diff --git a/src/uu/tr/src/convert.rs b/src/uu/tr/src/convert.rs
index 27f31491f..44ee67ad1 100644
--- a/src/uu/tr/src/convert.rs
+++ b/src/uu/tr/src/convert.rs
@@ -15,7 +15,7 @@ fn parse_octal(input: &str) -> IResult<&str, char> {
         preceded(tag("\\"), recognize(many_m_n(1, 3, one_of("01234567")))),
         |out: &str| {
             u32::from_str_radix(out, 8)
-                .map(char::from_u32)
+                .map(std::char::from_u32)
                 .ok()
                 .flatten()
         },
diff --git a/src/uu/tr/src/operation.rs b/src/uu/tr/src/operation.rs
index 1f17809ec..e22bc4276 100644
--- a/src/uu/tr/src/operation.rs
+++ b/src/uu/tr/src/operation.rs
@@ -76,7 +76,7 @@ impl Sequence {
     pub fn flatten(&self) -> Box<dyn Iterator<Item = char>> {
         match self {
             Sequence::Char(c) => Box::new(std::iter::once(*c)),
-            Sequence::CharRange(l, r) => Box::new((*l..=*r).flat_map(char::from_u32)),
+            Sequence::CharRange(l, r) => Box::new((*l..=*r).flat_map(std::char::from_u32)),
             Sequence::CharStar(c) => Box::new(std::iter::repeat(*c)),
             Sequence::CharRepeat(c, n) => Box::new(std::iter::repeat(*c).take(*n)),
             Sequence::Alnum => Box::new(('0'..='9').chain('A'..='Z').chain('a'..='z')),
@@ -85,7 +85,7 @@ impl Sequence {
             Sequence::Control => Box::new(
                 (0..=31)
                     .chain(std::iter::once(127))
-                    .flat_map(char::from_u32),
+                    .flat_map(std::char::from_u32),
             ),
             Sequence::Digit => Box::new('0'..='9'),
             Sequence::Graph => Box::new(
@@ -98,7 +98,7 @@ impl Sequence {
                     .chain(91..=96)
                     .chain(123..=126)
                     .chain(std::iter::once(32)) // space
-                    .flat_map(char::from_u32),
+                    .flat_map(std::char::from_u32),
             ),
             Sequence::Lower => Box::new('a'..='z'),
             Sequence::Print => Box::new(
@@ -110,14 +110,14 @@ impl Sequence {
                     .chain(58..=64)
                     .chain(91..=96)
                     .chain(123..=126)
-                    .flat_map(char::from_u32),
+                    .flat_map(std::char::from_u32),
             ),
             Sequence::Punct => Box::new(
                 (33..=47)
                     .chain(58..=64)
                     .chain(91..=96)
                     .chain(123..=126)
-                    .flat_map(char::from_u32),
+                    .flat_map(std::char::from_u32),
             ),
             Sequence::Space => Box::new(unicode_table::SPACES.iter().cloned()),
             Sequence::Upper => Box::new('A'..='Z'),
@@ -410,7 +410,11 @@ impl DeleteOperation {
 impl SymbolTranslator for DeleteOperation {
     fn translate(&mut self, current: char) -> Option<char> {
         let found = self.set.iter().any(|sequence| sequence.eq(&current));
-        (self.complement_flag == found).then(|| current)
+        if self.complement_flag == found {
+            Some(current)
+        } else {
+            None
+        }
     }
 }
 
@@ -466,7 +470,7 @@ pub enum TranslateOperation {
 impl TranslateOperation {
     fn next_complement_char(iter: u32, ignore_list: &[char]) -> (u32, char) {
         (iter..)
-            .filter_map(char::from_u32)
+            .filter_map(std::char::from_u32)
             .filter(|c| !ignore_list.iter().any(|s| s.eq(c)))
             .map(|c| (u32::from(c) + 1, c))
             .next()
@@ -498,7 +502,7 @@ impl SymbolTranslator for TranslateOperation {
             TranslateOperation::Standard(TranslateOperationStandard { translation_map }) => Some(
                 translation_map
                     .iter()
-                    .find_map(|(l, r)| l.eq(&current).then(|| *r))
+                    .find_map(|(l, r)| if l.eq(&current) { Some(*r) } else { None })
                     .unwrap_or(current),
             ),
             TranslateOperation::Complement(TranslateOperationComplement {
diff --git a/tests/by-util/test_tr.rs b/tests/by-util/test_tr.rs
index 5f60f8d2a..417df6ec4 100644
--- a/tests/by-util/test_tr.rs
+++ b/tests/by-util/test_tr.rs
@@ -1,3 +1,4 @@
+// spell-checker:ignore aabbaa aabbcc aabc abbb abcc abcdefabcdef abcdefghijk abcdefghijklmn abcdefghijklmnop ABCDEFGHIJKLMNOPQRS abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ ABCDEFZZ abcxyz ABCXYZ abcxyzabcxyz ABCXYZABCXYZ acbdef alnum amzamz AMZXAMZ bbbd cclass cefgm cntrl compl dabcdef dncase Gzabcdefg PQRST upcase wxyzz xdigit xycde xyyye xyyz xyzzzzxyzzzz ZABCDEF Zamz
 use crate::common::util::*;
 
 #[test]