Rollup merge of rust-lang#67237 - llogiq:improve-str, r=Dylan-DPC

Some small readability improvements

src/libcore/char/methods.rs

@@ -553,8 +553,7 @@ impl char {
     pub fn is_alphabetic(self) -> bool {
         match self {
             'a'..='z' | 'A'..='Z' => true,
-            c if c > '\x7f' => derived_property::Alphabetic(c),
-            _ => false,
+            c => c > '\x7f' && derived_property::Alphabetic(c),
         }
     }
 
@@ -585,8 +584,7 @@ impl char {
     pub fn is_lowercase(self) -> bool {
         match self {
             'a'..='z' => true,
-            c if c > '\x7f' => derived_property::Lowercase(c),
-            _ => false,
+            c => c > '\x7f' && derived_property::Lowercase(c),
         }
     }
 
@@ -617,8 +615,7 @@ impl char {
     pub fn is_uppercase(self) -> bool {
         match self {
             'A'..='Z' => true,
-            c if c > '\x7f' => derived_property::Uppercase(c),
-            _ => false,
+            c => c > '\x7f' && derived_property::Uppercase(c),
         }
     }
 
@@ -646,8 +643,7 @@ impl char {
     pub fn is_whitespace(self) -> bool {
         match self {
             ' ' | '\x09'..='\x0d' => true,
-            c if c > '\x7f' => property::White_Space(c),
-            _ => false,
+            c => c > '\x7f' && property::White_Space(c),
         }
     }
 
@@ -744,8 +740,7 @@ impl char {
     pub fn is_numeric(self) -> bool {
         match self {
             '0'..='9' => true,
-            c if c > '\x7f' => general_category::N(c),
-            _ => false,
+            c => c > '\x7f' && general_category::N(c),
         }
     }
 

src/libcore/str/pattern.rs

@@ -296,12 +296,7 @@ unsafe impl<'a> Searcher<'a> for CharSearcher<'a> {
     fn next_match(&mut self) -> Option<(usize, usize)> {
         loop {
             // get the haystack after the last character found
-            let bytes = if let Some(slice) = self.haystack.as_bytes()
-                                                 .get(self.finger..self.finger_back) {
-                slice
-            } else {
-                return None;
-            };
+            let bytes = self.haystack.as_bytes().get(self.finger..self.finger_back)?;
             // the last byte of the utf8 encoded needle
             let last_byte = unsafe { *self.utf8_encoded.get_unchecked(self.utf8_size - 1) };
             if let Some(index) = memchr::memchr(last_byte, bytes) {