diff --git a/crates/codegen/src/ts.rs b/crates/codegen/src/ts.rs
index 544612e..0f82b2b 100644
--- a/crates/codegen/src/ts.rs
+++ b/crates/codegen/src/ts.rs
@@ -6,6 +6,12 @@ pub struct Codegen {
     pub emitted: String,
 }
 
+impl Default for Codegen {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Codegen {
     pub fn new() -> Self {
         Self { emitted: String::new() }
@@ -63,11 +69,11 @@ impl Codegen {
                     "write_file" => { format!("writeFile({}, {}){}\n", self.gen_ir(&args[0], false), self.gen_ir(&args[1], false), semicolon!()) },
                     "read"       => { format!("read({}){}\n"         , self.gen_ir(&args[0], false), semicolon!()) },
                     "read_file"  => { format!("readFile({}){}\n"     , self.gen_ir(&args[0], false), semicolon!()) },
-                    "emit" => { format!("{}", self.gen_ir(&args[0], false).trim_start_matches('"').trim_end_matches('"')) },
-                    
+                    "emit" => { self.gen_ir(&args[0], false).trim_start_matches('"').trim_end_matches('"').to_string() },
+
                     "get" => { format!("{}[{}]", self.gen_ir(&args[0], false), self.gen_ir(&args[1], false)) },
                     "len" => { format!("{}.length", self.gen_ir(&args[0], false)) },
-                    
+
                     "throw" => { format!("throw new Error({}){}", self.gen_ir(&args[0], false), semicolon!()) },
                     _ => unreachable!(format!("Unknown intrinsic: {}", name)) // Shoul be handled by lowering
                 }
@@ -99,7 +105,7 @@ impl Codegen {
             IRKind::Do { body, .. } => {
                 let mut out = "{\n".to_string();
                 for expr in body {
-                    out.push_str(&self.gen_ir(&expr, true));
+                    out.push_str(&self.gen_ir(expr, true));
                 }
                 out.push_str("}\n");
                 out
diff --git a/crates/diagnostic/src/lib.rs b/crates/diagnostic/src/lib.rs
index eb02dd0..0ed7f74 100644
--- a/crates/diagnostic/src/lib.rs
+++ b/crates/diagnostic/src/lib.rs
@@ -15,6 +15,12 @@ pub enum Kind {
     TypecheckError(typecheck::TypecheckError),
 }
 
+impl Default for Diagnostics {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Diagnostics {
     pub fn new() -> Self {
         Self {
@@ -126,7 +132,7 @@ impl Diagnostics {
             _ => None,
         });
         let typecheck_error = self.errors.iter().filter_map(|kind| match kind {
-            Kind::TypecheckError(error) => Some(error.clone()),
+            Kind::TypecheckError(error) => Some(<&typecheck::TypecheckError>::clone(&error)),
             _ => None,
         });
         // TODO: so many .iter(), maybe collapse them into one?
@@ -138,12 +144,12 @@ impl Diagnostics {
 
             let report = Report::build(ReportKind::Error, (), span.start)
                 .with_message(
-                    format!("{}", message)
+                    message.to_string()
                 )
                 .with_label(
                     Label::new(span.clone())
                     .with_message(
-                        format!("{}", message)
+                        message.to_string()
                     )
                     .with_color(Color::Red)
                 );
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 79f226c..380cee0 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -94,7 +94,7 @@ pub struct IR {
     pub span: Range<usize>
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct LoweringError {
     pub span: Range<usize>,
     pub message: String,
diff --git a/crates/lexer/src/lib.rs b/crates/lexer/src/lib.rs
index 16210c8..dd8b9e9 100644
--- a/crates/lexer/src/lib.rs
+++ b/crates/lexer/src/lib.rs
@@ -165,9 +165,10 @@ pub fn lexer() -> impl Parser<char, Vec<(Token, Span)>, Error = Simple<char>> {
         .repeated()
 }
 
+#[allow(clippy::type_complexity)]
 pub fn lex(src: String) -> (Option<Vec<(Token, std::ops::Range<usize>)>>, Vec<Simple<char>>) {
     let (tokens, lex_error) = lexer().parse_recovery(src.as_str());
-    return (tokens, lex_error);
+    (tokens, lex_error)
 }
 
 #[cfg(test)]
diff --git a/crates/parser/src/lib.rs b/crates/parser/src/lib.rs
index 3a1dfe6..262eb05 100644
--- a/crates/parser/src/lib.rs
+++ b/crates/parser/src/lib.rs
@@ -286,7 +286,7 @@ fn expr_parser() -> impl Parser<Token, Vec<Spanned<Expr>>, Error = Simple<Token>
             .map_with_span(|body, span| {
                 (
                     Expr::Do {
-                        body: (body.clone(), span.clone()),
+                        body: (body, span.clone()),
                     },
                     span,
                 )
@@ -366,13 +366,14 @@ fn expr_parser() -> impl Parser<Token, Vec<Spanned<Expr>>, Error = Simple<Token>
         .then_ignore(end())
 }
 
+#[allow(clippy::type_complexity)] // We are going to use this once anyway, why we need to make a type?
 pub fn parse(tokens: Vec<(Token, std::ops::Range<usize>)>, len: usize) -> (Option<Vec<(Expr, std::ops::Range<usize>)>>, Vec<Simple<Token>>) {
     let (ast, parse_error) = expr_parser().parse_recovery(Stream::from_iter(
         len..len + 1,
         tokens.into_iter(),
     ));
 
-    return (ast, parse_error)
+    (ast, parse_error)
 }
 
 #[cfg(test)]
diff --git a/crates/typecheck/src/lib.rs b/crates/typecheck/src/lib.rs
index 8105a5f..e2c2e12 100644
--- a/crates/typecheck/src/lib.rs
+++ b/crates/typecheck/src/lib.rs
@@ -29,7 +29,7 @@ pub struct TypecheckError {
     pub span: std::ops::Range<usize>,
 }
 
-pub fn check(irs: &Vec<IR>) -> Result<(), Vec<TypecheckError>> {
+pub fn check(irs: &[IR]) -> Result<(), Vec<TypecheckError>> {
     let mut errors = Vec::new();
     for ir in irs {
         match &ir.kind {
diff --git a/test.hz b/test.hz
deleted file mode 100644
index 7a7089d..0000000
--- a/test.hz
+++ /dev/null
@@ -1,3 +0,0 @@
-fun main : int = do
-    "Hello, World" |> @write();
-end;