Moved register state to scopes

src/build/core/Variable.go

@@ -15,12 +15,12 @@ type Variable struct {
 
 // Variable returns the variable with the given name or `nil` if it doesn't exist.
 func (s *state) Variable(name string) *Variable {
-	return s.Scope()[name]
+	return s.Scope().variables[name]
 }
 
 // VariableInRegister returns the variable that occupies the given register or `nil` if none occupy the register.
 func (s *state) VariableInRegister(register cpu.Register) *Variable {
-	for _, v := range s.Scope() {
+	for _, v := range s.Scope().variables {
 		if v.Register == register {
 			return v
 		}