diff --git a/Nub.Lang/Nub.Lang/Backend/Custom/Generator.cs b/Nub.Lang/Nub.Lang/Backend/Custom/Generator.cs
index cf0ca35..0612329 100644
--- a/Nub.Lang/Nub.Lang/Backend/Custom/Generator.cs
+++ b/Nub.Lang/Nub.Lang/Backend/Custom/Generator.cs
@@ -12,7 +12,7 @@ public class Generator
     private readonly StringBuilder _builder;
     private readonly LabelFactory _labelFactory;
     
-    public Generator(IReadOnlyCollection<DefinitionNode> definitions)
+    public Generator(List<DefinitionNode> definitions)
     {
         _definitions = [];
         _builder = new StringBuilder();
diff --git a/Nub.Lang/Nub.Lang/Backend/Custom/SymbolTable.cs b/Nub.Lang/Nub.Lang/Backend/Custom/SymbolTable.cs
index 9a7824a..2ad9b87 100644
--- a/Nub.Lang/Nub.Lang/Backend/Custom/SymbolTable.cs
+++ b/Nub.Lang/Nub.Lang/Backend/Custom/SymbolTable.cs
@@ -90,7 +90,7 @@ public class SymbolTable
         return variables;
     }
     
-    public Func ResolveFunc(string name, IReadOnlyCollection<Type> parameterTypes)
+    public Func ResolveFunc(string name, List<Type> parameterTypes)
     {
         var func = _funcDefinitions.FirstOrDefault(f => f.SignatureMatches(name, parameterTypes));
         if (func == null)
@@ -101,7 +101,7 @@ public class SymbolTable
         return func;
     }
     
-    public LocalFunc ResolveLocalFunc(string name, IReadOnlyCollection<Type> parameterTypes)
+    public LocalFunc ResolveLocalFunc(string name, List<Type> parameterTypes)
     {
         var func = ResolveFunc(name, parameterTypes);
         if (func is not LocalFunc localFunc)
@@ -111,7 +111,7 @@ public class SymbolTable
         return localFunc;
     }
     
-    public ExternFunc ResolveExternFunc(string name, IReadOnlyCollection<Type> parameterTypes)
+    public ExternFunc ResolveExternFunc(string name, List<Type> parameterTypes)
     {
         var func = ResolveFunc(name, parameterTypes);
         if (func is not ExternFunc externFunc)
@@ -151,7 +151,7 @@ public class GlobalVariable(string name, Type type, string identifier) : Variabl
 
 public abstract class Func
 {
-    protected Func(string name, string startLabel, IReadOnlyCollection<FuncParameter> parameters, Optional<Type> returnType)
+    protected Func(string name, string startLabel, List<FuncParameter> parameters, Optional<Type> returnType)
     {
         Name = name;
         Parameters = parameters;
@@ -161,10 +161,10 @@ public abstract class Func
 
     public string Name { get; }
     public string StartLabel { get; }
-    public IReadOnlyCollection<FuncParameter> Parameters { get; }
+    public List<FuncParameter> Parameters { get; }
     public Optional<Type> ReturnType { get; }
 
-    public bool SignatureMatches(string name, IReadOnlyCollection<Type> parameterTypes)
+    public bool SignatureMatches(string name, List<Type> parameterTypes)
     {
         return Name == name 
                && Parameters.Count == parameterTypes.Count 
@@ -174,21 +174,21 @@ public abstract class Func
 
 public class ExternFunc : Func
 {
-    public ExternFunc(string name, string startLabel, IReadOnlyCollection<FuncParameter> parameters, Optional<Type> returnType) : base(name, startLabel, parameters, returnType)
+    public ExternFunc(string name, string startLabel, List<FuncParameter> parameters, Optional<Type> returnType) : base(name, startLabel, parameters, returnType)
     {
     }
 }
 
 public class LocalFunc : Func
 {
-    public LocalFunc(string name, string startLabel, string endLabel, IReadOnlyCollection<FuncParameter> parameters, Optional<Type> returnType, IReadOnlyCollection<Variable> variables) : base(name, startLabel, parameters, returnType)
+    public LocalFunc(string name, string startLabel, string endLabel, List<FuncParameter> parameters, Optional<Type> returnType, List<Variable> variables) : base(name, startLabel, parameters, returnType)
     {
         EndLabel = endLabel;
         Variables = variables;
     }
 
     public string EndLabel { get; }
-    public IReadOnlyCollection<Variable> Variables { get; }
+    public List<Variable> Variables { get; }
     public int StackAllocation => Variables.OfType<LocalVariable>().Sum(variable => variable.Offset);
 
     public Variable ResolveVariable(string name)
diff --git a/Nub.Lang/Nub.Lang/Frontend/Lexing/Lexer.cs b/Nub.Lang/Nub.Lang/Frontend/Lexing/Lexer.cs
index 9295c63..021b47f 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Lexing/Lexer.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Lexing/Lexer.cs
@@ -48,7 +48,7 @@ public class Lexer
     private string _src = string.Empty;
     private int _index;
 
-    public IReadOnlyCollection<Token> Lex(string src)
+    public List<Token> Lex(string src)
     {
         _src = src;
         _index = 0;
diff --git a/Nub.Lang/Nub.Lang/Frontend/Parsing/BlockNode.cs b/Nub.Lang/Nub.Lang/Frontend/Parsing/BlockNode.cs
index 972f19a..213cc7c 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Parsing/BlockNode.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Parsing/BlockNode.cs
@@ -1,6 +1,6 @@
 namespace Nub.Lang.Frontend.Parsing;
 
-public class BlockNode(IReadOnlyCollection<StatementNode> statements) : Node
+public class BlockNode(List<StatementNode> statements) : Node
 {
-    public IReadOnlyCollection<StatementNode> Statements { get; } = statements;
+    public List<StatementNode> Statements { get; } = statements;
 }
\ No newline at end of file
diff --git a/Nub.Lang/Nub.Lang/Frontend/Parsing/ExternFuncDefinitionNode.cs b/Nub.Lang/Nub.Lang/Frontend/Parsing/ExternFuncDefinitionNode.cs
index 540cb90..3c6455d 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Parsing/ExternFuncDefinitionNode.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Parsing/ExternFuncDefinitionNode.cs
@@ -2,10 +2,10 @@
 
 namespace Nub.Lang.Frontend.Parsing;
 
-public class ExternFuncDefinitionNode(string name, IReadOnlyCollection<FuncParameter> parameters, Optional<Type> returnType) : DefinitionNode
+public class ExternFuncDefinitionNode(string name, List<FuncParameter> parameters, Optional<Type> returnType) : DefinitionNode
 {
     public string Name { get; } = name;
-    public IReadOnlyCollection<FuncParameter> Parameters { get; } = parameters;
+    public List<FuncParameter> Parameters { get; } = parameters;
     public Optional<Type> ReturnType { get; } = returnType;
 
     public override string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
diff --git a/Nub.Lang/Nub.Lang/Frontend/Parsing/FuncCall.cs b/Nub.Lang/Nub.Lang/Frontend/Parsing/FuncCall.cs
index 322ce20..e5e8e85 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Parsing/FuncCall.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Parsing/FuncCall.cs
@@ -1,9 +1,9 @@
 namespace Nub.Lang.Frontend.Parsing;
 
-public class FuncCall(string name, IReadOnlyCollection<ExpressionNode> parameters)
+public class FuncCall(string name, List<ExpressionNode> parameters)
 {
     public string Name { get; } = name;
-    public IReadOnlyCollection<ExpressionNode> Parameters { get; } = parameters;
+    public List<ExpressionNode> Parameters { get; } = parameters;
 
     public override string ToString() => $"{Name}()";
 }
\ No newline at end of file
diff --git a/Nub.Lang/Nub.Lang/Frontend/Parsing/LocalFuncDefinitionNode.cs b/Nub.Lang/Nub.Lang/Frontend/Parsing/LocalFuncDefinitionNode.cs
index aa65420..d508a79 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Parsing/LocalFuncDefinitionNode.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Parsing/LocalFuncDefinitionNode.cs
@@ -2,10 +2,10 @@
 
 namespace Nub.Lang.Frontend.Parsing;
 
-public class LocalFuncDefinitionNode(string name, IReadOnlyCollection<FuncParameter> parameters, BlockNode body, Optional<Type> returnType) : DefinitionNode
+public class LocalFuncDefinitionNode(string name, List<FuncParameter> parameters, BlockNode body, Optional<Type> returnType) : DefinitionNode
 {
     public string Name { get; } = name;
-    public IReadOnlyCollection<FuncParameter> Parameters { get; } = parameters;
+    public List<FuncParameter> Parameters { get; } = parameters;
     public BlockNode Body { get; } = body;
     public Optional<Type> ReturnType { get; } = returnType;
 
diff --git a/Nub.Lang/Nub.Lang/Frontend/Parsing/ModuleNode.cs b/Nub.Lang/Nub.Lang/Frontend/Parsing/ModuleNode.cs
index f5e6231..c992fde 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Parsing/ModuleNode.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Parsing/ModuleNode.cs
@@ -1,8 +1,8 @@
 namespace Nub.Lang.Frontend.Parsing;
 
-public class ModuleNode(string path, IReadOnlyCollection<string> imports, IReadOnlyCollection<DefinitionNode> definitions) : Node
+public class ModuleNode(string path, List<string> imports, List<DefinitionNode> definitions) : Node
 {
     public string Path { get; } = path;
-    public IReadOnlyCollection<string> Imports { get; } = imports;
-    public IReadOnlyCollection<DefinitionNode> Definitions { get; } = definitions;
+    public List<string> Imports { get; } = imports;
+    public List<DefinitionNode> Definitions { get; } = definitions;
 }
\ No newline at end of file
diff --git a/Nub.Lang/Nub.Lang/Frontend/Parsing/Parser.cs b/Nub.Lang/Nub.Lang/Frontend/Parsing/Parser.cs
index f546899..1950127 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Parsing/Parser.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Parsing/Parser.cs
@@ -6,10 +6,10 @@ namespace Nub.Lang.Frontend.Parsing;
 
 public class Parser
 {
-    private IReadOnlyCollection<Token> _tokens = [];
+    private List<Token> _tokens = [];
     private int _index;
     
-    public ModuleNode ParseModule(IReadOnlyCollection<Token> tokens, string path)
+    public ModuleNode ParseModule(List<Token> tokens, string path)
     {
         _index = 0;
         _tokens = tokens;
diff --git a/Nub.Lang/Nub.Lang/Frontend/Parsing/Syscall.cs b/Nub.Lang/Nub.Lang/Frontend/Parsing/Syscall.cs
index eb76aaf..7c0ab16 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Parsing/Syscall.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Parsing/Syscall.cs
@@ -1,6 +1,6 @@
 namespace Nub.Lang.Frontend.Parsing;
 
-public class Syscall(IReadOnlyCollection<ExpressionNode> parameters)
+public class Syscall(List<ExpressionNode> parameters)
 {
-    public IReadOnlyCollection<ExpressionNode> Parameters { get; } = parameters;
+    public List<ExpressionNode> Parameters { get; } = parameters;
 }
\ No newline at end of file
diff --git a/Nub.Lang/Nub.Lang/Frontend/Typing/ExpressionTyper.cs b/Nub.Lang/Nub.Lang/Frontend/Typing/ExpressionTyper.cs
index a700751..f0c3d6e 100644
--- a/Nub.Lang/Nub.Lang/Frontend/Typing/ExpressionTyper.cs
+++ b/Nub.Lang/Nub.Lang/Frontend/Typing/ExpressionTyper.cs
@@ -3,10 +3,10 @@ using Nub.Lang.Frontend.Parsing;
 
 namespace Nub.Lang.Frontend.Typing;
 
-public class Func(string name, IReadOnlyCollection<FuncParameter> parameters, Optional<BlockNode> body, Optional<Type> returnType)
+public class Func(string name, List<FuncParameter> parameters, Optional<BlockNode> body, Optional<Type> returnType)
 {
     public string Name { get; } = name;
-    public IReadOnlyCollection<FuncParameter> Parameters { get; } = parameters;
+    public List<FuncParameter> Parameters { get; } = parameters;
     public Optional<BlockNode> Body { get; } = body;
     public Optional<Type> ReturnType { get; } = returnType;
 }
@@ -17,7 +17,7 @@ public class ExpressionTyper
     private readonly List<GlobalVariableDefinitionNode> _variableDefinitions;
     private readonly Stack<Variable> _variables;
 
-    public ExpressionTyper(IReadOnlyCollection<DefinitionNode> definitions)
+    public ExpressionTyper(List<DefinitionNode> definitions)
     {
         _variables = new Stack<Variable>();
         _functions = [];
diff --git a/Nub.Lang/Nub.Lang/Program.cs b/Nub.Lang/Nub.Lang/Program.cs
index 0e936c4..2ad2dd0 100644
--- a/Nub.Lang/Nub.Lang/Program.cs
+++ b/Nub.Lang/Nub.Lang/Program.cs
@@ -42,7 +42,7 @@ internal static class Program
         }
 
         var modules = RunFrontend(input);
-        var definitions = modules.SelectMany(f => f.Definitions).ToArray();
+        var definitions = modules.SelectMany(f => f.Definitions).ToList();
 
         var typer = new ExpressionTyper(definitions);
         typer.Populate();
@@ -54,7 +54,7 @@ internal static class Program
         return 0;
     }
 
-    private static IEnumerable<ModuleNode> RunFrontend(string path)
+    private static List<ModuleNode> RunFrontend(string path)
     {
         List<ModuleNode> modules = [];
         RunFrontend(path, modules);
diff --git a/Nub.Lang/Nub.Lang/Type.cs b/Nub.Lang/Nub.Lang/Type.cs
index 16cef56..39ee50d 100644
--- a/Nub.Lang/Nub.Lang/Type.cs
+++ b/Nub.Lang/Nub.Lang/Type.cs
@@ -45,13 +45,13 @@ public record StringType : Type
 
 public record DelegateType : Type
 {
-    public DelegateType(IReadOnlyCollection<Type> parameters, Optional<Type> returnType)
+    public DelegateType(List<Type> parameters, Optional<Type> returnType)
     {
         Parameters = parameters;
         ReturnType = returnType;
     }
     
-    public IReadOnlyCollection<Type> Parameters { get; }
+    public List<Type> Parameters { get; }
     public Optional<Type> ReturnType { get; }
 
     public override string ToString() => $"({string.Join(", ", Parameters)}): {(ReturnType.HasValue ? ReturnType.Value.ToString() : "")}";