diff --git a/src/librustc/ich/impls_syntax.rs b/src/librustc/ich/impls_syntax.rs
index 57120d61e7c7b..c31a5c9d86d77 100644
--- a/src/librustc/ich/impls_syntax.rs
+++ b/src/librustc/ich/impls_syntax.rs
@@ -155,8 +155,8 @@ impl_stable_hash_for!(enum ::syntax::ast::LitKind {
     Bool(value)
 });
 
-impl_stable_hash_for!(enum ::syntax::ast::IntTy { Is, I8, I16, I32, I64, I128 });
-impl_stable_hash_for!(enum ::syntax::ast::UintTy { Us, U8, U16, U32, U64, U128 });
+impl_stable_hash_for!(enum ::syntax::ast::IntTy { Isize, I8, I16, I32, I64, I128 });
+impl_stable_hash_for!(enum ::syntax::ast::UintTy { Usize, U8, U16, U32, U64, U128 });
 impl_stable_hash_for!(enum ::syntax::ast::FloatTy { F32, F64 });
 impl_stable_hash_for!(enum ::syntax::ast::Unsafety { Unsafe, Normal });
 impl_stable_hash_for!(enum ::syntax::ast::Constness { Const, NotConst });
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index e21eb8bbf8ad2..daecba9938c51 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -754,13 +754,13 @@ impl<'tcx> CommonTypes<'tcx> {
             char: mk(TyChar),
             never: mk(TyNever),
             err: mk(TyError),
-            isize: mk(TyInt(ast::IntTy::Is)),
+            isize: mk(TyInt(ast::IntTy::Isize)),
             i8: mk(TyInt(ast::IntTy::I8)),
             i16: mk(TyInt(ast::IntTy::I16)),
             i32: mk(TyInt(ast::IntTy::I32)),
             i64: mk(TyInt(ast::IntTy::I64)),
             i128: mk(TyInt(ast::IntTy::I128)),
-            usize: mk(TyUint(ast::UintTy::Us)),
+            usize: mk(TyUint(ast::UintTy::Usize)),
             u8: mk(TyUint(ast::UintTy::U8)),
             u16: mk(TyUint(ast::UintTy::U16)),
             u32: mk(TyUint(ast::UintTy::U32)),
@@ -1912,7 +1912,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     pub fn mk_mach_int(self, tm: ast::IntTy) -> Ty<'tcx> {
         match tm {
-            ast::IntTy::Is   => self.types.isize,
+            ast::IntTy::Isize   => self.types.isize,
             ast::IntTy::I8   => self.types.i8,
             ast::IntTy::I16  => self.types.i16,
             ast::IntTy::I32  => self.types.i32,
@@ -1923,7 +1923,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     pub fn mk_mach_uint(self, tm: ast::UintTy) -> Ty<'tcx> {
         match tm {
-            ast::UintTy::Us   => self.types.usize,
+            ast::UintTy::Usize   => self.types.usize,
             ast::UintTy::U8   => self.types.u8,
             ast::UintTy::U16  => self.types.u16,
             ast::UintTy::U32  => self.types.u32,
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 2a8c259dff89b..34a7d4ad7cfd0 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -520,7 +520,7 @@ impl<'a, 'tcx> Integer {
             attr::SignedInt(IntTy::I32) | attr::UnsignedInt(UintTy::U32) => I32,
             attr::SignedInt(IntTy::I64) | attr::UnsignedInt(UintTy::U64) => I64,
             attr::SignedInt(IntTy::I128) | attr::UnsignedInt(UintTy::U128) => I128,
-            attr::SignedInt(IntTy::Is) | attr::UnsignedInt(UintTy::Us) => {
+            attr::SignedInt(IntTy::Isize) | attr::UnsignedInt(UintTy::Usize) => {
                 dl.ptr_sized_integer()
             }
         }
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 2cea8c01cdf96..e5f6ac8853067 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -1575,7 +1575,7 @@ impl ReprOptions {
     pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
 
     pub fn discr_type(&self) -> attr::IntType {
-        self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
+        self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
     }
 
     /// Returns true if this `#[repr()]` should inhabit "smart enum
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 433c72f4b2ca6..cf784b7cafb87 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -1478,13 +1478,6 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
         }
     }
 
-    pub fn is_uint(&self) -> bool {
-        match self.sty {
-            TyInfer(IntVar(_)) | TyUint(ast::UintTy::Us) => true,
-            _ => false
-        }
-    }
-
     pub fn is_char(&self) -> bool {
         match self.sty {
             TyChar => true,
@@ -1512,7 +1505,7 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
 
     pub fn is_machine(&self) -> bool {
         match self.sty {
-            TyInt(ast::IntTy::Is) | TyUint(ast::UintTy::Us) => false,
+            TyInt(ast::IntTy::Isize) | TyUint(ast::UintTy::Usize) => false,
             TyInt(..) | TyUint(..) | TyFloat(..) => true,
             _ => false,
         }
diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index 85052052b32f7..638859af0f7d3 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -55,7 +55,7 @@ macro_rules! typed_literal {
             SignedInt(ast::IntTy::I32)   => ConstInt::I32($lit),
             SignedInt(ast::IntTy::I64)   => ConstInt::I64($lit),
             SignedInt(ast::IntTy::I128)   => ConstInt::I128($lit),
-            SignedInt(ast::IntTy::Is) => match $tcx.sess.target.isize_ty {
+            SignedInt(ast::IntTy::Isize) => match $tcx.sess.target.isize_ty {
                 ast::IntTy::I16 => ConstInt::Isize(ConstIsize::Is16($lit)),
                 ast::IntTy::I32 => ConstInt::Isize(ConstIsize::Is32($lit)),
                 ast::IntTy::I64 => ConstInt::Isize(ConstIsize::Is64($lit)),
@@ -66,7 +66,7 @@ macro_rules! typed_literal {
             UnsignedInt(ast::UintTy::U32) => ConstInt::U32($lit),
             UnsignedInt(ast::UintTy::U64) => ConstInt::U64($lit),
             UnsignedInt(ast::UintTy::U128) => ConstInt::U128($lit),
-            UnsignedInt(ast::UintTy::Us) => match $tcx.sess.target.usize_ty {
+            UnsignedInt(ast::UintTy::Usize) => match $tcx.sess.target.usize_ty {
                 ast::UintTy::U16 => ConstInt::Usize(ConstUsize::Us16($lit)),
                 ast::UintTy::U32 => ConstInt::Usize(ConstUsize::Us32($lit)),
                 ast::UintTy::U64 => ConstInt::Usize(ConstUsize::Us64($lit)),
@@ -84,13 +84,13 @@ impl IntTypeExt for attr::IntType {
             SignedInt(ast::IntTy::I32)     => tcx.types.i32,
             SignedInt(ast::IntTy::I64)     => tcx.types.i64,
             SignedInt(ast::IntTy::I128)     => tcx.types.i128,
-            SignedInt(ast::IntTy::Is)   => tcx.types.isize,
+            SignedInt(ast::IntTy::Isize)   => tcx.types.isize,
             UnsignedInt(ast::UintTy::U8)    => tcx.types.u8,
             UnsignedInt(ast::UintTy::U16)   => tcx.types.u16,
             UnsignedInt(ast::UintTy::U32)   => tcx.types.u32,
             UnsignedInt(ast::UintTy::U64)   => tcx.types.u64,
             UnsignedInt(ast::UintTy::U128)   => tcx.types.u128,
-            UnsignedInt(ast::UintTy::Us) => tcx.types.usize,
+            UnsignedInt(ast::UintTy::Usize) => tcx.types.usize,
         }
     }
 
@@ -105,13 +105,13 @@ impl IntTypeExt for attr::IntType {
             (SignedInt(ast::IntTy::I32), ConstInt::I32(_)) => {},
             (SignedInt(ast::IntTy::I64), ConstInt::I64(_)) => {},
             (SignedInt(ast::IntTy::I128), ConstInt::I128(_)) => {},
-            (SignedInt(ast::IntTy::Is), ConstInt::Isize(_)) => {},
+            (SignedInt(ast::IntTy::Isize), ConstInt::Isize(_)) => {},
             (UnsignedInt(ast::UintTy::U8), ConstInt::U8(_)) => {},
             (UnsignedInt(ast::UintTy::U16), ConstInt::U16(_)) => {},
             (UnsignedInt(ast::UintTy::U32), ConstInt::U32(_)) => {},
             (UnsignedInt(ast::UintTy::U64), ConstInt::U64(_)) => {},
             (UnsignedInt(ast::UintTy::U128), ConstInt::U128(_)) => {},
-            (UnsignedInt(ast::UintTy::Us), ConstInt::Usize(_)) => {},
+            (UnsignedInt(ast::UintTy::Usize), ConstInt::Usize(_)) => {},
             _ => bug!("disr type mismatch: {:?} vs {:?}", self, val),
         }
     }
diff --git a/src/librustc_const_eval/eval.rs b/src/librustc_const_eval/eval.rs
index 81cd63b5407c3..418bd4b5effc6 100644
--- a/src/librustc_const_eval/eval.rs
+++ b/src/librustc_const_eval/eval.rs
@@ -133,8 +133,8 @@ fn eval_const_expr_partial<'a, 'tcx>(cx: &ConstContext<'a, 'tcx>,
                 (&LitKind::Int(I128_OVERFLOW, Signed(IntTy::I128)), _) => {
                     Some(I128(i128::min_value()))
                 },
-                (&LitKind::Int(n, _), &ty::TyInt(IntTy::Is)) |
-                (&LitKind::Int(n, Signed(IntTy::Is)), _) => {
+                (&LitKind::Int(n, _), &ty::TyInt(IntTy::Isize)) |
+                (&LitKind::Int(n, Signed(IntTy::Isize)), _) => {
                     match tcx.sess.target.isize_ty {
                         IntTy::I16 => if n == I16_OVERFLOW {
                             Some(Isize(Is16(i16::min_value())))
@@ -478,7 +478,7 @@ fn cast_const_int<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         ty::TyInt(ast::IntTy::I32) => Ok(Integral(I32(v as i128 as i32))),
         ty::TyInt(ast::IntTy::I64) => Ok(Integral(I64(v as i128 as i64))),
         ty::TyInt(ast::IntTy::I128) => Ok(Integral(I128(v as i128))),
-        ty::TyInt(ast::IntTy::Is) => {
+        ty::TyInt(ast::IntTy::Isize) => {
             Ok(Integral(Isize(ConstIsize::new_truncating(v as i128, tcx.sess.target.isize_ty))))
         },
         ty::TyUint(ast::UintTy::U8) => Ok(Integral(U8(v as u8))),
@@ -486,7 +486,7 @@ fn cast_const_int<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         ty::TyUint(ast::UintTy::U32) => Ok(Integral(U32(v as u32))),
         ty::TyUint(ast::UintTy::U64) => Ok(Integral(U64(v as u64))),
         ty::TyUint(ast::UintTy::U128) => Ok(Integral(U128(v as u128))),
-        ty::TyUint(ast::UintTy::Us) => {
+        ty::TyUint(ast::UintTy::Usize) => {
             Ok(Integral(Usize(ConstUsize::new_truncating(v, tcx.sess.target.usize_ty))))
         },
         ty::TyFloat(fty) => {
diff --git a/src/librustc_const_math/err.rs b/src/librustc_const_math/err.rs
index 1e9c2badd6860..bd0a332436e64 100644
--- a/src/librustc_const_math/err.rs
+++ b/src/librustc_const_math/err.rs
@@ -75,13 +75,13 @@ impl ConstMathErr {
             ULitOutOfRange(ast::UintTy::U32) => "literal out of range for u32",
             ULitOutOfRange(ast::UintTy::U64) => "literal out of range for u64",
             ULitOutOfRange(ast::UintTy::U128) => "literal out of range for u128",
-            ULitOutOfRange(ast::UintTy::Us) => "literal out of range for usize",
+            ULitOutOfRange(ast::UintTy::Usize) => "literal out of range for usize",
             LitOutOfRange(ast::IntTy::I8) => "literal out of range for i8",
             LitOutOfRange(ast::IntTy::I16) => "literal out of range for i16",
             LitOutOfRange(ast::IntTy::I32) => "literal out of range for i32",
             LitOutOfRange(ast::IntTy::I64) => "literal out of range for i64",
             LitOutOfRange(ast::IntTy::I128) => "literal out of range for i128",
-            LitOutOfRange(ast::IntTy::Is) => "literal out of range for isize",
+            LitOutOfRange(ast::IntTy::Isize) => "literal out of range for isize",
         }
     }
 }
diff --git a/src/librustc_const_math/int.rs b/src/librustc_const_math/int.rs
index 08473d729e4e5..4ec27d7ade560 100644
--- a/src/librustc_const_math/int.rs
+++ b/src/librustc_const_math/int.rs
@@ -12,8 +12,8 @@ use std::cmp::Ordering;
 use syntax::attr::IntType;
 use syntax::ast::{IntTy, UintTy};
 
-use super::is::*;
-use super::us::*;
+use super::isize::*;
+use super::usize::*;
 use super::err::*;
 
 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, Hash, Eq, PartialEq)]
@@ -83,7 +83,7 @@ impl ConstInt {
             UintTy::U16 if val <= ubounds::U16MAX => Some(U16(val as u16)),
             UintTy::U32 if val <= ubounds::U32MAX => Some(U32(val as u32)),
             UintTy::U64 if val <= ubounds::U64MAX => Some(U64(val as u64)),
-            UintTy::Us if val <= ubounds::U64MAX => ConstUsize::new(val as u64, usize_ty).ok()
+            UintTy::Usize if val <= ubounds::U64MAX => ConstUsize::new(val as u64, usize_ty).ok()
                 .map(Usize),
             UintTy::U128 => Some(U128(val)),
             _ => None
@@ -98,7 +98,7 @@ impl ConstInt {
             IntTy::I16 if val <= ibounds::I16MAX => Some(I16(val as i16)),
             IntTy::I32 if val <= ibounds::I32MAX => Some(I32(val as i32)),
             IntTy::I64 if val <= ibounds::I64MAX => Some(I64(val as i64)),
-            IntTy::Is if val <= ibounds::I64MAX => ConstIsize::new(val as i64, isize_ty).ok()
+            IntTy::Isize if val <= ibounds::I64MAX => ConstIsize::new(val as i64, isize_ty).ok()
                 .map(Isize),
             IntTy::I128 => Some(I128(val)),
             _ => None
@@ -112,7 +112,7 @@ impl ConstInt {
             UintTy::U16 => U16(val as u16),
             UintTy::U32 => U32(val as u32),
             UintTy::U64 => U64(val as u64),
-            UintTy::Us => Usize(ConstUsize::new_truncating(val, usize_ty)),
+            UintTy::Usize => Usize(ConstUsize::new_truncating(val, usize_ty)),
             UintTy::U128 => U128(val)
         }
     }
@@ -124,7 +124,7 @@ impl ConstInt {
             IntTy::I16 => I16(val as i16),
             IntTy::I32 => I32(val as i32),
             IntTy::I64 => I64(val as i64),
-            IntTy::Is => Isize(ConstIsize::new_truncating(val, isize_ty)),
+            IntTy::Isize => Isize(ConstIsize::new_truncating(val, isize_ty)),
             IntTy::I128 => I128(val)
         }
     }
@@ -280,13 +280,13 @@ impl ConstInt {
             ConstInt::I32(_) => IntType::SignedInt(IntTy::I32),
             ConstInt::I64(_) => IntType::SignedInt(IntTy::I64),
             ConstInt::I128(_) => IntType::SignedInt(IntTy::I128),
-            ConstInt::Isize(_) => IntType::SignedInt(IntTy::Is),
+            ConstInt::Isize(_) => IntType::SignedInt(IntTy::Isize),
             ConstInt::U8(_) => IntType::UnsignedInt(UintTy::U8),
             ConstInt::U16(_) => IntType::UnsignedInt(UintTy::U16),
             ConstInt::U32(_) => IntType::UnsignedInt(UintTy::U32),
             ConstInt::U64(_) => IntType::UnsignedInt(UintTy::U64),
             ConstInt::U128(_) => IntType::UnsignedInt(UintTy::U128),
-            ConstInt::Usize(_) => IntType::UnsignedInt(UintTy::Us),
+            ConstInt::Usize(_) => IntType::UnsignedInt(UintTy::Usize),
         }
     }
 }
diff --git a/src/librustc_const_math/is.rs b/src/librustc_const_math/isize.rs
similarity index 92%
rename from src/librustc_const_math/is.rs
rename to src/librustc_const_math/isize.rs
index 50dfb60112991..18acc782775d8 100644
--- a/src/librustc_const_math/is.rs
+++ b/src/librustc_const_math/isize.rs
@@ -38,9 +38,9 @@ impl ConstIsize {
     pub fn new(i: i64, isize_ty: ast::IntTy) -> Result<Self, ConstMathErr> {
         match isize_ty {
             ast::IntTy::I16 if i as i16 as i64 == i => Ok(Is16(i as i16)),
-            ast::IntTy::I16 => Err(LitOutOfRange(ast::IntTy::Is)),
+            ast::IntTy::I16 => Err(LitOutOfRange(ast::IntTy::Isize)),
             ast::IntTy::I32 if i as i32 as i64 == i => Ok(Is32(i as i32)),
-            ast::IntTy::I32 => Err(LitOutOfRange(ast::IntTy::Is)),
+            ast::IntTy::I32 => Err(LitOutOfRange(ast::IntTy::Isize)),
             ast::IntTy::I64 => Ok(Is64(i)),
             _ => unreachable!(),
         }
diff --git a/src/librustc_const_math/lib.rs b/src/librustc_const_math/lib.rs
index 095b8bb50dc6c..2d98bc48d2816 100644
--- a/src/librustc_const_math/lib.rs
+++ b/src/librustc_const_math/lib.rs
@@ -30,12 +30,12 @@ extern crate serialize as rustc_serialize; // used by deriving
 
 mod float;
 mod int;
-mod us;
-mod is;
+mod usize;
+mod isize;
 mod err;
 
 pub use float::*;
 pub use int::*;
-pub use us::*;
-pub use is::*;
+pub use usize::*;
+pub use isize::*;
 pub use err::{ConstMathErr, Op};
diff --git a/src/librustc_const_math/us.rs b/src/librustc_const_math/usize.rs
similarity index 99%
rename from src/librustc_const_math/us.rs
rename to src/librustc_const_math/usize.rs
index 9876bc4d779a0..56995f08f05b8 100644
--- a/src/librustc_const_math/us.rs
+++ b/src/librustc_const_math/usize.rs
@@ -38,9 +38,9 @@ impl ConstUsize {
     pub fn new(i: u64, usize_ty: ast::UintTy) -> Result<Self, ConstMathErr> {
         match usize_ty {
             ast::UintTy::U16 if i as u16 as u64 == i => Ok(Us16(i as u16)),
-            ast::UintTy::U16 => Err(ULitOutOfRange(ast::UintTy::Us)),
+            ast::UintTy::U16 => Err(ULitOutOfRange(ast::UintTy::Usize)),
             ast::UintTy::U32 if i as u32 as u64 == i => Ok(Us32(i as u32)),
-            ast::UintTy::U32 => Err(ULitOutOfRange(ast::UintTy::Us)),
+            ast::UintTy::U32 => Err(ULitOutOfRange(ast::UintTy::Usize)),
             ast::UintTy::U64 => Ok(Us64(i)),
             _ => unreachable!(),
         }
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index c109a47f79867..5456b0d252b67 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -140,7 +140,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
                         match lit.node {
                             ast::LitKind::Int(v, ast::LitIntType::Signed(_)) |
                             ast::LitKind::Int(v, ast::LitIntType::Unsuffixed) => {
-                                let int_type = if let ast::IntTy::Is = t {
+                                let int_type = if let ast::IntTy::Isize = t {
                                     cx.sess().target.isize_ty
                                 } else {
                                     t
@@ -163,7 +163,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
                         };
                     }
                     ty::TyUint(t) => {
-                        let uint_type = if let ast::UintTy::Us = t {
+                        let uint_type = if let ast::UintTy::Usize = t {
                             cx.sess().target.usize_ty
                         } else {
                             t
@@ -230,7 +230,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
         // warnings are consistent between 32- and 64-bit platforms
         fn int_ty_range(int_ty: ast::IntTy) -> (i128, i128) {
             match int_ty {
-                ast::IntTy::Is => (i64::min_value() as i128, i64::max_value() as i128),
+                ast::IntTy::Isize => (i64::min_value() as i128, i64::max_value() as i128),
                 ast::IntTy::I8 => (i8::min_value() as i64 as i128, i8::max_value() as i128),
                 ast::IntTy::I16 => (i16::min_value() as i64 as i128, i16::max_value() as i128),
                 ast::IntTy::I32 => (i32::min_value() as i64 as i128, i32::max_value() as i128),
@@ -241,7 +241,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
 
         fn uint_ty_range(uint_ty: ast::UintTy) -> (u128, u128) {
             match uint_ty {
-                ast::UintTy::Us => (u64::min_value() as u128, u64::max_value() as u128),
+                ast::UintTy::Usize => (u64::min_value() as u128, u64::max_value() as u128),
                 ast::UintTy::U8 => (u8::min_value() as u128, u8::max_value() as u128),
                 ast::UintTy::U16 => (u16::min_value() as u128, u16::max_value() as u128),
                 ast::UintTy::U32 => (u32::min_value() as u128, u32::max_value() as u128),
@@ -252,7 +252,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
 
         fn int_ty_bits(int_ty: ast::IntTy, isize_ty: ast::IntTy) -> u64 {
             match int_ty {
-                ast::IntTy::Is => int_ty_bits(isize_ty, isize_ty),
+                ast::IntTy::Isize => int_ty_bits(isize_ty, isize_ty),
                 ast::IntTy::I8 => 8,
                 ast::IntTy::I16 => 16 as u64,
                 ast::IntTy::I32 => 32,
@@ -263,7 +263,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
 
         fn uint_ty_bits(uint_ty: ast::UintTy, usize_ty: ast::UintTy) -> u64 {
             match uint_ty {
-                ast::UintTy::Us => uint_ty_bits(usize_ty, usize_ty),
+                ast::UintTy::Usize => uint_ty_bits(usize_ty, usize_ty),
                 ast::UintTy::U8 => 8,
                 ast::UintTy::U16 => 16,
                 ast::UintTy::U32 => 32,
@@ -387,7 +387,7 @@ fn is_ffi_safe(ty: attr::IntType) -> bool {
         attr::SignedInt(ast::IntTy::I32) | attr::UnsignedInt(ast::UintTy::U32) |
         attr::SignedInt(ast::IntTy::I64) | attr::UnsignedInt(ast::UintTy::U64) |
         attr::SignedInt(ast::IntTy::I128) | attr::UnsignedInt(ast::UintTy::U128) => true,
-        attr::SignedInt(ast::IntTy::Is) | attr::UnsignedInt(ast::UintTy::Us) => false
+        attr::SignedInt(ast::IntTy::Isize) | attr::UnsignedInt(ast::UintTy::Usize) => false
     }
 }
 
diff --git a/src/librustc_mir/build/expr/as_rvalue.rs b/src/librustc_mir/build/expr/as_rvalue.rs
index ee0b7bb7a8bc4..d3cc952759058 100644
--- a/src/librustc_mir/build/expr/as_rvalue.rs
+++ b/src/librustc_mir/build/expr/as_rvalue.rs
@@ -392,7 +392,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     ast::IntTy::I32 => ConstInt::I32(-1),
                     ast::IntTy::I64 => ConstInt::I64(-1),
                     ast::IntTy::I128 => ConstInt::I128(-1),
-                    ast::IntTy::Is => {
+                    ast::IntTy::Isize => {
                         let int_ty = self.hir.tcx().sess.target.isize_ty;
                         let val = ConstIsize::new(-1, int_ty).unwrap();
                         ConstInt::Isize(val)
@@ -424,7 +424,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     ast::IntTy::I32 => ConstInt::I32(i32::min_value()),
                     ast::IntTy::I64 => ConstInt::I64(i64::min_value()),
                     ast::IntTy::I128 => ConstInt::I128(i128::min_value()),
-                    ast::IntTy::Is => {
+                    ast::IntTy::Isize => {
                         let int_ty = self.hir.tcx().sess.target.isize_ty;
                         let min = match int_ty {
                             ast::IntTy::I16 => std::i16::MIN as i64,
diff --git a/src/librustc_mir/build/misc.rs b/src/librustc_mir/build/misc.rs
index 8486c63baac66..a3350cb1671d2 100644
--- a/src/librustc_mir/build/misc.rs
+++ b/src/librustc_mir/build/misc.rs
@@ -74,7 +74,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     ast::UintTy::U32 => ConstInt::U32(0),
                     ast::UintTy::U64 => ConstInt::U64(0),
                     ast::UintTy::U128 => ConstInt::U128(0),
-                    ast::UintTy::Us => {
+                    ast::UintTy::Usize => {
                         let uint_ty = self.hir.tcx().sess.target.usize_ty;
                         let val = ConstUsize::new(0, uint_ty).unwrap();
                         ConstInt::Usize(val)
@@ -95,7 +95,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     ast::IntTy::I32 => ConstInt::I32(0),
                     ast::IntTy::I64 => ConstInt::I64(0),
                     ast::IntTy::I128 => ConstInt::I128(0),
-                    ast::IntTy::Is => {
+                    ast::IntTy::Isize => {
                         let int_ty = self.hir.tcx().sess.target.isize_ty;
                         let val = ConstIsize::new(0, int_ty).unwrap();
                         ConstInt::Isize(val)
diff --git a/src/librustc_mir/interpret/cast.rs b/src/librustc_mir/interpret/cast.rs
index 6f4a28fb28f01..b476ea5685229 100644
--- a/src/librustc_mir/interpret/cast.rs
+++ b/src/librustc_mir/interpret/cast.rs
@@ -49,7 +49,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
             IntTy::I32 => v as i32 as u128,
             IntTy::I64 => v as i64 as u128,
             IntTy::I128 => v as u128,
-            IntTy::Is => {
+            IntTy::Isize => {
                 let ty = self.tcx.sess.target.isize_ty;
                 self.int_to_int(v, ty)
             }
@@ -62,7 +62,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
             UintTy::U32 => v as u32 as u128,
             UintTy::U64 => v as u64 as u128,
             UintTy::U128 => v,
-            UintTy::Us => {
+            UintTy::Usize => {
                 let ty = self.tcx.sess.target.usize_ty;
                 self.int_to_uint(v, ty)
             }
@@ -124,8 +124,8 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
         match ty.sty {
             // Casting to a reference or fn pointer is not permitted by rustc, no need to support it here.
             TyRawPtr(_) |
-            TyInt(IntTy::Is) |
-            TyUint(UintTy::Us) => Ok(PrimVal::Ptr(ptr)),
+            TyInt(IntTy::Isize) |
+            TyUint(UintTy::Usize) => Ok(PrimVal::Ptr(ptr)),
             TyInt(_) | TyUint(_) => err!(ReadPointerAsBytes),
             _ => err!(Unimplemented(format!("ptr to {:?} cast", ty))),
         }
diff --git a/src/librustc_mir/interpret/const_eval.rs b/src/librustc_mir/interpret/const_eval.rs
index a37cf41baaba3..d02b18fa77bcd 100644
--- a/src/librustc_mir/interpret/const_eval.rs
+++ b/src/librustc_mir/interpret/const_eval.rs
@@ -106,7 +106,7 @@ pub fn eval_body_as_integer<'a, 'tcx>(
         TyInt(IntTy::I32) => ConstInt::I32(prim as i128 as i32),
         TyInt(IntTy::I64) => ConstInt::I64(prim as i128 as i64),
         TyInt(IntTy::I128) => ConstInt::I128(prim as i128),
-        TyInt(IntTy::Is) => ConstInt::Isize(
+        TyInt(IntTy::Isize) => ConstInt::Isize(
             ConstIsize::new(prim as i128 as i64, tcx.sess.target.isize_ty)
                 .expect("miri should already have errored"),
         ),
@@ -115,7 +115,7 @@ pub fn eval_body_as_integer<'a, 'tcx>(
         TyUint(UintTy::U32) => ConstInt::U32(prim as u32),
         TyUint(UintTy::U64) => ConstInt::U64(prim as u64),
         TyUint(UintTy::U128) => ConstInt::U128(prim),
-        TyUint(UintTy::Us) => ConstInt::Usize(
+        TyUint(UintTy::Usize) => ConstInt::Usize(
             ConstUsize::new(prim as u64, tcx.sess.target.usize_ty)
                 .expect("miri should already have errored"),
         ),
diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index 89d0e91a7ec86..913e69fa945db 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -1165,7 +1165,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                     I32 => 4,
                     I64 => 8,
                     I128 => 16,
-                    Is => self.memory.pointer_size(),
+                    Isize => self.memory.pointer_size(),
                 };
                 PrimValKind::from_int_size(size)
             }
@@ -1178,7 +1178,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                     U32 => 4,
                     U64 => 8,
                     U128 => 16,
-                    Us => self.memory.pointer_size(),
+                    Usize => self.memory.pointer_size(),
                 };
                 PrimValKind::from_uint_size(size)
             }
@@ -1292,7 +1292,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                     I32 => 4,
                     I64 => 8,
                     I128 => 16,
-                    Is => self.memory.pointer_size(),
+                    Isize => self.memory.pointer_size(),
                 };
                 self.memory.read_primval(ptr, ptr_align, size, true)?
             }
@@ -1305,7 +1305,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                     U32 => 4,
                     U64 => 8,
                     U128 => 16,
-                    Us => self.memory.pointer_size(),
+                    Usize => self.memory.pointer_size(),
                 };
                 self.memory.read_primval(ptr, ptr_align, size, false)?
             }
diff --git a/src/librustc_mir/monomorphize/item.rs b/src/librustc_mir/monomorphize/item.rs
index c3fb126ea1822..0880767bca281 100644
--- a/src/librustc_mir/monomorphize/item.rs
+++ b/src/librustc_mir/monomorphize/item.rs
@@ -292,13 +292,13 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
             ty::TyChar              => output.push_str("char"),
             ty::TyStr               => output.push_str("str"),
             ty::TyNever             => output.push_str("!"),
-            ty::TyInt(ast::IntTy::Is)    => output.push_str("isize"),
+            ty::TyInt(ast::IntTy::Isize)    => output.push_str("isize"),
             ty::TyInt(ast::IntTy::I8)    => output.push_str("i8"),
             ty::TyInt(ast::IntTy::I16)   => output.push_str("i16"),
             ty::TyInt(ast::IntTy::I32)   => output.push_str("i32"),
             ty::TyInt(ast::IntTy::I64)   => output.push_str("i64"),
             ty::TyInt(ast::IntTy::I128)   => output.push_str("i128"),
-            ty::TyUint(ast::UintTy::Us)   => output.push_str("usize"),
+            ty::TyUint(ast::UintTy::Usize)   => output.push_str("usize"),
             ty::TyUint(ast::UintTy::U8)   => output.push_str("u8"),
             ty::TyUint(ast::UintTy::U16)  => output.push_str("u16"),
             ty::TyUint(ast::UintTy::U32)  => output.push_str("u32"),
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index b49d9d2c7cf11..d94b73d7f3e89 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -1204,14 +1204,14 @@ impl PrimitiveTypeTable {
         table.intern("char", TyChar);
         table.intern("f32", TyFloat(FloatTy::F32));
         table.intern("f64", TyFloat(FloatTy::F64));
-        table.intern("isize", TyInt(IntTy::Is));
+        table.intern("isize", TyInt(IntTy::Isize));
         table.intern("i8", TyInt(IntTy::I8));
         table.intern("i16", TyInt(IntTy::I16));
         table.intern("i32", TyInt(IntTy::I32));
         table.intern("i64", TyInt(IntTy::I64));
         table.intern("i128", TyInt(IntTy::I128));
         table.intern("str", TyStr);
-        table.intern("usize", TyUint(UintTy::Us));
+        table.intern("usize", TyUint(UintTy::Usize));
         table.intern("u8", TyUint(UintTy::U8));
         table.intern("u16", TyUint(UintTy::U16));
         table.intern("u32", TyUint(UintTy::U32));
diff --git a/src/librustc_trans/intrinsic.rs b/src/librustc_trans/intrinsic.rs
index 3cd60e7f1bc7f..6b122627f0935 100644
--- a/src/librustc_trans/intrinsic.rs
+++ b/src/librustc_trans/intrinsic.rs
@@ -1246,7 +1246,7 @@ fn generic_simd_intrinsic<'a, 'tcx>(
 fn int_type_width_signed(ty: Ty, ccx: &CrateContext) -> Option<(u64, bool)> {
     match ty.sty {
         ty::TyInt(t) => Some((match t {
-            ast::IntTy::Is => {
+            ast::IntTy::Isize => {
                 match &ccx.tcx().sess.target.target.target_pointer_width[..] {
                     "16" => 16,
                     "32" => 32,
@@ -1261,7 +1261,7 @@ fn int_type_width_signed(ty: Ty, ccx: &CrateContext) -> Option<(u64, bool)> {
             ast::IntTy::I128 => 128,
         }, true)),
         ty::TyUint(t) => Some((match t {
-            ast::UintTy::Us => {
+            ast::UintTy::Usize => {
                 match &ccx.tcx().sess.target.target.target_pointer_width[..] {
                     "16" => 16,
                     "32" => 32,
diff --git a/src/librustc_trans/mir/rvalue.rs b/src/librustc_trans/mir/rvalue.rs
index 9d705eda9fbef..8d57b59e8c7e1 100644
--- a/src/librustc_trans/mir/rvalue.rs
+++ b/src/librustc_trans/mir/rvalue.rs
@@ -718,13 +718,13 @@ fn get_overflow_intrinsic(oop: OverflowOp, bcx: &Builder, ty: Ty) -> ValueRef {
     let tcx = bcx.tcx();
 
     let new_sty = match ty.sty {
-        TyInt(Is) => match &tcx.sess.target.target.target_pointer_width[..] {
+        TyInt(Isize) => match &tcx.sess.target.target.target_pointer_width[..] {
             "16" => TyInt(I16),
             "32" => TyInt(I32),
             "64" => TyInt(I64),
             _ => panic!("unsupported target word size")
         },
-        TyUint(Us) => match &tcx.sess.target.target.target_pointer_width[..] {
+        TyUint(Usize) => match &tcx.sess.target.target.target_pointer_width[..] {
             "16" => TyUint(U16),
             "32" => TyUint(U32),
             "64" => TyUint(U64),
diff --git a/src/librustc_trans/type_.rs b/src/librustc_trans/type_.rs
index b9daaf5a44808..6cbe175d4d8d5 100644
--- a/src/librustc_trans/type_.rs
+++ b/src/librustc_trans/type_.rs
@@ -147,7 +147,7 @@ impl Type {
 
     pub fn int_from_ty(ccx: &CrateContext, t: ast::IntTy) -> Type {
         match t {
-            ast::IntTy::Is => ccx.isize_ty(),
+            ast::IntTy::Isize => ccx.isize_ty(),
             ast::IntTy::I8 => Type::i8(ccx),
             ast::IntTy::I16 => Type::i16(ccx),
             ast::IntTy::I32 => Type::i32(ccx),
@@ -158,7 +158,7 @@ impl Type {
 
     pub fn uint_from_ty(ccx: &CrateContext, t: ast::UintTy) -> Type {
         match t {
-            ast::UintTy::Us => ccx.isize_ty(),
+            ast::UintTy::Usize => ccx.isize_ty(),
             ast::UintTy::U8 => Type::i8(ccx),
             ast::UintTy::U16 => Type::i16(ccx),
             ast::UintTy::U32 => Type::i32(ccx),
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index 7c199587c9898..201997a74b73f 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -233,7 +233,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
             CastError::NeedViaPtr => {
                 let mut err = make_invalid_casting_error(fcx.tcx.sess, self.span, self.expr_ty,
                                                          self.cast_ty, fcx);
-                if self.cast_ty.is_uint() {
+                if self.cast_ty.is_integral() {
                     err.help(&format!("cast through {} first",
                                       match e {
                                           CastError::NeedViaPtr => "a raw pointer",
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 53bb0e577a4b6..6f83ecab01a1c 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -494,7 +494,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
                 let lang_def_id = lang_items.i128_impl();
                 self.assemble_inherent_impl_for_primitive(lang_def_id);
             }
-            ty::TyInt(ast::IntTy::Is) => {
+            ty::TyInt(ast::IntTy::Isize) => {
                 let lang_def_id = lang_items.isize_impl();
                 self.assemble_inherent_impl_for_primitive(lang_def_id);
             }
@@ -518,7 +518,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
                 let lang_def_id = lang_items.u128_impl();
                 self.assemble_inherent_impl_for_primitive(lang_def_id);
             }
-            ty::TyUint(ast::UintTy::Us) => {
+            ty::TyUint(ast::UintTy::Usize) => {
                 let lang_def_id = lang_items.usize_impl();
                 self.assemble_inherent_impl_for_primitive(lang_def_id);
             }
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 7a49c3549abdf..6d68824980b6a 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -2219,7 +2219,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         // First, try built-in indexing.
         match (adjusted_ty.builtin_index(), &index_ty.sty) {
-            (Some(ty), &ty::TyUint(ast::UintTy::Us)) | (Some(ty), &ty::TyInfer(ty::IntVar(_))) => {
+            (Some(ty), &ty::TyUint(ast::UintTy::Usize)) |
+            (Some(ty), &ty::TyInfer(ty::IntVar(_))) => {
                 debug!("try_index_step: success, using built-in indexing");
                 let adjustments = autoderef.adjust_steps(lvalue_pref);
                 self.apply_adjustments(base_expr, adjustments);
diff --git a/src/librustc_typeck/coherence/inherent_impls.rs b/src/librustc_typeck/coherence/inherent_impls.rs
index 569b6a2febb45..4256a1fe12b60 100644
--- a/src/librustc_typeck/coherence/inherent_impls.rs
+++ b/src/librustc_typeck/coherence/inherent_impls.rs
@@ -200,7 +200,7 @@ impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for InherentCollect<'a, 'tcx> {
                                           "i128",
                                           item.span);
             }
-            ty::TyInt(ast::IntTy::Is) => {
+            ty::TyInt(ast::IntTy::Isize) => {
                 self.check_primitive_impl(def_id,
                                           lang_items.isize_impl(),
                                           "isize",
@@ -242,7 +242,7 @@ impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for InherentCollect<'a, 'tcx> {
                                           "u128",
                                           item.span);
             }
-            ty::TyUint(ast::UintTy::Us) => {
+            ty::TyUint(ast::UintTy::Usize) => {
                 self.check_primitive_impl(def_id,
                                           lang_items.usize_impl(),
                                           "usize",
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 10cb2e5f3fdaf..265114ae826f4 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -2011,7 +2011,7 @@ impl PrimitiveType {
 impl From<ast::IntTy> for PrimitiveType {
     fn from(int_ty: ast::IntTy) -> PrimitiveType {
         match int_ty {
-            ast::IntTy::Is => PrimitiveType::Isize,
+            ast::IntTy::Isize => PrimitiveType::Isize,
             ast::IntTy::I8 => PrimitiveType::I8,
             ast::IntTy::I16 => PrimitiveType::I16,
             ast::IntTy::I32 => PrimitiveType::I32,
@@ -2024,7 +2024,7 @@ impl From<ast::IntTy> for PrimitiveType {
 impl From<ast::UintTy> for PrimitiveType {
     fn from(uint_ty: ast::UintTy) -> PrimitiveType {
         match uint_ty {
-            ast::UintTy::Us => PrimitiveType::Usize,
+            ast::UintTy::Usize => PrimitiveType::Usize,
             ast::UintTy::U8 => PrimitiveType::U8,
             ast::UintTy::U16 => PrimitiveType::U16,
             ast::UintTy::U32 => PrimitiveType::U32,
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 15682b2d459fa..e08a2cbfd0846 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1324,7 +1324,7 @@ pub enum ImplItemKind {
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy,
          PartialOrd, Ord)]
 pub enum IntTy {
-    Is,
+    Isize,
     I8,
     I16,
     I32,
@@ -1347,7 +1347,7 @@ impl fmt::Display for IntTy {
 impl IntTy {
     pub fn ty_to_string(&self) -> &'static str {
         match *self {
-            IntTy::Is => "isize",
+            IntTy::Isize => "isize",
             IntTy::I8 => "i8",
             IntTy::I16 => "i16",
             IntTy::I32 => "i32",
@@ -1365,7 +1365,7 @@ impl IntTy {
 
     pub fn bit_width(&self) -> Option<usize> {
         Some(match *self {
-            IntTy::Is => return None,
+            IntTy::Isize => return None,
             IntTy::I8 => 8,
             IntTy::I16 => 16,
             IntTy::I32 => 32,
@@ -1378,7 +1378,7 @@ impl IntTy {
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy,
          PartialOrd, Ord)]
 pub enum UintTy {
-    Us,
+    Usize,
     U8,
     U16,
     U32,
@@ -1389,7 +1389,7 @@ pub enum UintTy {
 impl UintTy {
     pub fn ty_to_string(&self) -> &'static str {
         match *self {
-            UintTy::Us => "usize",
+            UintTy::Usize => "usize",
             UintTy::U8 => "u8",
             UintTy::U16 => "u16",
             UintTy::U32 => "u32",
@@ -1404,7 +1404,7 @@ impl UintTy {
 
     pub fn bit_width(&self) -> Option<usize> {
         Some(match *self {
-            UintTy::Us => return None,
+            UintTy::Usize => return None,
             UintTy::U8 => 8,
             UintTy::U16 => 16,
             UintTy::U32 => 32,
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index cc72ff7d15d2b..0b868b514fe96 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -1071,8 +1071,8 @@ fn int_type_of_word(s: &str) -> Option<IntType> {
         "u64" => Some(UnsignedInt(ast::UintTy::U64)),
         "i128" => Some(SignedInt(ast::IntTy::I128)),
         "u128" => Some(UnsignedInt(ast::UintTy::U128)),
-        "isize" => Some(SignedInt(ast::IntTy::Is)),
-        "usize" => Some(UnsignedInt(ast::UintTy::Us)),
+        "isize" => Some(SignedInt(ast::IntTy::Isize)),
+        "usize" => Some(UnsignedInt(ast::UintTy::Usize)),
         _ => None
     }
 }
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 34e5610901ed8..be0bfd6677bd8 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -694,17 +694,17 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     }
     fn expr_usize(&self, span: Span, i: usize) -> P<ast::Expr> {
         self.expr_lit(span, ast::LitKind::Int(i as u128,
-                                              ast::LitIntType::Unsigned(ast::UintTy::Us)))
+                                              ast::LitIntType::Unsigned(ast::UintTy::Usize)))
     }
     fn expr_isize(&self, sp: Span, i: isize) -> P<ast::Expr> {
         if i < 0 {
             let i = (-i) as u128;
-            let lit_ty = ast::LitIntType::Signed(ast::IntTy::Is);
+            let lit_ty = ast::LitIntType::Signed(ast::IntTy::Isize);
             let lit = self.expr_lit(sp, ast::LitKind::Int(i, lit_ty));
             self.expr_unary(sp, ast::UnOp::Neg, lit)
         } else {
             self.expr_lit(sp, ast::LitKind::Int(i as u128,
-                                                ast::LitIntType::Signed(ast::IntTy::Is)))
+                                                ast::LitIntType::Signed(ast::IntTy::Isize)))
         }
     }
     fn expr_u32(&self, sp: Span, u: u32) -> P<ast::Expr> {
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index 59996d1e4a7b1..7fcd88c94ca6f 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -326,13 +326,13 @@ pub mod rt {
         );
     }
 
-    impl_to_tokens_int! { signed, isize, ast::IntTy::Is }
+    impl_to_tokens_int! { signed, isize, ast::IntTy::Isize }
     impl_to_tokens_int! { signed, i8,  ast::IntTy::I8 }
     impl_to_tokens_int! { signed, i16, ast::IntTy::I16 }
     impl_to_tokens_int! { signed, i32, ast::IntTy::I32 }
     impl_to_tokens_int! { signed, i64, ast::IntTy::I64 }
 
-    impl_to_tokens_int! { unsigned, usize, ast::UintTy::Us }
+    impl_to_tokens_int! { unsigned, usize, ast::UintTy::Usize }
     impl_to_tokens_int! { unsigned, u8,   ast::UintTy::U8 }
     impl_to_tokens_int! { unsigned, u16,  ast::UintTy::U16 }
     impl_to_tokens_int! { unsigned, u32,  ast::UintTy::U32 }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index a38ceba2f45a9..a9b1e4aaa6006 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -603,13 +603,13 @@ pub fn integer_lit(s: &str, suffix: Option<Symbol>, diag: Option<(Span, &Handler
             err!(diag, |span, diag| diag.span_bug(span, "found empty literal suffix in Some"));
         }
         ty = match &*suf.as_str() {
-            "isize" => ast::LitIntType::Signed(ast::IntTy::Is),
+            "isize" => ast::LitIntType::Signed(ast::IntTy::Isize),
             "i8"  => ast::LitIntType::Signed(ast::IntTy::I8),
             "i16" => ast::LitIntType::Signed(ast::IntTy::I16),
             "i32" => ast::LitIntType::Signed(ast::IntTy::I32),
             "i64" => ast::LitIntType::Signed(ast::IntTy::I64),
             "i128" => ast::LitIntType::Signed(ast::IntTy::I128),
-            "usize" => ast::LitIntType::Unsigned(ast::UintTy::Us),
+            "usize" => ast::LitIntType::Unsigned(ast::UintTy::Usize),
             "u8"  => ast::LitIntType::Unsigned(ast::UintTy::U8),
             "u16" => ast::LitIntType::Unsigned(ast::UintTy::U16),
             "u32" => ast::LitIntType::Unsigned(ast::UintTy::U32),
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index 29f5196c9bd6f..48872cb1313d7 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -833,14 +833,14 @@ fn find_repr_type_name(diagnostic: &Handler, type_attrs: &[ast::Attribute]) -> &
                 attr::ReprPacked | attr::ReprSimd | attr::ReprAlign(_) => continue,
                 attr::ReprExtern => "i32",
 
-                attr::ReprInt(attr::SignedInt(ast::IntTy::Is)) => "isize",
+                attr::ReprInt(attr::SignedInt(ast::IntTy::Isize)) => "isize",
                 attr::ReprInt(attr::SignedInt(ast::IntTy::I8)) => "i8",
                 attr::ReprInt(attr::SignedInt(ast::IntTy::I16)) => "i16",
                 attr::ReprInt(attr::SignedInt(ast::IntTy::I32)) => "i32",
                 attr::ReprInt(attr::SignedInt(ast::IntTy::I64)) => "i64",
                 attr::ReprInt(attr::SignedInt(ast::IntTy::I128)) => "i128",
 
-                attr::ReprInt(attr::UnsignedInt(ast::UintTy::Us)) => "usize",
+                attr::ReprInt(attr::UnsignedInt(ast::UintTy::Usize)) => "usize",
                 attr::ReprInt(attr::UnsignedInt(ast::UintTy::U8)) => "u8",
                 attr::ReprInt(attr::UnsignedInt(ast::UintTy::U16)) => "u16",
                 attr::ReprInt(attr::UnsignedInt(ast::UintTy::U32)) => "u32",
diff --git a/src/test/ui/fat-ptr-cast.stderr b/src/test/ui/fat-ptr-cast.stderr
index 35a97749e0024..b3c2b23cd3272 100644
--- a/src/test/ui/fat-ptr-cast.stderr
+++ b/src/test/ui/fat-ptr-cast.stderr
@@ -11,18 +11,24 @@ error[E0606]: casting `&[i32]` as `isize` is invalid
    |
 21 |     a as isize; //~ ERROR casting
    |     ^^^^^^^^^^
+   |
+   = help: cast through a raw pointer first
 
 error[E0606]: casting `&[i32]` as `i16` is invalid
   --> $DIR/fat-ptr-cast.rs:22:5
    |
 22 |     a as i16; //~ ERROR casting `&[i32]` as `i16` is invalid
    |     ^^^^^^^^
+   |
+   = help: cast through a raw pointer first
 
 error[E0606]: casting `&[i32]` as `u32` is invalid
   --> $DIR/fat-ptr-cast.rs:23:5
    |
 23 |     a as u32; //~ ERROR casting `&[i32]` as `u32` is invalid
    |     ^^^^^^^^
+   |
+   = help: cast through a raw pointer first
 
 error[E0605]: non-primitive cast: `std::boxed::Box<[i32]>` as `usize`
   --> $DIR/fat-ptr-cast.rs:24:5