Merge pull request #1959 from DarkEld3r/1884-borrowed-box-any

Fix borrowed_box lint for Box<Any>

clippy_lints/src/types.rs

@@ -10,7 +10,7 @@ use syntax::ast::{IntTy, UintTy, FloatTy};
 use syntax::attr::IntType;
 use syntax::codemap::Span;
 use utils::{comparisons, higher, in_external_macro, in_macro, match_def_path, snippet, span_help_and_lint, span_lint,
-            span_lint_and_sugg, opt_def_id, last_path_segment, type_size};
+            span_lint_and_sugg, opt_def_id, last_path_segment, type_size, match_path_old};
 use utils::paths;
 
 /// Handles all the linting of funky types
@@ -212,6 +212,11 @@ fn check_ty(cx: &LateContext, ast_ty: &hir::Ty, is_local: bool) {
                         let PathParameters::AngleBracketedParameters(ref ab_data) = bx.parameters,
                         let [ref inner] = *ab_data.types
                     ], {
+                        if is_any_trait(inner) {
+                            // Ignore `Box<Any>` types, see #1884 for details.
+                            return;
+                        }
+
                         let ltopt = if lt.is_elided() {
                             "".to_owned()
                         } else {
@@ -249,6 +254,21 @@ fn check_ty(cx: &LateContext, ast_ty: &hir::Ty, is_local: bool) {
     }
 }
 
+// Returns true if given type is `Any` trait.
+fn is_any_trait(t: &hir::Ty) -> bool {
+    if_let_chain! {[
+        let TyTraitObject(ref traits, _) = t.node,
+        traits.len() >= 1,
+        // Only Send/Sync can be used as additional traits, so it is enough to
+        // check only the first trait.
+        match_path_old(&traits[0].trait_ref.path, &paths::ANY_TRAIT)
+    ], {
+        return true;
+    }}
+
+    false
+}
+
 #[allow(missing_copy_implementations)]
 pub struct LetPass;
 

clippy_lints/src/utils/paths.rs

@@ -1,6 +1,7 @@
 //! This module contains paths to types and functions Clippy needs to know
 //! about.
 
+pub const ANY_TRAIT: [&'static str; 3] = ["std", "any", "Any"];
 pub const ASMUT_TRAIT: [&'static str; 3] = ["core", "convert", "AsMut"];
 pub const ASREF_TRAIT: [&'static str; 3] = ["core", "convert", "AsRef"];
 pub const BEGIN_PANIC: [&'static str; 3] = ["std", "panicking", "begin_panic"];

tests/ui/borrow_box.rs

@@ -28,7 +28,57 @@ impl<'a> Test4 for Test3<'a> {
     }
 }
 
+use std::any::Any;
+
+pub fn test5(foo: &mut Box<Any>) {
+    println!("{:?}", foo)
+}
+
+pub fn test6() {
+    let foo: &Box<Any>;
+}
+
+struct Test7<'a> {
+    foo: &'a Box<Any>
+}
+
+trait Test8 {
+    fn test8(a: &Box<Any>);
+}
+
+impl<'a> Test8 for Test7<'a> {
+    fn test8(a: &Box<Any>) {
+        unimplemented!();
+    }
+}
+
+pub fn test9(foo: &mut Box<Any + Send + Sync>) {
+    let _ = foo;
+}
+
+pub fn test10() {
+    let foo: &Box<Any + Send + 'static>;
+}
+
+struct Test11<'a> {
+    foo: &'a Box<Any + Send>
+}
+
+trait Test12 {
+    fn test4(a: &Box<Any + 'static>);
+}
+
+impl<'a> Test12 for Test11<'a> {
+    fn test4(a: &Box<Any + 'static>) {
+        unimplemented!();
+    }
+}
+
 fn main(){
     test1(&mut Box::new(false));
     test2();
+    test5(&mut (Box::new(false) as Box<Any>));
+    test6();
+    test9(&mut (Box::new(false) as Box<Any + Send + Sync>));
+    test10();
 }