diff --git a/build.rs b/build.rs
index 2bf51d40ab..7a1eba6439 100644
--- a/build.rs
+++ b/build.rs
@@ -43,7 +43,8 @@ fn compare_license_text(path: &Path, expected_lines: &[&str]) {
     let reader = BufReader::new(file);
 
     for (i, (file_line, expected_line)) in reader.lines().zip(expected_lines).enumerate() {
-        let file_line = file_line.expect(&format!("Can't read line {} in file \"{}\"!", i + 1, path.display()));
+        let file_line =
+            file_line.unwrap_or_else(|_| panic!("Can't read line {} in file \"{}\"!", i + 1, path.display()));
 
         assert!(
             &file_line == expected_line,
@@ -75,7 +76,7 @@ fn check_file_licenses<P: AsRef<Path>>(path: P) {
 
         // Check all files with the ".rs" extension.
         if entry_type.is_file() && entry.file_name().to_str().unwrap_or("").ends_with(".rs") {
-            compare_license_text(&entry.path(), &license_lines);
+            compare_license_text(entry.path(), &license_lines);
         }
     }
 
diff --git a/compiler/compiler/src/compiler.rs b/compiler/compiler/src/compiler.rs
index 43fa0909f7..c77e044e5a 100644
--- a/compiler/compiler/src/compiler.rs
+++ b/compiler/compiler/src/compiler.rs
@@ -174,7 +174,7 @@ impl<'a> Compiler<'a> {
         self.parse_program()?;
         let symbol_table = self.compiler_stages()?;
 
-        let bytecode = CodeGenerator::do_pass((&self.ast, &self.handler))?;
+        let bytecode = CodeGenerator::do_pass((&self.ast, self.handler))?;
 
         Ok((symbol_table, bytecode))
     }
diff --git a/compiler/parser/src/tokenizer/mod.rs b/compiler/parser/src/tokenizer/mod.rs
index 20e838804e..e119db2063 100644
--- a/compiler/parser/src/tokenizer/mod.rs
+++ b/compiler/parser/src/tokenizer/mod.rs
@@ -20,7 +20,6 @@
 //! separated by whitespace.
 
 pub(crate) mod token;
-use std::iter;
 
 pub use self::token::KEYWORD_TOKENS;
 pub(crate) use self::token::*;
@@ -31,6 +30,8 @@ pub(crate) use self::lexer::*;
 use leo_errors::Result;
 use leo_span::span::{BytePos, Pos, Span};
 
+use std::iter;
+
 /// Creates a new vector of spanned tokens from a given file path and source code text.
 pub(crate) fn tokenize(input: &str, start_pos: BytePos) -> Result<Vec<SpannedToken>> {
     tokenize_iter(input, start_pos).collect()
@@ -65,6 +66,7 @@ pub(crate) fn tokenize_iter(mut input: &str, mut lo: BytePos) -> impl '_ + Itera
 mod tests {
     use super::*;
     use leo_span::{source_map::FileName, symbol::create_session_if_not_set_then};
+    use std::fmt::Write as _;
 
     #[test]
     fn test_tokenizer() {
@@ -147,7 +149,7 @@ mod tests {
             let tokens = tokenize(&sf.src, sf.start_pos).unwrap();
             let mut output = String::new();
             for SpannedToken { token, .. } in tokens.iter() {
-                output += &format!("{} ", token);
+                write!(output, "{} ", token).expect("failed to write to string");
             }
 
             assert_eq!(
diff --git a/compiler/passes/src/code_generation/visit_expressions.rs b/compiler/passes/src/code_generation/visit_expressions.rs
index 665803dcfa..92610cc9f2 100644
--- a/compiler/passes/src/code_generation/visit_expressions.rs
+++ b/compiler/passes/src/code_generation/visit_expressions.rs
@@ -15,12 +15,13 @@
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::CodeGenerator;
-
 use leo_ast::{
     AccessExpression, BinaryExpression, BinaryOperation, CallExpression, CircuitInitExpression, ErrExpression,
     Expression, Identifier, LiteralExpression, MemberAccess, TernaryExpression, UnaryExpression, UnaryOperation,
 };
 
+use std::fmt::Write as _;
+
 /// Implement the necessary methods to visit nodes in the AST.
 // Note: We opt for this option instead of using `Visitor` and `Director` because this pass requires
 // a post-order traversal of the AST. This is sufficient since this implementation is intended to be
@@ -171,12 +172,12 @@ impl<'a> CodeGenerator<'a> {
             };
 
             // Push operand name to circuit init instruction.
-            circuit_init_instruction.push_str(&format!("{} ", operand))
+            write!(circuit_init_instruction, "{} ", operand).expect("failed to write to string");
         }
 
         // Push destination register to circuit init instruction.
         let destination_register = format!("r{}", self.next_register);
-        circuit_init_instruction.push_str(&format!("into {};\n", destination_register));
+        writeln!(circuit_init_instruction, "into {};", destination_register).expect("failed to write to string");
         instructions.push_str(&circuit_init_instruction);
 
         // Increment the register counter.
@@ -205,14 +206,14 @@ impl<'a> CodeGenerator<'a> {
         let mut instructions = String::new();
 
         for argument in input.arguments.iter() {
-            let (argument, argument_instructions) = self.visit_expression(&argument);
-            call_instruction.push_str(&format!("{} ", argument));
+            let (argument, argument_instructions) = self.visit_expression(argument);
+            write!(call_instruction, "{} ", argument).expect("failed to write to string");
             instructions.push_str(&argument_instructions);
         }
 
         // Push destination register to call instruction.
         let destination_register = format!("r{}", self.next_register);
-        call_instruction.push_str(&format!("into {};\n", destination_register));
+        writeln!(call_instruction, "into {};", destination_register).expect("failed to write to string");
         instructions.push_str(&call_instruction);
 
         // Increment the register counter.
diff --git a/compiler/passes/src/code_generation/visit_program.rs b/compiler/passes/src/code_generation/visit_program.rs
index 9d2a969538..9e82c33390 100644
--- a/compiler/passes/src/code_generation/visit_program.rs
+++ b/compiler/passes/src/code_generation/visit_program.rs
@@ -19,7 +19,7 @@ use crate::CodeGenerator;
 use leo_ast::{Circuit, CircuitMember, Function, Program};
 
 use itertools::Itertools;
-use std::collections::HashMap;
+use std::{collections::HashMap, fmt::Write as _};
 
 impl<'a> CodeGenerator<'a> {
     pub(crate) fn visit_program(&mut self, input: &'a Program) -> String {
@@ -34,7 +34,7 @@ impl<'a> CodeGenerator<'a> {
                 .join("\n"),
         );
 
-        program_string.push_str("\n");
+        program_string.push('\n');
 
         // Visit each `Function` in the Leo AST and produce a bytecode function.
         program_string.push_str(
@@ -69,7 +69,7 @@ impl<'a> CodeGenerator<'a> {
                 CircuitMember::CircuitVariable(name, type_) => (name, type_),
             };
 
-            output_string.push_str(&format!("    {} as {};\n", name, type_,))
+            writeln!(output_string, "    {} as {};", name, type_,).expect("failed to write to string");
         }
 
         output_string
@@ -80,7 +80,8 @@ impl<'a> CodeGenerator<'a> {
         let mut output_string = String::from("record");
         self.composite_mapping
             .insert(&record.identifier.name, output_string.clone());
-        output_string.push_str(&format!(" {}:\n", record.identifier.to_string().to_lowercase())); // todo: check if this is safe from name conflicts.
+        writeln!(output_string, " {}:", record.identifier.to_string().to_lowercase())
+            .expect("failed to write to string"); // todo: check if this is safe from name conflicts.
 
         // Construct and append the record variables.
         for var in record.members.iter() {
@@ -88,10 +89,12 @@ impl<'a> CodeGenerator<'a> {
                 CircuitMember::CircuitVariable(name, type_) => (name, type_),
             };
 
-            output_string.push_str(&format!(
-                "    {} as {}.private;\n", // todo: CAUTION private record variables only.
+            writeln!(
+                output_string,
+                "    {} as {}.private;", // todo: CAUTION private record variables only.
                 name, type_,
-            ))
+            )
+            .expect("failed to write to string");
         }
 
         output_string
@@ -116,7 +119,8 @@ impl<'a> CodeGenerator<'a> {
 
             let type_string =
                 self.visit_type_with_visibility(&input.get_variable().type_, Some(input.get_variable().mode()));
-            function_string.push_str(&format!("    input {} as {};\n", register_string, type_string,))
+            writeln!(function_string, "    input {} as {};", register_string, type_string,)
+                .expect("failed to write to string");
         }
 
         //  Construct and append the function body.
diff --git a/compiler/passes/src/code_generation/visit_statements.rs b/compiler/passes/src/code_generation/visit_statements.rs
index 2c854ab2f9..e87733cd98 100644
--- a/compiler/passes/src/code_generation/visit_statements.rs
+++ b/compiler/passes/src/code_generation/visit_statements.rs
@@ -55,7 +55,7 @@ impl<'a> CodeGenerator<'a> {
             true => {
                 let (operand, expression_instructions) = self.visit_expression(&input.value);
                 self.variable_mapping
-                    .insert(&input.variable_names[0].identifier.name, operand.clone());
+                    .insert(&input.variable_names[0].identifier.name, operand);
                 expression_instructions
             }
         }
diff --git a/compiler/passes/src/code_generation/visit_type.rs b/compiler/passes/src/code_generation/visit_type.rs
index 4a29d7e470..eb11b51697 100644
--- a/compiler/passes/src/code_generation/visit_type.rs
+++ b/compiler/passes/src/code_generation/visit_type.rs
@@ -17,6 +17,7 @@
 use crate::CodeGenerator;
 
 use leo_ast::{ParamMode, Type};
+use std::fmt::Write as _;
 
 impl<'a> CodeGenerator<'a> {
     pub(crate) fn visit_type(&mut self, input: &'a Type) -> String {
@@ -47,7 +48,7 @@ impl<'a> CodeGenerator<'a> {
         } else {
             // Append `.private` to return type.
             // todo: CAUTION private by default.
-            return_type.push_str(&format!(".{}", visibility.unwrap_or(ParamMode::Private).to_string()));
+            write!(return_type, ".{}", visibility.unwrap_or(ParamMode::Private)).expect("failed to write to string");
         }
 
         return_type
diff --git a/leo/api.rs b/leo/api.rs
index 7da4bf429b..65fc5cf28b 100644
--- a/leo/api.rs
+++ b/leo/api.rs
@@ -86,10 +86,6 @@ impl Api {
         }
     }
 
-    pub fn host(&self) -> &str {
-        &*self.host
-    }
-
     /// Returns the token for bearer auth, otherwise None.
     /// The [`auth_token`] should be passed into the Api through Context.
     pub fn auth_token(&self) -> Option<String> {
diff --git a/leo/commands/build.rs b/leo/commands/build.rs
index ba6be02386..4ef490ebce 100644
--- a/leo/commands/build.rs
+++ b/leo/commands/build.rs
@@ -25,7 +25,6 @@ use leo_package::{
     source::{MainFile, MAIN_FILENAME, SOURCE_DIRECTORY_NAME},
 };
 
-use snarkvm::prelude::*;
 use snarkvm_circuit::prelude::*;
 
 use clap::StructOpt;
@@ -159,7 +158,7 @@ impl Command for Build {
             &handler,
             main_file_path,
             output_directory,
-            Some(self.compiler_options.clone().into()),
+            Some(self.compiler_options.into()),
         );
         program.parse_input(input_path.to_path_buf())?;
 
diff --git a/leo/errors/src/emitter/mod.rs b/leo/errors/src/emitter/mod.rs
index f08d959cbd..180f9f0afc 100644
--- a/leo/errors/src/emitter/mod.rs
+++ b/leo/errors/src/emitter/mod.rs
@@ -299,7 +299,7 @@ mod tests {
             });
             assert_eq!(count_err(res.unwrap_err().to_string()), 2);
 
-            let () = Handler::with(|_| Ok(())).unwrap();
+            Handler::with(|_| Ok(())).unwrap();
         })
     }
 }
diff --git a/leo/span/src/source_map.rs b/leo/span/src/source_map.rs
index e80088a9e4..15ee2b10d0 100644
--- a/leo/span/src/source_map.rs
+++ b/leo/span/src/source_map.rs
@@ -429,7 +429,7 @@ fn analyze_source_file(src: &str, source_file_start_pos: BytePos) -> (Vec<BytePo
             // The slow path:
             // This is either ASCII control character "DEL" or the beginning of
             // a multibyte char. Just decode to `char`.
-            let c = (&src[i..]).chars().next().unwrap();
+            let c = (src[i..]).chars().next().unwrap();
             char_len = c.len_utf8();
 
             if char_len > 1 {