Fix improper_ctypes lint for individual foreign items

src/librustc_lint/types.rs

@@ -790,21 +790,18 @@ impl LintPass for ImproperCTypes {
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImproperCTypes {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_foreign_item(&mut self, cx: &LateContext, it: &hir::ForeignItem) {
         let mut vis = ImproperCTypesVisitor { cx: cx };
-        if let hir::ItemKind::ForeignMod(ref nmod) = it.node {
-            if nmod.abi != Abi::RustIntrinsic && nmod.abi != Abi::PlatformIntrinsic {
-                for ni in &nmod.items {
-                    match ni.node {
-                        hir::ForeignItemKind::Fn(ref decl, _, _) => {
-                            vis.check_foreign_fn(ni.id, decl);
-                        }
-                        hir::ForeignItemKind::Static(ref ty, _) => {
-                            vis.check_foreign_static(ni.id, ty.span);
-                        }
-                        hir::ForeignItemKind::Type => ()
-                    }
+        let abi = cx.tcx.hir.get_foreign_abi(it.id);
+        if abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic {
+            match it.node {
+                hir::ForeignItemKind::Fn(ref decl, _, _) => {
+                    vis.check_foreign_fn(it.id, decl);
+                }
+                hir::ForeignItemKind::Static(ref ty, _) => {
+                    vis.check_foreign_static(it.id, ty.span);
                 }
+                hir::ForeignItemKind::Type => ()
             }
         }
     }

src/test/ui/lint-ctypes.rs

@@ -88,6 +88,13 @@ extern {
     pub fn good15(p: TransparentLifetime);
     pub fn good16(p: TransparentUnit<ZeroSize>);
     pub fn good17(p: TransparentCustomZst);
+    #[allow(improper_ctypes)]
+    pub fn good18(_: &String);
+}
+
+#[allow(improper_ctypes)]
+extern {
+    pub fn good19(_: &String);
 }
 
 #[cfg(not(target_arch = "wasm32"))]