librustc: Stop parsing impl Type : Trait and fix several declarations that slipped through. r=tjc

src/libcargo/cargo.rc

@@ -71,7 +71,7 @@ pub struct Package {
     versions: ~[(~str, ~str)]
 }
 
-pub impl Package : cmp::Ord {
+pub impl cmp::Ord for Package {
     pure fn lt(&self, other: &Package) -> bool {
         if (*self).name.lt(&(*other).name) { return true; }
         if (*other).name.lt(&(*self).name) { return false; }

src/libcore/at_vec.rs

@@ -173,7 +173,7 @@ pub mod traits {
     use kinds::Copy;
     use ops::Add;
 
-    pub impl<T: Copy> @[T] : Add<&[const T],@[T]> {
+    pub impl<T: Copy> Add<&[const T],@[T]> for @[T] {
         #[inline(always)]
         pure fn add(&self, rhs: & &self/[const T]) -> @[T] {
             append(*self, (*rhs))

src/libcore/num/f32.rs

@@ -282,7 +282,7 @@ impl num::One for f32 {
     static pure fn one() -> f32 { 1.0 }
 }
 
-pub impl f32: NumCast {
+pub impl NumCast for f32 {
     /**
      * Cast `n` to an `f32`
      */

src/libcore/num/f64.rs

@@ -297,7 +297,7 @@ impl cmp::Ord for f64 {
     pure fn gt(&self, other: &f64) -> bool { (*self) > (*other) }
 }
 
-pub impl f64: NumCast {
+pub impl NumCast for f64 {
     /**
      * Cast `n` to an `f64`
      */

src/libcore/num/float.rs

@@ -415,7 +415,7 @@ impl num::One for float {
     static pure fn one() -> float { 1.0 }
 }
 
-pub impl float: NumCast {
+pub impl NumCast for float {
     /**
      * Cast `n` to a `float`
      */

src/libcore/num/int-template/i16.rs

@@ -17,7 +17,7 @@ mod inst {
     pub const bits: uint = ::u16::bits;
 }
 
-pub impl i16: NumCast {
+pub impl NumCast for i16 {
     /**
      * Cast `n` to a `i16`
      */

src/libcore/num/int-template/i32.rs

@@ -17,7 +17,7 @@ mod inst {
     pub const bits: uint = ::u32::bits;
 }
 
-pub impl i32: NumCast {
+pub impl NumCast for i32 {
     /**
      * Cast `n` to a `i32`
      */

src/libcore/num/int-template/i64.rs

@@ -17,7 +17,7 @@ mod inst {
     pub const bits: uint = ::u64::bits;
 }
 
-pub impl i64: NumCast {
+pub impl NumCast for i64 {
     /**
      * Cast `n` to a `i64`
      */

src/libcore/num/int-template/i8.rs

@@ -17,7 +17,7 @@ mod inst {
     pub const bits: uint = ::u8::bits;
 }
 
-pub impl i8: NumCast {
+pub impl NumCast for i8 {
     /**
      * Cast `n` to a `i8`
      */

src/libcore/num/int-template/int.rs

@@ -58,7 +58,7 @@ mod inst {
     }
 }
 
-pub impl int: NumCast {
+pub impl NumCast for int {
     /**
      * Cast `n` to a `int`
      */

src/libcore/num/uint-template/u16.rs

@@ -19,7 +19,7 @@ mod inst {
     pub const bits: uint = 16;
 }
 
-pub impl u16: NumCast {
+pub impl NumCast for u16 {
     /**
      * Cast `n` to a `u16`
      */

src/libcore/num/uint-template/u32.rs

@@ -19,7 +19,7 @@ mod inst {
     pub const bits: uint = 32;
 }
 
-pub impl u32: NumCast {
+pub impl NumCast for u32 {
     /**
      * Cast `n` to a `u32`
      */

src/libcore/num/uint-template/u64.rs

@@ -19,7 +19,7 @@ mod inst {
     pub const bits: uint = 64;
 }
 
-pub impl u64: num::NumCast {
+pub impl NumCast for u64 {
     /**
      * Cast `n` to a `u64`
      */

src/libcore/num/uint-template/u8.rs

@@ -26,7 +26,7 @@ mod inst {
     pub pure fn is_ascii(x: T) -> bool { return 0 as T == x & 128 as T; }
 }
 
-pub impl u8: NumCast {
+pub impl NumCast for u8 {
     /**
      * Cast `n` to a `u8`
      */

src/libcore/num/uint-template/uint.rs

@@ -110,7 +110,7 @@ pub mod inst {
         return true;
     }
 
-    pub impl uint: iter::Times {
+    pub impl iter::Times for uint {
         #[inline(always)]
         /**
         * A convenience form for basic iteration. Given a uint `x`,
@@ -209,7 +209,7 @@ pub mod inst {
     }
 }
 
-pub impl uint: NumCast {
+pub impl NumCast for uint {
     /**
      * Cast `n` to a `uint`
      */

src/libcore/pipes.rs

@@ -1211,11 +1211,11 @@ pub trait Select2<T: Owned, U: Owned> {
     fn select() -> Either<T, U>;
 }
 
-impl<T: Owned, U: Owned,
+impl<T: Owned,
+     U: Owned,
      Left: Selectable GenericPort<T>,
      Right: Selectable GenericPort<U>>
-    (Left, Right): Select2<T, U> {
+     Select2<T,U> for (Left, Right) {
-
     fn select() -> Either<T, U> {
         match self {
           (ref lp, ref rp) => match select2i(lp, rp) {

src/libcore/str.rs

@@ -2328,7 +2328,7 @@ pub trait OwnedStr {
     fn push_char(&mut self, c: char);
 }
 
-pub impl ~str : OwnedStr {
+pub impl OwnedStr for ~str {
     fn push_str(&mut self, v: &str) {
         push_str(self, v);
     }

src/libcore/to_bytes.rs

@@ -170,7 +170,7 @@ impl IterBytes for char {
 pub mod x32 {
     use to_bytes::{Cb, IterBytes};
 
-    pub impl uint: IterBytes {
+    pub impl IterBytes for uint {
         #[inline(always)]
         pure fn iter_bytes(&self, lsb0: bool, f: Cb) {
             (*self as u32).iter_bytes(lsb0, f)
@@ -182,7 +182,7 @@ pub mod x32 {
 pub mod x64 {
     use to_bytes::{Cb, IterBytes};
 
-    pub impl uint: IterBytes {
+    pub impl IterBytes for uint {
         #[inline(always)]
         pure fn iter_bytes(&self, lsb0: bool, f: Cb) {
             (*self as u64).iter_bytes(lsb0, f)

src/librustc/driver/driver.rs

@@ -175,6 +175,7 @@ pub fn time<T>(do_it: bool, what: ~str, thunk: fn() -> T) -> T {
     rv
 }
 
+#[deriving_eq]
 pub enum compile_upto {
     cu_parse,
     cu_expand,
@@ -183,13 +184,6 @@ pub enum compile_upto {
     cu_everything,
 }
 
-pub impl compile_upto : cmp::Eq {
-    pure fn eq(&self, other: &compile_upto) -> bool {
-        ((*self) as uint) == ((*other) as uint)
-    }
-    pure fn ne(&self, other: &compile_upto) -> bool { !(*self).eq(other) }
-}
-
 pub fn compile_upto(sess: Session, cfg: ast::crate_cfg,
                     input: input, upto: compile_upto,
                     outputs: Option<output_filenames>)

src/librustc/driver/session.rs

@@ -29,24 +29,12 @@ use syntax::parse::parse_sess;
 use syntax::{ast, codemap};
 use syntax;
 
+#[deriving_eq]
 pub enum os { os_win32, os_macos, os_linux, os_android, os_freebsd, }
 
-pub impl os : cmp::Eq {
+#[deriving_eq]
-    pure fn eq(&self, other: &os) -> bool {
-        ((*self) as uint) == ((*other) as uint)
-    }
-    pure fn ne(&self, other: &os) -> bool { !(*self).eq(other) }
-}
-
 pub enum arch { arch_x86, arch_x86_64, arch_arm, }
 
-pub impl arch : cmp::Eq {
-    pure fn eq(&self, other: &arch) -> bool {
-        ((*self) as uint) == ((*other) as uint)
-    }
-    pure fn ne(&self, other: &arch) -> bool { !(*self).eq(other) }
-}
-
 pub enum crate_type { bin_crate, lib_crate, unknown_crate, }
 
 pub type config =
@@ -117,6 +105,7 @@ pub fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
     ]
 }
 
+#[deriving_eq]
 pub enum OptLevel {
     No, // -O0
     Less, // -O1
@@ -124,13 +113,6 @@ pub enum OptLevel {
     Aggressive // -O3
 }
 
-pub impl OptLevel : cmp::Eq {
-    pure fn eq(&self, other: &OptLevel) -> bool {
-        ((*self) as uint) == ((*other) as uint)
-    }
-    pure fn ne(&self, other: &OptLevel) -> bool { !(*self).eq(other) }
-}
-
 pub type options =
     // The crate config requested for the session, which may be combined
     // with additional crate configurations during the compile process

src/librustc/lib/llvm.rs

@@ -132,6 +132,7 @@ pub enum RealPredicate {
 
 // enum for the LLVM TypeKind type - must stay in sync with the def of
 // LLVMTypeKind in llvm/include/llvm-c/Core.h
+#[deriving_eq]
 pub enum TypeKind {
     Void      = 0,
     Half      = 1,
@@ -151,46 +152,6 @@ pub enum TypeKind {
     X86_MMX   = 15
 }
 
-pub impl TypeKind : cmp::Eq {
-    pure fn eq(&self, other: &TypeKind) -> bool {
-        match ((*self), (*other)) {
-            (Void, Void) => true,
-            (Half, Half) => true,
-            (Float, Float) => true,
-            (Double, Double) => true,
-            (X86_FP80, X86_FP80) => true,
-            (FP128, FP128) => true,
-            (PPC_FP128, PPC_FP128) => true,
-            (Label, Label) => true,
-            (Integer, Integer) => true,
-            (Function, Function) => true,
-            (Struct, Struct) => true,
-            (Array, Array) => true,
-            (Pointer, Pointer) => true,
-            (Vector, Vector) => true,
-            (Metadata, Metadata) => true,
-            (X86_MMX, X86_MMX) => true,
-            (Void, _) => false,
-            (Half, _) => false,
-            (Float, _) => false,
-            (Double, _) => false,
-            (X86_FP80, _) => false,
-            (FP128, _) => false,
-            (PPC_FP128, _) => false,
-            (Label, _) => false,
-            (Integer, _) => false,
-            (Function, _) => false,
-            (Struct, _) => false,
-            (Array, _) => false,
-            (Pointer, _) => false,
-            (Vector, _) => false,
-            (Metadata, _) => false,
-            (X86_MMX, _) => false,
-        }
-    }
-    pure fn ne(&self, other: &TypeKind) -> bool { !(*self).eq(other) }
-}
-
 pub enum AtomicBinOp {
     Xchg = 0,
     Add  = 1,

src/librustc/middle/borrowck/mod.rs

@@ -449,7 +449,7 @@ impl LoanKind {
 
 /// Creates and returns a new root_map
 
-pub impl root_map_key : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for root_map_key {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         to_bytes::iter_bytes_2(&self.id, &self.derefs, lsb0, f);
     }

src/librustc/middle/mem_categorization.rs

@@ -281,12 +281,12 @@ pub trait ast_node {
     fn span() -> span;
 }
 
-pub impl @ast::expr: ast_node {
+pub impl ast_node for @ast::expr {
     fn id() -> ast::node_id { self.id }
     fn span() -> span { self.span }
 }
 
-pub impl @ast::pat: ast_node {
+pub impl ast_node for @ast::pat {
     fn id() -> ast::node_id { self.id }
     fn span() -> span { self.span }
 }
@@ -295,7 +295,7 @@ pub trait get_type_for_node {
     fn ty<N: ast_node>(node: N) -> ty::t;
 }
 
-pub impl ty::ctxt: get_type_for_node {
+pub impl get_type_for_node for ty::ctxt {
     fn ty<N: ast_node>(node: N) -> ty::t {
         ty::node_id_to_type(self, node.id())
     }

src/librustc/middle/trans/base.rs

@@ -108,7 +108,7 @@ pub trait get_insn_ctxt {
     fn insn_ctxt(s: &str) -> icx_popper;
 }
 
-pub impl @crate_ctxt: get_insn_ctxt {
+pub impl get_insn_ctxt for @crate_ctxt {
     fn insn_ctxt(s: &str) -> icx_popper {
         debug!("new insn_ctxt: %s", s);
         if self.sess.count_llvm_insns() {
@@ -118,13 +118,13 @@ pub impl @crate_ctxt: get_insn_ctxt {
     }
 }
 
-pub impl block: get_insn_ctxt {
+pub impl get_insn_ctxt for block {
     fn insn_ctxt(s: &str) -> icx_popper {
         self.ccx().insn_ctxt(s)
     }
 }
 
-pub impl fn_ctxt: get_insn_ctxt {
+pub impl get_insn_ctxt for fn_ctxt {
     fn insn_ctxt(s: &str) -> icx_popper {
         self.ccx.insn_ctxt(s)
     }

src/librustc/middle/trans/common.rs

@@ -532,13 +532,13 @@ pub trait get_node_info {
     fn info() -> Option<node_info>;
 }
 
-pub impl @ast::expr: get_node_info {
+pub impl get_node_info for @ast::expr {
     fn info() -> Option<node_info> {
         Some({id: self.id, span: self.span})
     }
 }
 
-pub impl ast::blk: get_node_info {
+pub impl get_node_info for ast::blk {
     fn info() -> Option<node_info> {
         Some({id: self.node.id, span: self.span})
     }
@@ -547,7 +547,7 @@ pub impl ast::blk: get_node_info {
 // XXX: Work around a trait parsing bug. remove after snapshot
 pub type optional_boxed_ast_expr = Option<@ast::expr>;
 
-pub impl optional_boxed_ast_expr: get_node_info {
+pub impl get_node_info for optional_boxed_ast_expr {
     fn info() -> Option<node_info> {
         self.chain_ref(|s| s.info())
     }
@@ -1280,7 +1280,7 @@ pub struct mono_id_ {
 
 pub type mono_id = @mono_id_;
 
-pub impl mono_param_id : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for mono_param_id {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         match /*bad*/copy *self {
           mono_precise(t, mids) =>
@@ -1294,7 +1294,7 @@ pub impl mono_param_id : to_bytes::IterBytes {
     }
 }
 
-pub impl mono_id_ : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for mono_id_ {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         to_bytes::iter_bytes_2(&self.def, &self.params, lsb0, f);
     }

src/librustc/middle/trans/datum.rs

@@ -104,6 +104,7 @@ use core::uint;
 use core::vec;
 use syntax::parse::token::special_idents;
 
+#[deriving_eq]
 pub enum CopyAction {
     INIT,
     DROP_EXISTING
@@ -150,14 +151,14 @@ pub impl DatumMode {
     }
 }
 
-pub impl DatumMode: cmp::Eq {
+pub impl cmp::Eq for DatumMode {
     pure fn eq(&self, other: &DatumMode) -> bool {
         (*self) as uint == (*other as uint)
     }
     pure fn ne(&self, other: &DatumMode) -> bool { !(*self).eq(other) }
 }
 
-pub impl DatumMode: to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for DatumMode {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as uint).iter_bytes(lsb0, f)
     }
@@ -846,14 +847,3 @@ pub impl DatumBlock {
     }
 }
 
-pub impl CopyAction : cmp::Eq {
-    pure fn eq(&self, other: &CopyAction) -> bool {
-        match ((*self), (*other)) {
-            (INIT, INIT) => true,
-            (DROP_EXISTING, DROP_EXISTING) => true,
-            (INIT, _) => false,
-            (DROP_EXISTING, _) => false,
-        }
-    }
-    pure fn ne(&self, other: &CopyAction) -> bool { !(*self).eq(other) }
-}

src/librustc/middle/ty.rs

@@ -657,46 +657,46 @@ pub trait Vid {
     pure fn to_uint() -> uint;
 }
 
-pub impl TyVid: Vid {
+pub impl Vid for TyVid {
     pure fn to_uint() -> uint { *self }
 }
 
-pub impl TyVid: ToStr {
+pub impl ToStr for TyVid {
     pure fn to_str(&self) -> ~str { fmt!("<V%u>", self.to_uint()) }
 }
 
-pub impl IntVid: Vid {
+pub impl Vid for IntVid {
     pure fn to_uint() -> uint { *self }
 }
 
-pub impl IntVid: ToStr {
+pub impl ToStr for IntVid {
     pure fn to_str(&self) -> ~str { fmt!("<VI%u>", self.to_uint()) }
 }
 
-pub impl FloatVid: Vid {
+pub impl Vid for FloatVid {
     pure fn to_uint() -> uint { *self }
 }
 
-pub impl FloatVid: ToStr {
+pub impl ToStr for FloatVid {
     pure fn to_str(&self) -> ~str { fmt!("<VF%u>", self.to_uint()) }
 }
 
-pub impl RegionVid: Vid {
+pub impl Vid for RegionVid {
     pure fn to_uint() -> uint { *self }
 }
 
-pub impl RegionVid: ToStr {
+pub impl ToStr for RegionVid {
     pure fn to_str(&self) -> ~str { fmt!("%?", self) }
 }
 
-pub impl FnSig : ToStr {
+pub impl ToStr for FnSig {
     pure fn to_str(&self) -> ~str {
         // grr, without tcx not much we can do.
         return ~"(...)";
     }
 }
 
-pub impl InferTy: ToStr {
+pub impl ToStr for InferTy {
     pure fn to_str(&self) -> ~str {
         match *self {
             TyVar(ref v) => v.to_str(),
@@ -706,7 +706,7 @@ pub impl InferTy: ToStr {
     }
 }
 
-pub impl IntVarValue : ToStr {
+pub impl ToStr for IntVarValue {
     pure fn to_str(&self) -> ~str {
         match *self {
             IntType(ref v) => v.to_str(),
@@ -715,25 +715,25 @@ pub impl IntVarValue : ToStr {
     }
 }
 
-pub impl TyVid : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for TyVid {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         self.to_uint().iter_bytes(lsb0, f)
     }
 }
 
-pub impl IntVid : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for IntVid {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         self.to_uint().iter_bytes(lsb0, f)
     }
 }
 
-pub impl FloatVid : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for FloatVid {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         self.to_uint().iter_bytes(lsb0, f)
     }
 }
 
-pub impl RegionVid : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for RegionVid {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         self.to_uint().iter_bytes(lsb0, f)
     }

src/librustc/middle/typeck/check/mod.rs

@@ -620,7 +620,7 @@ pub fn check_item(ccx: @mut CrateCtxt, it: @ast::item) {
     }
 }
 
-pub impl FnCtxt: AstConv {
+pub impl AstConv for FnCtxt {
     fn tcx(@mut self) -> ty::ctxt { self.ccx.tcx }
     fn ccx(@mut self) -> @mut CrateCtxt { self.ccx }
 
@@ -654,7 +654,7 @@ pub impl FnCtxt {
     }
 }
 
-pub impl @mut FnCtxt: region_scope {
+pub impl region_scope for @mut FnCtxt {
     pure fn anon_region(span: span) -> Result<ty::Region, ~str> {
         // XXX: Unsafe to work around purity
         unsafe {

src/librustc/middle/typeck/collect.rs

@@ -121,7 +121,7 @@ pub impl @mut CrateCtxt {
     }
 }
 
-pub impl CrateCtxt: AstConv {
+pub impl AstConv for CrateCtxt {
     fn tcx(@mut self) -> ty::ctxt { self.tcx }
     fn ccx(@mut self) -> @mut CrateCtxt { self }
 

src/librustc/middle/typeck/infer/glb.rs

@@ -27,7 +27,7 @@ use std::list;
 
 pub enum Glb = CombineFields;  // "greatest lower bound" (common subtype)
 
-pub impl Glb: Combine {
+pub impl Combine for Glb {
     fn infcx() -> @mut InferCtxt { self.infcx }
     fn tag() -> ~str { ~"glb" }
     fn a_is_expected() -> bool { self.a_is_expected }

src/librustc/middle/typeck/infer/lattice.rs

@@ -57,7 +57,7 @@ pub trait LatticeValue {
 
 pub type LatticeOp<T> = &fn(cf: &CombineFields, a: &T, b: &T) -> cres<T>;
 
-pub impl ty::t: LatticeValue {
+pub impl LatticeValue for ty::t {
     static fn sub(cf: &CombineFields, a: &ty::t, b: &ty::t) -> ures {
         Sub(*cf).tys(*a, *b).to_ures()
     }
@@ -301,7 +301,7 @@ pub trait TyLatticeDir {
     fn ty_bot(t: ty::t) -> cres<ty::t>;
 }
 
-pub impl Lub: LatticeDir {
+pub impl LatticeDir for Lub {
     fn combine_fields() -> CombineFields { *self }
     fn bnd<T:Copy>(b: &Bounds<T>) -> Option<T> { b.ub }
     fn with_bnd<T:Copy>(b: &Bounds<T>, +t: T) -> Bounds<T> {
@@ -309,13 +309,13 @@ pub impl Lub: LatticeDir {
     }
 }
 
-pub impl Lub: TyLatticeDir {
+pub impl TyLatticeDir for Lub {
     fn ty_bot(t: ty::t) -> cres<ty::t> {
         Ok(t)
     }
 }
 
-pub impl Glb: LatticeDir {
+pub impl LatticeDir for Glb {
     fn combine_fields() -> CombineFields { *self }
     fn bnd<T:Copy>(b: &Bounds<T>) -> Option<T> { b.lb }
     fn with_bnd<T:Copy>(b: &Bounds<T>, +t: T) -> Bounds<T> {
@@ -323,7 +323,7 @@ pub impl Glb: LatticeDir {
     }
 }
 
-pub impl Glb: TyLatticeDir {
+pub impl TyLatticeDir for Glb {
     fn ty_bot(_t: ty::t) -> cres<ty::t> {
         Ok(ty::mk_bot(self.infcx.tcx))
     }

src/librustc/middle/typeck/infer/lub.rs

@@ -36,7 +36,7 @@ pub impl Lub {
     fn ty_bot(b: ty::t) -> cres<ty::t> { self.bot_ty(b) } // commutative
 }
 
-pub impl Lub: Combine {
+pub impl Combine for Lub {
     fn infcx() -> @mut InferCtxt { self.infcx }
     fn tag() -> ~str { ~"lub" }
     fn a_is_expected() -> bool { self.a_is_expected }

src/librustc/middle/typeck/infer/sub.rs

@@ -32,7 +32,7 @@ pub fn macros() {
 
 pub enum Sub = CombineFields;  // "subtype", "subregion" etc
 
-pub impl Sub: Combine {
+pub impl Combine for Sub {
     fn infcx() -> @mut InferCtxt { self.infcx }
     fn tag() -> ~str { ~"sub" }
     fn a_is_expected() -> bool { self.a_is_expected }

src/librustc/middle/typeck/infer/to_str.rs

@@ -28,13 +28,13 @@ pub trait InferStr {
     fn inf_str(&self, cx: &InferCtxt) -> ~str;
 }
 
-pub impl ty::t : InferStr {
+pub impl InferStr for ty::t {
     fn inf_str(&self, cx: &InferCtxt) -> ~str {
         ty_to_str(cx.tcx, *self)
     }
 }
 
-pub impl FnSig : InferStr {
+pub impl InferStr for FnSig {
     fn inf_str(&self, cx: &InferCtxt) -> ~str {
         fmt!("(%s) -> %s",
              str::connect(self.inputs.map(|a| a.ty.inf_str(cx)), ", "),
@@ -42,19 +42,19 @@ pub impl FnSig : InferStr {
     }
 }
 
-pub impl ty::mt : InferStr {
+pub impl InferStr for ty::mt {
     fn inf_str(&self, cx: &InferCtxt) -> ~str {
         mt_to_str(cx.tcx, *self)
     }
 }
 
-pub impl ty::Region : InferStr {
+pub impl InferStr for ty::Region {
     fn inf_str(&self, _cx: &InferCtxt) -> ~str {
         fmt!("%?", *self)
     }
 }
 
-pub impl<V:InferStr> Bound<V> : InferStr {
+pub impl<V:InferStr> InferStr for Bound<V> {
     fn inf_str(&self, cx: &InferCtxt) -> ~str {
         match *self {
           Some(ref v) => v.inf_str(cx),
@@ -63,7 +63,7 @@ pub impl<V:InferStr> Bound<V> : InferStr {
     }
 }
 
-pub impl<T:InferStr> Bounds<T> : InferStr {
+pub impl<T:InferStr> InferStr for Bounds<T> {
     fn inf_str(&self, cx: &InferCtxt) -> ~str {
         fmt!("{%s <: %s}",
              self.lb.inf_str(cx),
@@ -71,7 +71,7 @@ pub impl<T:InferStr> Bounds<T> : InferStr {
     }
 }
 
-pub impl<V:Vid ToStr, T:InferStr> VarValue<V, T> : InferStr {
+pub impl<V:Vid ToStr, T:InferStr> InferStr for VarValue<V, T> {
     fn inf_str(&self, cx: &InferCtxt) -> ~str {
         match *self {
           Redirect(ref vid) => fmt!("Redirect(%s)", vid.to_str()),
@@ -81,13 +81,13 @@ pub impl<V:Vid ToStr, T:InferStr> VarValue<V, T> : InferStr {
     }
 }
 
-pub impl IntVarValue : InferStr {
+pub impl InferStr for IntVarValue {
     fn inf_str(&self, _cx: &InferCtxt) -> ~str {
         self.to_str()
     }
 }
 
-pub impl ast::float_ty : InferStr {
+pub impl InferStr for ast::float_ty {
     fn inf_str(&self, _cx: &InferCtxt) -> ~str {
         self.to_str()
     }

src/librustc/middle/typeck/infer/unify.rs

@@ -237,35 +237,35 @@ pub impl InferCtxt {
 
 // ______________________________________________________________________
 
-pub impl ty::TyVid : UnifyVid<Bounds<ty::t>> {
+pub impl UnifyVid<Bounds<ty::t>> for ty::TyVid {
     static fn appropriate_vals_and_bindings(infcx: &v/mut InferCtxt)
         -> &v/mut ValsAndBindings<ty::TyVid, Bounds<ty::t>> {
         return &mut infcx.ty_var_bindings;
     }
 }
 
-pub impl ty::IntVid : UnifyVid<Option<IntVarValue>> {
+pub impl UnifyVid<Option<IntVarValue>> for ty::IntVid {
     static fn appropriate_vals_and_bindings(infcx: &v/mut InferCtxt)
         -> &v/mut ValsAndBindings<ty::IntVid, Option<IntVarValue>> {
         return &mut infcx.int_var_bindings;
     }
 }
 
-pub impl IntVarValue : SimplyUnifiable {
+pub impl SimplyUnifiable for IntVarValue {
     static fn to_type_err(err: expected_found<IntVarValue>)
         -> ty::type_err {
         return ty::terr_int_mismatch(err);
     }
 }
 
-pub impl ty::FloatVid : UnifyVid<Option<ast::float_ty>> {
+pub impl UnifyVid<Option<ast::float_ty>> for ty::FloatVid {
     static fn appropriate_vals_and_bindings(infcx: &v/mut InferCtxt)
         -> &v/mut ValsAndBindings<ty::FloatVid, Option<ast::float_ty>> {
         return &mut infcx.float_var_bindings;
     }
 }
 
-pub impl ast::float_ty : SimplyUnifiable {
+pub impl SimplyUnifiable for ast::float_ty {
     static fn to_type_err(err: expected_found<ast::float_ty>)
         -> ty::type_err {
         return ty::terr_float_mismatch(err);

src/librustc/middle/typeck/rscope.rs

@@ -26,7 +26,7 @@ pub trait region_scope {
 }
 
 pub enum empty_rscope { empty_rscope }
-pub impl empty_rscope: region_scope {
+pub impl region_scope for empty_rscope {
     pure fn anon_region(_span: span) -> Result<ty::Region, ~str> {
         result::Ok(ty::re_static)
     }
@@ -40,7 +40,7 @@ pub impl empty_rscope: region_scope {
 }
 
 pub enum type_rscope = Option<ty::region_variance>;
-pub impl type_rscope: region_scope {
+pub impl region_scope for type_rscope {
     pure fn anon_region(_span: span) -> Result<ty::Region, ~str> {
         match *self {
           Some(_) => result::Ok(ty::re_bound(ty::br_self)),
@@ -73,7 +73,7 @@ pub fn in_anon_rscope<RS: region_scope Copy Durable>(self: RS, r: ty::Region)
     -> @anon_rscope {
     @anon_rscope({anon: r, base: self as region_scope})
 }
-pub impl @anon_rscope: region_scope {
+pub impl region_scope for @anon_rscope {
     pure fn anon_region(_span: span) -> Result<ty::Region, ~str> {
         result::Ok(self.anon)
     }
@@ -96,7 +96,7 @@ pub fn in_binding_rscope<RS: region_scope Copy Durable>(self: RS)
     let base = self as region_scope;
     @mut binding_rscope { base: base, anon_bindings: 0 }
 }
-pub impl @mut binding_rscope: region_scope {
+pub impl region_scope for @mut binding_rscope {
     pure fn anon_region(_span: span) -> Result<ty::Region, ~str> {
         // XXX: Unsafe to work around purity
         unsafe {

src/librustc/rustc.rc

@@ -296,18 +296,12 @@ pub fn run_compiler(args: &~[~str], demitter: diagnostic::Emitter) {
     compile_input(sess, cfg, input, &odir, &ofile);
 }
 
+#[deriving_eq]
 pub enum monitor_msg {
     fatal,
     done,
 }
 
-pub impl monitor_msg : cmp::Eq {
-    pure fn eq(&self, other: &monitor_msg) -> bool {
-        ((*self) as uint) == ((*other) as uint)
-    }
-    pure fn ne(&self, other: &monitor_msg) -> bool { !(*self).eq(other) }
-}
-
 /*
 This is a sanity check that any failure of the compiler is performed
 through the diagnostic module and reported properly - we shouldn't be calling

src/librustdoc/config.rs

@@ -59,7 +59,7 @@ pub struct Config {
     pandoc_cmd: Option<~str>
 }
 
-pub impl Config: Clone {
+pub impl Clone for Config {
     fn clone(&self) -> Config { copy *self }
 }
 

src/librustdoc/markdown_pass.rs

@@ -761,7 +761,7 @@ fn should_write_impl_header() {
 
 #[test]
 fn should_write_impl_header_with_trait() {
-    let markdown = test::render(~"impl int: j { fn a() { } }");
+    let markdown = test::render(~"impl j for int { fn a() { } }");
     assert str::contains(markdown, ~"## Implementation of `j` for `int`");
 }
 

src/librustdoc/tystr_pass.rs

@@ -297,7 +297,7 @@ fn fold_impl(
 
 #[test]
 fn should_add_impl_trait_types() {
-    let doc = test::mk_doc(~"impl int: j { fn a<T>() { } }");
+    let doc = test::mk_doc(~"impl j for int { fn a<T>() { } }");
     assert doc.cratemod().impls()[0].trait_types[0] == ~"j";
 }
 

src/libstd/flatpipes.rs

@@ -258,7 +258,7 @@ pub trait ByteChan {
 
 const CONTINUE: [u8 * 4] = [0xAA, 0xBB, 0xCC, 0xDD];
 
-pub impl<T,U:Unflattener<T>,P:BytePort> FlatPort<T, U, P>: GenericPort<T> {
+pub impl<T,U:Unflattener<T>,P:BytePort> GenericPort<T> for FlatPort<T, U, P> {
     fn recv() -> T {
         match self.try_recv() {
             Some(val) => val,
@@ -358,7 +358,7 @@ pub mod flatteners {
         bogus: ()
     }
 
-    pub impl<T: Copy Owned> PodUnflattener<T>: Unflattener<T> {
+    pub impl<T: Copy Owned> Unflattener<T> for PodUnflattener<T> {
         fn unflatten(&self, buf: ~[u8]) -> T {
             assert size_of::<T>() != 0;
             assert size_of::<T>() == buf.len();
@@ -368,7 +368,7 @@ pub mod flatteners {
         }
     }
 
-    pub impl<T: Copy Owned> PodFlattener<T>: Flattener<T> {
+    pub impl<T: Copy Owned> Flattener<T> for PodFlattener<T> {
         fn flatten(&self, val: T) -> ~[u8] {
             assert size_of::<T>() != 0;
             let val: *T = ptr::to_unsafe_ptr(&val);
@@ -406,36 +406,32 @@ pub mod flatteners {
         serialize_value: SerializeValue<T>
     }
 
-    pub impl<D: Decoder, T: Decodable<D>>
+    pub impl<D: Decoder, T: Decodable<D>> Unflattener<T>
-        DeserializingUnflattener<D, T>: Unflattener<T> {
+            for DeserializingUnflattener<D, T> {
         fn unflatten(&self, buf: ~[u8]) -> T {
             (self.deserialize_buffer)(buf)
         }
     }
 
-    pub impl<S: Encoder, T: Encodable<S>>
+    pub impl<S: Encoder, T: Encodable<S>> Flattener<T>
-        SerializingFlattener<S, T>: Flattener<T> {
+            for SerializingFlattener<S, T> {
         fn flatten(&self, val: T) -> ~[u8] {
             (self.serialize_value)(&val)
         }
     }
 
-    pub impl<D: Decoder, T: Decodable<D>>
+    pub impl<D: Decoder, T: Decodable<D>> DeserializingUnflattener<D, T> {
-        DeserializingUnflattener<D, T> {
+        static fn new(deserialize_buffer: DeserializeBuffer<T>)
-
+                   -> DeserializingUnflattener<D, T> {
-        static fn new(deserialize_buffer: DeserializeBuffer<T>
-                     ) -> DeserializingUnflattener<D, T> {
             DeserializingUnflattener {
                 deserialize_buffer: deserialize_buffer
             }
         }
     }
 
-    pub impl<S: Encoder, T: Encodable<S>>
+    pub impl<S: Encoder, T: Encodable<S>> SerializingFlattener<S, T> {
-        SerializingFlattener<S, T> {
+        static fn new(serialize_value: SerializeValue<T>)
-
+                   -> SerializingFlattener<S, T> {
-        static fn new(serialize_value: SerializeValue<T>
-                     ) -> SerializingFlattener<S, T> {
             SerializingFlattener {
                 serialize_value: serialize_value
             }
@@ -523,7 +519,7 @@ pub mod bytepipes {
         writer: W
     }
 
-    pub impl<R: Reader> ReaderBytePort<R>: BytePort {
+    pub impl<R: Reader> BytePort for ReaderBytePort<R> {
         fn try_recv(&self, count: uint) -> Option<~[u8]> {
             let mut left = count;
             let mut bytes = ~[];
@@ -545,7 +541,7 @@ pub mod bytepipes {
         }
     }
 
-    pub impl<W: Writer> WriterByteChan<W>: ByteChan {
+    pub impl<W: Writer> ByteChan for WriterByteChan<W> {
         fn send(&self, val: ~[u8]) {
             self.writer.write(val);
         }
@@ -576,7 +572,7 @@ pub mod bytepipes {
         chan: pipes::Chan<~[u8]>
     }
 
-    pub impl PipeBytePort: BytePort {
+    pub impl BytePort for PipeBytePort {
         fn try_recv(&self, count: uint) -> Option<~[u8]> {
             if self.buf.len() >= count {
                 let mut bytes = ::core::util::replace(&mut self.buf, ~[]);
@@ -608,7 +604,7 @@ pub mod bytepipes {
         }
     }
 
-    pub impl PipeByteChan: ByteChan {
+    pub impl ByteChan for PipeByteChan {
         fn send(&self, val: ~[u8]) {
             self.chan.send(val)
         }

src/libstd/json.rs

@@ -82,7 +82,7 @@ pub fn Encoder(wr: io::Writer) -> Encoder {
     Encoder { wr: wr }
 }
 
-pub impl Encoder: serialize::Encoder {
+pub impl serialize::Encoder for Encoder {
     fn emit_nil(&self) { self.wr.write_str("null") }
 
     fn emit_uint(&self, v: uint) { self.emit_float(v as float); }
@@ -217,7 +217,7 @@ pub fn PrettyEncoder(wr: io::Writer) -> PrettyEncoder {
     PrettyEncoder { wr: wr, indent: 0 }
 }
 
-pub impl PrettyEncoder: serialize::Encoder {
+pub impl serialize::Encoder for PrettyEncoder {
     fn emit_nil(&self) { self.wr.write_str("null") }
 
     fn emit_uint(&self, v: uint) { self.emit_float(v as float); }
@@ -323,7 +323,7 @@ pub impl PrettyEncoder: serialize::Encoder {
     }
 }
 
-pub impl<S: serialize::Encoder> Json: serialize::Encodable<S> {
+pub impl<S: serialize::Encoder> serialize::Encodable<S> for Json {
     fn encode(&self, s: &S) {
         match *self {
             Number(v) => v.encode(s),
@@ -768,7 +768,7 @@ priv impl Decoder {
     }
 }
 
-pub impl Decoder: serialize::Decoder {
+pub impl serialize::Decoder for Decoder {
     fn read_nil(&self) -> () {
         debug!("read_nil");
         match *self.pop() {

src/libstd/prettyprint.rs

@@ -22,7 +22,7 @@ pub fn Serializer(wr: io::Writer) -> Serializer {
     Serializer { wr: wr }
 }
 
-pub impl Serializer: serialize::Encoder {
+pub impl serialize::Encoder for Serializer {
     fn emit_nil(&self) {
         self.wr.write_str(~"()")
     }

src/libstd/serialize.rs

@@ -113,210 +113,210 @@ pub trait Decodable<D: Decoder> {
     static fn decode(&self, d: &D) -> Self;
 }
 
-pub impl<S: Encoder> uint: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for uint {
     fn encode(&self, s: &S) { s.emit_uint(*self) }
 }
 
-pub impl<D: Decoder> uint: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for uint {
     static fn decode(&self, d: &D) -> uint {
         d.read_uint()
     }
 }
 
-pub impl<S: Encoder> u8: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for u8 {
     fn encode(&self, s: &S) { s.emit_u8(*self) }
 }
 
-pub impl<D: Decoder> u8: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for u8 {
     static fn decode(&self, d: &D) -> u8 {
         d.read_u8()
     }
 }
 
-pub impl<S: Encoder> u16: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for u16 {
     fn encode(&self, s: &S) { s.emit_u16(*self) }
 }
 
-pub impl<D: Decoder> u16: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for u16 {
     static fn decode(&self, d: &D) -> u16 {
         d.read_u16()
     }
 }
 
-pub impl<S: Encoder> u32: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for u32 {
     fn encode(&self, s: &S) { s.emit_u32(*self) }
 }
 
-pub impl<D: Decoder> u32: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for u32 {
     static fn decode(&self, d: &D) -> u32 {
         d.read_u32()
     }
 }
 
-pub impl<S: Encoder> u64: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for u64 {
     fn encode(&self, s: &S) { s.emit_u64(*self) }
 }
 
-pub impl<D: Decoder> u64: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for u64 {
     static fn decode(&self, d: &D) -> u64 {
         d.read_u64()
     }
 }
 
-pub impl<S: Encoder> int: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for int {
     fn encode(&self, s: &S) { s.emit_int(*self) }
 }
 
-pub impl<D: Decoder> int: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for int {
     static fn decode(&self, d: &D) -> int {
         d.read_int()
     }
 }
 
-pub impl<S: Encoder> i8: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for i8 {
     fn encode(&self, s: &S) { s.emit_i8(*self) }
 }
 
-pub impl<D: Decoder> i8: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for i8 {
     static fn decode(&self, d: &D) -> i8 {
         d.read_i8()
     }
 }
 
-pub impl<S: Encoder> i16: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for i16 {
     fn encode(&self, s: &S) { s.emit_i16(*self) }
 }
 
-pub impl<D: Decoder> i16: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for i16 {
     static fn decode(&self, d: &D) -> i16 {
         d.read_i16()
     }
 }
 
-pub impl<S: Encoder> i32: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for i32 {
     fn encode(&self, s: &S) { s.emit_i32(*self) }
 }
 
-pub impl<D: Decoder> i32: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for i32 {
     static fn decode(&self, d: &D) -> i32 {
         d.read_i32()
     }
 }
 
-pub impl<S: Encoder> i64: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for i64 {
     fn encode(&self, s: &S) { s.emit_i64(*self) }
 }
 
-pub impl<D: Decoder> i64: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for i64 {
     static fn decode(&self, d: &D) -> i64 {
         d.read_i64()
     }
 }
 
-pub impl<S: Encoder> &str: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for &str {
     fn encode(&self, s: &S) { s.emit_borrowed_str(*self) }
 }
 
-pub impl<S: Encoder> ~str: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for ~str {
     fn encode(&self, s: &S) { s.emit_owned_str(*self) }
 }
 
-pub impl<D: Decoder> ~str: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for ~str {
     static fn decode(&self, d: &D) -> ~str {
         d.read_owned_str()
     }
 }
 
-pub impl<S: Encoder> @str: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for @str {
     fn encode(&self, s: &S) { s.emit_managed_str(*self) }
 }
 
-pub impl<D: Decoder> @str: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for @str {
     static fn decode(&self, d: &D) -> @str {
         d.read_managed_str()
     }
 }
 
-pub impl<S: Encoder> float: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for float {
     fn encode(&self, s: &S) { s.emit_float(*self) }
 }
 
-pub impl<D: Decoder> float: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for float {
     static fn decode(&self, d: &D) -> float {
         d.read_float()
     }
 }
 
-pub impl<S: Encoder> f32: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for f32 {
     fn encode(&self, s: &S) { s.emit_f32(*self) }
 }
 
-pub impl<D: Decoder> f32: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for f32 {
     static fn decode(&self, d: &D) -> f32 {
         d.read_f32() }
 }
 
-pub impl<S: Encoder> f64: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for f64 {
     fn encode(&self, s: &S) { s.emit_f64(*self) }
 }
 
-pub impl<D: Decoder> f64: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for f64 {
     static fn decode(&self, d: &D) -> f64 {
         d.read_f64()
     }
 }
 
-pub impl<S: Encoder> bool: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for bool {
     fn encode(&self, s: &S) { s.emit_bool(*self) }
 }
 
-pub impl<D: Decoder> bool: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for bool {
     static fn decode(&self, d: &D) -> bool {
         d.read_bool()
     }
 }
 
-pub impl<S: Encoder> (): Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for () {
     fn encode(&self, s: &S) { s.emit_nil() }
 }
 
-pub impl<D: Decoder> (): Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for () {
     static fn decode(&self, d: &D) -> () {
         d.read_nil()
     }
 }
 
-pub impl<S: Encoder, T: Encodable<S>> &T: Encodable<S> {
+pub impl<S: Encoder, T: Encodable<S>> Encodable<S> for &T {
     fn encode(&self, s: &S) {
         s.emit_borrowed(|| (**self).encode(s))
     }
 }
 
-pub impl<S: Encoder, T: Encodable<S>> ~T: Encodable<S> {
+pub impl<S: Encoder, T: Encodable<S>> Encodable<S> for ~T {
     fn encode(&self, s: &S) {
         s.emit_owned(|| (**self).encode(s))
     }
 }
 
-pub impl<D: Decoder, T: Decodable<D>> ~T: Decodable<D> {
+pub impl<D: Decoder, T: Decodable<D>> Decodable<D> for ~T {
     static fn decode(&self, d: &D) -> ~T {
         d.read_owned(|| ~Decodable::decode(d))
     }
 }
 
-pub impl<S: Encoder, T: Encodable<S>> @T: Encodable<S> {
+pub impl<S: Encoder, T: Encodable<S>> Encodable<S> for @T {
     fn encode(&self, s: &S) {
         s.emit_managed(|| (**self).encode(s))
     }
 }
 
-pub impl<D: Decoder, T: Decodable<D>> @T: Decodable<D> {
+pub impl<D: Decoder, T: Decodable<D>> Decodable<D> for @T {
     static fn decode(&self, d: &D) -> @T {
         d.read_managed(|| @Decodable::decode(d))
     }
 }
 
-pub impl<S: Encoder, T: Encodable<S>> &[T]: Encodable<S> {
+pub impl<S: Encoder, T: Encodable<S>> Encodable<S> for &[T] {
     fn encode(&self, s: &S) {
         do s.emit_borrowed_vec(self.len()) {
             for self.eachi |i, e| {
@@ -326,7 +326,7 @@ pub impl<S: Encoder, T: Encodable<S>> &[T]: Encodable<S> {
     }
 }
 
-pub impl<S: Encoder, T: Encodable<S>> ~[T]: Encodable<S> {
+pub impl<S: Encoder, T: Encodable<S>> Encodable<S> for ~[T] {
     fn encode(&self, s: &S) {
         do s.emit_owned_vec(self.len()) {
             for self.eachi |i, e| {
@@ -336,7 +336,7 @@ pub impl<S: Encoder, T: Encodable<S>> ~[T]: Encodable<S> {
     }
 }
 
-pub impl<D: Decoder, T: Decodable<D>> ~[T]: Decodable<D> {
+pub impl<D: Decoder, T: Decodable<D>> Decodable<D> for ~[T] {
     static fn decode(&self, d: &D) -> ~[T] {
         do d.read_owned_vec |len| {
             do vec::from_fn(len) |i| {
@@ -346,7 +346,7 @@ pub impl<D: Decoder, T: Decodable<D>> ~[T]: Decodable<D> {
     }
 }
 
-pub impl<S: Encoder, T: Encodable<S>> @[T]: Encodable<S> {
+pub impl<S: Encoder, T: Encodable<S>> Encodable<S> for @[T] {
     fn encode(&self, s: &S) {
         do s.emit_managed_vec(self.len()) {
             for self.eachi |i, e| {
@@ -356,7 +356,7 @@ pub impl<S: Encoder, T: Encodable<S>> @[T]: Encodable<S> {
     }
 }
 
-pub impl<D: Decoder, T: Decodable<D>> @[T]: Decodable<D> {
+pub impl<D: Decoder, T: Decodable<D>> Decodable<D> for @[T] {
     static fn decode(&self, d: &D) -> @[T] {
         do d.read_managed_vec |len| {
             do at_vec::from_fn(len) |i| {
@@ -366,7 +366,7 @@ pub impl<D: Decoder, T: Decodable<D>> @[T]: Decodable<D> {
     }
 }
 
-pub impl<S: Encoder, T: Encodable<S>> Option<T>: Encodable<S> {
+pub impl<S: Encoder, T: Encodable<S>> Encodable<S> for Option<T> {
     fn encode(&self, s: &S) {
         do s.emit_enum(~"option") {
             match *self {
@@ -381,7 +381,7 @@ pub impl<S: Encoder, T: Encodable<S>> Option<T>: Encodable<S> {
     }
 }
 
-pub impl<D: Decoder, T: Decodable<D>> Option<T>: Decodable<D> {
+pub impl<D: Decoder, T: Decodable<D>> Decodable<D> for Option<T> {
     static fn decode(&self, d: &D) -> Option<T> {
         do d.read_enum(~"option") {
             do d.read_enum_variant |i| {
@@ -396,11 +396,8 @@ pub impl<D: Decoder, T: Decodable<D>> Option<T>: Decodable<D> {
     }
 }
 
-pub impl<
+pub impl<S: Encoder, T0: Encodable<S>, T1: Encodable<S>> Encodable<S>
-    S: Encoder,
+        for (T0, T1) {
-    T0: Encodable<S>,
-    T1: Encodable<S>
-> (T0, T1): Encodable<S> {
     fn encode(&self, s: &S) {
         match *self {
             (ref t0, ref t1) => {
@@ -413,11 +410,8 @@ pub impl<
     }
 }
 
-pub impl<
+pub impl<D: Decoder, T0: Decodable<D>, T1: Decodable<D>> Decodable<D>
-    D: Decoder,
+        for (T0, T1) {
-    T0: Decodable<D>,
-    T1: Decodable<D>
-> (T0, T1): Decodable<D> {
     static fn decode(&self, d: &D) -> (T0, T1) {
         do d.read_tup(2) {
             (
@@ -433,7 +427,7 @@ pub impl<
     T0: Encodable<S>,
     T1: Encodable<S>,
     T2: Encodable<S>
-> (T0, T1, T2): Encodable<S> {
+> Encodable<S> for (T0, T1, T2) {
     fn encode(&self, s: &S) {
         match *self {
             (ref t0, ref t1, ref t2) => {
@@ -452,7 +446,7 @@ pub impl<
     T0: Decodable<D>,
     T1: Decodable<D>,
     T2: Decodable<D>
-> (T0, T1, T2): Decodable<D> {
+> Decodable<D> for (T0, T1, T2) {
     static fn decode(&self, d: &D) -> (T0, T1, T2) {
         do d.read_tup(3) {
             (
@@ -470,7 +464,7 @@ pub impl<
     T1: Encodable<S>,
     T2: Encodable<S>,
     T3: Encodable<S>
-> (T0, T1, T2, T3): Encodable<S> {
+> Encodable<S> for (T0, T1, T2, T3) {
     fn encode(&self, s: &S) {
         match *self {
             (ref t0, ref t1, ref t2, ref t3) => {
@@ -491,7 +485,7 @@ pub impl<
     T1: Decodable<D>,
     T2: Decodable<D>,
     T3: Decodable<D>
-> (T0, T1, T2, T3): Decodable<D> {
+> Decodable<D> for (T0, T1, T2, T3) {
     static fn decode(&self, d: &D) -> (T0, T1, T2, T3) {
         do d.read_tup(4) {
             (
@@ -511,7 +505,7 @@ pub impl<
     T2: Encodable<S>,
     T3: Encodable<S>,
     T4: Encodable<S>
-> (T0, T1, T2, T3, T4): Encodable<S> {
+> Encodable<S> for (T0, T1, T2, T3, T4) {
     fn encode(&self, s: &S) {
         match *self {
             (ref t0, ref t1, ref t2, ref t3, ref t4) => {
@@ -534,7 +528,7 @@ pub impl<
     T2: Decodable<D>,
     T3: Decodable<D>,
     T4: Decodable<D>
-> (T0, T1, T2, T3, T4): Decodable<D> {
+> Decodable<D> for (T0, T1, T2, T3, T4) {
     static fn decode(&self, d: &D)
       -> (T0, T1, T2, T3, T4) {
         do d.read_tup(5) {
@@ -558,7 +552,7 @@ pub trait EncoderHelpers {
     fn emit_from_vec<T>(&self, v: &[T], f: fn(v: &T));
 }
 
-pub impl<S: Encoder> S: EncoderHelpers {
+pub impl<S: Encoder> EncoderHelpers for S {
     fn emit_from_vec<T>(&self, v: &[T], f: fn(v: &T)) {
         do self.emit_owned_vec(v.len()) {
             for v.eachi |i, e| {
@@ -574,7 +568,7 @@ pub trait DecoderHelpers {
     fn read_to_vec<T>(&self, f: fn() -> T) -> ~[T];
 }
 
-pub impl<D: Decoder> D: DecoderHelpers {
+pub impl<D: Decoder> DecoderHelpers for D {
     fn read_to_vec<T>(&self, f: fn() -> T) -> ~[T] {
         do self.read_owned_vec |len| {
             do vec::from_fn(len) |i| {

src/libstd/workcache.rs

@@ -138,7 +138,7 @@ impl WorkKey {
 
 type WorkMap = LinearMap<WorkKey, ~str>;
 
-pub impl<S: Encoder> WorkMap: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for WorkMap {
     fn encode(&self, s: &S) {
         let mut d = ~[];
         for self.each |&(k, v)| {
@@ -149,7 +149,7 @@ pub impl<S: Encoder> WorkMap: Encodable<S> {
     }
 }
 
-pub impl<D: Decoder> WorkMap: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for WorkMap {
     static fn decode(&self, d: &D) -> WorkMap {
         let v : ~[(WorkKey,~str)] = Decodable::decode(d);
         let mut w = LinearMap::new();

src/libsyntax/ast.rs

@@ -32,7 +32,7 @@ macro_rules! interner_key (
 #[deriving_eq]
 pub struct ident { repr: uint }
 
-pub impl<S: Encoder> ident: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for ident {
     fn encode(&self, s: &S) {
         let intr = match unsafe {
             task::local_data::local_data_get(interner_key!())
@@ -45,7 +45,7 @@ pub impl<S: Encoder> ident: Encodable<S> {
     }
 }
 
-pub impl<D: Decoder> ident: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for ident {
     static fn decode(d: &D) -> ident {
         let intr = match unsafe {
             task::local_data::local_data_get(interner_key!())
@@ -58,7 +58,7 @@ pub impl<D: Decoder> ident: Decodable<D> {
     }
 }
 
-pub impl ident: to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for ident {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         self.repr.iter_bytes(lsb0, f)
     }
@@ -211,7 +211,7 @@ pub enum binding_mode {
     bind_infer
 }
 
-pub impl binding_mode : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for binding_mode {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         match *self {
           bind_by_copy => 0u8.iter_bytes(lsb0, f),
@@ -256,7 +256,7 @@ pub enum pat_ {
 #[deriving_eq]
 pub enum mutability { m_mutbl, m_imm, m_const, }
 
-pub impl mutability : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for mutability {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }
@@ -269,13 +269,13 @@ pub enum Abi {
     RustAbi
 }
 
-pub impl Abi : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for Abi {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as uint).iter_bytes(lsb0, f)
     }
 }
 
-pub impl Abi : ToStr {
+pub impl ToStr for Abi {
     pure fn to_str(&self) -> ~str {
         match *self {
             RustAbi => ~"\"rust\""
@@ -292,13 +292,13 @@ pub enum Sigil {
     ManagedSigil
 }
 
-pub impl Sigil : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for Sigil {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as uint).iter_bytes(lsb0, f)
     }
 }
 
-pub impl Sigil : ToStr {
+pub impl ToStr for Sigil {
     pure fn to_str(&self) -> ~str {
         match *self {
             BorrowedSigil => ~"&",
@@ -377,7 +377,7 @@ pub enum inferable<T> {
     infer(node_id)
 }
 
-pub impl<T: to_bytes::IterBytes> inferable<T> : to_bytes::IterBytes {
+pub impl<T: to_bytes::IterBytes> to_bytes::IterBytes for inferable<T> {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         match *self {
           expl(ref t) =>
@@ -395,7 +395,7 @@ pub impl<T: to_bytes::IterBytes> inferable<T> : to_bytes::IterBytes {
 #[deriving_eq]
 pub enum rmode { by_ref, by_val, by_copy }
 
-pub impl rmode : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for rmode {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }
@@ -736,13 +736,13 @@ pub enum trait_method {
 #[deriving_eq]
 pub enum int_ty { ty_i, ty_char, ty_i8, ty_i16, ty_i32, ty_i64, }
 
-pub impl int_ty : ToStr {
+pub impl ToStr for int_ty {
     pure fn to_str(&self) -> ~str {
         ::ast_util::int_ty_to_str(*self)
     }
 }
 
-pub impl int_ty : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for int_ty {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }
@@ -753,13 +753,13 @@ pub impl int_ty : to_bytes::IterBytes {
 #[deriving_eq]
 pub enum uint_ty { ty_u, ty_u8, ty_u16, ty_u32, ty_u64, }
 
-pub impl uint_ty : ToStr {
+pub impl ToStr for uint_ty {
     pure fn to_str(&self) -> ~str {
         ::ast_util::uint_ty_to_str(*self)
     }
 }
 
-pub impl uint_ty : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for uint_ty {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }
@@ -770,13 +770,13 @@ pub impl uint_ty : to_bytes::IterBytes {
 #[deriving_eq]
 pub enum float_ty { ty_f, ty_f32, ty_f64, }
 
-pub impl float_ty : ToStr {
+pub impl ToStr for float_ty {
     pure fn to_str(&self) -> ~str {
         ::ast_util::float_ty_to_str(*self)
     }
 }
 
-pub impl float_ty : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for float_ty {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }
@@ -830,7 +830,7 @@ pub enum Onceness {
     Many
 }
 
-pub impl Onceness : ToStr {
+pub impl ToStr for Onceness {
     pure fn to_str(&self) -> ~str {
         match *self {
             Once => ~"once",
@@ -839,7 +839,7 @@ pub impl Onceness : ToStr {
     }
 }
 
-pub impl Onceness : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for Onceness {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as uint).iter_bytes(lsb0, f);
     }
@@ -889,7 +889,7 @@ pub enum ty_ {
     ty_infer,
 }
 
-pub impl Ty : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for Ty {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         to_bytes::iter_bytes_2(&self.span.lo, &self.span.hi, lsb0, f);
     }
@@ -925,7 +925,7 @@ pub enum purity {
     extern_fn, // declared with "extern fn"
 }
 
-pub impl purity : ToStr {
+pub impl ToStr for purity {
     pure fn to_str(&self) -> ~str {
         match *self {
             impure_fn => ~"impure",
@@ -936,7 +936,7 @@ pub impl purity : ToStr {
     }
 }
 
-pub impl purity : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for purity {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }
@@ -951,7 +951,7 @@ pub enum ret_style {
     return_val, // everything else
 }
 
-pub impl ret_style : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for ret_style {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }
@@ -1232,7 +1232,7 @@ pub enum item_ {
 #[deriving_eq]
 pub enum struct_mutability { struct_mutable, struct_immutable }
 
-pub impl struct_mutability : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for struct_mutability {
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as u8).iter_bytes(lsb0, f)
     }

src/libsyntax/ast_map.rs

@@ -34,7 +34,7 @@ pub enum path_elt {
     path_name(ident)
 }
 
-pub impl path_elt : cmp::Eq {
+pub impl cmp::Eq for path_elt {
     pure fn eq(&self, other: &path_elt) -> bool {
         match (*self) {
             path_mod(e0a) => {

src/libsyntax/ast_util.rs

@@ -198,7 +198,7 @@ pub pure fn is_call_expr(e: @expr) -> bool {
 }
 
 // This makes def_id hashable
-pub impl def_id : to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for def_id {
     #[inline(always)]
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         to_bytes::iter_bytes_2(&self.crate, &self.node, lsb0, f);
@@ -303,7 +303,7 @@ pub trait inlined_item_utils {
     fn accept<E>(&self, e: E, v: visit::vt<E>);
 }
 
-pub impl inlined_item: inlined_item_utils {
+pub impl inlined_item_utils for inlined_item {
     fn ident(&self) -> ident {
         match *self {
             ii_item(i) => /* FIXME (#2543) */ copy i.ident,

src/libsyntax/codemap.rs

@@ -46,71 +46,71 @@ pub enum CharPos = uint;
 // XXX: Lots of boilerplate in these impls, but so far my attempts to fix
 // have been unsuccessful
 
-pub impl BytePos: Pos {
+pub impl Pos for BytePos {
     static pure fn from_uint(n: uint) -> BytePos { BytePos(n) }
     pure fn to_uint(&self) -> uint { **self }
 }
 
-pub impl BytePos: cmp::Eq {
+pub impl cmp::Eq for BytePos {
     pure fn eq(&self, other: &BytePos) -> bool { **self == **other }
     pure fn ne(&self, other: &BytePos) -> bool { !(*self).eq(other) }
 }
 
-pub impl BytePos: cmp::Ord {
+pub impl cmp::Ord for BytePos {
     pure fn lt(&self, other: &BytePos) -> bool { **self < **other }
     pure fn le(&self, other: &BytePos) -> bool { **self <= **other }
     pure fn ge(&self, other: &BytePos) -> bool { **self >= **other }
     pure fn gt(&self, other: &BytePos) -> bool { **self > **other }
 }
 
-pub impl BytePos: Add<BytePos, BytePos> {
+pub impl Add<BytePos, BytePos> for BytePos {
     pure fn add(&self, rhs: &BytePos) -> BytePos {
         BytePos(**self + **rhs)
     }
 }
 
-pub impl BytePos: Sub<BytePos, BytePos> {
+pub impl Sub<BytePos, BytePos> for BytePos {
     pure fn sub(&self, rhs: &BytePos) -> BytePos {
         BytePos(**self - **rhs)
     }
 }
 
-pub impl BytePos: to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for BytePos {
     pure fn iter_bytes(&self, +lsb0: bool, &&f: to_bytes::Cb) {
         (**self).iter_bytes(lsb0, f)
     }
 }
 
-pub impl CharPos: Pos {
+pub impl Pos for CharPos {
     static pure fn from_uint(n: uint) -> CharPos { CharPos(n) }
     pure fn to_uint(&self) -> uint { **self }
 }
 
-pub impl CharPos: cmp::Eq {
+pub impl cmp::Eq for CharPos {
     pure fn eq(&self, other: &CharPos) -> bool { **self == **other }
     pure fn ne(&self, other: &CharPos) -> bool { !(*self).eq(other) }
 }
 
-pub impl CharPos: cmp::Ord {
+pub impl cmp::Ord for CharPos {
     pure fn lt(&self, other: &CharPos) -> bool { **self < **other }
     pure fn le(&self, other: &CharPos) -> bool { **self <= **other }
     pure fn ge(&self, other: &CharPos) -> bool { **self >= **other }
     pure fn gt(&self, other: &CharPos) -> bool { **self > **other }
 }
 
-pub impl CharPos: to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for CharPos {
     pure fn iter_bytes(&self, +lsb0: bool, &&f: to_bytes::Cb) {
         (**self).iter_bytes(lsb0, f)
     }
 }
 
-pub impl CharPos: Add<CharPos, CharPos> {
+pub impl Add<CharPos,CharPos> for CharPos {
     pure fn add(&self, rhs: &CharPos) -> CharPos {
         CharPos(**self + **rhs)
     }
 }
 
-pub impl CharPos: Sub<CharPos, CharPos> {
+pub impl Sub<CharPos,CharPos> for CharPos {
     pure fn sub(&self, rhs: &CharPos) -> CharPos {
         CharPos(**self - **rhs)
     }
@@ -133,19 +133,19 @@ pub struct span {
 #[deriving_eq]
 pub struct spanned<T> { node: T, span: span }
 
-pub impl span : cmp::Eq {
+pub impl cmp::Eq for span {
     pure fn eq(&self, other: &span) -> bool {
         return (*self).lo == (*other).lo && (*self).hi == (*other).hi;
     }
     pure fn ne(&self, other: &span) -> bool { !(*self).eq(other) }
 }
 
-pub impl<S: Encoder> span: Encodable<S> {
+pub impl<S: Encoder> Encodable<S> for span {
     /* Note #1972 -- spans are encoded but not decoded */
     fn encode(&self, _s: &S) { }
 }
 
-pub impl<D: Decoder> span: Decodable<D> {
+pub impl<D: Decoder> Decodable<D> for span {
     static fn decode(_d: &D) -> span {
         dummy_sp()
     }

src/libsyntax/ext/pipes/ast_builder.rs

@@ -54,7 +54,7 @@ pub trait append_types {
     fn add_tys(+tys: ~[@ast::Ty]) -> @ast::path;
 }
 
-pub impl @ast::path: append_types {
+pub impl append_types for @ast::path {
     fn add_ty(ty: @ast::Ty) -> @ast::path {
         @ast::path { types: vec::append_one(self.types, ty),
                      .. *self}
@@ -112,7 +112,7 @@ pub trait ext_ctxt_ast_builder {
     fn strip_bounds(bounds: &[ast::ty_param]) -> ~[ast::ty_param];
 }
 
-pub impl ext_ctxt: ext_ctxt_ast_builder {
+pub impl ext_ctxt_ast_builder for ext_ctxt {
     fn ty_option(ty: @ast::Ty) -> @ast::Ty {
         self.ty_path_ast_builder(path_global(~[
             self.ident_of(~"core"),

src/libsyntax/ext/pipes/check.rs

@@ -37,7 +37,7 @@ use ext::base::ext_ctxt;
 use ext::pipes::proto::{state, protocol, next_state};
 use ext::pipes::proto;
 
-pub impl ext_ctxt: proto::visitor<(), (), ()>  {
+pub impl proto::visitor<(), (), ()> for ext_ctxt {
     fn visit_proto(_proto: protocol,
                    _states: &[()]) { }
 

src/libsyntax/ext/pipes/parse_proto.rs

@@ -22,7 +22,7 @@ pub trait proto_parser {
     fn parse_message(state: state);
 }
 
-pub impl parser::Parser: proto_parser {
+pub impl proto_parser for parser::Parser {
     fn parse_proto(id: ~str) -> protocol {
         let proto = protocol(id, self.span);
 

src/libsyntax/ext/pipes/pipec.rs

@@ -45,7 +45,7 @@ pub trait gen_init {
     fn gen_init_bounded(ext_cx: ext_ctxt) -> @ast::expr;
 }
 
-pub impl message: gen_send {
+pub impl gen_send for message {
     fn gen_send(cx: ext_ctxt, try: bool) -> @ast::item {
         debug!("pipec: gen_send");
         match self {
@@ -201,7 +201,7 @@ pub impl message: gen_send {
     }
 }
 
-pub impl state: to_type_decls {
+pub impl to_type_decls for state {
     fn to_type_decls(cx: ext_ctxt) -> ~[@ast::item] {
         debug!("pipec: to_type_decls");
         // This compiles into two different type declarations. Say the
@@ -305,8 +305,7 @@ pub impl state: to_type_decls {
     }
 }
 
-pub impl protocol: gen_init {
+pub impl gen_init for protocol {
-
     fn gen_init(cx: ext_ctxt) -> @ast::item {
         let ext_cx = cx;
 

src/libsyntax/ext/pipes/proto.rs

@@ -21,7 +21,7 @@ use core::to_str::ToStr;
 
 pub enum direction { send, recv }
 
-pub impl direction : cmp::Eq {
+pub impl cmp::Eq for direction {
     pure fn eq(&self, other: &direction) -> bool {
         match ((*self), (*other)) {
             (send, send) => true,
@@ -33,7 +33,7 @@ pub impl direction : cmp::Eq {
     pure fn ne(&self, other: &direction) -> bool { !(*self).eq(other) }
 }
 
-pub impl direction: ToStr {
+pub impl ToStr for direction {
     pure fn to_str(&self) -> ~str {
         match *self {
           send => ~"Send",
@@ -156,7 +156,6 @@ pub struct protocol_ {
 }
 
 pub impl protocol_ {
-
     /// Get a state.
     fn get_state(name: ~str) -> state {
         self.states.find(|i| i.name == name).get()

src/libsyntax/fold.rs

@@ -692,7 +692,7 @@ pub fn default_ast_fold() -> ast_fold_fns {
           new_span: noop_span};
 }
 
-pub impl ast_fold_fns: ast_fold {
+pub impl ast_fold for ast_fold_fns {
     /* naturally, a macro to write these would be nice */
     fn fold_crate(c: crate) -> crate {
         let (n, s) = (self.fold_crate)(c.node, c.span, self as ast_fold);

src/libsyntax/parse/lexer.rs

@@ -127,7 +127,7 @@ impl reader for StringReader {
     fn dup(@mut self) -> reader { dup_string_reader(self) as reader }
 }
 
-pub impl TtReader: reader {
+pub impl reader for TtReader {
     fn is_eof(@mut self) -> bool { self.cur_tok == token::EOF }
     fn next_token(@mut self) -> TokenAndSpan { tt_next_token(self) }
     fn fatal(@mut self, m: ~str) -> ! {

src/libsyntax/parse/obsolete.rs

@@ -45,10 +45,11 @@ pub enum ObsoleteSyntax {
     ObsoleteMoveInit,
     ObsoleteBinaryMove,
     ObsoleteUnsafeBlock,
-    ObsoleteUnenforcedBound
+    ObsoleteUnenforcedBound,
+    ObsoleteImplSyntax
 }
 
-pub impl ObsoleteSyntax: to_bytes::IterBytes {
+pub impl to_bytes::IterBytes for ObsoleteSyntax {
     #[inline(always)]
     pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
         (*self as uint).iter_bytes(lsb0, f);
@@ -115,6 +116,10 @@ pub impl Parser {
                 "unenforced type parameter bound",
                 "use trait bounds on the functions that take the type as \
                  arguments, not on the types themselves"
+            ),
+            ObsoleteImplSyntax => (
+                "colon-separated impl syntax",
+                "write `impl Trait for Type`"
             )
         };
 

src/libsyntax/parse/parser.rs

@@ -74,7 +74,7 @@ use parse::obsolete::{ObsoleteLet, ObsoleteFieldTerminator};
 use parse::obsolete::{ObsoleteMoveInit, ObsoleteBinaryMove};
 use parse::obsolete::{ObsoleteStructCtor, ObsoleteWith};
 use parse::obsolete::{ObsoleteSyntax, ObsoleteLowerCaseKindBounds};
-use parse::obsolete::{ObsoleteUnsafeBlock};
+use parse::obsolete::{ObsoleteUnsafeBlock, ObsoleteImplSyntax};
 use parse::prec::{as_prec, token_to_binop};
 use parse::token::{can_begin_expr, is_ident, is_ident_or_path};
 use parse::token::{is_plain_ident, INTERPOLATED, special_idents};
@@ -2829,16 +2829,11 @@ pub impl Parser {
         // XXX: clownshoes
         let ident = special_idents::clownshoes_extensions;
 
-        // Parse the type. (If this is `impl trait for type`, however, this
+        // Parse the trait.
-        // actually parses the trait.)
         let mut ty = self.parse_ty(false);
 
         // Parse traits, if necessary.
-        let opt_trait = if self.token == token::COLON {
+        let opt_trait = if self.eat_keyword(~"for") {
-            // Old-style trait.
-            self.bump();
-            Some(self.parse_trait_ref())
-        } else if self.eat_keyword(~"for") {
             // New-style trait. Reinterpret the type as a trait.
             let opt_trait_ref = match ty.node {
                 ty_path(path, node_id) => {
@@ -2855,6 +2850,9 @@ pub impl Parser {
 
             ty = self.parse_ty(false);
             opt_trait_ref
+        } else if self.eat(token::COLON) {
+            self.obsolete(copy self.span, ObsoleteImplSyntax);
+            Some(self.parse_trait_ref())
         } else {
             None
         };

src/libsyntax/util/interner.rs

@@ -42,7 +42,7 @@ pub trait Interner<T:Eq IterBytes Hash Const Copy> {
     fn len() -> uint;
 }
 
-pub impl <T:Eq IterBytes Hash Const Copy> hash_interner<T>: Interner<T> {
+pub impl<T:Eq IterBytes Hash Const Copy> Interner<T> for hash_interner<T> {
     fn intern(val: T) -> uint {
         match self.map.find(&val) {
           Some(idx) => return idx,

src/test/auxiliary/cci_class_cast.rs

@@ -17,7 +17,7 @@ pub mod kitty {
       name : ~str,
     }
 
-    pub impl cat : ToStr {
+    pub impl ToStr for cat {
        pure fn to_str(&self) -> ~str { copy self.name }
     }
 

src/test/auxiliary/crate-method-reexport-grrrrrrr2.rs

@@ -19,7 +19,7 @@ pub mod name_pool {
         fn add(s: ~str);
     }
 
-    pub impl name_pool: add {
+    pub impl add for name_pool {
         fn add(s: ~str) {
         }
     }
@@ -34,7 +34,7 @@ pub mod rust {
         fn cx();
     }
 
-    pub impl rt: cx {
+    pub impl cx for rt {
         fn cx() {
         }
     }

src/test/auxiliary/issue-3012-1.rs

@@ -16,7 +16,7 @@ pub mod socket {
         sockfd: libc::c_int,
     }
 
-    pub impl socket_handle : Drop {
+    pub impl Drop for socket_handle {
         fn finalize(&self) {
             /* c::close(self.sockfd); */
         }

src/test/auxiliary/issue2170lib.rs

@@ -15,7 +15,7 @@ pub struct rsrc {
   x: i32,
 }
 
-pub impl rsrc : Drop {
+pub impl Drop for rsrc {
     fn finalize(&self) {
         foo(self.x);
     }

src/test/auxiliary/trait_inheritance_overloading_xc.rs

@@ -17,25 +17,25 @@ pub struct MyInt {
     val: int
 }
 
-pub impl MyInt : Add<MyInt, MyInt> {
+pub impl Add<MyInt, MyInt> for MyInt {
     pure fn add(&self, other: &MyInt) -> MyInt { mi(self.val + other.val) }
 }
 
-pub impl MyInt : Sub<MyInt, MyInt> {
+pub impl Sub<MyInt, MyInt> for MyInt {
     pure fn sub(&self, other: &MyInt) -> MyInt { mi(self.val - other.val) }
 }
 
-pub impl MyInt : Mul<MyInt, MyInt> {
+pub impl Mul<MyInt, MyInt> for MyInt {
     pure fn mul(&self, other: &MyInt) -> MyInt { mi(self.val * other.val) }
 }
 
-pub impl MyInt : Eq {
+pub impl Eq for MyInt {
     pure fn eq(&self, other: &MyInt) -> bool { self.val == other.val }
 
     pure fn ne(&self, other: &MyInt) -> bool { !self.eq(other) }
 }
 
-pub impl MyInt : MyNum;
+pub impl MyNum for MyInt;
 
 pure fn mi(v: int) -> MyInt { MyInt { val: v } }
 

src/test/compile-fail/issue-3953.rs

@@ -19,7 +19,7 @@ trait Hahaha: Eq Eq Eq Eq Eq Eq Eq Eq Eq Eq Eq Eq Eq Eq Eq Eq //~ ERROR Duplicat
 
 enum Lol = int;
 
-pub impl Lol: Hahaha { }
+pub impl Hahaha for Lol { }
 
 impl Eq for Lol {
     pure fn eq(&self, other: &Lol) -> bool { **self != **other }

src/test/compile-fail/issue-3969.rs

@@ -16,7 +16,7 @@ trait BikeMethods {
     fn woops(&const self) -> ~str;
 }
 
-pub impl Bike : BikeMethods {
+pub impl BikeMethods for Bike {
     static fn woops(&const self) -> ~str { ~"foo" }
     //~^ ERROR method `woops` is declared as static in its impl, but not in its trait
 }

src/test/compile-fail/missing-derivable-attr.rs

@@ -20,7 +20,7 @@ impl MyEq for int {
     pure fn eq(&self, other: &int) -> bool { *self == *other }
 }
 
-impl A : MyEq;  //~ ERROR missing method
+impl MyEq for A;  //~ ERROR missing method
 
 fn main() {
 }

src/test/run-pass/issue-2718.rs

@@ -20,6 +20,7 @@ pub mod pipes {
         mut payload: Option<T>
     }
 
+    #[deriving_eq]
     pub enum state {
         empty,
         full,
@@ -27,13 +28,6 @@ pub mod pipes {
         terminated
     }
 
-    pub impl state : cmp::Eq {
-        pure fn eq(&self, other: &state) -> bool {
-            ((*self) as uint) == ((*other) as uint)
-        }
-        pure fn ne(&self, other: &state) -> bool { !(*self).eq(other) }
-    }
-
     pub type packet<T> = {
         mut state: state,
         mut blocked_task: Option<task::Task>,
@@ -161,7 +155,7 @@ pub mod pipes {
         mut p: Option<*packet<T>>,
     }
 
-    pub impl<T: Owned> send_packet<T> : Drop {
+    pub impl<T: Owned> Drop for send_packet<T> {
         fn finalize(&self) {
             if self.p != None {
                 let mut p = None;
@@ -189,7 +183,7 @@ pub mod pipes {
         mut p: Option<*packet<T>>,
     }
 
-    pub impl<T: Owned> recv_packet<T> : Drop {
+    pub impl<T: Owned> Drop for recv_packet<T> {
         fn finalize(&self) {
             if self.p != None {
                 let mut p = None;

src/test/run-pass/issue-3563-3.rs

@@ -23,8 +23,7 @@ extern mod std;
 use io::WriterUtil;
 
 // Represents a position on a canvas.
-struct Point
+struct Point {
-{
     x: int,
     y: int,
 }
@@ -108,8 +107,7 @@ impl AsciiArt
 
 // Allows AsciiArt to be converted to a string using the libcore ToStr trait.
 // Note that the %s fmt! specifier will not call this automatically.
-impl AsciiArt : ToStr
+impl ToStr for AsciiArt {
-{
     pure fn to_str(&self) -> ~str
     {
         // Convert each line into a string.
@@ -139,8 +137,7 @@ trait Canvas
 // Here we provide an implementation of the Canvas methods for AsciiArt.
 // Other implementations could also be provided (e.g. for PDF or Apple's Quartz)
 // and code can use them polymorphically via the Canvas trait.
-impl AsciiArt : Canvas
+impl Canvas for AsciiArt {
-{
     fn add_point(&mut self, shape: Point)
     {
         self.add_pt(shape.x, shape.y);

src/test/run-pass/issue-3979.rs

@@ -31,7 +31,7 @@ impl Positioned for Point {
     }
 }
 
-impl Point: Movable;
+impl Movable for Point;
 
 pub fn main() {
     let p = Point{ x: 1, y: 2};

src/test/run-pass/pipe-presentation-examples.rs

@@ -81,7 +81,7 @@ pub struct Buffer {
 
 }
 
-pub impl Buffer : Drop {
+pub impl Drop for Buffer {
     fn finalize(&self) {}
 }
 

src/test/run-pass/static-impl.rs

@@ -17,12 +17,12 @@ pub trait plus {
 
 mod a {
     use plus;
-    pub impl uint: plus { fn plus() -> int { self as int + 20 } }
+    pub impl plus for uint { fn plus() -> int { self as int + 20 } }
 }
 
 mod b {
     use plus;
-    pub impl ~str: plus { fn plus() -> int { 200 } }
+    pub impl plus for ~str { fn plus() -> int { 200 } }
 }
 
 trait uint_utils {

src/test/run-pass/static-methods-in-traits2.rs

@@ -2,7 +2,7 @@ pub trait Number: NumConv {
     static pure fn from<T:Number>(n: T) -> Self;
 }
 
-pub impl float: Number {
+pub impl Number for float {
     static pure fn from<T:Number>(n: T) -> float { n.to_float() }
 }
 
@@ -10,7 +10,7 @@ pub trait NumConv {
     pure fn to_float(&self) -> float;
 }
 
-pub impl float: NumConv {
+pub impl NumConv for float {
     pure fn to_float(&self) -> float { *self }
 }
 

src/test/run-pass/trait-inheritance-num2.rs

@@ -21,84 +21,84 @@ use std::cmp::FuzzyEq;
 pub trait TypeExt {}
 
 
-pub impl u8: TypeExt {}
+pub impl TypeExt for u8 {}
-pub impl u16: TypeExt {}
+pub impl TypeExt for u16 {}
-pub impl u32: TypeExt {}
+pub impl TypeExt for u32 {}
-pub impl u64: TypeExt {}
+pub impl TypeExt for u64 {}
-pub impl uint: TypeExt {}
+pub impl TypeExt for uint {}
 
-pub impl i8: TypeExt {}
+pub impl TypeExt for i8 {}
-pub impl i16: TypeExt {}
+pub impl TypeExt for i16 {}
-pub impl i32: TypeExt {}
+pub impl TypeExt for i32 {}
-pub impl i64: TypeExt {}
+pub impl TypeExt for i64 {}
-pub impl int: TypeExt {}
+pub impl TypeExt for int {}
 
-pub impl f32: TypeExt {}
+pub impl TypeExt for f32 {}
-pub impl f64: TypeExt {}
+pub impl TypeExt for f64 {}
-pub impl float: TypeExt {}
+pub impl TypeExt for float {}
 
 
 pub trait NumExt: TypeExt Eq Ord NumCast {}
 
-pub impl u8: NumExt {}
+pub impl NumExt for u8 {}
-pub impl u16: NumExt {}
+pub impl NumExt for u16 {}
-pub impl u32: NumExt {}
+pub impl NumExt for u32 {}
-pub impl u64: NumExt {}
+pub impl NumExt for u64 {}
-pub impl uint: NumExt {}
+pub impl NumExt for uint {}
 
-pub impl i8: NumExt {}
+pub impl NumExt for i8 {}
-pub impl i16: NumExt {}
+pub impl NumExt for i16 {}
-pub impl i32: NumExt {}
+pub impl NumExt for i32 {}
-pub impl i64: NumExt {}
+pub impl NumExt for i64 {}
-pub impl int: NumExt {}
+pub impl NumExt for int {}
 
-pub impl f32: NumExt {}
+pub impl NumExt for f32 {}
-pub impl f64: NumExt {}
+pub impl NumExt for f64 {}
-pub impl float: NumExt {}
+pub impl NumExt for float {}
 
 
 pub trait UnSignedExt: NumExt {}
 
-pub impl u8: UnSignedExt {}
+pub impl UnSignedExt for u8 {}
-pub impl u16: UnSignedExt {}
+pub impl UnSignedExt for u16 {}
-pub impl u32: UnSignedExt {}
+pub impl UnSignedExt for u32 {}
-pub impl u64: UnSignedExt {}
+pub impl UnSignedExt for u64 {}
-pub impl uint: UnSignedExt {}
+pub impl UnSignedExt for uint {}
 
 
 pub trait SignedExt: NumExt {}
 
-pub impl i8: SignedExt {}
+pub impl SignedExt for i8 {}
-pub impl i16: SignedExt {}
+pub impl SignedExt for i16 {}
-pub impl i32: SignedExt {}
+pub impl SignedExt for i32 {}
-pub impl i64: SignedExt {}
+pub impl SignedExt for i64 {}
-pub impl int: SignedExt {}
+pub impl SignedExt for int {}
 
-pub impl f32: SignedExt {}
+pub impl SignedExt for f32 {}
-pub impl f64: SignedExt {}
+pub impl SignedExt for f64 {}
-pub impl float: SignedExt {}
+pub impl SignedExt for float {}
 
 
 pub trait IntegerExt: NumExt {}
 
-pub impl u8: IntegerExt {}
+pub impl IntegerExt for u8 {}
-pub impl u16: IntegerExt {}
+pub impl IntegerExt for u16 {}
-pub impl u32: IntegerExt {}
+pub impl IntegerExt for u32 {}
-pub impl u64: IntegerExt {}
+pub impl IntegerExt for u64 {}
-pub impl uint: IntegerExt {}
+pub impl IntegerExt for uint {}
 
-pub impl i8: IntegerExt {}
+pub impl IntegerExt for i8 {}
-pub impl i16: IntegerExt {}
+pub impl IntegerExt for i16 {}
-pub impl i32: IntegerExt {}
+pub impl IntegerExt for i32 {}
-pub impl i64: IntegerExt {}
+pub impl IntegerExt for i64 {}
-pub impl int: IntegerExt {}
+pub impl IntegerExt for int {}
 
 
 pub trait FloatExt: NumExt FuzzyEq<Self> {}
 
-pub impl f32: FloatExt {}
+pub impl FloatExt for f32 {}
-pub impl f64: FloatExt {}
+pub impl FloatExt for f64 {}
-pub impl float: FloatExt {}
+pub impl FloatExt for float {}
 
 
 fn test_float_ext<T:FloatExt>(n: T) { io::println(fmt!("%?", n < n)) }

src/test/run-pass/trait-inheritance-num3.rs

@@ -13,7 +13,7 @@ use num::NumCast::from;
 
 pub trait NumExt: Eq Ord NumCast {}
 
-pub impl f32: NumExt {}
+pub impl NumExt for f32 {}
 
 fn num_eq_one<T:NumExt>(n: T) { io::println(fmt!("%?", n == from(1))) }
 

src/test/run-pass/trait-inheritance-num5.rs

@@ -13,8 +13,8 @@ use num::NumCast::from;
 
 pub trait NumExt: Eq NumCast {}
 
-pub impl f32: NumExt {}
+pub impl NumExt for f32 {}
-pub impl int: NumExt {}
+pub impl NumExt for int {}
 
 fn num_eq_one<T:NumExt>() -> T {
     from(1)

src/test/run-pass/trait-inheritance-overloading-simple.rs

@@ -19,7 +19,7 @@ impl Eq for MyInt {
     pure fn ne(&self, other: &MyInt) -> bool { !self.eq(other) }
 }
 
-impl MyInt : MyNum;
+impl MyNum for MyInt;
 
 fn f<T:MyNum>(x: T, y: T) -> bool {
     return x == y;

src/test/run-pass/trait-inheritance-overloading.rs

@@ -31,7 +31,7 @@ impl Eq for MyInt {
     pure fn ne(&self, other: &MyInt) -> bool { !self.eq(other) }
 }
 
-impl MyInt : MyNum;
+impl MyNum for MyInt;
 
 fn f<T:Copy MyNum>(x: T, y: T) -> (T, T, T) {
     return (x + y, x - y, x * y);

src/test/run-pass/trait-inheritance-subst.rs

@@ -20,7 +20,7 @@ impl Add<MyInt, MyInt> for MyInt {
     pure fn add(other: &MyInt) -> MyInt { mi(self.val + other.val) }
 }
 
-impl MyInt : MyNum;
+impl MyNum for MyInt;
 
 fn f<T:MyNum>(x: T, y: T) -> T {
     return x.add(&y);

src/test/run-pass/trait-inheritance-subst2.rs

@@ -30,7 +30,7 @@ impl Add<MyInt, MyInt> for MyInt {
     fn add(other: &MyInt) -> MyInt { self.chomp(other) }
 }
 
-impl MyInt : MyNum;
+impl MyNum for MyInt;
 
 fn f<T:MyNum>(x: T, y: T) -> T {
     return x.add(&y).chomp(&y);

src/test/run-pass/trait-inheritance2.rs

@@ -19,7 +19,7 @@ struct A { x: int }
 impl Foo for A { fn f() -> int { 10 } }
 impl Bar for A { fn g() -> int { 20 } }
 impl Baz for A { fn h() -> int { 30 } }
-impl A : Quux;
+impl Quux for A;
 
 fn f<T: Quux Foo Bar Baz>(a: &T) {
     assert a.f() == 10;

src/test/run-pass/trait-static-method-overwriting.rs

@@ -19,7 +19,7 @@ mod base {
         dummy: (),
     }
 
-    pub impl Foo : ::base::HasNew<Foo> {
+    pub impl ::base::HasNew<Foo> for Foo {
         static pure fn new() -> Foo {
 			unsafe { io::println("Foo"); }
             Foo { dummy: () }
@@ -30,7 +30,7 @@ mod base {
         dummy: (),
     }
 
-    pub impl Bar : ::base::HasNew<Bar> {
+    pub impl ::base::HasNew<Bar> for Bar {
         static pure fn new() -> Bar {
 			unsafe { io::println("Bar"); }
             Bar { dummy: () }