Avoid throwing when register is void

valuescript_vm/src/bytecode_decoder.rs

@@ -132,7 +132,10 @@ impl BytecodeDecoder {
       }
       BytecodeType::Function => self.decode_function_header(),
       BytecodeType::Pointer => self.decode_pointer(),
-      BytecodeType::Register => registers[self.decode_register_index().unwrap()].clone(),
+      BytecodeType::Register => match registers[self.decode_register_index().unwrap()].clone() {
+        Val::Void => Val::Undefined,
+        val => val,
+      },
       BytecodeType::Builtin => Val::Static(BUILTIN_VALS[self.decode_varsize_uint()]),
       BytecodeType::Class => Val::Class(Rc::new(VsClass {
         constructor: self.decode_val(registers),

valuescript_vm/src/bytecode_stack_frame.rs

@@ -403,8 +403,20 @@ impl StackFrameTrait for BytecodeStackFrame {
       }
 
       Throw => {
-        let error = self.decoder.decode_val(&self.registers);
-        return Err(error);
+        return match self.decoder.peek_type() {
+          BytecodeType::Register => {
+            self.decoder.decode_type();
+
+            // Avoid the void->undefined conversion here
+            let error = self.registers[self.decoder.decode_register_index().unwrap()].clone();
+
+            match error {
+              Val::Void => Ok(FrameStepOk::Continue),
+              _ => Err(error),
+            }
+          }
+          _ => Err(self.decoder.decode_val(&self.registers)),
+        };
       }
 
       Import | ImportStar => {

valuescript_vm/src/vs_function.rs

@@ -42,7 +42,7 @@ impl VsFunction {
     }
 
     while registers.len() < registers.capacity() {
-      registers.push(Val::Undefined);
+      registers.push(Val::Void);
     }
 
     return Box::new(BytecodeStackFrame {