1 files changed, 6 insertions, 0 deletions
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 79c8046f9b7..2d596564d52 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -326,6 +326,12 @@ impl EarlyLintPass for UnsafeCode {
                 self.report_unsafe(cx, it.span, BuiltinUnsafe::GlobalAsm);
             }
 
+            ast::ItemKind::ForeignMod(ForeignMod { safety, .. }) => {
+                if let Safety::Unsafe(_) = safety {
+                    self.report_unsafe(cx, it.span, BuiltinUnsafe::UnsafeExternBlock);
+                }
+            }
+
             _ => {}
         }
     }