chore: fix compile warnings

src/expr.rs

@@ -1148,10 +1148,10 @@ pub(crate) fn is_simple_block(
     attrs: Option<&[ast::Attribute]>,
     source_map: &SourceMap,
 ) -> bool {
-    (block.stmts.len() == 1
+    block.stmts.len() == 1
         && stmt_is_expr(&block.stmts[0])
         && !block_contains_comment(block, source_map)
-        && attrs.map_or(true, |a| a.is_empty()))
+        && attrs.map_or(true, |a| a.is_empty())
 }
 
 /// Checks whether a block contains at most one statement or expression, and no

src/items.rs

@@ -2585,7 +2585,7 @@ fn compute_budgets_for_params(
     ret_str_len: usize,
     fn_brace_style: FnBraceStyle,
     force_vertical_layout: bool,
-) -> Option<((usize, usize, Indent))> {
+) -> Option<(usize, usize, Indent)> {
     debug!(
         "compute_budgets_for_params {} {:?}, {}, {:?}",
         result.len(),

src/modules.rs

@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::path::{Path, PathBuf};
 
-use rustc_errors::{Diagnostic, PResult};
+use rustc_errors::PResult;
 use rustc_parse::{new_sub_parser_from_file, parser, DirectoryOwnership};
 use rustc_session::parse::ParseSess;
 use rustc_span::symbol::{sym, Symbol};