Yet more Clippy

There are a few changes packed into this one.

- Cut unnecessary negations (mostly shuffling if/else blocks)
- Use isize::min_value() instead of std::isize::MIN, etc
    - rust-lang/rust-clippy#2380
- Rename some shadowing variables
- Cut some unnecessary references
- Use <struct>::default instead of Default::default
- Update inclusive range syntax
- Cut open import
- Self
- dyn trait

rust_src/remacs-lib/files.rs

@@ -76,9 +76,9 @@ fn generate_temporary_filename(name: &mut String) {
     }
     for byte in bytes.iter_mut() {
         *byte = match *byte % 62 {
-            v @ 0...9 => v + b'0',
-            v @ 10...35 => v - 10 + b'a',
-            v @ 36...61 => v - 36 + b'A',
+            v @ 0..=9 => v + b'0',
+            v @ 10..=35 => v - 10 + b'a',
+            v @ 36..=61 => v - 36 + b'A',
             _ => unreachable!(),
         }
     }

rust_src/src/buffers.rs

@@ -180,7 +180,7 @@ impl LispBufferRef {
         let mut name: LispStringRef = copy_sequence(name.into()).force_string();
         name.set_intervals(ptr::null_mut());
         b.name_ = name.into();
-        b.undo_list_ = if name.byte_at(0) != b' ' { Qnil } else { Qt };
+        b.undo_list_ = (name.byte_at(0) == b' ').into();
 
         b.reset();
         b.reset_local_variables(true);
@@ -1409,7 +1409,7 @@ fn get_truename_buffer_1(filename: LispSymbolOrString) -> LispObject {
 /// for positions far away from POS).
 #[lisp_fn]
 pub fn overlay_recenter(pos: LispNumber) {
-    let p = clip_to_bounds(std::isize::MIN, pos.to_fixnum(), std::isize::MAX);
+    let p = clip_to_bounds(isize::min_value(), pos.to_fixnum(), isize::max_value());
     unsafe {
         recenter_overlay_lists(ThreadState::current_buffer_unchecked().as_mut(), p);
     }

rust_src/src/character.rs

@@ -88,7 +88,7 @@ pub fn multibyte_char_to_unibyte(ch: Codepoint) -> EmacsInt {
         // a latin1 char, so let's let it slide.
         ch.into()
     } else {
-        ch.to_byte8().map(EmacsInt::from).unwrap_or(-1)
+        ch.to_byte8().map_or(-1, EmacsInt::from)
     }
 }
 

rust_src/src/cmds.rs

@@ -436,7 +436,7 @@ fn internal_self_insert(mut c: Codepoint, n: usize) -> EmacsInt {
     } else if n > 1 {
         let mut strn: Vec<libc::c_uchar> = match n.checked_mul(len) {
             Some(size_bytes) => Vec::with_capacity(size_bytes),
-            None => unsafe { memory_full(std::usize::MAX) },
+            None => unsafe { memory_full(usize::max_value()) },
         };
         for _ in 0..n {
             strn.extend_from_slice(&str[0..len]);

rust_src/src/decompress.rs

@@ -22,7 +22,7 @@ pub fn zlib_available_p() -> bool {
     true
 }
 
-fn create_buffer_decoder<'a>(buffer: &'a [u8]) -> Box<Read + 'a> {
+fn create_buffer_decoder<'a>(buffer: &'a [u8]) -> Box<dyn Read + 'a> {
     let magic_number = buffer[0];
 
     match magic_number {

rust_src/src/dired_unix.rs

@@ -92,9 +92,9 @@ impl StringExt for String {
         // So here make sure just one '/' between dir&file.
         let last_char = dir.as_str().chars().last().unwrap();
         if last_char == '/' {
-            dir + &self
+            dir + self
         } else {
-            dir + "/" + &self
+            dir + "/" + self
         }
     }
 }
@@ -245,9 +245,6 @@ fn read_dir(dname: &str, fnames: &mut Vec<String>, match_re: Option<LispObject>)
         fnames.push(dotdot);
     }
 
-    // NOTE: The allow can be dropped when the issue
-    // https://github.com/rust-lang/rust-clippy/issues/3913 is resolved
-    #[allow(clippy::identity_conversion)]
     for fname in fs::read_dir(dir_p)? {
         let fname = fname?;
         let f_enc = match fname.file_name().into_string() {

rust_src/src/editfns.rs

@@ -458,15 +458,13 @@ pub fn byte_to_string(byte: EmacsInt) -> LispObject {
 /// Return the first character in STRING.
 #[lisp_fn]
 pub fn string_to_char(string: LispStringRef) -> EmacsInt {
-    if !string.is_empty() {
-        if string.is_multibyte() {
-            let (cp, _) = multibyte_char_at(string.as_slice());
-            EmacsInt::from(cp)
-        } else {
-            EmacsInt::from(string.byte_at(0))
-        }
-    } else {
+    if string.is_empty() {
         0
+    } else if string.is_multibyte() {
+        let (cp, _) = multibyte_char_at(string.as_slice());
+        EmacsInt::from(cp)
+    } else {
+        EmacsInt::from(string.byte_at(0))
     }
 }
 

rust_src/src/filelock.rs

@@ -25,7 +25,6 @@ use crate::{
     remacs_sys::{Qnil, Qstringp, Qt},
     threads::ThreadState,
 };
-use LockState::*;
 
 /// An arbitrary limit on lock contents length when it is stored in the
 /// contents of the lock file.  8 K should be plenty big enough in practice.
@@ -47,7 +46,7 @@ struct LockInfo {
 impl LockInfo {
     /// Parses a string like `USER@HOST.PID:BOOT_TIME` into a [`LockInfo`].
     /// Returns [`None`] if the parse fails.
-    fn parse(data: &str) -> Option<LockInfo> {
+    fn parse(data: &str) -> Option<Self> {
         // Treat "\357\200\242" (U+F022 in UTF-8) as if it were ":" (Bug#24656).
         // This works around a bug in the Linux CIFS kernel client, which can
         // mistakenly transliterate ':' to U+F022 in symlink contents.
@@ -86,7 +85,7 @@ impl LockInfo {
             )
         };
 
-        Some(LockInfo {
+        Some(Self {
             user,
             host,
             pid,
@@ -244,22 +243,22 @@ fn current_lock_owner(path: &Path) -> Result<LockState> {
             if info.host.as_bytes() == system_name().as_slice() {
                 if info.pid == std::process::id() as i32 {
                     // We own it.
-                    LockedByUs
+                    LockState::LockedByUs
                 } else if process_exists(info.pid) && boot_time_within_one_second(&info) {
                     // An existing process on this machine owns it.
-                    LockedBy(info)
+                    LockState::LockedBy(info)
                 } else {
                     // The owner process is dead or has a strange pid, so try to
                     // zap the lockfile.
                     remove_file(path)?;
-                    NotLocked
+                    LockState::NotLocked
                 }
             } else {
-                LockedBy(info)
+                LockState::LockedBy(info)
             }
         }
 
-        None => NotLocked,
+        None => LockState::NotLocked,
     };
 
     Ok(result)
@@ -329,9 +328,9 @@ pub fn file_locked_p(filename: LispStringRef) -> LispObject {
     let path = make_lock_name(expand_file_name(filename, None));
 
     match current_lock_owner(&path) {
-        Ok(NotLocked) | Err(_) => Qnil,
-        Ok(LockedByUs) => Qt,
-        Ok(LockedBy(info)) => LispObject::from(info.user.as_str()),
+        Ok(LockState::NotLocked) | Err(_) => Qnil,
+        Ok(LockState::LockedByUs) => Qt,
+        Ok(LockState::LockedBy(info)) => LispObject::from(info.user.as_str()),
     }
 }
 

rust_src/src/fns.rs

@@ -591,10 +591,10 @@ pub fn copy_sequence(mut arg: LispObject) -> LispObject {
         let mut new = unsafe { make_uninit_bool_vector(nbits).force_bool_vector() };
         new.as_mut_slice().copy_from_slice(boolvec.as_slice());
         new.into()
-    } else if !(arg.is_cons() || arg.is_vector() || arg.is_string()) {
-        wrong_type!(Qsequencep, arg);
-    } else {
+    } else if arg.is_cons() || arg.is_vector() || arg.is_string() {
         unsafe { lisp_concat(1, &mut arg, arg.get_type(), false) }
+    } else {
+        wrong_type!(Qsequencep, arg);
     }
 }
 

rust_src/src/fonts.rs

@@ -117,7 +117,7 @@ impl LispFontObjectRef {
         unsafe { font_add_log(c_str.as_ptr(), self.into(), result.into()) }
     }
 
-    pub fn close(mut self, mut _frame: LispFrameRef) {
+    pub fn close(mut self, mut frame: LispFrameRef) {
         if data::aref(self.into(), FONT_TYPE_INDEX.into()).is_nil() {
             // Already closed
             return;
@@ -130,11 +130,11 @@ impl LispFontObjectRef {
             #[cfg(feature = "window-system")]
             {
                 #[cfg(feature = "window-system-x11")]
-                let mut display_info = &mut *(*_frame.output_data.x).display_info;
+                let mut display_info = &mut *(*frame.output_data.x).display_info;
                 #[cfg(feature = "window-system-nextstep")]
-                let mut display_info = &mut *(*_frame.output_data.ns).display_info;
+                let mut display_info = &mut *(*frame.output_data.ns).display_info;
                 #[cfg(feature = "window-system-w32")]
-                let mut display_info = &mut *(*_frame.output_data.w32).display_info;
+                let mut display_info = &mut *(*frame.output_data.w32).display_info;
                 debug_assert!(display_info.n_fonts > 0);
                 display_info.n_fonts -= 1;
             }

rust_src/src/frames.rs

@@ -633,12 +633,12 @@ pub fn frame_focus(frame: LispFrameLiveOrSelected) -> LispObject {
 ///
 /// If there is no window system support, this function does nothing.
 #[lisp_fn(min = "1", name = "x-focus-frame", c_name = "x_focus_frame")]
-pub fn x_focus_frame_lisp(_frame: LispFrameLiveOrSelected, _noactivate: bool) {
+pub fn x_focus_frame_lisp(frame: LispFrameLiveOrSelected, noactivate: bool) {
     #[cfg(feature = "window-system")]
     {
-        let mut frame_ref: LispFrameRef = _frame.into();
+        let mut frame_ref: LispFrameRef = frame.into();
         unsafe {
-            x_focus_frame(frame_ref.as_mut(), _noactivate);
+            x_focus_frame(frame_ref.as_mut(), noactivate);
         }
     }
 }

rust_src/src/keyboard.rs

@@ -360,10 +360,10 @@ pub fn input_pending_p(check_timers: bool) -> bool {
         // Process non-user-visible events (Bug#10195).
         process_special_events();
 
-        let val = if !check_timers {
-            0
-        } else {
+        let val = if check_timers {
             READABLE_EVENTS_DO_TIMERS_NOW
+        } else {
+            0
         };
 
         get_input_pending(val | READABLE_EVENTS_FILTER_EVENTS)

rust_src/src/lread.rs

@@ -207,10 +207,10 @@ pub unsafe extern "C" fn readbyte_from_stdio() -> i32 {
 
     unblock_input();
 
-    if c != libc::EOF {
-        c
-    } else {
+    if c == libc::EOF {
         -1
+    } else {
+        c
     }
 }
 

rust_src/src/marker.rs

@@ -561,17 +561,20 @@ fn set_marker_internal_else(
     // Don't believe BYTEPOS if it comes from a different buffer,
     // since that buffer might have a very different correspondence
     // between character and byte positions.
-    if bytepos == -1
+    bytepos = if bytepos == -1
         || !position
             .as_marker()
             .map_or(false, |m| m.buffer() == Some(buf))
     {
-        bytepos = buf.charpos_to_bytepos(charpos);
+        buf.charpos_to_bytepos(charpos)
     } else {
-        let beg = buf.buffer_beg_byte(restricted);
-        let end = buf.buffer_end_byte(restricted);
-        bytepos = clip_to_bounds(beg, bytepos as EmacsInt, end);
-    }
+        clip_to_bounds(
+            buf.buffer_beg_byte(restricted),
+            bytepos as EmacsInt,
+            buf.buffer_end_byte(restricted),
+        )
+    };
+
     attach_marker(marker.as_mut(), buf.as_mut(), charpos, bytepos);
 }
 

rust_src/src/multibyte.rs

@@ -96,10 +96,10 @@ pub struct Codepoint(u32);
 impl Codepoint {
     // Equivalent to BYTE8_TO_CHAR
     /// Create a codepoint from a raw byte. If non-ascii, byte8 encode it.
-    pub fn from_raw(byte: u8) -> Codepoint {
-        match Codepoint::from(byte) {
+    pub fn from_raw(byte: u8) -> Self {
+        match Self::from(byte) {
             cp if cp.is_ascii() => cp,
-            cp => Codepoint::from(cp.0 + BYTE8_OFFSET),
+            cp => Self::from(cp.0 + BYTE8_OFFSET),
         }
     }
 
@@ -145,9 +145,10 @@ impl Codepoint {
     /// Note that this does not check if the codepoint is within the
     /// appropriate range.
     pub fn to_byte8_unchecked(self) -> u8 {
-        match self.is_byte8() {
-            true => (self.0 - BYTE8_OFFSET) as u8,
-            false => (self.0 & 0xFF) as u8,
+        if self.is_byte8() {
+            (self.0 - BYTE8_OFFSET) as u8
+        } else {
+            (self.0 & 0xFF) as u8
         }
     }
 
@@ -165,16 +166,17 @@ impl Codepoint {
     }
 
     // Equivalent to UNIBYTE_TO_CHAR
-    pub fn unibyte_to_char(self) -> Codepoint {
-        match self.is_ascii() {
-            true => self,
-            false => Codepoint::from_raw(self.0 as u8),
+    pub fn unibyte_to_char(self) -> Self {
+        if self.is_ascii() {
+            self
+        } else {
+            Self::from_raw(self.0 as u8)
         }
     }
 
     // Equivalent to MAKE_CHAR_MULTIBYTE
     /// Transform an 8-bit codepoint to its byte8 encoded form.
-    pub fn to_multibyte(self) -> Codepoint {
+    pub fn to_multibyte(self) -> Self {
         debug_assert!(self.is_single_byte());
         self.unibyte_to_char()
     }
@@ -211,7 +213,7 @@ impl Codepoint {
             to[0] = 0xF8;
             5
         } else if cp <= MAX_CHAR {
-            let b = Codepoint::from(cp).to_byte8_unchecked();
+            let b = Self::from(cp).to_byte8_unchecked();
             to[1] = 0x80 | (b & 0x3F);
             to[0] = 0xC0 | ((b >> 6) & 1);
             2
@@ -222,11 +224,11 @@ impl Codepoint {
 
     /// If character code C has modifier masks, reflect them to the character
     /// code if possible. Return the resulting code.
-    pub fn resolve_modifier_mask(self) -> Codepoint {
+    pub fn resolve_modifier_mask(self) -> Self {
         let mut cp = self.0;
         // A non-ASCII character can't reflect modifier bits to the code.
-        if !Codepoint::from(cp & !char_bits::CHAR_MODIFIER_MASK).is_ascii() {
-            return Codepoint::from(cp);
+        if !Self::from(cp & !char_bits::CHAR_MODIFIER_MASK).is_ascii() {
+            return Self::from(cp);
         }
         let ascii = (cp & 0x7F) as u8;
         // For Meta, Shift, and Control modifiers, we need special care.
@@ -253,7 +255,7 @@ impl Codepoint {
                 cp &= 0x1F | (!0x7F & !char_bits::CHAR_CTL);
             }
         }
-        Codepoint::from(cp)
+        Self::from(cp)
     }
 }
 
@@ -322,7 +324,7 @@ impl From<Codepoint> for LispObject {
 impl From<LispObject> for Codepoint {
     fn from(o: LispObject) -> Self {
         match o.as_fixnum() {
-            Some(i) if 0 <= i && i <= EmacsInt::from(MAX_CHAR) => Codepoint::from(i as u32),
+            Some(i) if 0 <= i && i <= EmacsInt::from(MAX_CHAR) => Self::from(i as u32),
             _ => wrong_type!(Qcharacterp, o),
         }
     }
@@ -1080,10 +1082,10 @@ pub unsafe extern "C" fn str_to_unibyte(
         srcslice = &srcslice[cplen..];
         dstslice[i as usize] = if cp.val() > MAX_5_BYTE_CHAR {
             cp.to_byte8_unchecked()
-        } else if !cp.is_ascii() {
-            return i;
-        } else {
+        } else if cp.is_ascii() {
             cp.0 as c_uchar
+        } else {
+            return i;
         };
     }
     chars

rust_src/src/numbers.rs

@@ -325,7 +325,7 @@ pub fn random(limit: LispObject) -> LispObject {
         let mut seed = [0; 32];
         let mut values: Vec<u8> = s.as_slice().to_vec();
         values.resize(32, 0);
-        seed.copy_from_slice(&values.as_slice());
+        seed.copy_from_slice(values.as_slice());
         *rng = StdRng::from_seed(seed);
     }