Enable and fix several more clippy lints.

lib/codegen/src/isa/encoding.rs

@@ -18,8 +18,8 @@ pub struct Encoding {
 
 impl Encoding {
     /// Create a new `Encoding` containing `(recipe, bits)`.
-    pub fn new(recipe: u16, bits: u16) -> Encoding {
-        Encoding { recipe, bits }
+    pub fn new(recipe: u16, bits: u16) -> Self {
+        Self { recipe, bits }
     }
 
     /// Get the recipe number in this encoding.
@@ -122,10 +122,10 @@ impl EncInfo {
     ///
     /// Returns 0 for illegal encodings.
     pub fn bytes(&self, enc: Encoding) -> CodeOffset {
-        self.sizing
-            .get(enc.recipe())
-            .map(|s| CodeOffset::from(s.bytes))
-            .unwrap_or(0)
+        self.sizing.get(enc.recipe()).map_or(
+            0,
+            |s| CodeOffset::from(s.bytes),
+        )
     }
 
     /// Get the branch range that is supported by `enc`, if any.

lib/codegen/src/isa/riscv/abi.rs

@@ -24,8 +24,8 @@ struct Args {
 }
 
 impl Args {
-    fn new(bits: u16, enable_e: bool) -> Args {
-        Args {
+    fn new(bits: u16, enable_e: bool) -> Self {
+        Self {
             pointer_bits: bits,
             pointer_bytes: u32::from(bits) / 8,
             pointer_type: Type::int(bits).unwrap(),

lib/codegen/src/isa/stack.rs

@@ -23,10 +23,10 @@ pub struct StackRef {
 
 impl StackRef {
     /// Get a reference to the stack slot `ss` using one of the base pointers in `mask`.
-    pub fn masked(ss: StackSlot, mask: StackBaseMask, frame: &StackSlots) -> Option<StackRef> {
+    pub fn masked(ss: StackSlot, mask: StackBaseMask, frame: &StackSlots) -> Option<Self> {
         // Try an SP-relative reference.
         if mask.contains(StackBase::SP) {
-            return Some(StackRef::sp(ss, frame));
+            return Some(Self::sp(ss, frame));
         }
 
         // No reference possible with this mask.
@@ -34,7 +34,7 @@ impl StackRef {
     }
 
     /// Get a reference to `ss` using the stack pointer as a base.
-    pub fn sp(ss: StackSlot, frame: &StackSlots) -> StackRef {
+    pub fn sp(ss: StackSlot, frame: &StackSlots) -> Self {
         let size = frame.frame_size.expect(
             "Stack layout must be computed before referencing stack slots",
         );
@@ -48,7 +48,7 @@ impl StackRef {
             let sp_offset = -(size as StackOffset);
             slot.offset.unwrap() - sp_offset
         };
-        StackRef {
+        Self {
             base: StackBase::SP,
             offset,
         }

lib/codegen/src/isa/x86/abi.rs

@@ -34,8 +34,8 @@ struct Args {
 }
 
 impl Args {
-    fn new(bits: u16, gpr: &'static [RU], fpr_limit: usize, call_conv: CallConv) -> Args {
-        Args {
+    fn new(bits: u16, gpr: &'static [RU], fpr_limit: usize, call_conv: CallConv) -> Self {
+        Self {
             pointer_bytes: u32::from(bits) / 8,
             pointer_bits: bits,
             pointer_type: ir::Type::int(bits).unwrap(),
@@ -44,7 +44,7 @@ impl Args {
             fpr_limit,
             fpr_used: 0,
             offset: 0,
-            call_conv: call_conv,
+            call_conv,
         }
     }
 }
@@ -205,7 +205,7 @@ fn callee_saved_gprs_used(flags: &shared_settings::Flags, func: &ir::Function) -
     }
 
     used.intersect(&all_callee_saved);
-    return used;
+    used
 }
 
 pub fn prologue_epilogue(func: &mut ir::Function, isa: &TargetIsa) -> result::CtonResult {