Rollup merge of #136906 - chenyukang:yukang-fix-136741-closure-body, r=oli-obk

Add checking for unnecessary delims in closure body

Fixes #136741

4 files changed, 12 insertions, 5 deletions

diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 2f398cea926..510f37f37e2 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -3526,7 +3526,7 @@ 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 --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index d3942a1c816..a9eb1739f7f 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -1,7 +1,7 @@
 use std::iter;
 
 use rustc_ast::util::{classify, parser};
-use rustc_ast::{self as ast, ExprKind, HasAttrs as _, StmtKind};
+use rustc_ast::{self as ast, ExprKind, FnRetTy, HasAttrs as _, StmtKind};
 use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{MultiSpan, pluralize};
@@ -599,6 +599,7 @@ enum UnusedDelimsCtx {
     AnonConst,
     MatchArmExpr,
     IndexExpr,
+    ClosureBody,
 }
 
 impl From<UnusedDelimsCtx> for &'static str {
@@ -620,6 +621,7 @@ impl From<UnusedDelimsCtx> for &'static str {
             UnusedDelimsCtx::ArrayLenExpr | UnusedDelimsCtx::AnonConst => "const expression",
             UnusedDelimsCtx::MatchArmExpr => "match arm expression",
             UnusedDelimsCtx::IndexExpr => "index expression",
+            UnusedDelimsCtx::ClosureBody => "closure body",
         }
     }
 }
@@ -919,6 +921,11 @@ trait UnusedDelimLint {
                 let (args_to_check, ctx) = match *call_or_other {
                     Call(_, ref args) => (&args[..], UnusedDelimsCtx::FunctionArg),
                     MethodCall(ref call) => (&call.args[..], UnusedDelimsCtx::MethodArg),
+                    Closure(ref closure)
+                        if matches!(closure.fn_decl.output, FnRetTy::Default(_)) =>
+                    {
+                        (&[closure.body.clone()][..], UnusedDelimsCtx::ClosureBody)
+                    }
                     // actual catch-all arm
                     _ => {
                         return;
@@ -1508,6 +1515,7 @@ impl UnusedDelimLint for UnusedBraces {
                             && (ctx != UnusedDelimsCtx::AnonConst
                                 || (matches!(expr.kind, ast::ExprKind::Lit(_))
                                     && !expr.span.from_expansion()))
+                            && ctx != UnusedDelimsCtx::ClosureBody
                             && !cx.sess().source_map().is_multiline(value.span)
                             && value.attrs.is_empty()
                             && !value.span.from_expansion()
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 9ed7124a11c..d6cc98d505c 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -2206,7 +2206,7 @@ impl<'a> Parser<'a> {
 
             if self.look_ahead(1, |t| *t == token::Bang) && 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 --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index e015eb7a636..8114021510e 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -328,8 +328,7 @@ impl<'ast, 'ra, '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)
             };