remove uncessary parens in closure body

Author: chenyukang

Diff for: compiler/rustc_errors/src/emitter.rs

@@ -3449,7 +3449,7 @@ pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
     // All the chars that differ in capitalization are confusable (above):
     let confusable = iter::zip(found.chars(), suggested.chars())
         .filter(|(f, s)| f != s)
-        .all(|(f, s)| (ascii_confusables.contains(&f) || ascii_confusables.contains(&s)));
+        .all(|(f, s)| ascii_confusables.contains(&f) || ascii_confusables.contains(&s));
     confusable && found.to_lowercase() == suggested.to_lowercase()
             // FIXME: We sometimes suggest the same thing we already have, which is a
             //        bug, but be defensive against that here.

Diff for: compiler/rustc_mir_transform/src/coverage/counters/node_flow.rs

@@ -261,7 +261,7 @@ impl<'a, Node: Idx> SpantreeBuilder<'a, Node> {
         debug_assert!(
             span_edges
                 .iter_enumerated()
-                .all(|(node, span_edge)| { span_edge.is_some() <= self.is_supernode(node) }),
+                .all(|(node, span_edge)| span_edge.is_some() <= self.is_supernode(node)),
             "only supernodes can have a span edge",
         );
         debug_assert!(

Diff for: compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -160,7 +160,7 @@ fn create_mappings(extracted_mappings: &ExtractedMappings) -> Vec<Mapping> {
              condition_info: _,
              true_index: _,
              false_index: _,
-         }| { Mapping { kind: MappingKind::Branch { true_bcb, false_bcb }, span } },
+         }| Mapping { kind: MappingKind::Branch { true_bcb, false_bcb }, span },
     ));
 
     for (decision, branches) in mcdc_mappings {

Diff for: compiler/rustc_parse/src/parser/item.rs

@@ -2189,7 +2189,7 @@ impl<'a> Parser<'a> {
 
             if self.look_ahead(1, |t| *t == token::Not) && self.look_ahead(2, |t| t.is_ident()) {
                 return IsMacroRulesItem::Yes { has_bang: true };
-            } else if self.look_ahead(1, |t| (t.is_ident())) {
+            } else if self.look_ahead(1, |t| t.is_ident()) {
                 // macro_rules foo
                 self.dcx().emit_err(errors::MacroRulesMissingBang {
                     span: macro_rules_span,

Diff for: compiler/rustc_resolve/src/late/diagnostics.rs

@@ -326,8 +326,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                 let module_did = mod_prefix.as_ref().and_then(Res::mod_def_id);
 
                 let mod_prefix =
-                    mod_prefix.map_or_else(String::new, |res| (format!("{} ", res.descr())));
-
+                    mod_prefix.map_or_else(String::new, |res| format!("{} ", res.descr()));
                 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)), module_did, None)
             };
 

Diff for: src/librustdoc/html/format.rs

@@ -1440,7 +1440,7 @@ impl clean::FnDecl {
         fmt::from_fn(move |f| {
             // First, generate the text form of the declaration, with no line wrapping, and count the bytes.
             let mut counter = WriteCounter(0);
-            write!(&mut counter, "{:#}", fmt::from_fn(|f| { self.inner_full_print(None, f, cx) }))
+            write!(&mut counter, "{:#}", fmt::from_fn(|f| self.inner_full_print(None, f, cx)))
                 .unwrap();
             // If the text form was over 80 characters wide, we will line-wrap our output.
             let line_wrapping_indent =