diff --git a/cranelift/codegen/meta/src/cdsl/ast.rs b/cranelift/codegen/meta/src/cdsl/ast.rs
index 3a994f27ed..644e601924 100644
--- a/cranelift/codegen/meta/src/cdsl/ast.rs
+++ b/cranelift/codegen/meta/src/cdsl/ast.rs
@@ -581,7 +581,7 @@ impl Apply {
         pred
     }
 
-    pub fn rust_builder(&self, defined_vars: &Vec<VarIndex>, var_pool: &VarPool) -> String {
+    pub fn rust_builder(&self, defined_vars: &[VarIndex], var_pool: &VarPool) -> String {
         let mut args = self
             .args
             .iter()
diff --git a/cranelift/src/bugpoint.rs b/cranelift/src/bugpoint.rs
index 2d753548b8..43ba5e2fda 100644
--- a/cranelift/src/bugpoint.rs
+++ b/cranelift/src/bugpoint.rs
@@ -202,13 +202,7 @@ impl Mutator for ReplaceInstWithConst {
 
             // Copy result SSA names into our own vector; otherwise we couldn't mutably borrow pos
             // in the loop below.
-            let results = pos
-                .func
-                .dfg
-                .inst_results(prev_inst)
-                .iter()
-                .cloned()
-                .collect::<Vec<_>>();
+            let results = pos.func.dfg.inst_results(prev_inst).to_vec();
 
             // Detach results from the previous instruction, since we're going to reuse them.
             pos.func.dfg.clear_results(prev_inst);
@@ -390,15 +384,12 @@ impl Mutator for RemoveUnusedEntities {
                 let mut signatures_usage_map = HashMap::new();
                 for ebb in func.layout.ebbs() {
                     for inst in func.layout.ebb_insts(ebb) {
-                        match func.dfg[inst] {
-                            // Add new cases when there are new instruction formats taking a `SigRef`.
-                            InstructionData::CallIndirect { sig_ref, .. } => {
-                                signatures_usage_map
-                                    .entry(sig_ref)
-                                    .or_insert_with(Vec::new)
-                                    .push(SigRefUser::Instruction(inst));
-                            }
-                            _ => {}
+                        // Add new cases when there are new instruction formats taking a `SigRef`.
+                        if let InstructionData::CallIndirect { sig_ref, .. } = func.dfg[inst] {
+                            signatures_usage_map
+                                .entry(sig_ref)
+                                .or_insert_with(Vec::new)
+                                .push(SigRefUser::Instruction(inst));
                         }
                     }
                 }
@@ -500,15 +491,14 @@ impl Mutator for RemoveUnusedEntities {
                 let mut global_value_usage_map = HashMap::new();
                 for ebb in func.layout.ebbs() {
                     for inst in func.layout.ebb_insts(ebb) {
-                        match func.dfg[inst] {
-                            // Add new cases when there are new instruction formats taking a `GlobalValue`.
-                            InstructionData::UnaryGlobalValue { global_value, .. } => {
-                                global_value_usage_map
-                                    .entry(global_value)
-                                    .or_insert_with(Vec::new)
-                                    .push(inst);
-                            }
-                            _ => {}
+                        // Add new cases when there are new instruction formats taking a `GlobalValue`.
+                        if let InstructionData::UnaryGlobalValue { global_value, .. } =
+                            func.dfg[inst]
+                        {
+                            global_value_usage_map
+                                .entry(global_value)
+                                .or_insert_with(Vec::new)
+                                .push(inst);
                         }
                     }
                 }
@@ -519,8 +509,9 @@ impl Mutator for RemoveUnusedEntities {
                         // These can create cyclic references, which cause complications. Just skip
                         // the global value removal for now.
                         // FIXME Handle them in a better way.
-                        GlobalValueData::Load { base: _, .. }
-                        | GlobalValueData::IAddImm { base: _, .. } => return None,
+                        GlobalValueData::Load { .. } | GlobalValueData::IAddImm { .. } => {
+                            return None
+                        }
                     }
                 }
 
@@ -647,11 +638,11 @@ impl Mutator for MergeBlocks {
         // we'll start back to this EBB.
         self.prev_ebb = Some(pred.ebb);
 
-        return Some((
+        Some((
             func,
             format!("merged {} and {}", pred.ebb, ebb),
             ProgressStatus::ExpandedOrShrinked,
-        ));
+        ))
     }
 
     fn did_crash(&mut self) {
@@ -701,9 +692,9 @@ fn reduce(
 
     match context.check_for_crash(&func) {
         CheckResult::Succeed => {
-            return Err(format!(
-                "Given function compiled successfully or gave a verifier error."
-            ));
+            return Err(
+                "Given function compiled successfully or gave a verifier error.".to_string(),
+            );
         }
         CheckResult::Crash(_) => {}
     }
@@ -926,8 +917,8 @@ mod tests {
 
     #[test]
     fn test_reduce() {
-        const TEST: &'static str = include_str!("../tests/bugpoint_test.clif");
-        const EXPECTED: &'static str = include_str!("../tests/bugpoint_test_expected.clif");
+        const TEST: &str = include_str!("../tests/bugpoint_test.clif");
+        const EXPECTED: &str = include_str!("../tests/bugpoint_test_expected.clif");
 
         let test_file = parse_test(TEST, ParseOptions::default()).unwrap();
 
diff --git a/cranelift/src/cat.rs b/cranelift/src/cat.rs
index a98e509698..4477f10222 100644
--- a/cranelift/src/cat.rs
+++ b/cranelift/src/cat.rs
@@ -8,7 +8,7 @@ use crate::CommandResult;
 use cranelift_reader::parse_functions;
 
 pub fn run(files: &[String]) -> CommandResult {
-    for (i, f) in files.into_iter().enumerate() {
+    for (i, f) in files.iter().enumerate() {
         if i != 0 {
             println!();
         }
diff --git a/cranelift/src/disasm.rs b/cranelift/src/disasm.rs
index 78bf92999e..5e6d3bbe33 100644
--- a/cranelift/src/disasm.rs
+++ b/cranelift/src/disasm.rs
@@ -25,12 +25,7 @@ impl binemit::RelocSink for PrintRelocs {
         offset: binemit::CodeOffset,
     ) {
         if self.flag_print {
-            write!(
-                &mut self.text,
-                "reloc_ebb: {} {} at {}\n",
-                r, offset, where_
-            )
-            .unwrap();
+            writeln!(&mut self.text, "reloc_ebb: {} {} at {}", r, offset, where_).unwrap();
         }
     }
 
@@ -42,9 +37,9 @@ impl binemit::RelocSink for PrintRelocs {
         addend: binemit::Addend,
     ) {
         if self.flag_print {
-            write!(
+            writeln!(
                 &mut self.text,
-                "reloc_external: {} {} {} at {}\n",
+                "reloc_external: {} {} {} at {}",
                 r, name, addend, where_
             )
             .unwrap();
@@ -53,7 +48,7 @@ impl binemit::RelocSink for PrintRelocs {
 
     fn reloc_jt(&mut self, where_: binemit::CodeOffset, r: binemit::Reloc, jt: ir::JumpTable) {
         if self.flag_print {
-            write!(&mut self.text, "reloc_jt: {} {} at {}\n", r, jt, where_).unwrap();
+            writeln!(&mut self.text, "reloc_jt: {} {} at {}", r, jt, where_).unwrap();
         }
     }
 
@@ -64,9 +59,9 @@ impl binemit::RelocSink for PrintRelocs {
         constant: ir::ConstantOffset,
     ) {
         if self.flag_print {
-            write!(
+            writeln!(
                 &mut self.text,
-                "reloc_constant: {} {} at {}\n",
+                "reloc_constant: {} {} at {}",
                 reloc, constant, code_offset
             )
             .unwrap();
@@ -91,7 +86,7 @@ impl PrintTraps {
 impl binemit::TrapSink for PrintTraps {
     fn trap(&mut self, offset: binemit::CodeOffset, _srcloc: ir::SourceLoc, code: ir::TrapCode) {
         if self.flag_print {
-            write!(&mut self.text, "trap: {} at {}\n", code, offset).unwrap();
+            writeln!(&mut self.text, "trap: {} at {}", code, offset).unwrap();
         }
     }
 }
@@ -113,7 +108,7 @@ impl PrintStackmaps {
 impl binemit::StackmapSink for PrintStackmaps {
     fn add_stackmap(&mut self, offset: binemit::CodeOffset, _: binemit::Stackmap) {
         if self.flag_print {
-            write!(&mut self.text, "add_stackmap at {}\n", offset).unwrap();
+            writeln!(&mut self.text, "add_stackmap at {}", offset).unwrap();
         }
     }
 }
diff --git a/cranelift/src/print_cfg.rs b/cranelift/src/print_cfg.rs
index 30d91b5862..2f739f9f9d 100644
--- a/cranelift/src/print_cfg.rs
+++ b/cranelift/src/print_cfg.rs
@@ -9,7 +9,7 @@ use cranelift_codegen::cfg_printer::CFGPrinter;
 use cranelift_reader::parse_functions;
 
 pub fn run(files: &[String]) -> CommandResult {
-    for (i, f) in files.into_iter().enumerate() {
+    for (i, f) in files.iter().enumerate() {
         if i != 0 {
             println!();
         }
diff --git a/cranelift/src/run.rs b/cranelift/src/run.rs
index a3cd94b25d..701104fcf5 100644
--- a/cranelift/src/run.rs
+++ b/cranelift/src/run.rs
@@ -52,7 +52,7 @@ fn iterate_files(files: Vec<String>) -> impl Iterator<Item = PathBuf> {
         .filter(|f| match f {
             Ok(d) => {
                 // filter out hidden files (starting with .)
-                !d.file_name().to_str().map_or(false, |s| s.starts_with("."))
+                !d.file_name().to_str().map_or(false, |s| s.starts_with('.'))
                     // filter out directories
                     && !d.file_type().is_dir()
             }
@@ -96,7 +96,7 @@ fn create_target_isa(isa_spec: &IsaSpec) -> Result<Box<dyn TargetIsa>, String> {
         let builder = host_isa_builder()?;
         Ok(builder.finish(flags.clone()))
     } else {
-        Err(String::from("A target ISA was specified in the file but should not have been--only the host ISA can be used for running CLIF files"))?
+        Err(String::from("A target ISA was specified in the file but should not have been--only the host ISA can be used for running CLIF files"))
     }
 }
 
diff --git a/cranelift/src/utils.rs b/cranelift/src/utils.rs
index 908b310007..f520aaa000 100644
--- a/cranelift/src/utils.rs
+++ b/cranelift/src/utils.rs
@@ -49,8 +49,8 @@ impl OwnedFlagsOrIsa {
     /// Produce a FlagsOrIsa reference.
     pub fn as_fisa(&self) -> FlagsOrIsa {
         match *self {
-            OwnedFlagsOrIsa::Flags(ref flags) => FlagsOrIsa::from(flags),
-            OwnedFlagsOrIsa::Isa(ref isa) => FlagsOrIsa::from(&**isa),
+            Self::Flags(ref flags) => FlagsOrIsa::from(flags),
+            Self::Isa(ref isa) => FlagsOrIsa::from(&**isa),
         }
     }
 }