Fix #[derive] for empty tuple structs/variants

3 files changed, 8 insertions, 8 deletions

diff --git a/src/libsyntax_ext/deriving/decodable.rs b/src/libsyntax_ext/deriving/decodable.rs
index 9a332227053..f395f7bd0c4 100644
--- a/src/libsyntax_ext/deriving/decodable.rs
+++ b/src/libsyntax_ext/deriving/decodable.rs
@@ -110,7 +110,7 @@ fn decodable_substructure(cx: &mut ExtCtxt,
     return match *substr.fields {
         StaticStruct(_, ref summary) => {
             let nfields = match *summary {
-                Unnamed(ref fields) => fields.len(),
+                Unnamed(ref fields, _) => fields.len(),
                 Named(ref fields) => fields.len(),
             };
             let read_struct_field = cx.ident_of("read_struct_field");
@@ -193,9 +193,9 @@ fn decode_static_fields<F>(cx: &mut ExtCtxt,
     where F: FnMut(&mut ExtCtxt, Span, InternedString, usize) -> P<Expr>
 {
     match *fields {
-        Unnamed(ref fields) => {
+        Unnamed(ref fields, is_tuple) => {
             let path_expr = cx.expr_path(outer_pat_path);
-            if fields.is_empty() {
+            if !is_tuple {
                 path_expr
             } else {
                 let fields = fields.iter()
diff --git a/src/libsyntax_ext/deriving/default.rs b/src/libsyntax_ext/deriving/default.rs
index 9df3db938b1..449c1ff066b 100644
--- a/src/libsyntax_ext/deriving/default.rs
+++ b/src/libsyntax_ext/deriving/default.rs
@@ -57,8 +57,8 @@ fn default_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructur
     return match *substr.fields {
         StaticStruct(_, ref summary) => {
             match *summary {
-                Unnamed(ref fields) => {
-                    if fields.is_empty() {
+                Unnamed(ref fields, is_tuple) => {
+                    if !is_tuple {
                         cx.expr_ident(trait_span, substr.type_ident)
                     } else {
                         let exprs = fields.iter().map(|sp| default_call(*sp)).collect();
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index cd49e7ec9d2..22e98fb213f 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -294,8 +294,8 @@ pub struct FieldInfo<'a> {
 
 /// Fields for a static method
 pub enum StaticFields {
-    /// Tuple structs/enum variants like this.
-    Unnamed(Vec<Span>),
+    /// Tuple and unit structs/enum variants like this.
+    Unnamed(Vec<Span>, bool /*is tuple*/),
     /// Normal structs/struct variants.
     Named(Vec<(Ident, Span)>),
 }
@@ -1470,7 +1470,7 @@ impl<'a> TraitDef<'a> {
             (_, false) => Named(named_idents),
             // empty structs
             _ if struct_def.is_struct() => Named(named_idents),
-            _ => Unnamed(just_spans),
+            _ => Unnamed(just_spans, struct_def.is_tuple()),
         }
     }