Implement RFC 2585: unsafe blocks in unsafe fn

src/librustdoc/core.rs

@@ -226,6 +226,11 @@ where
 {
     let warnings_lint_name = lint::builtin::WARNINGS.name;
 
+    // Whitelist feature-gated lints to avoid feature errors when trying to
+    // allow all lints.
+    // FIXME(LeSeulArtichaut): handle feature-gated lints properly.
+    let unsafe_op_in_unsafe_fn_name = rustc_lint::builtin::UNSAFE_OP_IN_UNSAFE_FN.name;
+
     whitelisted_lints.push(warnings_lint_name.to_owned());
     whitelisted_lints.extend(lint_opts.iter().map(|(lint, _)| lint).cloned());
 
@@ -236,7 +241,13 @@ where
     };
 
     let lint_opts = lints()
-        .filter_map(|lint| if lint.name == warnings_lint_name { None } else { filter_call(lint) })
+        .filter_map(|lint| {
+            if lint.name == warnings_lint_name || lint.name == unsafe_op_in_unsafe_fn_name {
+                None
+            } else {
+                filter_call(lint)
+            }
+        })
         .chain(lint_opts.into_iter())
         .collect::<Vec<_>>();