,
     pub __bindgen_padding_0: u64,
diff --git a/tests/expectations/tests/use-core.rs b/tests/expectations/tests/use-core.rs
index f09d1519..dd13156f 100644
--- a/tests/expectations/tests/use-core.rs
+++ b/tests/expectations/tests/use-core.rs
@@ -37,5 +37,8 @@ fn bindgen_test_layout_foo() {
 impl Clone for foo {
     fn clone(&self) -> Self { *self }
 }
+impl Default for foo {
+    fn default() -> Self { unsafe { ::core::mem::zeroed() } }
+}
 pub type fooFunction =
     ::core::option::Option<unsafe extern "C" fn(bar: ::std::os::raw::c_int)>;
diff --git a/tests/expectations/tests/using.rs b/tests/expectations/tests/using.rs
index dbb6c84f..1638287a 100644
--- a/tests/expectations/tests/using.rs
+++ b/tests/expectations/tests/using.rs
@@ -10,5 +10,8 @@ pub struct Point<T> {
     pub x: T,
     pub y: T,
 }
+impl <T> Default for Point<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type IntPoint2D = Point<::std::os::raw::c_int>;
 pub type IntVec2D = Point<::std::os::raw::c_int>;
diff --git a/tests/expectations/tests/var-tracing.rs b/tests/expectations/tests/var-tracing.rs
index 7a09bcb6..ba10cf22 100644
--- a/tests/expectations/tests/var-tracing.rs
+++ b/tests/expectations/tests/var-tracing.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Bar {
     pub m_baz: ::std::os::raw::c_int,
 }
@@ -37,7 +37,7 @@ impl Bar {
     }
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Baz {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/variadic-method.rs b/tests/expectations/tests/variadic-method.rs
index 45155128..542e1e75 100644
--- a/tests/expectations/tests/variadic-method.rs
+++ b/tests/expectations/tests/variadic-method.rs
@@ -9,7 +9,7 @@ extern "C" {
     pub fn foo(fmt: *const ::std::os::raw::c_char, ...);
 }
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct Bar {
     pub _address: u8,
 }
diff --git a/tests/expectations/tests/variadic_template_function.rs b/tests/expectations/tests/variadic_template_function.rs
index cd99df96..32be9f68 100644
--- a/tests/expectations/tests/variadic_template_function.rs
+++ b/tests/expectations/tests/variadic_template_function.rs
@@ -10,3 +10,6 @@ pub struct VariadicFunctionObject<T> {
     pub _address: u8,
     pub _phantom_0: ::std::marker::PhantomData<T>,
 }
+impl <T> Default for VariadicFunctionObject<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/vector.rs b/tests/expectations/tests/vector.rs
index 4b689744..31bc8fd7 100644
--- a/tests/expectations/tests/vector.rs
+++ b/tests/expectations/tests/vector.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct foo {
     pub mMember: [::std::os::raw::c_longlong; 1usize],
 }
diff --git a/tests/expectations/tests/virtual_dtor.rs b/tests/expectations/tests/virtual_dtor.rs
index de5e01af..0c410977 100644
--- a/tests/expectations/tests/virtual_dtor.rs
+++ b/tests/expectations/tests/virtual_dtor.rs
@@ -5,6 +5,7 @@
 
 
 #[repr(C)]
+#[derive(Default)]
 pub struct nsSlots__bindgen_vtable {
 }
 #[repr(C)]
@@ -19,3 +20,6 @@ fn bindgen_test_layout_nsSlots() {
     assert_eq! (::std::mem::align_of::<nsSlots>() , 8usize , concat ! (
                 "Alignment of " , stringify ! ( nsSlots ) ));
 }
+impl Default for nsSlots {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/virtual_inheritance.rs b/tests/expectations/tests/virtual_inheritance.rs
index e0510730..6896eb31 100644
--- a/tests/expectations/tests/virtual_inheritance.rs
+++ b/tests/expectations/tests/virtual_inheritance.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct A {
     pub foo: ::std::os::raw::c_int,
 }
@@ -25,6 +25,7 @@ impl Clone for A {
     fn clone(&self) -> Self { *self }
 }
 #[repr(C)]
+#[derive(Default)]
 pub struct B__bindgen_vtable {
 }
 #[repr(C)]
@@ -48,7 +49,11 @@ fn bindgen_test_layout_B() {
 impl Clone for B {
     fn clone(&self) -> Self { *self }
 }
+impl Default for B {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
+#[derive(Default)]
 pub struct C__bindgen_vtable {
 }
 #[repr(C)]
@@ -72,6 +77,9 @@ fn bindgen_test_layout_C() {
 impl Clone for C {
     fn clone(&self) -> Self { *self }
 }
+impl Default for C {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
 #[derive(Debug, Copy)]
 pub struct D {
@@ -89,3 +97,6 @@ fn bindgen_test_layout_D() {
 impl Clone for D {
     fn clone(&self) -> Self { *self }
 }
+impl Default for D {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/virtual_overloaded.rs b/tests/expectations/tests/virtual_overloaded.rs
index 9937cf5d..e7ae9f4a 100644
--- a/tests/expectations/tests/virtual_overloaded.rs
+++ b/tests/expectations/tests/virtual_overloaded.rs
@@ -5,6 +5,7 @@
 
 
 #[repr(C)]
+#[derive(Default)]
 pub struct C__bindgen_vtable {
 }
 #[repr(C)]
@@ -22,3 +23,6 @@ fn bindgen_test_layout_C() {
 impl Clone for C {
     fn clone(&self) -> Self { *self }
 }
+impl Default for C {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/vtable_recursive_sig.rs b/tests/expectations/tests/vtable_recursive_sig.rs
index 6cf3135f..716ce39f 100644
--- a/tests/expectations/tests/vtable_recursive_sig.rs
+++ b/tests/expectations/tests/vtable_recursive_sig.rs
@@ -19,7 +19,11 @@ fn bindgen_test_layout_Derived() {
 impl Clone for Derived {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Derived {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 #[repr(C)]
+#[derive(Default)]
 pub struct Base__bindgen_vtable {
 }
 #[repr(C)]
@@ -37,3 +41,6 @@ fn bindgen_test_layout_Base() {
 impl Clone for Base {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Base {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/expectations/tests/weird_bitfields.rs b/tests/expectations/tests/weird_bitfields.rs
index 98765b09..a2841e34 100644
--- a/tests/expectations/tests/weird_bitfields.rs
+++ b/tests/expectations/tests/weird_bitfields.rs
@@ -99,6 +99,9 @@ fn bindgen_test_layout_Weird() {
 impl Clone for Weird {
     fn clone(&self) -> Self { *self }
 }
+impl Default for Weird {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 impl Weird {
     #[inline]
     pub fn bitTest(&self) -> ::std::os::raw::c_uint {
diff --git a/tests/expectations/tests/what_is_going_on.rs b/tests/expectations/tests/what_is_going_on.rs
index d0265c4e..46af0139 100644
--- a/tests/expectations/tests/what_is_going_on.rs
+++ b/tests/expectations/tests/what_is_going_on.rs
@@ -5,7 +5,7 @@
 
 
 #[repr(C)]
-#[derive(Debug, Copy)]
+#[derive(Debug, Default, Copy)]
 pub struct UnknownUnits {
     pub _address: u8,
 }
@@ -27,4 +27,7 @@ pub struct PointTyped<units, F> {
     pub y: F,
     pub _phantom_0: ::std::marker::PhantomData<units>,
 }
+impl <units, F> Default for PointTyped<units, F> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
 pub type IntPoint = PointTyped<UnknownUnits, f32>;
diff --git a/tests/expectations/tests/whitelist-namespaces-basic.rs b/tests/expectations/tests/whitelist-namespaces-basic.rs
index 06f24ff0..ba96895b 100644
--- a/tests/expectations/tests/whitelist-namespaces-basic.rs
+++ b/tests/expectations/tests/whitelist-namespaces-basic.rs
@@ -14,7 +14,7 @@ pub mod root {
             #[allow(unused_imports)]
             use self::super::super::super::root;
             #[repr(C)]
-            #[derive(Debug, Copy)]
+            #[derive(Debug, Default, Copy)]
             pub struct Helper {
                 pub _address: u8,
             }
diff --git a/tests/expectations/tests/whitelist-namespaces.rs b/tests/expectations/tests/whitelist-namespaces.rs
index d3707800..5e47c9d6 100644
--- a/tests/expectations/tests/whitelist-namespaces.rs
+++ b/tests/expectations/tests/whitelist-namespaces.rs
@@ -14,7 +14,7 @@ pub mod root {
             #[allow(unused_imports)]
             use self::super::super::super::root;
             #[repr(C)]
-            #[derive(Debug, Copy)]
+            #[derive(Debug, Default, Copy)]
             pub struct Helper {
                 pub _address: u8,
             }
@@ -30,7 +30,7 @@ pub mod root {
             }
         }
         #[repr(C)]
-        #[derive(Debug, Copy)]
+        #[derive(Debug, Default, Copy)]
         pub struct Test {
             pub helper: root::outer::inner::Helper,
         }
diff --git a/tests/expectations/tests/whitelist_basic.rs b/tests/expectations/tests/whitelist_basic.rs
index 0104f049..d67fb7a3 100644
--- a/tests/expectations/tests/whitelist_basic.rs
+++ b/tests/expectations/tests/whitelist_basic.rs
@@ -16,3 +16,9 @@ pub struct WhitelistMe<T> {
 pub struct WhitelistMe_Inner<T> {
     pub bar: T,
 }
+impl <T> Default for WhitelistMe_Inner<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
+impl <T> Default for WhitelistMe<T> {
+    fn default() -> Self { unsafe { ::std::mem::zeroed() } }
+}
diff --git a/tests/headers/no-derive-debug.h b/tests/headers/no-derive-debug.h
index 4a49e404..c780d2d8 100644
--- a/tests/headers/no-derive-debug.h
+++ b/tests/headers/no-derive-debug.h
@@ -1,4 +1,4 @@
-// bindgen-flags: --no-derive-debug --blacklist-type foo --raw-line "#[repr(C)] #[derive(Copy, Clone)] pub struct foo { bar: ::std::os::raw::c_int, }"
+// bindgen-flags: --no-derive-debug --blacklist-type foo --raw-line "#[repr(C)] #[derive(Copy, Clone, Default)] pub struct foo { bar: ::std::os::raw::c_int, }"
 
 struct foo {
   int bar;
diff --git a/tests/headers/no-derive-default.h b/tests/headers/no-derive-default.h
new file mode 100644
index 00000000..207b93b6
--- /dev/null
+++ b/tests/headers/no-derive-default.h
@@ -0,0 +1,15 @@
+// bindgen-flags: --no-derive-default --blacklist-type foo --raw-line "#[repr(C)] #[derive(Copy, Clone, Debug)] pub struct foo { bar: ::std::os::raw::c_int, }"
+
+struct foo {
+  int bar;
+};
+
+/**
+ * bar should compile. It will normally derive default, but our blacklist of foo
+ * and replacement for another type that doesn't implement it would prevent it
+ * from building if --no-derive-default didn't work.
+ */
+struct bar {
+  struct foo foo;
+  int baz;
+};
diff --git a/tests/tests.rs b/tests/tests.rs
index 5b0ccd11..ef5b2c24 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -104,6 +104,7 @@ fn create_bindgen_builder(header: &PathBuf) -> Result<Option<Builder>, Error> {
         .ok_or(Error::new(ErrorKind::Other, "Invalid header file name")));
 
     let prepend = ["bindgen",
+                   "--with-derive-default",
                    header_str,
                    "--raw-line",
                    "",