Auto merge of #21614 - kvark:typedef, r=huonw

Fixes #21497 

I don't know if this can be tested with built-in tests.

src/libsyntax/ext/deriving/bounds.rs

@@ -51,7 +51,8 @@ pub fn expand_deriving_bound<F>(cx: &mut ExtCtxt,
         path: Path::new(vec!("std", "marker", name)),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
-        methods: vec!()
+        methods: Vec::new(),
+        associated_types: Vec::new(),
     };
 
     trait_def.expand(cx, mitem, item, push)

src/libsyntax/ext/deriving/clone.rs

@@ -44,7 +44,8 @@ pub fn expand_deriving_clone<F>(cx: &mut ExtCtxt,
                     cs_clone("Clone", c, s, sub)
                 }),
             }
-        )
+        ),
+        associated_types: Vec::new(),
     };
 
     trait_def.expand(cx, mitem, item, push)

src/libsyntax/ext/deriving/cmp/eq.rs

@@ -88,7 +88,8 @@ pub fn expand_deriving_eq<F>(cx: &mut ExtCtxt,
         methods: vec!(
             md!("eq", cs_eq),
             md!("ne", cs_ne)
-        )
+        ),
+        associated_types: Vec::new(),
     };
     trait_def.expand(cx, mitem, item, push)
 }

src/libsyntax/ext/deriving/cmp/ord.rs

@@ -78,7 +78,8 @@ pub fn expand_deriving_ord<F>(cx: &mut ExtCtxt,
             md!("le", true, true),
             md!("gt", false, false),
             md!("ge", false, true)
-        ]
+        ],
+        associated_types: Vec::new(),
     };
     trait_def.expand(cx, mitem, item, push)
 }

src/libsyntax/ext/deriving/cmp/totaleq.rs

@@ -61,7 +61,8 @@ pub fn expand_deriving_totaleq<F>(cx: &mut ExtCtxt,
                     cs_total_eq_assert(a, b, c)
                 })
             }
-        )
+        ),
+        associated_types: Vec::new(),
     };
     trait_def.expand(cx, mitem, item, push)
 }

src/libsyntax/ext/deriving/cmp/totalord.rs

@@ -45,7 +45,8 @@ pub fn expand_deriving_totalord<F>(cx: &mut ExtCtxt,
                     cs_cmp(a, b, c)
                 }),
             }
-        )
+        ),
+        associated_types: Vec::new(),
     };
 
     trait_def.expand(cx, mitem, item, push)

src/libsyntax/ext/deriving/decodable.rs

@@ -79,7 +79,9 @@ fn expand_deriving_decodable_imp<F>(cx: &mut ExtCtxt,
                 combine_substructure: combine_substructure(box |a, b, c| {
                     decodable_substructure(a, b, c, krate)
                 }),
-            })
+            }
+        ),
+        associated_types: Vec::new(),
     };
 
     trait_def.expand(cx, mitem, item, push)

src/libsyntax/ext/deriving/default.rs

@@ -43,7 +43,9 @@ pub fn expand_deriving_default<F>(cx: &mut ExtCtxt,
                 combine_substructure: combine_substructure(box |a, b, c| {
                     default_substructure(a, b, c)
                 })
-            })
+            }
+        ),
+        associated_types: Vec::new(),
     };
     trait_def.expand(cx, mitem, item, push)
 }

src/libsyntax/ext/deriving/encodable.rs

@@ -155,7 +155,9 @@ fn expand_deriving_encodable_imp<F>(cx: &mut ExtCtxt,
                 combine_substructure: combine_substructure(box |a, b, c| {
                     encodable_substructure(a, b, c)
                 }),
-            })
+            }
+        ),
+        associated_types: Vec::new(),
     };
 
     trait_def.expand(cx, mitem, item, push)

src/libsyntax/ext/deriving/generic/mod.rs

@@ -228,6 +228,8 @@ pub struct TraitDef<'a> {
     pub generics: LifetimeBounds<'a>,
 
     pub methods: Vec<MethodDef<'a>>,
+
+    pub associated_types: Vec<(ast::Ident, Ty<'a>)>,
 }
 
 
@@ -387,6 +389,22 @@ impl<'a> TraitDef<'a> {
                            methods: Vec<P<ast::Method>>) -> P<ast::Item> {
         let trait_path = self.path.to_path(cx, self.span, type_ident, generics);
 
+        // Transform associated types from `deriving::ty::Ty` into `ast::Typedef`
+        let associated_types = self.associated_types.iter().map(|&(ident, ref type_def)| {
+            P(ast::Typedef {
+                id: ast::DUMMY_NODE_ID,
+                span: self.span,
+                ident: ident,
+                vis: ast::Inherited,
+                attrs: Vec::new(),
+                typ: type_def.to_ty(cx,
+                    self.span,
+                    type_ident,
+                    generics
+                ),
+            })
+        });
+
         let Generics { mut lifetimes, ty_params, mut where_clause } =
             self.generics.to_generics(cx, self.span, type_ident, generics);
         let mut ty_params = ty_params.into_vec();
@@ -494,7 +512,11 @@ impl<'a> TraitDef<'a> {
                           methods.into_iter()
                                  .map(|method| {
                                      ast::MethodImplItem(method)
-                                 }).collect()))
+                                 }).chain(
+                                     associated_types.map(|type_| {
+                                         ast::TypeImplItem(type_)
+                                     })
+                                 ).collect()))
     }
 
     fn expand_struct_def(&self,

src/libsyntax/ext/deriving/hash.rs

@@ -54,7 +54,8 @@ pub fn expand_deriving_hash<F>(cx: &mut ExtCtxt,
                     hash_substructure(a, b, c)
                 })
             }
-        )
+        ),
+        associated_types: Vec::new(),
     };
 
     hash_trait_def.expand(cx, mitem, item, push);

src/libsyntax/ext/deriving/primitive.rs

@@ -65,7 +65,9 @@ pub fn expand_deriving_from_primitive<F>(cx: &mut ExtCtxt,
                 combine_substructure: combine_substructure(box |c, s, sub| {
                     cs_from("u64", c, s, sub)
                 }),
-            })
+            }
+        ),
+        associated_types: Vec::new(),
     };
 
     trait_def.expand(cx, mitem, item, push)

src/libsyntax/ext/deriving/rand.rs

@@ -49,7 +49,8 @@ pub fn expand_deriving_rand<F>(cx: &mut ExtCtxt,
                     rand_substructure(a, b, c)
                 })
             }
-        )
+        ),
+        associated_types: Vec::new(),
     };
     trait_def.expand(cx, mitem, item, push)
 }

src/libsyntax/ext/deriving/show.rs

@@ -35,10 +35,10 @@ pub fn expand_deriving_show<F>(cx: &mut ExtCtxt,
     let trait_def = TraitDef {
         span: span,
         attributes: Vec::new(),
-        path: Path::new(vec!("std", "fmt", "Debug")),
+        path: Path::new(vec!["std", "fmt", "Debug"]),
         additional_bounds: Vec::new(),
         generics: LifetimeBounds::empty(),
-        methods: vec!(
+        methods: vec![
             MethodDef {
                 name: "fmt",
                 generics: LifetimeBounds::empty(),
@@ -50,7 +50,8 @@ pub fn expand_deriving_show<F>(cx: &mut ExtCtxt,
                     show_substructure(a, b, c)
                 })
             }
-        )
+        ],
+        associated_types: Vec::new(),
     };
     trait_def.expand(cx, mitem, item, push)
 }