[WIP] Add lint for int to ptr cast

src/librustc_lint/builtin.rs

@@ -31,6 +31,7 @@
 use rustc::hir::def::Def;
 use rustc::hir::def_id::DefId;
 use rustc::cfg;
+use rustc::ty::cast::CastKind;
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, Ty};
 use rustc::traits::{self, Reveal};
@@ -1225,3 +1226,40 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnionsWithDropFields {
         }
     }
 }
+
+/// Lint for casting from non-{i,u}size integers to pointers.
+pub struct IntToPtrCast;
+
+declare_lint! {
+    INT_TO_PTR_CAST,
+    Warn,
+    "casting from non-{i,u}size integers to pointers"
+}
+
+impl LintPass for IntToPtrCast {
+    fn get_lints(&self) -> LintArray {
+        lint_array!(INT_TO_PTR_CAST)
+    }
+}
+
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for IntToPtrCast {
+    fn check_expr(&mut self, ctx: &LateContext, expr: &hir::Expr) {
+        if let hir::ExprCast(ref source, _) = expr.node {
+            if let Some(&CastKind::AddrPtrCast) = ctx.tables.cast_kinds.get(&source.id) {
+                let source_ty = &ctx.tables.expr_ty(&source).sty;
+                match source_ty {
+                    &ty::TyInt(ast::IntTy::Is) |
+                    &ty::TyUint(ast::UintTy::Us) => {},
+                    &ty::TyInt(_) |
+                    &ty::TyUint(_) => {
+                        ctx.span_lint(
+                            INT_TO_PTR_CAST,
+                            expr.span,
+                            "casting from a different-size integer to a pointer");
+                    },
+                    _ => {},
+                };
+            }
+        }
+    }
+}

src/librustc_lint/lib.rs

@@ -141,6 +141,7 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
                  PluginAsLibrary,
                  MutableTransmutes,
                  UnionsWithDropFields,
+                 IntToPtrCast,
                  );
 
     add_builtin_with_new!(sess,

src/libstd/sys/windows/backtrace/mod.rs

@@ -95,8 +95,8 @@ pub fn unwind_backtrace(frames: &mut [Frame])
                frame.AddrReturn.Offset == 0 { break }
 
             frames[i] = Frame {
-                symbol_addr: (addr - 1) as *const c_void,
-                exact_position: (addr - 1) as *const c_void,
+                symbol_addr: (addr - 1) as usize as *const c_void,
+                exact_position: (addr - 1) as usize as *const c_void,
             };
             i += 1;
         }

src/libstd/sys/windows/net.rs

@@ -282,7 +282,7 @@ impl Socket {
 
     fn set_no_inherit(&self) -> io::Result<()> {
         sys::cvt(unsafe {
-            c::SetHandleInformation(self.0 as c::HANDLE,
+            c::SetHandleInformation(self.0 as usize as c::HANDLE,
                                     c::HANDLE_FLAG_INHERIT, 0)
         }).map(|_| ())
     }

src/libstd/sys_common/at_exit_imp.rs

@@ -48,7 +48,7 @@ pub fn cleanup() {
         unsafe {
             LOCK.lock();
             let queue = QUEUE;
-            QUEUE = if i == ITERS - 1 {1} else {0} as *mut _;
+            QUEUE = if i == ITERS - 1 {1usize} else {0usize} as *mut _;
             LOCK.unlock();
 
             // make sure we're not recursively cleaning up