Make instruction private again

src/include/migraph/instruction.hpp

@@ -71,7 +71,7 @@ struct instruction
     // internal
     void replace_argument(instruction_ref old, instruction_ref new_ins);
 
-    public:
+    private:
     operation op;
     shape result;
     std::vector<instruction_ref> output;

src/opt/memory_coloring_impl.cpp

@@ -228,9 +228,9 @@ void memory_coloring_impl::rewrite()
 
             if(is_allocate(ins))
             {
-                assert(!ins->arguments.empty());
+                assert(!ins->inputs().empty());
                 p_program->replace_instruction(
-                    ins, load{ins->arguments.at(0)->result, offset}, scratch_param);
+                    ins, load{ins->inputs().at(0)->get_shape(), offset}, scratch_param);
             }
             else if(is_literal(ins))
             {