echo: remove code made obsolete by MSRV 1.79

Author: cakebaker

src/uu/echo/src/echo.rs

@@ -208,13 +208,6 @@ fn print_escaped(input: &[u8], output: &mut StdoutLock) -> io::Result<ControlFlo
         }
 
         if let Some(next) = iter.next() {
-            // For extending lifetime
-            // Unnecessary when using Rust >= 1.79.0
-            // https://github.com/rust-lang/rust/pull/121346
-            // TODO: when we have a MSRV >= 1.79.0, delete these "hold" bindings
-            let hold_one_byte_outside_of_match: [u8; 1_usize];
-            let hold_two_bytes_outside_of_match: [u8; 2_usize];
-
             let unescaped: &[u8] = match *next {
                 b'\\' => br"\",
                 b'a' => b"\x07",
@@ -230,12 +223,7 @@ fn print_escaped(input: &[u8], output: &mut StdoutLock) -> io::Result<ControlFlo
                     if let Some(parsed_hexadecimal_number) =
                         parse_backslash_number(&mut iter, BackslashNumberType::Hexadecimal)
                     {
-                        // TODO: remove when we have a MSRV >= 1.79.0
-                        hold_one_byte_outside_of_match = [parsed_hexadecimal_number];
-
-                        // TODO: when we have a MSRV >= 1.79.0, return reference to a temporary array:
-                        // &[parsed_hexadecimal_number]
-                        &hold_one_byte_outside_of_match
+                        &[parsed_hexadecimal_number]
                     } else {
                         // "\x" with any non-hexadecimal digit after means "\x" is treated literally
                         br"\x"
@@ -246,22 +234,15 @@ fn print_escaped(input: &[u8], output: &mut StdoutLock) -> io::Result<ControlFlo
                         &mut iter,
                         BackslashNumberType::OctalStartingWithZero,
                     ) {
-                        // TODO: remove when we have a MSRV >= 1.79.0
-                        hold_one_byte_outside_of_match = [parsed_octal_number];
-
-                        // TODO: when we have a MSRV >= 1.79.0, return reference to a temporary array:
-                        // &[parsed_octal_number]
-                        &hold_one_byte_outside_of_match
+                        &[parsed_octal_number]
                     } else {
                         // "\0" with any non-octal digit after it means "\0" is treated as ASCII '\0' (NUL), 0x00
                         b"\0"
                     }
                 }
                 other_byte => {
                     // Backslash and the following byte are treated literally
-                    hold_two_bytes_outside_of_match = [b'\\', other_byte];
-
-                    &hold_two_bytes_outside_of_match
+                    &[b'\\', other_byte]
                 }
             };