Rollup merge of rust-lang#69495 - matthiaskrgr:op_ref, r=oli-obk

don't take redundant references to operands

src/libcore/str/pattern.rs

@@ -1050,7 +1050,7 @@ impl TwoWaySearcher {
         // &v[..period]. If it is, we use "Algorithm CP1". Otherwise we use
         // "Algorithm CP2", which is optimized for when the period of the needle
         // is large.
-        if &needle[..crit_pos] == &needle[period..period + crit_pos] {
+        if needle[..crit_pos] == needle[period..period + crit_pos] {
             // short period case -- the period is exact
             // compute a separate critical factorization for the reversed needle
             // x = u' v' where |v'| < period(x).

src/librustc/ty/error.rs

@@ -341,7 +341,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     db.note("distinct uses of `impl Trait` result in different opaque types");
                     let e_str = values.expected.to_string();
                     let f_str = values.found.to_string();
-                    if &e_str == &f_str && &e_str == "impl std::future::Future" {
+                    if e_str == f_str && &e_str == "impl std::future::Future" {
                         // FIXME: use non-string based check.
                         db.help(
                             "if both `Future`s have the same `Output` type, consider \

src/librustc_infer/infer/error_reporting/mod.rs

@@ -745,7 +745,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             .join(", ");
         if !lifetimes.is_empty() {
             if sub.regions().count() < len {
-                value.push_normal(lifetimes + &", ");
+                value.push_normal(lifetimes + ", ");
             } else {
                 value.push_normal(lifetimes);
             }

src/librustdoc/core.rs

@@ -283,7 +283,7 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
         .filter_map(|lint| {
             // We don't want to whitelist *all* lints so let's
             // ignore those ones.
-            if whitelisted_lints.iter().any(|l| &lint.name == l) {
+            if whitelisted_lints.iter().any(|l| lint.name == l) {
                 None
             } else {
                 Some((lint::LintId::of(lint), lint::Allow))