- Adjust Environment to use BoundNode for the function registry and

correctly initialize the `TypeChecker` with argument types during
  macro expansion.
- Refactor `Specializer::compile` to perform type checking with provided
  arguments before specialization and to correctly extract the return
  type.
- Enhance the `Dumper` to introspect and display specialized closure
  bodies.
- Update `LambdaCollector` to use `BoundNode` consistently.
- Modify `TypeChecker` to accept and inject specialized argument types
  for lambdas.

src/ast/compiler/dumper.rs

@@ -1,5 +1,7 @@
 use crate::ast::nodes::Node;
 use crate::ast::compiler::bound_nodes::BoundKind;
+use crate::ast::types::Value;
+use crate::ast::vm::Closure;
 use std::fmt::Debug;
 
 /// Human-readable AST dumper for the bound AST.
@@ -34,7 +36,31 @@ impl Dumper {
     fn visit<T: Debug>(&mut self, node: &Node<BoundKind<T>, T>) {
         match &node.kind {
             BoundKind::Nop => self.log("Nop", node),
-            BoundKind::Constant(v) => self.log(&format!("Constant: {}", v), node),
+            BoundKind::Constant(v) => {
+                self.log(&format!("Constant: {}", v), node);
+                // Introspect Closure AST if possible
+                if let Value::Object(obj) = v {
+                    if let Some(closure) = obj.as_any().downcast_ref::<Closure>() {
+                        self.indent += 1;
+                        self.write_indent();
+                        self.output.push_str("--- Specialized Body ---\n");
+                        // We need to cast the inner TypedNode to the generic T required by visit.
+                        // Since Dumper is generic over T, but Closure stores TypedNode (where T = StaticType),
+                        // we can only fully dump if T is StaticType.
+                        // However, we can hack it by creating a new Dumper for the inner AST string.
+                        
+                        // We can't call self.visit because types mismatch if T != StaticType.
+                        // So we just recursively dump to string and append.
+                        let inner_dump = Dumper::dump(&closure.function_node);
+                        for line in inner_dump.lines() {
+                            self.write_indent();
+                            self.output.push_str(line);
+                            self.output.push('\n');
+                        }
+                        self.indent -= 1;
+                    }
+                }
+            },
             BoundKind::Get { addr, name } => self.log(&format!("Get: {} ({:?})", name.name, addr), node),
             
             BoundKind::Set { addr, value } => {

src/ast/compiler/lambda_collector.rs

@@ -1,21 +1,20 @@
 use std::collections::HashMap;
-use crate::ast::compiler::TypedNode;
-use crate::ast::compiler::bound_nodes::{BoundKind, Address};
+use crate::ast::compiler::bound_nodes::{BoundKind, Address, BoundNode};
 
 /// A pass that collects all global function definitions (lambdas) into a registry.
 /// This allows the Specializer to retrieve the original AST of a function for monomorphization.
 pub struct LambdaCollector<'a> {
-    registry: &'a mut HashMap<u32, TypedNode>,
+    registry: &'a mut HashMap<u32, BoundNode>,
 }
 
 impl<'a> LambdaCollector<'a> {
     /// Performs a full traversal of the AST and populates the provided registry.
-    pub fn collect(node: &TypedNode, registry: &'a mut HashMap<u32, TypedNode>) {
+    pub fn collect(node: &BoundNode, registry: &'a mut HashMap<u32, BoundNode>) {
         let mut collector = Self { registry };
         collector.visit(node);
     }
 
-    fn visit(&mut self, node: &TypedNode) {
+    fn visit(&mut self, node: &BoundNode) {
         match &node.kind {
             BoundKind::Block { exprs } => {
                 for expr in exprs {
@@ -50,8 +49,6 @@ impl<'a> LambdaCollector<'a> {
             }
 
             BoundKind::Lambda { body, .. } => {
-                // Nested functions are not yet supported for global specialization 
-                // but we traverse them to find potential global definitions inside (if allowed).
                 self.visit(body);
             }
 
@@ -83,7 +80,7 @@ impl<'a> LambdaCollector<'a> {
                 self.visit(bound_expanded);
             }
 
-            _ => {} // Leaf nodes (Constant, Get, Nop, etc.)
+            _ => {} // Leaf nodes
         }
     }
 }

src/ast/compiler/specializer.rs

@@ -2,7 +2,7 @@ use std::collections::HashMap;
 use std::rc::Rc;
 use std::cell::RefCell;
 use crate::ast::types::{StaticType, Value, Signature};
-use crate::ast::compiler::bound_nodes::{BoundKind, Address, TypedNode};
+use crate::ast::compiler::bound_nodes::{BoundKind, Address, TypedNode, BoundNode};
 use crate::ast::nodes::Node;
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -11,11 +11,11 @@ pub struct MonoCacheKey {
     pub arg_types: Vec<StaticType>,
 }
 
-pub type CompileFunc = Rc<dyn Fn(TypedNode, &[StaticType]) -> Result<(Value, StaticType), String>>;
+pub type CompileFunc = Rc<dyn Fn(BoundNode, &[StaticType]) -> Result<(Value, StaticType), String>>;
 pub type RtlLookupFunc = Rc<dyn Fn(&str, &[StaticType]) -> Option<(Value, StaticType)>>;
 
 pub trait FunctionRegistry {
-    fn resolve(&self, addr: Address) -> Option<TypedNode>;
+    fn resolve(&self, addr: Address) -> Option<BoundNode>;
 }
 
 pub type MonoCache = HashMap<MonoCacheKey, (Value, StaticType)>;
@@ -182,18 +182,21 @@ impl Specializer {
             if let Some(compiler) = &self.compiler {
                 match compiler(func_node, &arg_types) {
                     Ok((compiled_val, ret_ty)) => {
+                        let res_val: Value = compiled_val;
+                        let res_ty: StaticType = ret_ty;
+                        
                         // Store in cache
-                        self.cache.borrow_mut().insert(key, (compiled_val.clone(), ret_ty.clone()));
+                        self.cache.borrow_mut().insert(key, (res_val.clone(), res_ty.clone()));
 
                         let specialized_callee = Node {
                             identity: new_callee.identity.clone(),
-                            kind: BoundKind::Constant(compiled_val),
+                            kind: BoundKind::Constant(res_val),
                             ty: StaticType::Function(Box::new(Signature {
                                 params: arg_types,
-                                ret: ret_ty.clone(),
+                                ret: res_ty.clone(),
                             })),
                         };
-                        return (specialized_callee, new_args, ret_ty);
+                        return (specialized_callee, new_args, res_ty);
                     },
                     Err(_) => {
                         // Fallback on error

src/ast/compiler/type_checker.rs

@@ -46,12 +46,66 @@ impl TypeChecker {
         Self { global_types }
     }
 
-    pub fn check(&self, node: BoundNode) -> Result<TypedNode, String> {
-        // Start with a root context. Root scope has no upvalues.
-        // We assume 1000 slots for global script level if needed, but Binder handles it.
-        // Actually, Binder already assigned slot indices. We need to know the max slot.
-        let mut ctx = TypeContext::new(256, vec![], None);
-        self.check_node(node, &mut ctx)
+    pub fn check(&self, node: BoundNode, arg_types: &[StaticType]) -> Result<TypedNode, String> {
+        match node.kind {
+            BoundKind::Lambda { param_count, upvalues, body } => {
+                // 1. Determine types of captured variables (Root lambdas have none)
+                let mut upvalue_types = Vec::with_capacity(upvalues.len());
+                for _ in &upvalues {
+                    upvalue_types.push(StaticType::Any);
+                }
+
+                // 2. Create the specialized context
+                let root_ctx = TypeContext::new(0, vec![], None);
+                let mut lambda_ctx = TypeContext::new(param_count + 64, upvalue_types, Some(&root_ctx));
+                
+                // 3. INJECT specialized argument types into slots
+                for (i, ty) in arg_types.iter().enumerate() {
+                    if (i as u32) < param_count {
+                        lambda_ctx.set_local_type(i as u32, ty.clone());
+                    }
+                }
+
+                // 4. Check body with the new types
+                let body_typed = self.check_node((*body).clone(), &mut lambda_ctx)?;
+                let ret_ty = body_typed.ty.clone();
+
+                // 5. Construct specialized function type
+                let final_params = if arg_types.is_empty() {
+                    vec![StaticType::Any; param_count as usize]
+                } else {
+                    arg_types.to_vec()
+                };
+
+                let fn_ty = StaticType::Function(Box::new(crate::ast::types::Signature {
+                    params: final_params,
+                    ret: ret_ty,
+                }));
+
+                Ok(Node {
+                    identity: node.identity,
+                    kind: BoundKind::Lambda { 
+                        param_count, 
+                        upvalues, 
+                        body: Rc::new(body_typed) 
+                    },
+                    ty: fn_ty,
+                })
+            }
+            _ => {
+                // Fallback: Wrap in implicit lambda
+                let virtual_lambda = BoundNode {
+                    identity: node.identity.clone(),
+                    kind: BoundKind::Lambda { 
+                        param_count: 0, 
+                        upvalues: vec![], 
+                        body: Rc::new(node) 
+                    },
+                    ty: (),
+                };
+                self.check(virtual_lambda, &[])
+            }
+        }
     }
 
     fn check_node(&self, node: BoundNode, ctx: &mut TypeContext) -> Result<TypedNode, String> {