diff options
Diffstat (limited to 'src/libsyntax_ext')
| -rw-r--r-- | src/libsyntax_ext/deriving/generic/mod.rs | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs index 5abf524313a..2b565ca51e9 100644 --- a/src/libsyntax_ext/deriving/generic/mod.rs +++ b/src/libsyntax_ext/deriving/generic/mod.rs @@ -413,7 +413,24 @@ impl<'a> TraitDef<'a> { attr::find_repr_attrs(&cx.parse_sess.span_diagnostic, attr) .contains(&attr::ReprPacked) }); - let use_temporaries = is_packed; + let has_no_type_params = match item.node { + ast::ItemKind::Struct(_, ref generics) | + ast::ItemKind::Enum(_, ref generics) | + ast::ItemKind::Union(_, ref generics) => { + generics.ty_params.is_empty() + } + _ => { + // Non-ADT derive is an error, but it should have been + // set earlier; see + // libsyntax/ext/expand.rs:MacroExpander::expand() + return; + } + }; + let is_always_copy = + attr::contains_name(&item.attrs, "rustc_copy_clone_marker") && + has_no_type_params; + let use_temporaries = is_packed && is_always_copy; + let newitem = match item.node { ast::ItemKind::Struct(ref struct_def, ref generics) => { self.expand_struct_def(cx, &struct_def, item.ident, generics, from_scratch, @@ -440,12 +457,7 @@ impl<'a> TraitDef<'a> { return; } } - _ => { - // Non-ADT derive is an error, but it should have been - // set earlier; see - // libsyntax/ext/expand.rs:MacroExpander::expand() - return; - } + _ => unreachable!(), }; // Keep the lint attributes of the previous item to control how the // generated implementations are linted |