rollup merge of #22502: nikomatsakis/deprecate-bracket-bracket

Conflicts:
	src/libcollections/slice.rs
	src/libcollections/str.rs
	src/librustc/middle/lang_items.rs
	src/librustc_back/rpath.rs
	src/librustc_typeck/check/regionck.rs
	src/libstd/ffi/os_str.rs
	src/libsyntax/diagnostic.rs
	src/libsyntax/parse/parser.rs
	src/libsyntax/util/interner.rs
	src/test/run-pass/regions-refcell.rs

src/libtest/lib.rs

@@ -720,7 +720,7 @@ fn should_sort_failures_before_printing_them() {
 
     st.write_failures().unwrap();
     let s = match st.out {
-        Raw(ref m) => String::from_utf8_lossy(&m[]),
+        Raw(ref m) => String::from_utf8_lossy(&m[..]),
         Pretty(_) => unreachable!()
     };
 
@@ -833,7 +833,7 @@ pub fn filter_tests(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> Vec<TestDescA
         None => filtered,
         Some(ref filter) => {
             filtered.into_iter().filter(|test| {
-                test.desc.name.as_slice().contains(&filter[])
+                test.desc.name.as_slice().contains(&filter[..])
             }).collect()
         }
     };