Refactor closure instantiation and inlining

This commit makes several changes related to how closures are handled:

- **Dumper:** Removes redundant introspection of closure ASTs, as this
  is no longer relevant.
- **Optimizer:** Updates `try_inline` to accept `ExecNode` for
  parameters and adds a check to ensure the `function_node` is a
  `Lambda` before attempting inlining.
- **Environment:** Simplifies closure creation by passing an `ExecNode`
  for parameters and ensuring the correct `stack_size` is used.
- **VM:** Adjusts `Closure` to store an `ExecNode` for parameters and
  updates `VM::unpack` to accept an `ExecNode`.

src/ast/vm.rs

@@ -1,6 +1,5 @@
 use crate::ast::compiler::bound_nodes::{Address, AnalyzedNode, BoundKind};
 use crate::ast::compiler::lowering::ExecNode;
-use crate::ast::compiler::bound_nodes::Node;
 use crate::ast::types::{Object, Value};
 use std::any::Any;
 use std::cell::RefCell;
@@ -8,8 +7,8 @@ use std::rc::Rc;
 
 #[derive(Debug, Clone)]
 pub struct Closure {
-    /// The analyzed parameter pattern.
-    pub parameter_node: Rc<AnalyzedNode>,
+    /// The executable parameter pattern.
+    pub parameter_node: Rc<ExecNode>,
     /// The analyzed body (before TCO).
     pub function_node: Rc<AnalyzedNode>,
     /// The executable node (after TCO).
@@ -23,7 +22,7 @@ pub struct Closure {
 impl Closure {
     #[inline]
     pub fn new(
-        params: Rc<AnalyzedNode>,
+        params: Rc<ExecNode>,
         body: Rc<AnalyzedNode>,
         exec: Rc<ExecNode>,
         upvalues: Vec<Rc<RefCell<Value>>>,
@@ -512,7 +511,7 @@ impl VM {
                 }
                 let stack_size = node.ty.stack_size;
                 let closure = Closure::new(
-                    params.ty.original.clone(),
+                    params.clone(),
                     body.ty.original.clone(),
                     body.clone(),
                     captured,
@@ -1026,9 +1025,9 @@ impl VM {
         }
     }
 
-    fn unpack<T>(
+    fn unpack(
         &mut self,
-        pattern: &Node<T>,
+        pattern: &ExecNode,
         values: &[Value],
         offset: &mut usize,
     ) -> Result<(), String> {