Fix `clippy::needless_borrow` in the compiler

`x clippy compiler -Aclippy::all -Wclippy::needless_borrow --fix`.

Then I had to remove a few unnecessary parens and muts that were exposed
now.

7 files changed, 20 insertions, 20 deletions

diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index f2eed5c9be5..6e0765f74fe 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -75,7 +75,7 @@ pub(crate) fn parse_token_trees<'a>(
 
             let mut buffer = Vec::with_capacity(1);
             for unmatched in unmatched_delims {
-                if let Some(err) = make_unclosed_delims_error(unmatched, &sess) {
+                if let Some(err) = make_unclosed_delims_error(unmatched, sess) {
                     err.buffer(&mut buffer);
                 }
             }
@@ -362,7 +362,7 @@ impl<'a> StringReader<'a> {
         if contains_text_flow_control_chars(content) {
             let span = self.mk_sp(start, self.pos);
             self.sess.buffer_lint_with_diagnostic(
-                &TEXT_DIRECTION_CODEPOINT_IN_COMMENT,
+                TEXT_DIRECTION_CODEPOINT_IN_COMMENT,
                 span,
                 ast::CRATE_NODE_ID,
                 "unicode codepoint changing visible direction of text present in comment",
@@ -683,7 +683,7 @@ impl<'a> StringReader<'a> {
         } else {
             // Before Rust 2021, only emit a lint for migration.
             self.sess.buffer_lint_with_diagnostic(
-                &RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX,
+                RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX,
                 prefix_span,
                 ast::CRATE_NODE_ID,
                 format!("prefix `{prefix}` is unknown"),
diff --git a/compiler/rustc_parse/src/lexer/tokentrees.rs b/compiler/rustc_parse/src/lexer/tokentrees.rs
index db795ce9f72..e646f5dfd85 100644
--- a/compiler/rustc_parse/src/lexer/tokentrees.rs
+++ b/compiler/rustc_parse/src/lexer/tokentrees.rs
@@ -97,7 +97,7 @@ impl<'a> TokenTreesReader<'a> {
             report_suspicious_mismatch_block(
                 &mut err,
                 &self.diag_info,
-                &self.string_reader.sess.source_map(),
+                self.string_reader.sess.source_map(),
                 *delim,
             )
         }
@@ -164,7 +164,7 @@ impl<'a> TokenTreesReader<'a> {
                         unclosed_delimiter = Some(sp);
                     };
                     for (brace, brace_span) in &self.diag_info.open_braces {
-                        if same_indentation_level(&sm, self.token.span, *brace_span)
+                        if same_indentation_level(sm, self.token.span, *brace_span)
                             && brace == &close_delim
                         {
                             // high likelihood of these two corresponding
@@ -271,7 +271,7 @@ impl<'a> TokenTreesReader<'a> {
         report_suspicious_mismatch_block(
             &mut err,
             &self.diag_info,
-            &self.string_reader.sess.source_map(),
+            self.string_reader.sess.source_map(),
             delim,
         );
         err.span_label(self.token.span, "unexpected closing delimiter");
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 57bc865a0ee..ecb840f067e 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1281,11 +1281,11 @@ impl<'a> Parser<'a> {
                 (BinOpKind::Ge, AssocOp::GreaterEqual | AssocOp::Greater) => {
                     let expr_to_str = |e: &Expr| {
                         self.span_to_snippet(e.span)
-                            .unwrap_or_else(|_| pprust::expr_to_string(&e))
+                            .unwrap_or_else(|_| pprust::expr_to_string(e))
                     };
                     err.chaining_sugg = Some(ComparisonOperatorsCannotBeChainedSugg::SplitComparison {
                         span: inner_op.span.shrink_to_hi(),
-                        middle_term: expr_to_str(&r1),
+                        middle_term: expr_to_str(r1),
                     });
                     false // Keep the current parse behavior, where the AST is `(x < y) < z`.
                 }
@@ -1506,7 +1506,7 @@ impl<'a> Parser<'a> {
 
     pub(super) fn maybe_report_ambiguous_plus(&mut self, impl_dyn_multi: bool, ty: &Ty) {
         if impl_dyn_multi {
-            self.sess.emit_err(AmbiguousPlus { sum_ty: pprust::ty_to_string(&ty), span: ty.span });
+            self.sess.emit_err(AmbiguousPlus { sum_ty: pprust::ty_to_string(ty), span: ty.span });
         }
     }
 
@@ -1939,7 +1939,7 @@ impl<'a> Parser<'a> {
         self.sess.emit_err(IncorrectAwait {
             span,
             sugg_span: (span, applicability),
-            expr: self.span_to_snippet(expr.span).unwrap_or_else(|_| pprust::expr_to_string(&expr)),
+            expr: self.span_to_snippet(expr.span).unwrap_or_else(|_| pprust::expr_to_string(expr)),
             question_mark: if is_question { "?" } else { "" },
         });
 
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index d8e99d34016..79567eb3898 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1060,7 +1060,7 @@ impl<'a> Parser<'a> {
         match &*components {
             // 1e2
             [IdentLike(i)] => {
-                DestructuredFloat::Single(Symbol::intern(&i), span)
+                DestructuredFloat::Single(Symbol::intern(i), span)
             }
             // 1.
             [IdentLike(i), Punct('.')] => {
@@ -1072,7 +1072,7 @@ impl<'a> Parser<'a> {
                 } else {
                     (span, span)
                 };
-                let symbol = Symbol::intern(&i);
+                let symbol = Symbol::intern(i);
                 DestructuredFloat::TrailingDot(symbol, ident_span, dot_span)
             }
             // 1.2 | 1.2e3
@@ -1088,8 +1088,8 @@ impl<'a> Parser<'a> {
                 } else {
                     (span, span, span)
                 };
-                let symbol1 = Symbol::intern(&i1);
-                let symbol2 = Symbol::intern(&i2);
+                let symbol1 = Symbol::intern(i1);
+                let symbol2 = Symbol::intern(i2);
                 DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span)
             }
             // 1e+ | 1e- (recovered)
@@ -2052,7 +2052,7 @@ impl<'a> Parser<'a> {
                     Err(err) => {
                         let span = token.uninterpolated_span();
                         self.bump();
-                        report_lit_error(&self.sess, err, lit, span);
+                        report_lit_error(self.sess, err, lit, span);
                         // Pack possible quotes and prefixes from the original literal into
                         // the error literal's symbol so they can be pretty-printed faithfully.
                         let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None);
@@ -3207,7 +3207,7 @@ impl<'a> Parser<'a> {
                     if let Some((ident, _)) = self.token.ident()
                         && !self.token.is_reserved_ident()
                         && self.look_ahead(1, |t| {
-                            AssocOp::from_token(&t).is_some()
+                            AssocOp::from_token(t).is_some()
                                 || matches!(t.kind, token::OpenDelim(_))
                                 || t.kind == token::Dot
                         })
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index d124ea571ab..23886b1208b 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -2271,7 +2271,7 @@ impl<'a> Parser<'a> {
             } else {
                 &[token::Semi, token::OpenDelim(Delimiter::Brace)]
             };
-            if let Err(mut err) = self.expected_one_of_not_found(&[], &expected) {
+            if let Err(mut err) = self.expected_one_of_not_found(&[], expected) {
                 if self.token.kind == token::CloseDelim(Delimiter::Brace) {
                     // The enclosing `mod`, `trait` or `impl` is being closed, so keep the `fn` in
                     // the AST for typechecking.
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 5cec3f5762d..15491cac56a 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -541,7 +541,7 @@ impl<'a> Parser<'a> {
         }
 
         self.sess
-            .emit_err(AmbiguousRangePattern { span: pat.span, pat: pprust::pat_to_string(&pat) });
+            .emit_err(AmbiguousRangePattern { span: pat.span, pat: pprust::pat_to_string(pat) });
     }
 
     /// Parse `&pat` / `&mut pat`.
@@ -641,7 +641,7 @@ impl<'a> Parser<'a> {
         self.sess.emit_err(if changed_any_binding {
             InvalidMutInPattern::NestedIdent {
                 span: lo.to(pat.span),
-                pat: pprust::pat_to_string(&pat),
+                pat: pprust::pat_to_string(pat),
             }
         } else {
             InvalidMutInPattern::NonIdent { span: lo.until(pat.span) }
diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_parse/src/validate_attr.rs
index e6c46fc2528..cbe75b3dab6 100644
--- a/compiler/rustc_parse/src/validate_attr.rs
+++ b/compiler/rustc_parse/src/validate_attr.rs
@@ -188,7 +188,7 @@ fn emit_malformed_attribute(
     }
     suggestions.sort();
     if should_warn(name) {
-        sess.buffer_lint(&ILL_FORMED_ATTRIBUTE_INPUT, span, ast::CRATE_NODE_ID, msg);
+        sess.buffer_lint(ILL_FORMED_ATTRIBUTE_INPUT, span, ast::CRATE_NODE_ID, msg);
     } else {
         sess.span_diagnostic
             .struct_span_err(span, error_msg)