6 files changed, 17 insertions, 16 deletions

diff --git a/crates/mbe/src/expander/matcher.rs b/crates/mbe/src/expander/matcher.rs
index b4f2fe9a4..0d694b1a7 100644
--- a/crates/mbe/src/expander/matcher.rs
+++ b/crates/mbe/src/expander/matcher.rs
@@ -645,7 +645,7 @@ fn match_loop(pattern: &MetaTemplate, src: &tt::Subtree) -> Match {
                     None if match_res.err.is_none() => {
                         bindings_builder.push_optional(&mut item.bindings, name);
                     }
-                    _ => {}
+                    None => {}
                 }
                 if let Some(err) = match_res.err {
                     res.add_err(err);
@@ -756,7 +756,7 @@ impl<'a> TtIter<'a> {
         let ok = match separator {
             Separator::Ident(lhs) if idx == 0 => match fork.expect_ident_or_underscore() {
                 Ok(rhs) => rhs.text == lhs.text,
-                _ => false,
+                Err(_) => false,
             },
             Separator::Literal(lhs) if idx == 0 => match fork.expect_literal() {
                 Ok(rhs) => match rhs {
@@ -764,11 +764,11 @@ impl<'a> TtIter<'a> {
                     tt::Leaf::Ident(rhs) => rhs.text == lhs.text,
                     tt::Leaf::Punct(_) => false,
                 },
-                _ => false,
+                Err(_) => false,
             },
             Separator::Puncts(lhss) if idx < lhss.len() => match fork.expect_punct() {
                 Ok(rhs) => rhs.char == lhss[idx].char,
-                _ => false,
+                Err(_) => false,
             },
             _ => false,
         };
diff --git a/crates/mbe/src/expander/transcriber.rs b/crates/mbe/src/expander/transcriber.rs
index 49a137577..4894e2a0c 100644
--- a/crates/mbe/src/expander/transcriber.rs
+++ b/crates/mbe/src/expander/transcriber.rs
@@ -241,6 +241,6 @@ fn push_fragment(buf: &mut Vec<tt::TokenTree>, fragment: Fragment) {
 fn push_subtree(buf: &mut Vec<tt::TokenTree>, tt: tt::Subtree) {
     match tt.delimiter {
         None => buf.extend(tt.token_trees),
-        _ => buf.push(tt.into()),
+        Some(_) => buf.push(tt.into()),
     }
 }
diff --git a/crates/mbe/src/lib.rs b/crates/mbe/src/lib.rs
index 8c8528aaf..fcc596756 100644
--- a/crates/mbe/src/lib.rs
+++ b/crates/mbe/src/lib.rs
@@ -135,7 +135,7 @@ impl Shift {
 
     /// Shift given TokenTree token id
     fn shift_all(self, tt: &mut tt::Subtree) {
-        for t in tt.token_trees.iter_mut() {
+        for t in &mut tt.token_trees {
             match t {
                 tt::TokenTree::Leaf(leaf) => match leaf {
                     tt::Leaf::Ident(ident) => ident.id = self.shift(ident.id),
@@ -188,7 +188,7 @@ impl MacroRules {
             }
         }
 
-        for rule in rules.iter() {
+        for rule in &rules {
             validate(&rule.lhs)?;
         }
 
@@ -241,7 +241,7 @@ impl MacroDef {
             }
             rules.push(rule);
         }
-        for rule in rules.iter() {
+        for rule in &rules {
             validate(&rule.lhs)?;
         }
 
@@ -268,7 +268,7 @@ impl MacroDef {
 }
 
 impl Rule {
-    fn parse(src: &mut TtIter, expect_arrow: bool) -> Result<Rule, ParseError> {
+    fn parse(src: &mut TtIter, expect_arrow: bool) -> Result<Self, ParseError> {
         let lhs = src
             .expect_subtree()
             .map_err(|()| ParseError::Expected("expected subtree".to_string()))?;
@@ -356,7 +356,7 @@ impl<T> ExpandResult<T> {
     }
 
     pub fn result(self) -> Result<T, ExpandError> {
-        self.err.map(Err).unwrap_or(Ok(self.value))
+        self.err.map_or(Ok(self.value), Err)
     }
 }
 
diff --git a/crates/mbe/src/subtree_source.rs b/crates/mbe/src/subtree_source.rs
index ee80807ad..ffc2a6017 100644
--- a/crates/mbe/src/subtree_source.rs
+++ b/crates/mbe/src/subtree_source.rs
@@ -115,7 +115,7 @@ impl<'a> TokenSource for SubtreeTokenSource {
     fn is_keyword(&self, kw: &str) -> bool {
         match self.cached.get(self.curr.1) {
             Some(t) => t.text == *kw,
-            _ => false,
+            None => false,
         }
     }
 }
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index cdc22425d..7526bd8e6 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -283,7 +283,7 @@ trait TokenConvertor {
                 let (id, idx) = self.id_alloc().open_delim(range);
                 subtree.delimiter = Some(tt::Delimiter { id, kind });
 
-                while self.peek().map(|it| it.kind() != closed).unwrap_or(false) {
+                while self.peek().map_or(false, |it| it.kind() != closed) {
                     self.collect_leaf(&mut subtree.token_trees);
                 }
                 let last_range = match self.bump() {
diff --git a/crates/mbe/src/tt_iter.rs b/crates/mbe/src/tt_iter.rs
index 5a4eca7bf..65da83476 100644
--- a/crates/mbe/src/tt_iter.rs
+++ b/crates/mbe/src/tt_iter.rs
@@ -121,10 +121,11 @@ impl<'a> TtIter<'a> {
 
         parser::parse_fragment(&mut src, &mut sink, fragment_kind);
 
-        let mut err = None;
-        if !sink.cursor.is_root() || sink.error {
-            err = Some(err!("expected {:?}", fragment_kind));
-        }
+        let mut err = if !sink.cursor.is_root() || sink.error {
+            Some(err!("expected {:?}", fragment_kind))
+        } else {
+            None
+        };
 
         let mut curr = buffer.begin();
         let mut res = vec![];