diff --git a/src/compiletest/runtest.rs b/src/compiletest/runtest.rs
index 6e2f62f870695..280480bb27656 100644
--- a/src/compiletest/runtest.rs
+++ b/src/compiletest/runtest.rs
@@ -273,7 +273,7 @@ fn run_debuginfo_test(config: &config, props: &TestProps, testfile: &Path) {
     };
     let config = &mut config;
     let cmds = props.debugger_cmds.connect("\n");
-    let check_lines = props.check_lines.clone();
+    let check_lines = &props.check_lines;
 
     // compile test file (it shoud have 'compile-flags:-g' in the header)
     let mut ProcRes = compile_test(config, props, testfile);
@@ -305,11 +305,34 @@ fn run_debuginfo_test(config: &config, props: &TestProps, testfile: &Path) {
 
     let num_check_lines = check_lines.len();
     if num_check_lines > 0 {
+        // Allow check lines to leave parts unspecified (e.g., uninitialized
+        // bits in the wrong case of an enum) with the notation "[...]".
+        let check_fragments: ~[~[&str]] = check_lines.map(|s| s.split_str_iter("[...]").collect());
         // check if each line in props.check_lines appears in the
         // output (in order)
         let mut i = 0u;
         for line in ProcRes.stdout.line_iter() {
-            if check_lines[i].trim() == line.trim() {
+            let mut rest = line.trim();
+            let mut first = true;
+            let mut failed = false;
+            for &frag in check_fragments[i].iter() {
+                let found = if first {
+                    if rest.starts_with(frag) { Some(0) } else { None }
+                } else {
+                    rest.find_str(frag)
+                };
+                match found {
+                    None => {
+                        failed = true;
+                        break;
+                    }
+                    Some(i) => {
+                        rest = rest.slice_from(i + frag.len());
+                    }
+                }
+                first = false;
+            }
+            if !failed && rest.len() == 0 {
                 i += 1u;
             }
             if i == num_check_lines {
diff --git a/src/libextra/enum_set.rs b/src/libextra/enum_set.rs
index 2b1246b0af007..3975e1a719750 100644
--- a/src/libextra/enum_set.rs
+++ b/src/libextra/enum_set.rs
@@ -136,7 +136,7 @@ mod test {
 
     use enum_set::*;
 
-    #[deriving(Eq)]
+    #[deriving(Eq)] #[repr(uint)]
     enum Foo {
         A, B, C
     }
diff --git a/src/librustc/lib/llvm.rs b/src/librustc/lib/llvm.rs
index 9e81ee5e64ccf..cb4656f39855f 100644
--- a/src/librustc/lib/llvm.rs
+++ b/src/librustc/lib/llvm.rs
@@ -145,6 +145,7 @@ pub static Vector: TypeKind    = 13;
 pub static Metadata: TypeKind  = 14;
 pub static X86_MMX: TypeKind   = 15;
 
+#[repr(C)]
 pub enum AtomicBinOp {
     Xchg = 0,
     Add  = 1,
@@ -159,6 +160,7 @@ pub enum AtomicBinOp {
     UMin = 10,
 }
 
+#[repr(C)]
 pub enum AtomicOrdering {
     NotAtomic = 0,
     Unordered = 1,
@@ -171,6 +173,7 @@ pub enum AtomicOrdering {
 }
 
 // Consts for the LLVMCodeGenFileType type (in include/llvm/c/TargetMachine.h)
+#[repr(C)]
 pub enum FileType {
     AssemblyFile = 0,
     ObjectFile = 1
@@ -192,6 +195,7 @@ pub enum AsmDialect {
 }
 
 #[deriving(Eq)]
+#[repr(C)]
 pub enum CodeGenOptLevel {
     CodeGenLevelNone = 0,
     CodeGenLevelLess = 1,
@@ -199,6 +203,7 @@ pub enum CodeGenOptLevel {
     CodeGenLevelAggressive = 3,
 }
 
+#[repr(C)]
 pub enum RelocMode {
     RelocDefault = 0,
     RelocStatic = 1,
@@ -206,6 +211,7 @@ pub enum RelocMode {
     RelocDynamicNoPic = 3,
 }
 
+#[repr(C)]
 pub enum CodeGenModel {
     CodeModelDefault = 0,
     CodeModelJITDefault = 1,
diff --git a/src/librustc/metadata/common.rs b/src/librustc/metadata/common.rs
index c3bc3e0fe25c1..3692d571a53a7 100644
--- a/src/librustc/metadata/common.rs
+++ b/src/librustc/metadata/common.rs
@@ -111,7 +111,7 @@ pub static tag_items_data_item_reexport_def_id: uint = 0x4e;
 pub static tag_items_data_item_reexport_name: uint = 0x4f;
 
 // used to encode crate_ctxt side tables
-#[deriving(Eq)]
+#[deriving(Eq)] #[repr(uint)]
 pub enum astencode_tag { // Reserves 0x50 -- 0x6f
     tag_ast = 0x50,
 
@@ -143,7 +143,7 @@ impl astencode_tag {
     pub fn from_uint(value : uint) -> Option<astencode_tag> {
         let is_a_tag = first_astencode_tag <= value && value <= last_astencode_tag;
         if !is_a_tag { None } else {
-            Some(unsafe { cast::transmute(value as int) })
+            Some(unsafe { cast::transmute(value) })
         }
     }
 }
diff --git a/src/librustc/metadata/encoder.rs b/src/librustc/metadata/encoder.rs
index fb52963f4fc9a..29ecae83f074f 100644
--- a/src/librustc/metadata/encoder.rs
+++ b/src/librustc/metadata/encoder.rs
@@ -941,6 +941,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         encode_family(ebml_w, 't');
         encode_bounds_and_type(ebml_w, ecx, &lookup_item_type(tcx, def_id));
         encode_name(ecx, ebml_w, item.ident);
+        encode_attributes(ebml_w, item.attrs);
         for v in (*enum_definition).variants.iter() {
             encode_variant_id(ebml_w, local_def(v.node.id));
         }
diff --git a/src/librustc/middle/lint.rs b/src/librustc/middle/lint.rs
index 6f4d94e2a647a..08f9f62fb0a46 100644
--- a/src/librustc/middle/lint.rs
+++ b/src/librustc/middle/lint.rs
@@ -10,6 +10,7 @@
 
 
 use driver::session;
+use middle::trans::adt; // for `adt::is_ffi_safe`
 use middle::ty;
 use middle::pat_util;
 use metadata::csearch;
@@ -900,6 +901,14 @@ fn check_item_ctypes(cx: &Context, it: &ast::item) {
                                 "found rust type `uint` in foreign module, while \
                                 libc::c_uint or libc::c_ulong should be used");
                     }
+                    ast::DefTy(def_id) => {
+                        if !adt::is_ffi_safe(cx.tcx, def_id) {
+                            cx.span_lint(ctypes, ty.span,
+                                         "found enum type without foreign-function-safe \
+                                          representation annotation in foreign module");
+                            // NOTE this message could be more helpful
+                        }
+                    }
                     _ => ()
                 }
             }
diff --git a/src/librustc/middle/trans/adt.rs b/src/librustc/middle/trans/adt.rs
index 5c255ad081811..1951c78334766 100644
--- a/src/librustc/middle/trans/adt.rs
+++ b/src/librustc/middle/trans/adt.rs
@@ -14,7 +14,8 @@
  * This module determines how to represent enums, structs, and tuples
  * based on their monomorphized types; it is responsible both for
  * choosing a representation and translating basic operations on
- * values of those types.
+ * values of those types.  (Note: exporting the representations for
+ * debuggers is handled in debuginfo.rs, not here.)
  *
  * Note that the interface treats everything as a general case of an
  * enum, so structs/tuples/etc. have one pseudo-variant with
@@ -29,8 +30,6 @@
  *   that might contain one and adjust GEP indices accordingly.  See
  *   issue #4578.
  *
- * - Using smaller integer types for discriminants.
- *
  * - Store nested enums' discriminants in the same word.  Rather, if
  *   some variants start with enums, and those enums representations
  *   have unused alignment padding between discriminant and body, the
@@ -56,16 +55,21 @@ use middle::trans::machine;
 use middle::trans::type_of;
 use middle::ty;
 use middle::ty::Disr;
+use syntax::abi::{X86, X86_64, Arm, Mips};
 use syntax::ast;
+use syntax::attr;
+use syntax::attr::IntType;
 use util::ppaux::ty_to_str;
 
 use middle::trans::type_::Type;
 
+type Hint = attr::ReprAttr;
+
 
 /// Representations.
 pub enum Repr {
     /// C-like enums; basically an int.
-    CEnum(Disr, Disr), // discriminant range
+    CEnum(IntType, Disr, Disr), // discriminant range (signedness based on the IntType)
     /**
      * Single-case variants, and structs/tuples/records.
      *
@@ -78,7 +82,7 @@ pub enum Repr {
      * General-case enums: for each case there is a struct, and they
      * all start with a field for the discriminant.
      */
-    General(~[Struct]),
+    General(IntType, ~[Struct]),
     /**
      * Two cases distinguished by a nullable pointer: the case with discriminant
      * `nndiscr` is represented by the struct `nonnull`, where the `ptrfield`th
@@ -141,38 +145,25 @@ fn represent_type_uncached(cx: &mut CrateContext, t: ty::t) -> Repr {
             return Univariant(mk_struct(cx, ftys, packed), dtor)
         }
         ty::ty_enum(def_id, ref substs) => {
-            struct Case { discr: Disr, tys: ~[ty::t] };
-            impl Case {
-                fn is_zerolen(&self, cx: &mut CrateContext) -> bool {
-                    mk_struct(cx, self.tys, false).size == 0
-                }
-                fn find_ptr(&self) -> Option<uint> {
-                    self.tys.iter().position(|&ty| mono_data_classify(ty) == MonoNonNull)
-                }
-            }
-
-            let cases = do ty::enum_variants(cx.tcx, def_id).map |vi| {
-                let arg_tys = do vi.args.map |&raw_ty| {
-                    ty::subst(cx.tcx, substs, raw_ty)
-                };
-                Case { discr: vi.disr_val, tys: arg_tys }
-            };
+            let cases = get_cases(cx.tcx, def_id, substs);
+            let hint = ty::lookup_repr_hint(cx.tcx, def_id);
 
             if cases.len() == 0 {
                 // Uninhabitable; represent as unit
+                assert_eq!(hint, attr::ReprAny);
                 return Univariant(mk_struct(cx, [], false), false);
             }
 
             if cases.iter().all(|c| c.tys.len() == 0) {
                 // All bodies empty -> intlike
                 let discrs = cases.map(|c| c.discr);
-                return CEnum(*discrs.iter().min().unwrap(), *discrs.iter().max().unwrap());
-            }
-
-            if cases.len() == 1 {
-                // Equivalent to a struct/tuple/newtype.
-                assert_eq!(cases[0].discr, 0);
-                return Univariant(mk_struct(cx, cases[0].tys, false), false)
+                let bounds = IntBounds {
+                    ulo: *discrs.iter().min().unwrap(),
+                    uhi: *discrs.iter().max().unwrap(),
+                    slo: discrs.iter().map(|n| *n as i64).min().unwrap(),
+                    shi: discrs.iter().map(|n| *n as i64).max().unwrap()
+                };
+                return mk_cenum(cx, hint, &bounds);
             }
 
             // Since there's at least one
@@ -184,7 +175,14 @@ fn represent_type_uncached(cx: &mut CrateContext, t: ty::t) -> Repr {
                                  ty::item_path_str(cx.tcx, def_id)))
             }
 
-            if cases.len() == 2 {
+            if cases.len() == 1 {
+                // Equivalent to a struct/tuple/newtype.
+                assert_eq!(hint, attr::ReprAny);
+                return Univariant(mk_struct(cx, cases[0].tys, false), false)
+            }
+
+            if cases.len() == 2 && hint == attr::ReprAny {
+                // Nullable pointer optimization
                 let mut discr = 0;
                 while discr < 2 {
                     if cases[1 - discr].is_zerolen(cx) {
@@ -207,13 +205,67 @@ fn represent_type_uncached(cx: &mut CrateContext, t: ty::t) -> Repr {
             }
 
             // The general case.
-            let discr = ~[ty::mk_uint()];
-            return General(cases.map(|c| mk_struct(cx, discr + c.tys, false)))
+            assert!((cases.len() - 1) as i64 >= 0);
+            let bounds = IntBounds { ulo: 0, uhi: (cases.len() - 1) as u64,
+                                     slo: 0, shi: (cases.len() - 1) as i64 };
+            let ity = range_to_inttype(cx, hint, &bounds);
+            let discr = ~[ty_of_inttype(ity)];
+            return General(ity, cases.map(|c| mk_struct(cx, discr + c.tys, false)))
         }
         _ => cx.sess.bug("adt::represent_type called on non-ADT type")
     }
 }
 
+/// Determine, without doing translation, whether an ADT must be FFI-safe.
+/// For use in lint or similar, where being sound but slightly incomplete is acceptable.
+pub fn is_ffi_safe(tcx: ty::ctxt, def_id: ast::DefId) -> bool {
+    match ty::get(ty::lookup_item_type(tcx, def_id).ty).sty {
+        ty::ty_enum(def_id, ref substs) => {
+            let cases = get_cases(tcx, def_id, substs);
+            // Univariant => like struct/tuple.
+            if cases.len() <= 2 {
+                return true;
+            }
+            let hint = ty::lookup_repr_hint(tcx, def_id);
+            // Appropriate representation explicitly selected?
+            if hint.is_ffi_safe() {
+                return true;
+            }
+            // Conservative approximation of nullable pointers, for Option<~T> etc.
+            if cases.len() == 2 && hint == attr::ReprAny &&
+                (cases[0].tys.is_empty() && cases[1].find_ptr().is_some() ||
+                 cases[1].tys.is_empty() && cases[0].find_ptr().is_some()) {
+                return true;
+            }
+            false
+        }
+        // struct, tuple, etc.
+        // (is this right in the present of typedefs?)
+        _ => true
+    }
+}
+
+// NOTE this should probably all be in ty
+struct Case { discr: Disr, tys: ~[ty::t] }
+impl Case {
+    fn is_zerolen(&self, cx: &mut CrateContext) -> bool {
+        mk_struct(cx, self.tys, false).size == 0
+    }
+    fn find_ptr(&self) -> Option<uint> {
+        self.tys.iter().position(|&ty| mono_data_classify(ty) == MonoNonNull)
+    }
+}
+
+fn get_cases(tcx: ty::ctxt, def_id: ast::DefId, substs: &ty::substs) -> ~[Case] {
+    do ty::enum_variants(tcx, def_id).map |vi| {
+        let arg_tys = do vi.args.map |&raw_ty| {
+            ty::subst(tcx, substs, raw_ty)
+        };
+        Case { discr: vi.disr_val, tys: arg_tys }
+    }
+}
+
+
 fn mk_struct(cx: &mut CrateContext, tys: &[ty::t], packed: bool) -> Struct {
     let lltys = tys.map(|&ty| type_of::sizing_type_of(cx, ty));
     let llty_rec = Type::struct_(lltys, packed);
@@ -225,6 +277,94 @@ fn mk_struct(cx: &mut CrateContext, tys: &[ty::t], packed: bool) -> Struct {
     }
 }
 
+struct IntBounds {
+    slo: i64,
+    shi: i64,
+    ulo: u64,
+    uhi: u64
+}
+
+fn mk_cenum(cx: &mut CrateContext, hint: Hint, bounds: &IntBounds) -> Repr {
+    let it = range_to_inttype(cx, hint, bounds);
+    match it {
+        attr::SignedInt(_) => CEnum(it, bounds.slo as Disr, bounds.shi as Disr),
+        attr::UnsignedInt(_) => CEnum(it, bounds.ulo, bounds.uhi)
+    }
+}
+
+fn range_to_inttype(cx: &mut CrateContext, hint: Hint, bounds: &IntBounds) -> IntType {
+    debug!("range_to_inttype: %? %?", hint, bounds);
+    // Lists of sizes to try.  u64 is always allowed as a fallback.
+    static choose_shortest: &'static[IntType] = &[
+        attr::UnsignedInt(ast::ty_u8), attr::SignedInt(ast::ty_i8),
+        attr::UnsignedInt(ast::ty_u16), attr::SignedInt(ast::ty_i16),
+        attr::UnsignedInt(ast::ty_u32), attr::SignedInt(ast::ty_i32)];
+    static at_least_32: &'static[IntType] = &[
+        attr::UnsignedInt(ast::ty_u32), attr::SignedInt(ast::ty_i32)];
+
+    let attempts;
+    match hint {
+        attr::ReprInt(span, ity) => {
+            if !bounds_usable(cx, ity, bounds) {
+                cx.sess.span_bug(span, "representation hint insufficient for discriminant range")
+            }
+            return ity;
+        }
+        attr::ReprExtern => {
+            attempts = match cx.sess.targ_cfg.arch {
+                X86 | X86_64 => at_least_32,
+                // WARNING: the ARM EABI has two variants; the one corresponding to `at_least_32`
+                // appears to be used on Linux and NetBSD, but some systems may use the variant
+                // corresponding to `choose_shortest`.  However, we don't run on those yet...?
+                Arm => at_least_32,
+                Mips => at_least_32,
+            }
+        }
+        attr::ReprAny => {
+            attempts = choose_shortest;
+        }
+    }
+    let mut best = attr::UnsignedInt(ast::ty_u64);
+    for &ity in attempts.iter() {
+        if bounds_usable(cx, ity, bounds) {
+            best = ity;
+            break;
+        }
+    }
+    return best;
+}
+
+pub fn ll_inttype(cx: &mut CrateContext, ity: IntType) -> Type {
+    match ity {
+        attr::SignedInt(t) => Type::int_from_ty(cx, t),
+        attr::UnsignedInt(t) => Type::uint_from_ty(cx, t)
+    }
+}
+
+fn bounds_usable(cx: &mut CrateContext, ity: IntType, bounds: &IntBounds) -> bool {
+    debug!("bounds_usable: %? %?", ity, bounds);
+    match ity {
+        attr::SignedInt(_) => {
+            let lllo = C_integral(ll_inttype(cx, ity), bounds.slo as u64, true);
+            let llhi = C_integral(ll_inttype(cx, ity), bounds.shi as u64, true);
+            bounds.slo == const_to_int(lllo) as i64 && bounds.shi == const_to_int(llhi) as i64
+        }
+        attr::UnsignedInt(_) => {
+            let lllo = C_integral(ll_inttype(cx, ity), bounds.ulo, false);
+            let llhi = C_integral(ll_inttype(cx, ity), bounds.uhi, false);
+            bounds.ulo == const_to_uint(lllo) as u64 && bounds.uhi == const_to_uint(llhi) as u64
+        }
+    }
+}
+
+fn ty_of_inttype(ity: IntType) -> ty::t {
+    match ity {
+        attr::SignedInt(t) => ty::mk_mach_int(t),
+        attr::UnsignedInt(t) => ty::mk_mach_uint(t)
+    }
+}
+
+
 /**
  * Returns the fields of a struct for the given representation.
  * All nominal types are LLVM structs, in order to be able to use
@@ -239,10 +379,10 @@ pub fn sizing_fields_of(cx: &mut CrateContext, r: &Repr) -> ~[Type] {
 }
 fn generic_fields_of(cx: &mut CrateContext, r: &Repr, sizing: bool) -> ~[Type] {
     match *r {
-        CEnum(*) => ~[Type::enum_discrim(cx)],
+        CEnum(ity, _, _) => ~[ll_inttype(cx, ity)],
         Univariant(ref st, _dtor) => struct_llfields(cx, st, sizing),
         NullablePointer{ nonnull: ref st, _ } => struct_llfields(cx, st, sizing),
-        General(ref sts) => {
+        General(_ity, ref sts) => {
             // To get "the" type of a general enum, we pick the case
             // with the largest alignment (so it will always align
             // correctly in containing structures) and pad it out.
@@ -288,7 +428,7 @@ pub fn trans_switch(bcx: @mut Block, r: &Repr, scrutinee: ValueRef)
     -> (_match::branch_kind, Option<ValueRef>) {
     match *r {
         CEnum(*) | General(*) => {
-            (_match::switch, Some(trans_get_discr(bcx, r, scrutinee)))
+            (_match::switch, Some(trans_get_discr(bcx, r, scrutinee, None)))
         }
         NullablePointer{ nonnull: ref nonnull, nndiscr, ptrfield, _ } => {
             (_match::switch, Some(nullable_bitdiscr(bcx, nonnull, nndiscr, ptrfield, scrutinee)))
@@ -302,17 +442,32 @@ pub fn trans_switch(bcx: @mut Block, r: &Repr, scrutinee: ValueRef)
 
 
 /// Obtain the actual discriminant of a value.
-pub fn trans_get_discr(bcx: @mut Block, r: &Repr, scrutinee: ValueRef)
+pub fn trans_get_discr(bcx: @mut Block, r: &Repr, scrutinee: ValueRef, cast_to: Option<Type>)
     -> ValueRef {
+    let signed;
+    let val;
     match *r {
-        CEnum(min, max) => load_discr(bcx, scrutinee, min, max),
-        Univariant(*) => C_disr(bcx.ccx(), 0),
-        General(ref cases) => load_discr(bcx, scrutinee, 0, (cases.len() - 1) as Disr),
+        CEnum(ity, min, max) => {
+            val = load_discr(bcx, ity, scrutinee, min, max);
+            signed = ity.is_signed();
+        }
+        General(ity, ref cases) => {
+            val = load_discr(bcx, ity, scrutinee, 0, (cases.len() - 1) as Disr);
+            signed = ity.is_signed();
+        }
+        Univariant(*) => {
+            val = C_u8(0);
+            signed = false;
+        }
         NullablePointer{ nonnull: ref nonnull, nndiscr, ptrfield, _ } => {
-            ZExt(bcx, nullable_bitdiscr(bcx, nonnull, nndiscr, ptrfield, scrutinee),
-                 Type::enum_discrim(bcx.ccx()))
+            val = nullable_bitdiscr(bcx, nonnull, nndiscr, ptrfield, scrutinee);
+            signed = false;
         }
     }
+    match cast_to {
+        None => val,
+        Some(llty) => if signed { SExt(bcx, val, llty) } else { ZExt(bcx, val, llty) }
+    }
 }
 
 fn nullable_bitdiscr(bcx: @mut Block, nonnull: &Struct, nndiscr: Disr, ptrfield: uint,
@@ -324,10 +479,15 @@ fn nullable_bitdiscr(bcx: @mut Block, nonnull: &Struct, nndiscr: Disr, ptrfield:
 }
 
 /// Helper for cases where the discriminant is simply loaded.
-fn load_discr(bcx: @mut Block, scrutinee: ValueRef, min: Disr, max: Disr)
+fn load_discr(bcx: @mut Block, ity: IntType, scrutinee: ValueRef, min: Disr, max: Disr)
     -> ValueRef {
     let ptr = GEPi(bcx, scrutinee, [0, 0]);
-    if max + 1 == min {
+    let llty = ll_inttype(bcx.ccx(), ity);
+    assert_eq!(val_ty(ptr), llty.ptr_to());
+    let bits = machine::llbitsize_of_real(bcx.ccx(), llty);
+    assert!(bits <= 64);
+    let mask = (-1u64 >> (64 - bits)) as Disr;
+    if (max + 1) & mask == min & mask {
         // i.e., if the range is everything.  The lo==hi case would be
         // rejected by the LLVM verifier (it would mean either an
         // empty set, which is impossible, or the entire range of the
@@ -350,15 +510,17 @@ fn load_discr(bcx: @mut Block, scrutinee: ValueRef, min: Disr, max: Disr)
  */
 pub fn trans_case(bcx: @mut Block, r: &Repr, discr: Disr) -> _match::opt_result {
     match *r {
-        CEnum(*) => {
-            _match::single_result(rslt(bcx, C_disr(bcx.ccx(), discr)))
+        CEnum(ity, _, _) => {
+            _match::single_result(rslt(bcx, C_integral(ll_inttype(bcx.ccx(), ity),
+                                                       discr as u64, true)))
+        }
+        General(ity, _) => {
+            _match::single_result(rslt(bcx, C_integral(ll_inttype(bcx.ccx(), ity),
+                                                       discr as u64, true)))
         }
         Univariant(*) => {
             bcx.ccx().sess.bug("no cases for univariants or structs")
         }
-        General(*) => {
-            _match::single_result(rslt(bcx, C_disr(bcx.ccx(), discr)))
-        }
         NullablePointer{ _ } => {
             assert!(discr == 0 || discr == 1);
             _match::single_result(rslt(bcx, C_i1(discr != 0)))
@@ -373,9 +535,14 @@ pub fn trans_case(bcx: @mut Block, r: &Repr, discr: Disr) -> _match::opt_result
  */
 pub fn trans_start_init(bcx: @mut Block, r: &Repr, val: ValueRef, discr: Disr) {
     match *r {
-        CEnum(min, max) => {
-            assert!(min <= discr && discr <= max);
-            Store(bcx, C_disr(bcx.ccx(), discr), GEPi(bcx, val, [0, 0]))
+        CEnum(ity, min, max) => {
+            assert_discr_in_range(ity, min, max, discr);
+            Store(bcx, C_integral(ll_inttype(bcx.ccx(), ity), discr as u64, true),
+                  GEPi(bcx, val, [0, 0]))
+        }
+        General(ity, _) => {
+            Store(bcx, C_integral(ll_inttype(bcx.ccx(), ity), discr as u64, true),
+                  GEPi(bcx, val, [0, 0]))
         }
         Univariant(ref st, true) => {
             assert_eq!(discr, 0);
@@ -385,9 +552,6 @@ pub fn trans_start_init(bcx: @mut Block, r: &Repr, val: ValueRef, discr: Disr) {
         Univariant(*) => {
             assert_eq!(discr, 0);
         }
-        General(*) => {
-            Store(bcx, C_disr(bcx.ccx(), discr), GEPi(bcx, val, [0, 0]))
-        }
         NullablePointer{ nonnull: ref nonnull, nndiscr, ptrfield, _ } => {
             if discr != nndiscr {
                 let llptrptr = GEPi(bcx, val, [0, ptrfield]);
@@ -398,6 +562,13 @@ pub fn trans_start_init(bcx: @mut Block, r: &Repr, val: ValueRef, discr: Disr) {
     }
 }
 
+fn assert_discr_in_range(ity: IntType, min: Disr, max: Disr, discr: Disr) {
+    match ity {
+        attr::UnsignedInt(_) => assert!(min <= discr && discr <= max),
+        attr::SignedInt(_) => assert!(min as i64 <= discr as i64 && discr as i64 <= max as i64)
+    }
+}
+
 /**
  * The number of fields in a given case; for use when obtaining this
  * information from the type or definition is less convenient.
@@ -409,7 +580,7 @@ pub fn num_args(r: &Repr, discr: Disr) -> uint {
             assert_eq!(discr, 0);
             st.fields.len() - (if dtor { 1 } else { 0 })
         }
-        General(ref cases) => cases[discr].fields.len() - 1,
+        General(_, ref cases) => cases[discr].fields.len() - 1,
         NullablePointer{ nonnull: ref nonnull, nndiscr, nullfields: ref nullfields, _ } => {
             if discr == nndiscr { nonnull.fields.len() } else { nullfields.len() }
         }
@@ -430,7 +601,7 @@ pub fn trans_field_ptr(bcx: @mut Block, r: &Repr, val: ValueRef, discr: Disr,
             assert_eq!(discr, 0);
             struct_field_ptr(bcx, st, val, ix, false)
         }
-        General(ref cases) => {
+        General(_, ref cases) => {
             struct_field_ptr(bcx, &cases[discr], val, ix + 1, true)
         }
         NullablePointer{ nonnull: ref nonnull, nullfields: ref nullfields, nndiscr, _ } => {
@@ -498,23 +669,22 @@ pub fn trans_drop_flag_ptr(bcx: @mut Block, r: &Repr, val: ValueRef) -> ValueRef
 pub fn trans_const(ccx: &mut CrateContext, r: &Repr, discr: Disr,
                    vals: &[ValueRef]) -> ValueRef {
     match *r {
-        CEnum(min, max) => {
+        CEnum(ity, min, max) => {
             assert_eq!(vals.len(), 0);
-            assert!(min <= discr && discr <= max);
-            C_disr(ccx, discr)
-        }
-        Univariant(ref st, _dro) => {
-            assert_eq!(discr, 0);
-            C_struct(build_const_struct(ccx, st, vals))
+            assert_discr_in_range(ity, min, max, discr);
+            C_integral(ll_inttype(ccx, ity), discr as u64, true)
         }
-        General(ref cases) => {
+        General(ity, ref cases) => {
             let case = &cases[discr];
             let max_sz = cases.iter().map(|x| x.size).max().unwrap();
-            let discr_ty = C_disr(ccx, discr);
-            let contents = build_const_struct(ccx, case,
-                                              ~[discr_ty] + vals);
+            let lldiscr = C_integral(ll_inttype(ccx, ity), discr as u64, true);
+            let contents = build_const_struct(ccx, case, ~[lldiscr] + vals);
             C_struct(contents + &[padding(max_sz - case.size)])
         }
+        Univariant(ref st, _dro) => {
+            assert!(discr == 0);
+            C_struct(build_const_struct(ccx, st, vals))
+        }
         NullablePointer{ nonnull: ref nonnull, nndiscr, ptrfield, _ } => {
             if discr == nndiscr {
                 C_struct(build_const_struct(ccx, nonnull, vals))
@@ -584,9 +754,19 @@ fn roundup(x: u64, a: u64) -> u64 { ((x + (a - 1)) / a) * a }
 pub fn const_get_discrim(ccx: &mut CrateContext, r: &Repr, val: ValueRef)
     -> Disr {
     match *r {
-        CEnum(*) => const_to_uint(val) as Disr,
+        CEnum(ity, _, _) => {
+            match ity {
+                attr::SignedInt(*) => const_to_int(val) as Disr,
+                attr::UnsignedInt(*) => const_to_uint(val) as Disr
+            }
+        }
+        General(ity, _) => {
+            match ity {
+                attr::SignedInt(*) => const_to_int(const_get_elt(ccx, val, [0])) as Disr,
+                attr::UnsignedInt(*) => const_to_uint(const_get_elt(ccx, val, [0])) as Disr
+            }
+        }
         Univariant(*) => 0,
-        General(*) => const_to_uint(const_get_elt(ccx, val, [0])) as Disr,
         NullablePointer{ nndiscr, ptrfield, _ } => {
             if is_null(const_struct_field(ccx, val, ptrfield)) {
                 /* subtraction as uint is ok because nndiscr is either 0 or 1 */
@@ -645,7 +825,3 @@ pub fn is_newtypeish(r: &Repr) -> bool {
         _ => false
     }
 }
-
-fn C_disr(cx: &CrateContext, i: Disr) -> ValueRef {
-    return C_integral(cx.int_type, i, false);
-}
diff --git a/src/librustc/middle/trans/debuginfo.rs b/src/librustc/middle/trans/debuginfo.rs
index 646f71ec28ad2..cf97f0bb3da7c 100644
--- a/src/librustc/middle/trans/debuginfo.rs
+++ b/src/librustc/middle/trans/debuginfo.rs
@@ -67,6 +67,7 @@ use std::hashmap::HashMap;
 use std::libc::{c_uint, c_ulonglong, c_longlong};
 use std::ptr;
 use std::vec;
+use syntax::attr;
 use syntax::codemap::Span;
 use syntax::{ast, codemap, ast_util, ast_map, opt_vec};
 use syntax::parse::token::special_idents;
@@ -1071,13 +1072,7 @@ fn enum_metadata(cx: &mut CrateContext,
         return composite_type_metadata(cx, Type::nil(), enum_name, [], [], [], span);
     }
 
-    // Prepare some data (llvm type, size, align, ...) about the discriminant. This data will be
-    // needed in all of the following cases.
-    let discriminant_llvm_type = Type::enum_discrim(cx);
-    let (discriminant_size, discriminant_align) = size_and_align_of(cx, discriminant_llvm_type);
-
-    assert!(Type::enum_discrim(cx) == cx.int_type);
-    let discriminant_type_metadata = type_metadata(cx, ty::mk_int(), span);
+    let type_rep = adt::represent_type(cx, enum_type);
 
     let variants: &[@ty::VariantInfo] = *ty::enum_variants(cx.tcx, enum_def_id);
 
@@ -1101,32 +1096,39 @@ fn enum_metadata(cx: &mut CrateContext,
     let loc = span_start(cx, span);
     let file_metadata = file_metadata(cx, loc.file.name);
 
-    let discriminant_type_metadata = do enum_name.with_c_str |enum_name| {
-        unsafe {
-            llvm::LLVMDIBuilderCreateEnumerationType(
-                DIB(cx),
-                file_metadata,
-                enum_name,
-                file_metadata,
-                loc.line as c_uint,
-                bytes_to_bits(discriminant_size),
-                bytes_to_bits(discriminant_align),
-                create_DIArray(DIB(cx), enumerators_metadata),
-                discriminant_type_metadata)
+    let discriminant_type_metadata = |inttype| {
+        let discriminant_llvm_type = adt::ll_inttype(cx, inttype);
+        let (discriminant_size, discriminant_align) = size_and_align_of(cx, discriminant_llvm_type);
+        let discriminant_type_metadata = type_metadata(cx, match inttype {
+            attr::SignedInt(t) => ty::mk_mach_int(t),
+            attr::UnsignedInt(t) => ty::mk_mach_uint(t)
+        }, span);
+        do enum_name.with_c_str |enum_name| {
+            unsafe {
+                llvm::LLVMDIBuilderCreateEnumerationType(
+                    DIB(cx),
+                    file_metadata,
+                    enum_name,
+                    file_metadata,
+                    loc.line as c_uint,
+                    bytes_to_bits(discriminant_size),
+                    bytes_to_bits(discriminant_align),
+                    create_DIArray(DIB(cx), enumerators_metadata),
+                    discriminant_type_metadata)
+            }
         }
     };
 
-    let type_rep = adt::represent_type(cx, enum_type);
-
     match *type_rep {
-        adt::CEnum(*) => {
-            return discriminant_type_metadata;
+        adt::CEnum(inttype, _min, _max) => {
+            return discriminant_type_metadata(inttype);
         }
         adt::Univariant(ref struct_def, _) => {
             assert!(variants.len() == 1);
             return adt_struct_metadata(cx, struct_def, variants[0], None, span);
         }
-        adt::General(ref struct_defs) => {
+        adt::General(inttype, ref struct_defs) => {
+            let discriminant_type_metadata = discriminant_type_metadata(inttype);
             let variants_member_metadata: ~[DIDescriptor] = do struct_defs
                 .iter()
                 .enumerate()
diff --git a/src/librustc/middle/trans/expr.rs b/src/librustc/middle/trans/expr.rs
index ce6fb6d3e7755..7283a113cc1af 100644
--- a/src/librustc/middle/trans/expr.rs
+++ b/src/librustc/middle/trans/expr.rs
@@ -1691,7 +1691,7 @@ fn trans_imm_cast(bcx: @mut Block, expr: @ast::Expr,
             (cast_enum, cast_float) => {
                 let bcx = bcx;
                 let repr = adt::represent_type(ccx, t_in);
-                let lldiscrim_a = adt::trans_get_discr(bcx, repr, llexpr);
+                let lldiscrim_a = adt::trans_get_discr(bcx, repr, llexpr, Some(Type::i64()));
                 match k_out {
                     cast_integral => int_cast(bcx, ll_t_out,
                                               val_ty(lldiscrim_a),
diff --git a/src/librustc/middle/trans/reflect.rs b/src/librustc/middle/trans/reflect.rs
index fb46aefbafe3b..eb232aa0e9214 100644
--- a/src/librustc/middle/trans/reflect.rs
+++ b/src/librustc/middle/trans/reflect.rs
@@ -25,7 +25,7 @@ use middle::ty;
 use util::ppaux::ty_to_str;
 
 use std::libc::c_uint;
-use std::option::None;
+use std::option::{Some,None};
 use std::vec;
 use syntax::ast::DefId;
 use syntax::ast;
@@ -309,7 +309,7 @@ impl Reflector {
                 };
                 let mut bcx = fcx.entry_bcx.unwrap();
                 let arg = BitCast(bcx, arg, llptrty);
-                let ret = adt::trans_get_discr(bcx, repr, arg);
+                let ret = adt::trans_get_discr(bcx, repr, arg, Some(ccx.int_type));
                 Store(bcx, ret, fcx.llretptr.unwrap());
                 match fcx.llreturn {
                     Some(llreturn) => cleanup_and_Br(bcx, bcx, llreturn),
diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 0958eeb7097a6..11c13247eee57 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -38,6 +38,7 @@ use syntax::ast::*;
 use syntax::ast_util::is_local;
 use syntax::ast_util;
 use syntax::attr;
+use syntax::attr::AttrMetaMethods;
 use syntax::codemap::Span;
 use syntax::codemap;
 use syntax::parse::token;
@@ -711,7 +712,7 @@ pub struct ParamBounds {
 
 pub type BuiltinBounds = EnumSet<BuiltinBound>;
 
-#[deriving(Clone, Eq, IterBytes, ToStr)]
+#[deriving(Clone, Eq, IterBytes, ToStr)] #[repr(uint)]
 pub enum BuiltinBound {
     BoundStatic,
     BoundSend,
@@ -4120,27 +4121,42 @@ pub fn lookup_trait_def(cx: ctxt, did: ast::DefId) -> @ty::TraitDef {
     }
 }
 
-/// Determine whether an item is annotated with an attribute
-pub fn has_attr(tcx: ctxt, did: DefId, attr: &str) -> bool {
+/// Iterate over meta_items of a definition.
+// (This should really be an iterator, but that would require csearch and
+// decoder to use iterators instead of higher-order functions.)
+pub fn each_attr(tcx: ctxt, did: DefId, f: &fn(@MetaItem) -> bool) -> bool {
     if is_local(did) {
         match tcx.items.find(&did.node) {
-            Some(
-                &ast_map::node_item(@ast::item {
-                    attrs: ref attrs,
-                    _
-                }, _)) => attr::contains_name(*attrs, attr),
+            Some(&ast_map::node_item(@ast::item {attrs: ref attrs, _}, _)) =>
+                attrs.iter().advance(|attr| f(attr.node.value)),
             _ => tcx.sess.bug(fmt!("has_attr: %? is not an item",
                                    did))
         }
     } else {
-        let mut ret = false;
+        let mut cont = true;
         do csearch::get_item_attrs(tcx.cstore, did) |meta_items| {
-            ret = ret || attr::contains_name(meta_items, attr);
+            if cont {
+                cont = meta_items.iter().advance(|ptrptr| f(*ptrptr));
+            }
         }
-        ret
+        return cont;
     }
 }
 
+/// Determine whether an item is annotated with an attribute
+pub fn has_attr(tcx: ctxt, did: DefId, attr: &str) -> bool {
+    let mut found = false;
+    each_attr(tcx, did, |item| {
+        if attr == item.name() {
+            found = true;
+            false
+        } else {
+            true
+        }
+    });
+    return found;
+}
+
 /// Determine whether an item is annotated with `#[packed]`
 pub fn lookup_packed(tcx: ctxt, did: DefId) -> bool {
     has_attr(tcx, did, "packed")
@@ -4151,6 +4167,16 @@ pub fn lookup_simd(tcx: ctxt, did: DefId) -> bool {
     has_attr(tcx, did, "simd")
 }
 
+// Obtain the the representation annotation for a definition.
+pub fn lookup_repr_hint(tcx: ctxt, did: DefId) -> attr::ReprAttr {
+    let mut acc = attr::ReprAny;
+    ty::each_attr(tcx, did, |meta| {
+        acc = attr::find_repr_attr(tcx.sess.diagnostic(), meta, acc);
+        true
+    });
+    return acc;
+}
+
 // Look up a field ID, whether or not it's local
 // Takes a list of type substs in case the struct is generic
 pub fn lookup_field_type(tcx: ctxt,
diff --git a/src/librustc/middle/typeck/check/mod.rs b/src/librustc/middle/typeck/check/mod.rs
index 0e335cf3f145d..2d3a5977ae05c 100644
--- a/src/librustc/middle/typeck/check/mod.rs
+++ b/src/librustc/middle/typeck/check/mod.rs
@@ -122,6 +122,7 @@ use syntax::ast;
 use syntax::ast_map;
 use syntax::ast_util::local_def;
 use syntax::ast_util;
+use syntax::attr;
 use syntax::codemap::Span;
 use syntax::codemap;
 use syntax::opt_vec::OptVec;
@@ -3160,9 +3161,38 @@ pub fn check_enum_variants(ccx: @mut CrateCtxt,
                            sp: Span,
                            vs: &[ast::variant],
                            id: ast::NodeId) {
+
+    fn disr_in_range(ccx: @mut CrateCtxt,
+                     ty: attr::IntType,
+                     disr: ty::Disr) -> bool {
+        fn uint_in_range(ccx: @mut CrateCtxt, ty: ast::uint_ty, disr: ty::Disr) -> bool {
+            match ty {
+                ast::ty_u8 => disr as u8 as Disr == disr,
+                ast::ty_u16 => disr as u16 as Disr == disr,
+                ast::ty_u32 => disr as u32 as Disr == disr,
+                ast::ty_u64 => disr as u64 as Disr == disr,
+                ast::ty_u => uint_in_range(ccx, ccx.tcx.sess.targ_cfg.uint_type, disr)
+            }
+        }
+        fn int_in_range(ccx: @mut CrateCtxt, ty: ast::int_ty, disr: ty::Disr) -> bool {
+            match ty {
+                ast::ty_i8 => disr as i8 as Disr == disr,
+                ast::ty_i16 => disr as i16 as Disr == disr,
+                ast::ty_i32 => disr as i32 as Disr == disr,
+                ast::ty_i64 => disr as i64 as Disr == disr,
+                ast::ty_i => int_in_range(ccx, ccx.tcx.sess.targ_cfg.int_type, disr)
+            }
+        }
+        match ty {
+            attr::UnsignedInt(ty) => uint_in_range(ccx, ty, disr),
+            attr::SignedInt(ty) => int_in_range(ccx, ty, disr)
+        }
+    }
+
     fn do_check(ccx: @mut CrateCtxt,
                 vs: &[ast::variant],
-                id: ast::NodeId)
+                id: ast::NodeId,
+                hint: attr::ReprAttr)
                 -> ~[@ty::VariantInfo] {
 
         let rty = ty::node_id_to_type(ccx.tcx, id);
@@ -3204,9 +3234,20 @@ pub fn check_enum_variants(ccx: @mut CrateCtxt,
                 None => ()
             };
 
-            // Check for duplicate discriminator values
+            // Check for duplicate discriminant values
             if disr_vals.contains(&current_disr_val) {
-                ccx.tcx.sess.span_err(v.span, "discriminator value already exists");
+                ccx.tcx.sess.span_err(v.span, "discriminant value already exists");
+            }
+            // Check for unrepresentable discriminant values
+            match hint {
+                attr::ReprAny | attr::ReprExtern => (),
+                attr::ReprInt(sp, ity) => {
+                    if !disr_in_range(ccx, ity, current_disr_val) {
+                        ccx.tcx.sess.span_err(v.span,
+                                              "discriminant value outside specified type");
+                        ccx.tcx.sess.span_note(sp, "discriminant type specified here");
+                    }
+                }
             }
             disr_vals.push(current_disr_val);
 
@@ -3220,8 +3261,13 @@ pub fn check_enum_variants(ccx: @mut CrateCtxt,
     }
 
     let rty = ty::node_id_to_type(ccx.tcx, id);
+    let hint = ty::lookup_repr_hint(ccx.tcx, ast::DefId { crate: ast::LOCAL_CRATE, node: id });
+    if hint != attr::ReprAny && vs.len() <= 1 {
+        ccx.tcx.sess.span_err(sp, fmt!("unsupported representation for %svariant enum",
+                                       if vs.len() == 1 { "uni" } else { "zero-" }))
+    }
 
-    let variants = do_check(ccx, vs, id);
+    let variants = do_check(ccx, vs, id, hint);
 
     // cache so that ty::enum_variants won't repeat this work
     ccx.tcx.enum_var_cache.insert(local_def(id), @variants);
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index fd0887de7224b..28aec5ce605d3 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -14,7 +14,7 @@ use extra;
 
 use ast;
 use ast::{Attribute, Attribute_, MetaItem, MetaWord, MetaNameValue, MetaList};
-use codemap::{Spanned, spanned, dummy_spanned};
+use codemap::{Span, Spanned, spanned, dummy_spanned};
 use codemap::BytePos;
 use diagnostic::span_handler;
 use parse::comments::{doc_comment_style, strip_doc_comment_decoration};
@@ -363,3 +363,117 @@ pub fn require_unique_names(diagnostic: @mut span_handler,
         }
     }
 }
+
+
+/**
+ * Fold this over attributes to parse #[repr(...)] forms.
+ *
+ * Valid repr contents: any of the primitive integral type names (see
+ * `int_type_of_word`, below) to specify the discriminant type; and `C`, to use
+ * the same discriminant size that the corresponding C enum would.  These are
+ * not allowed on univariant or zero-variant enums, which have no discriminant.
+ *
+ * If a discriminant type is so specified, then the discriminant will be
+ * present (before fields, if any) with that type; reprensentation
+ * optimizations which would remove it will not be done.
+ */
+pub fn find_repr_attr(diagnostic: @mut span_handler, attr: @ast::MetaItem, acc: ReprAttr)
+    -> ReprAttr {
+    let mut acc = acc;
+    match attr.node {
+        ast::MetaList(s, ref items) if "repr" == s => {
+            for item in items.iter() {
+                match item.node {
+                    ast::MetaWord(word) => {
+                        let word: &str = word;
+                        let hint = match word {
+                            // Can't use "extern" because it's not a lexical identifier.
+                            "C" => ReprExtern,
+                            _ => match int_type_of_word(word) {
+                                Some(ity) => ReprInt(item.span, ity),
+                                None => {
+                                    // Not a word we recognize
+                                    diagnostic.span_warn(item.span,
+                                                         "unrecognized representation hint");
+                                    ReprAny
+                                }
+                            }
+                        };
+                        if hint != ReprAny {
+                            if acc == ReprAny {
+                                acc = hint;
+                            } else if acc != hint {
+                                diagnostic.span_warn(item.span,
+                                                     "conflicting representation hint \
+                                                      ignored")
+                            }
+                        }
+                    }
+                    // Not a word:
+                    _ => diagnostic.span_warn(item.span, "unrecognized representation hint")
+                }
+            }
+        }
+        // Not a "repr" hint: ignore.
+        _ => { }
+    }
+    return acc;
+}
+
+fn int_type_of_word(s: &str) -> Option<IntType> {
+    match s {
+        "i8" => Some(SignedInt(ast::ty_i8)),
+        "u8" => Some(UnsignedInt(ast::ty_u8)),
+        "i16" => Some(SignedInt(ast::ty_i16)),
+        "u16" => Some(UnsignedInt(ast::ty_u16)),
+        "i32" => Some(SignedInt(ast::ty_i32)),
+        "u32" => Some(UnsignedInt(ast::ty_u32)),
+        "i64" => Some(SignedInt(ast::ty_i64)),
+        "u64" => Some(UnsignedInt(ast::ty_u64)),
+        "int" => Some(SignedInt(ast::ty_i)),
+        "uint" => Some(UnsignedInt(ast::ty_u)),
+        _ => None
+    }
+}
+
+#[deriving(Eq)]
+pub enum ReprAttr {
+    ReprAny,
+    ReprInt(Span, IntType),
+    ReprExtern
+}
+
+impl ReprAttr {
+    pub fn is_ffi_safe(&self) -> bool {
+        match *self {
+            ReprAny => false,
+            ReprInt(_sp, ity) => ity.is_ffi_safe(),
+            ReprExtern => true
+        }
+    }
+}
+
+#[deriving(Eq)]
+pub enum IntType {
+    SignedInt(ast::int_ty),
+    UnsignedInt(ast::uint_ty)
+}
+
+impl IntType {
+    #[inline]
+    pub fn is_signed(self) -> bool {
+        match self {
+            SignedInt(*) => true,
+            UnsignedInt(*) => false
+        }
+    }
+    fn is_ffi_safe(self) -> bool {
+        match self {
+            SignedInt(ast::ty_i8) | UnsignedInt(ast::ty_u8) |
+            SignedInt(ast::ty_i16) | UnsignedInt(ast::ty_u16) |
+            SignedInt(ast::ty_i32) | UnsignedInt(ast::ty_u32) |
+            SignedInt(ast::ty_i64) | UnsignedInt(ast::ty_u64) => true,
+            _ => false
+        }
+    }
+}
diff --git a/src/test/compile-fail/tag-variant-disr-dup.rs b/src/test/compile-fail/tag-variant-disr-dup.rs
index 216779fac7c46..d0608ec4c1927 100644
--- a/src/test/compile-fail/tag-variant-disr-dup.rs
+++ b/src/test/compile-fail/tag-variant-disr-dup.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-//error-pattern:discriminator value already exists
+//error-pattern:discriminant value already exists
 
 // black and white have the same discriminator value ...
 
@@ -20,4 +20,4 @@ enum color {
     white = 0x000000,
 }
 
-fn main() { }
\ No newline at end of file
+fn main() { }
diff --git a/src/test/debug-info/method-on-enum.rs b/src/test/debug-info/method-on-enum.rs
index c68b4e7deedf4..45b82984847d4 100644
--- a/src/test/debug-info/method-on-enum.rs
+++ b/src/test/debug-info/method-on-enum.rs
@@ -15,7 +15,7 @@
 // STACK BY REF
 // debugger:finish
 // debugger:print *self
-// check:$1 = {{Variant2, x = 1799, y = 1799}, {Variant2, 117901063}}
+// check:$1 = {{Variant2, [...]}, {Variant2, 117901063}}
 // debugger:print arg1
 // check:$2 = -1
 // debugger:print arg2
@@ -25,7 +25,7 @@
 // STACK BY VAL
 // debugger:finish
 // d ebugger:print self -- ignored for now because of issue #8512
-// c heck:$X = {{Variant2, x = 1799, y = 1799}, {Variant2, 117901063}}
+// c heck:$X = {{Variant2, [...]}, {Variant2, 117901063}}
 // debugger:print arg1
 // check:$4 = -3
 // debugger:print arg2
@@ -35,7 +35,7 @@
 // OWNED BY REF
 // debugger:finish
 // debugger:print *self
-// check:$6 = {{Variant1, x = 1799, y = 1799}, {Variant1, 117901063}}
+// check:$6 = {{Variant1, x = 1799, y = 1799}, {Variant1, [...]}}
 // debugger:print arg1
 // check:$7 = -5
 // debugger:print arg2
@@ -45,7 +45,7 @@
 // OWNED BY VAL
 // debugger:finish
 // d ebugger:print self -- ignored for now because of issue #8512
-// c heck:$X = {{Variant1, x = 1799, y = 1799}, {Variant1, 117901063}}
+// c heck:$X = {{Variant1, x = 1799, y = 1799}, {Variant1, [...]}}
 // debugger:print arg1
 // check:$9 = -7
 // debugger:print arg2
@@ -55,7 +55,7 @@
 // OWNED MOVED
 // debugger:finish
 // debugger:print *self
-// check:$11 = {{Variant1, x = 1799, y = 1799}, {Variant1, 117901063}}
+// check:$11 = {{Variant1, x = 1799, y = 1799}, {Variant1, [...]}}
 // debugger:print arg1
 // check:$12 = -9
 // debugger:print arg2
@@ -65,7 +65,7 @@
 // MANAGED BY REF
 // debugger:finish
 // debugger:print *self
-// check:$14 = {{Variant2, x = 1799, y = 1799}, {Variant2, 117901063}}
+// check:$14 = {{Variant2, [...]}, {Variant2, 117901063}}
 // debugger:print arg1
 // check:$15 = -11
 // debugger:print arg2
@@ -75,7 +75,7 @@
 // MANAGED BY VAL
 // debugger:finish
 // d ebugger:print self -- ignored for now because of issue #8512
-// c heck:$X = {{Variant2, x = 1799, y = 1799}, {Variant2, 117901063}}
+// c heck:$X = {{Variant2, [...]}, {Variant2, 117901063}}
 // debugger:print arg1
 // check:$17 = -13
 // debugger:print arg2
@@ -85,7 +85,7 @@
 // MANAGED SELF
 // debugger:finish
 // debugger:print self->val
-// check:$19 = {{Variant2, x = 1799, y = 1799}, {Variant2, 117901063}}
+// check:$19 = {{Variant2, [...]}, {Variant2, 117901063}}
 // debugger:print arg1
 // check:$20 = -15
 // debugger:print arg2
diff --git a/src/test/run-pass/issue-2718.rs b/src/test/run-pass/issue-2718.rs
index edfae096407b6..048a79b29aae6 100644
--- a/src/test/run-pass/issue-2718.rs
+++ b/src/test/run-pass/issue-2718.rs
@@ -26,7 +26,7 @@ pub mod pipes {
         payload: Option<T>
     }
 
-    #[deriving(Eq)]
+    #[deriving(Eq)] #[repr(int)]
     pub enum state {
         empty,
         full,
diff --git a/src/test/run-pass/small-enum-range-edge.rs b/src/test/run-pass/small-enum-range-edge.rs
new file mode 100644
index 0000000000000..a9fc13437abb4
--- /dev/null
+++ b/src/test/run-pass/small-enum-range-edge.rs
@@ -0,0 +1,32 @@
+// Copyright 2013 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.
+
+/*!
+ * Tests the range assertion wraparound case in trans::middle::adt::load_discr.
+ */
+
+#[repr(u8)]
+enum Eu { Lu = 0, Hu = 255 }
+static CLu: Eu = Lu;
+static CHu: Eu = Hu;
+
+#[repr(i8)]
+enum Es { Ls = -128, Hs = 127 }
+static CLs: Es = Ls;
+static CHs: Es = Hs;
+
+pub fn main() {
+    assert_eq!((Hu as u8) + 1, Lu as u8);
+    assert_eq!((Hs as i8) + 1, Ls as i8);
+    assert_eq!(CLu as u8, Lu as u8);
+    assert_eq!(CHu as u8, Hu as u8);
+    assert_eq!(CLs as i8, Ls as i8);
+    assert_eq!(CHs as i8, Hs as i8);
+}