check extern-items for well-formedness

Fixes rust-lang#25637

this is of course a [breaking-change] to these who relied on it

Author: Ariel Ben-Yehuda

src/librustc_typeck/check/regionck.rs

@@ -121,12 +121,12 @@ pub fn regionck_expr(fcx: &FnCtxt, e: &ast::Expr) {
     rcx.resolve_regions_and_report_errors();
 }
 
-pub fn regionck_item(fcx: &FnCtxt, item: &ast::Item) {
-    let mut rcx = Rcx::new(fcx, RepeatingScope(item.id), item.id, Subject(item.id));
+pub fn regionck_item(fcx: &FnCtxt, id: ast::NodeId) {
+    let mut rcx = Rcx::new(fcx, RepeatingScope(id), id, Subject(id));
     let tcx = fcx.tcx();
     rcx.free_region_map
        .relate_free_regions_from_predicates(tcx, &fcx.infcx().parameter_environment.caller_bounds);
-    rcx.visit_region_obligations(item.id);
+    rcx.visit_region_obligations(id);
     rcx.resolve_regions_and_report_errors();
 }
 

src/librustc_typeck/check/wf.rs

@@ -94,13 +94,13 @@ impl<'ccx, 'tcx> CheckTypeWellFormedVisitor<'ccx, 'tcx> {
                 }
             }
             ast::ItemFn(..) => {
-                self.check_item_type(item);
+                self.check_item_type(item.span, item.id);
             }
             ast::ItemStatic(..) => {
-                self.check_item_type(item);
+                self.check_item_type(item.span, item.id);
             }
             ast::ItemConst(..) => {
-                self.check_item_type(item);
+                self.check_item_type(item.span, item.id);
             }
             ast::ItemStruct(ref struct_def, ref ast_generics) => {
                 self.check_type_defn(item, |fcx| {
@@ -132,31 +132,31 @@ impl<'ccx, 'tcx> CheckTypeWellFormedVisitor<'ccx, 'tcx> {
         }
     }
 
-    fn with_fcx<F>(&mut self, item: &ast::Item, mut f: F) where
+    fn with_fcx<F>(&mut self, span: Span, id: ast::NodeId, mut f: F) where
         F: for<'fcx> FnMut(&mut CheckTypeWellFormedVisitor<'ccx, 'tcx>, &FnCtxt<'fcx, 'tcx>),
     {
         let ccx = self.ccx;
-        let item_def_id = local_def(item.id);
+        let item_def_id = local_def(id);
         let type_scheme = ccx.tcx.lookup_item_type(item_def_id);
         let type_predicates = ccx.tcx.lookup_predicates(item_def_id);
-        reject_non_type_param_bounds(ccx.tcx, item.span, &type_predicates);
-        let param_env = ccx.tcx.construct_parameter_environment(item.span,
+        reject_non_type_param_bounds(ccx.tcx, span, &type_predicates);
+        let param_env = ccx.tcx.construct_parameter_environment(span,
                                                                 &type_scheme.generics,
                                                                 &type_predicates,
-                                                                item.id);
+                                                                id);
         let tables = RefCell::new(ty::Tables::empty());
         let inh = Inherited::new(ccx.tcx, &tables, param_env);
-        let fcx = blank_fn_ctxt(ccx, &inh, ty::FnConverging(type_scheme.ty), item.id);
+        let fcx = blank_fn_ctxt(ccx, &inh, ty::FnConverging(type_scheme.ty), id);
         f(self, &fcx);
         fcx.select_all_obligations_or_error();
-        regionck::regionck_item(&fcx, item);
+        regionck::regionck_item(&fcx, id);
     }
 
     /// In a type definition, we check that to ensure that the types of the fields are well-formed.
     fn check_type_defn<F>(&mut self, item: &ast::Item, mut lookup_fields: F) where
         F: for<'fcx> FnMut(&FnCtxt<'fcx, 'tcx>) -> Vec<AdtVariant<'tcx>>,
     {
-        self.with_fcx(item, |this, fcx| {
+        self.with_fcx(item.span, item.id, |this, fcx| {
             let variants = lookup_fields(fcx);
             let mut bounds_checker = BoundsChecker::new(fcx,
                                                         item.id,
@@ -190,31 +190,30 @@ impl<'ccx, 'tcx> CheckTypeWellFormedVisitor<'ccx, 'tcx> {
         });
     }
 
-    fn check_item_type(&mut self,
-                       item: &ast::Item)
+    fn check_item_type(&mut self, span: Span, id: ast::NodeId)
     {
-        self.with_fcx(item, |this, fcx| {
+        self.with_fcx(span, id, |this, fcx| {
             let mut bounds_checker = BoundsChecker::new(fcx,
-                                                        item.id,
+                                                        id,
                                                         Some(&mut this.cache));
             debug!("check_item_type at bounds_checker.scope: {:?}", bounds_checker.scope);
 
-            let type_scheme = fcx.tcx().lookup_item_type(local_def(item.id));
-            let item_ty = fcx.instantiate_type_scheme(item.span,
+            let type_scheme = fcx.tcx().lookup_item_type(local_def(id));
+            let item_ty = fcx.instantiate_type_scheme(span,
                                                       &fcx.inh
                                                           .infcx
                                                           .parameter_environment
                                                           .free_substs,
                                                       &type_scheme.ty);
 
-            bounds_checker.check_traits_in_ty(item_ty, item.span);
+            bounds_checker.check_traits_in_ty(item_ty, span);
         });
     }
 
     fn check_impl(&mut self,
                   item: &ast::Item)
     {
-        self.with_fcx(item, |this, fcx| {
+        self.with_fcx(item.span, item.id, |this, fcx| {
             let mut bounds_checker = BoundsChecker::new(fcx,
                                                         item.id,
                                                         Some(&mut this.cache));
@@ -428,11 +427,16 @@ fn reject_shadowing_type_parameters<'tcx>(tcx: &ty::ctxt<'tcx>,
 }
 
 impl<'ccx, 'tcx, 'v> Visitor<'v> for CheckTypeWellFormedVisitor<'ccx, 'tcx> {
-    fn visit_item(&mut self, i: &ast::Item) {
+    fn visit_item(&mut self, i: &'v ast::Item) {
         self.check_item_well_formed(i);
         visit::walk_item(self, i);
     }
 
+    fn visit_foreign_item(&mut self, i: &'v ast::ForeignItem) {
+        self.check_item_type(i.span, i.id);
+        visit::walk_foreign_item(self, i);
+    }
+
     fn visit_fn(&mut self,
                 fk: visit::FnKind<'v>, fd: &'v ast::FnDecl,
                 b: &'v ast::Block, span: Span, id: ast::NodeId) {

src/test/compile-fail/issue-25637.rs

@@ -0,0 +1,22 @@
+//// Copyright 2015 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.
+
+extern {
+    fn foo(x: Option<str>);
+    //~^ ERROR the trait `core::marker::Sized` is not implemented
+
+    fn foo1(x: &'static Option<[u8]>);
+    //~^ ERROR the trait `core::marker::Sized` is not implemented
+
+    static FOO: &'static Option<[u16]>;
+    //~^ ERROR the trait `core::marker::Sized` is not implemented
+}
+
+fn main() {}