Update to the rustfmt in rust 1.28, which is now stable.

Also, rustfmt's --write-mode=check is now named --check.

lib/codegen/src/ir/extfunc.rs

@@ -62,7 +62,8 @@ impl Signature {
     /// Even if there are no stack arguments, this will set `params` to `Some(0)` instead
     /// of `None`. This indicates that the signature has been legalized.
     pub fn compute_argument_bytes(&mut self) {
-        let bytes = self.params
+        let bytes = self
+            .params
             .iter()
             .filter_map(|arg| match arg.location {
                 ArgumentLoc::Stack(offset) if offset >= 0 => {

lib/codegen/src/ir/layout.rs

@@ -182,7 +182,8 @@ impl Layout {
     /// Assign a valid sequence number to `inst` such that the numbers are still monotonic. This may
     /// require renumbering.
     fn assign_inst_seq(&mut self, inst: Inst) {
-        let ebb = self.inst_ebb(inst)
+        let ebb = self
+            .inst_ebb(inst)
             .expect("inst must be inserted before assigning an seq");
 
         // Get the sequence number immediately before `inst`.
@@ -569,7 +570,8 @@ impl Layout {
     /// Insert `inst` before the instruction `before` in the same EBB.
     pub fn insert_inst(&mut self, inst: Inst, before: Inst) {
         debug_assert_eq!(self.inst_ebb(inst), None);
-        let ebb = self.inst_ebb(before)
+        let ebb = self
+            .inst_ebb(before)
             .expect("Instruction before insertion point not in the layout");
         let after = self.insts[before].prev;
         {
@@ -643,7 +645,8 @@ impl Layout {
     ///     i4
     /// ```
     pub fn split_ebb(&mut self, new_ebb: Ebb, before: Inst) {
-        let old_ebb = self.inst_ebb(before)
+        let old_ebb = self
+            .inst_ebb(before)
             .expect("The `before` instruction must be in the layout");
         debug_assert!(!self.is_ebb_inserted(new_ebb));
 

lib/codegen/src/ir/stackslot.rs

@@ -309,7 +309,8 @@ impl StackSlots {
         let size = spill_size(ty);
 
         // Find the smallest existing slot that can fit the type.
-        if let Some(&ss) = self.emergency
+        if let Some(&ss) = self
+            .emergency
             .iter()
             .filter(|&&ss| self[ss].size >= size && !in_use.contains(&ss.into()))
             .min_by_key(|&&ss| self[ss].size)
@@ -318,7 +319,8 @@ impl StackSlots {
         }
 
         // Alternatively, use the largest available slot and make it larger.
-        if let Some(&ss) = self.emergency
+        if let Some(&ss) = self
+            .emergency
             .iter()
             .filter(|&&ss| !in_use.contains(&ss.into()))
             .max_by_key(|&&ss| self[ss].size)