From 038f528f452e35a5d586898c878b3b69fd8ff539 Mon Sep 17 00:00:00 2001
From: Taylor Cramer <cramertj@cs.washington.edu>
Date: Tue, 19 Apr 2016 16:27:01 -0700
Subject: [PATCH] Added lint for use imports which remove unsafe from name

---
 src/lib.rs                                    |  3 +
 src/unsafe_removed_from_name.rs               | 90 +++++++++++++++++++
 .../compile-fail/unsafe_removed_from_name.rs  | 12 +++
 3 files changed, 105 insertions(+)
 create mode 100644 src/unsafe_removed_from_name.rs
 create mode 100644 tests/compile-fail/unsafe_removed_from_name.rs

diff --git a/src/lib.rs b/src/lib.rs
index 6d98cf55f091..eee091e6195f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -109,6 +109,7 @@ pub mod transmute;
 pub mod types;
 pub mod unicode;
 pub mod unused_label;
+pub mod unsafe_removed_from_name;
 pub mod vec;
 pub mod zero_div_zero;
 // end lints modules, do not remove this comment, it’s used in `update_lints`
@@ -234,6 +235,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
     reg.register_late_lint_pass(box functions::Functions::new(conf.too_many_arguments_threshold));
     reg.register_early_lint_pass(box doc::Doc::new(conf.doc_valid_idents));
     reg.register_late_lint_pass(box neg_multiply::NegMultiply);
+    reg.register_late_lint_pass(box unsafe_removed_from_name::UnsafeNameRemoval);
 
     reg.register_lint_group("clippy_pedantic", vec![
         array_indexing::INDEXING_SLICING,
@@ -379,6 +381,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
         types::UNIT_CMP,
         unicode::ZERO_WIDTH_SPACE,
         unused_label::UNUSED_LABEL,
+        unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME,
         vec::USELESS_VEC,
         zero_div_zero::ZERO_DIVIDED_BY_ZERO,
     ]);
diff --git a/src/unsafe_removed_from_name.rs b/src/unsafe_removed_from_name.rs
new file mode 100644
index 000000000000..86860c67cfee
--- /dev/null
+++ b/src/unsafe_removed_from_name.rs
@@ -0,0 +1,90 @@
+use rustc::hir::*;
+use rustc::lint::*;
+use syntax::ast::{Name, NodeId};
+use syntax::codemap::Span;
+use syntax::parse::token::InternedString;
+use utils::span_lint;
+
+/// **What it does:** This lint checks for imports that remove "unsafe" from an item's name
+///
+/// **Why is this bad?** Renaming makes it less clear which traits and structures are unsafe.
+///
+/// **Known problems:** None.
+///
+/// **Example:**
+/// ```rust,ignore
+/// use std::cell::{UnsafeCell as TotallySafeCell};
+///
+/// extern crate crossbeam;
+/// use crossbeam::{spawn_unsafe as spawn};
+/// ```
+declare_lint! {
+    pub UNSAFE_REMOVED_FROM_NAME,
+    Warn,
+    "unsafe removed from name"
+}
+
+pub struct UnsafeNameRemoval;
+
+impl LintPass for UnsafeNameRemoval {
+    fn get_lints(&self) -> LintArray {
+        lint_array!(UNSAFE_REMOVED_FROM_NAME)
+    }
+}
+
+impl LateLintPass for UnsafeNameRemoval {
+    fn check_mod(&mut self, cx: &LateContext, m: &Mod, _: Span, _: NodeId) {
+        // only check top level `use` statements
+        for item in &m.item_ids {
+            self.lint_item(cx, cx.krate.item(item.id));
+        }
+    }
+}
+
+impl UnsafeNameRemoval {
+    fn lint_item(&self, cx: &LateContext, item: &Item) {
+        if let ItemUse(ref item_use) = item.node {
+            match item_use.node {
+                ViewPath_::ViewPathSimple(ref name, ref path) => {
+                    unsafe_to_safe_check(
+                        path.segments
+                            .last()
+                            .expect("use paths cannot be empty")
+                            .identifier.name,
+                        *name,
+                        cx, &item.span
+                        );
+                },
+                ViewPath_::ViewPathList(_, ref path_list_items) => {
+                    for path_list_item in path_list_items.iter() {
+                        let plid = path_list_item.node;
+                        if let (Some(name), Some(rename)) = (plid.name(), plid.rename()) {
+                            unsafe_to_safe_check(name, rename, cx, &item.span);
+                        };
+                    }
+                },
+                ViewPath_::ViewPathGlob(_) => {}
+            }
+        }
+    }
+}
+
+fn unsafe_to_safe_check(old_name: Name, new_name: Name, cx: &LateContext, span: &Span) {
+    let old_str = old_name.as_str();
+    let new_str = new_name.as_str();
+    if contains_unsafe(&old_str) && !contains_unsafe(&new_str) {
+        span_lint(
+            cx,
+            UNSAFE_REMOVED_FROM_NAME,
+            *span,
+            &format!(
+                "removed \"unsafe\" from the name of `{}` in use as `{}`",
+                old_str,
+                new_str
+            ));
+    }
+}
+
+fn contains_unsafe(name: &InternedString) -> bool {
+    name.contains("Unsafe") || name.contains("unsafe")
+}
diff --git a/tests/compile-fail/unsafe_removed_from_name.rs b/tests/compile-fail/unsafe_removed_from_name.rs
new file mode 100644
index 000000000000..facdb2c64edb
--- /dev/null
+++ b/tests/compile-fail/unsafe_removed_from_name.rs
@@ -0,0 +1,12 @@
+#![feature(plugin)]
+#![plugin(clippy)]
+#![allow(unused_imports)]
+#![deny(unsafe_removed_from_name)]
+
+use std::cell::{UnsafeCell as TotallySafeCell};
+//~^ ERROR removed "unsafe" from the name of `UnsafeCell` in use as `TotallySafeCell`
+
+use std::cell::UnsafeCell as TotallySafeCellAgain;
+//~^ ERROR removed "unsafe" from the name of `UnsafeCell` in use as `TotallySafeCellAgain`
+
+fn main() {}