rustc: remove misleading Ty::is_uint method.

Author: eddyb

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,

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",

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