Auto merge of #32294 - Manishearth:derive-fix, r=alexcrichton

Re-add double underscores in derive (fixes #32292)

@durka, sanity-check, please?

<s>Don't merge this yet, I need to add a test and test it locally.</s>

ready for review

Author: bors

src/libsyntax_ext/deriving/cmp/ord.rs

@@ -64,7 +64,7 @@ pub fn ordering_collapsed(cx: &mut ExtCtxt,
 
 pub fn cs_cmp(cx: &mut ExtCtxt, span: Span,
               substr: &Substructure) -> P<Expr> {
-    let test_id = cx.ident_of("cmp");
+    let test_id = cx.ident_of("__cmp");
     let equals_path = cx.path_global(span,
                                      cx.std_path(&["cmp", "Ordering", "Equal"]));
 
@@ -79,9 +79,9 @@ pub fn cs_cmp(cx: &mut ExtCtxt, span: Span,
                 ::std::cmp::Ordering::Equal => {
                     ...
                 }
-                cmp => cmp
+                __cmp => __cmp
             },
-        cmp => cmp
+        __cmp => __cmp
     }
     */
     cs_fold(
@@ -91,7 +91,7 @@ pub fn cs_cmp(cx: &mut ExtCtxt, span: Span,
         |cx, span, old, self_f, other_fs| {
             // match new {
             //     ::std::cmp::Ordering::Equal => old,
-            //     cmp => cmp
+            //     __cmp => __cmp
             // }
 
             let new = {

src/libsyntax_ext/deriving/cmp/partial_ord.rs

@@ -107,7 +107,7 @@ pub fn some_ordering_collapsed(cx: &mut ExtCtxt,
 
 pub fn cs_partial_cmp(cx: &mut ExtCtxt, span: Span,
               substr: &Substructure) -> P<Expr> {
-    let test_id = cx.ident_of("cmp");
+    let test_id = cx.ident_of("__cmp");
     let ordering = cx.path_global(span,
                                   cx.std_path(&["cmp", "Ordering", "Equal"]));
     let ordering_expr = cx.expr_path(ordering.clone());
@@ -124,9 +124,9 @@ pub fn cs_partial_cmp(cx: &mut ExtCtxt, span: Span,
                 ::std::option::Option::Some(::std::cmp::Ordering::Equal) => {
                     ...
                 }
-                cmp => cmp
+                __cmp => __cmp
             },
-        cmp => cmp
+        __cmp => __cmp
     }
     */
     cs_fold(
@@ -136,7 +136,7 @@ pub fn cs_partial_cmp(cx: &mut ExtCtxt, span: Span,
         |cx, span, old, self_f, other_fs| {
             // match new {
             //     Some(::std::cmp::Ordering::Equal) => old,
-            //     cmp => cmp
+            //     __cmp => __cmp
             // }
 
             let new = {

src/libsyntax_ext/deriving/generic/mod.rs

@@ -156,14 +156,14 @@
 //!
 //! ```{.text}
 //! EnumNonMatchingCollapsed(
-//!     vec![<ident of self>, <ident of arg_1>],
+//!     vec![<ident of self>, <ident of __arg_1>],
 //!     &[<ast::Variant for C0>, <ast::Variant for C1>],
-//!     &[<ident for self index value>, <ident of arg_1 index value>])
+//!     &[<ident for self index value>, <ident of __arg_1 index value>])
 //! ```
 //!
 //! It is the same for when the arguments are flipped to `C1 {x}` and
 //! `C0(a)`; the only difference is what the values of the identifiers
-//! <ident for self index value> and <ident of arg_1 index value> will
+//! <ident for self index value> and <ident of __arg_1 index value> will
 //! be in the generated code.
 //!
 //! `EnumNonMatchingCollapsed` deliberately provides far less information
@@ -843,7 +843,7 @@ impl<'a> MethodDef<'a> {
 
         for (i, ty) in self.args.iter().enumerate() {
             let ast_ty = ty.to_ty(cx, trait_.span, type_ident, generics);
-            let ident = cx.ident_of(&format!("arg_{}", i));
+            let ident = cx.ident_of(&format!("__arg_{}", i));
             arg_tys.push((ident, ast_ty));
 
             let arg_expr = cx.expr_ident(trait_.span, ident);
@@ -929,12 +929,12 @@ impl<'a> MethodDef<'a> {
     ///
     /// // equivalent to:
     /// impl PartialEq for A {
-    ///     fn eq(&self, arg_1: &A) -> bool {
+    ///     fn eq(&self, __arg_1: &A) -> bool {
     ///         match *self {
-    ///             A {x: ref self_0_0, y: ref self_0_1} => {
-    ///                 match *arg_1 {
-    ///                     A {x: ref self_1_0, y: ref self_1_1} => {
-    ///                         self_0_0.eq(self_1_0) && self_0_1.eq(self_1_1)
+    ///             A {x: ref __self_0_0, y: ref __self_0_1} => {
+    ///                 match *__arg_1 {
+    ///                     A {x: ref __self_1_0, y: ref __self_1_1} => {
+    ///                         __self_0_0.eq(__self_1_0) && __self_0_1.eq(__self_1_1)
     ///                     }
     ///                 }
     ///             }
@@ -960,7 +960,7 @@ impl<'a> MethodDef<'a> {
                 trait_.create_struct_pattern(cx,
                                              struct_path,
                                              struct_def,
-                                             &format!("self_{}",
+                                             &format!("__self_{}",
                                                      i),
                                              ast::Mutability::Immutable);
             patterns.push(pat);
@@ -1038,25 +1038,25 @@ impl<'a> MethodDef<'a> {
     /// // is equivalent to
     ///
     /// impl PartialEq for A {
-    ///     fn eq(&self, arg_1: &A) -> ::bool {
-    ///         match (&*self, &*arg_1) {
+    ///     fn eq(&self, __arg_1: &A) -> ::bool {
+    ///         match (&*self, &*__arg_1) {
     ///             (&A1, &A1) => true,
     ///             (&A2(ref self_0),
-    ///              &A2(ref arg_1_0)) => (*self_0).eq(&(*arg_1_0)),
+    ///              &A2(ref __arg_1_0)) => (*self_0).eq(&(*__arg_1_0)),
     ///             _ => {
-    ///                 let self_vi = match *self { A1(..) => 0, A2(..) => 1 };
-    ///                 let arg_1_vi = match *arg_1 { A1(..) => 0, A2(..) => 1 };
+    ///                 let __self_vi = match *self { A1(..) => 0, A2(..) => 1 };
+    ///                 let __arg_1_vi = match *__arg_1 { A1(..) => 0, A2(..) => 1 };
     ///                 false
     ///             }
     ///         }
     ///     }
     /// }
     /// ```
     ///
-    /// (Of course `self_vi` and `arg_1_vi` are unused for
+    /// (Of course `__self_vi` and `__arg_1_vi` are unused for
     /// `PartialEq`, and those subcomputations will hopefully be removed
-    /// as their results are unused.  The point of `self_vi` and
-    /// `arg_1_vi` is for `PartialOrd`; see #15503.)
+    /// as their results are unused.  The point of `__self_vi` and
+    /// `__arg_1_vi` is for `PartialOrd`; see #15503.)
     fn expand_enum_method_body<'b>(&self,
                                cx: &mut ExtCtxt,
                                trait_: &TraitDef<'b>,
@@ -1087,14 +1087,14 @@ impl<'a> MethodDef<'a> {
     /// for each of the self-args, carried in precomputed variables.
 
     /// ```{.text}
-    /// let self0_vi = unsafe {
+    /// let __self0_vi = unsafe {
     ///     std::intrinsics::discriminant_value(&self) } as i32;
-    /// let self1_vi = unsafe {
+    /// let __self1_vi = unsafe {
     ///     std::intrinsics::discriminant_value(&arg1) } as i32;
-    /// let self2_vi = unsafe {
+    /// let __self2_vi = unsafe {
     ///     std::intrinsics::discriminant_value(&arg2) } as i32;
     ///
-    /// if self0_vi == self1_vi && self0_vi == self2_vi && ... {
+    /// if __self0_vi == __self1_vi && __self0_vi == __self2_vi && ... {
     ///     match (...) {
     ///         (Variant1, Variant1, ...) => Body1
     ///         (Variant2, Variant2, ...) => Body2,
@@ -1122,9 +1122,9 @@ impl<'a> MethodDef<'a> {
         let self_arg_names = self_args.iter().enumerate()
             .map(|(arg_count, _self_arg)| {
                 if arg_count == 0 {
-                    "self".to_string()
+                    "__self".to_string()
                 } else {
-                    format!("arg_{}", arg_count)
+                    format!("__arg_{}", arg_count)
                 }
             })
             .collect::<Vec<String>>();
@@ -1261,17 +1261,17 @@ impl<'a> MethodDef<'a> {
             // with three Self args, builds three statements:
             //
             // ```
-            // let self0_vi = unsafe {
+            // let __self0_vi = unsafe {
             //     std::intrinsics::discriminant_value(&self) } as i32;
-            // let self1_vi = unsafe {
+            // let __self1_vi = unsafe {
             //     std::intrinsics::discriminant_value(&arg1) } as i32;
-            // let self2_vi = unsafe {
+            // let __self2_vi = unsafe {
             //     std::intrinsics::discriminant_value(&arg2) } as i32;
             // ```
             let mut index_let_stmts: Vec<ast::Stmt> = Vec::new();
 
             //We also build an expression which checks whether all discriminants are equal
-            // discriminant_test = self0_vi == self1_vi && self0_vi == self2_vi && ...
+            // discriminant_test = __self0_vi == __self1_vi && __self0_vi == __self2_vi && ...
             let mut discriminant_test = cx.expr_bool(sp, true);
 
             let target_type_name =
@@ -1321,7 +1321,7 @@ impl<'a> MethodDef<'a> {
             // down to desired l-values, but we cannot actually deref
             // them when they are fed as r-values into a tuple
             // expression; here add a layer of borrowing, turning
-            // `(*self, *arg_0, ...)` into `(&*self, &*arg_0, ...)`.
+            // `(*self, *__arg_0, ...)` into `(&*self, &*__arg_0, ...)`.
             let borrowed_self_args = self_args.move_map(|self_arg| cx.expr_addr_of(sp, self_arg));
             let match_arg = cx.expr(sp, ast::ExprKind::Tup(borrowed_self_args));
 
@@ -1335,7 +1335,7 @@ impl<'a> MethodDef<'a> {
             //      }
             //  }
             //  else {
-            //      <delegated expression referring to self0_vi, et al.>
+            //      <delegated expression referring to __self0_vi, et al.>
             //  }
             let all_match = cx.expr_match(sp, match_arg, match_arms);
             let arm_expr = cx.expr_if(sp, discriminant_test, all_match, Some(arm_expr));
@@ -1359,8 +1359,8 @@ impl<'a> MethodDef<'a> {
             // error-prone, since the catch-all as defined above would
             // generate code like this:
             //
-            //     _ => { let self0 = match *self { };
-            //            let self1 = match *arg_0 { };
+            //     _ => { let __self0 = match *self { };
+            //            let __self1 = match *__arg_0 { };
             //            <catch-all-expr> }
             //
             // Which is yields bindings for variables which type
@@ -1399,7 +1399,7 @@ impl<'a> MethodDef<'a> {
             // down to desired l-values, but we cannot actually deref
             // them when they are fed as r-values into a tuple
             // expression; here add a layer of borrowing, turning
-            // `(*self, *arg_0, ...)` into `(&*self, &*arg_0, ...)`.
+            // `(*self, *__arg_0, ...)` into `(&*self, &*__arg_0, ...)`.
             let borrowed_self_args = self_args.move_map(|self_arg| cx.expr_addr_of(sp, self_arg));
             let match_arg = cx.expr(sp, ast::ExprKind::Tup(borrowed_self_args));
             cx.expr_match(sp, match_arg, match_arms)
@@ -1613,8 +1613,8 @@ pub fn cs_fold<F>(use_foldl: bool,
 /// process the collected results. i.e.
 ///
 /// ```ignore
-/// f(cx, span, vec![self_1.method(arg_1_1, arg_2_1),
-///                  self_2.method(arg_1_2, arg_2_2)])
+/// f(cx, span, vec![self_1.method(__arg_1_1, __arg_2_1),
+///                  self_2.method(__arg_1_2, __arg_2_2)])
 /// ```
 #[inline]
 pub fn cs_same_method<F>(f: F,

src/test/run-pass/issue-32292.rs

@@ -0,0 +1,18 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![deny(warnings)]
+
+#[derive(Hash, Ord, PartialOrd, Eq, PartialEq, Debug, Clone, Copy)]
+struct Foo;
+
+fn main() {
+    let _ = Foo;
+}