"fix this code" is very broad, it will likely do better with more of a prompt.
"you will be given a section of code wrapped in ``` your task is analysis this code for any possible issues. You should list any issues you find and why you believe it's an issue. Then explain how to correct it"
But the context is there, e.g. I get a bad suggestion by LLM - I suggest a fix - it acknowledged the correction and ignores the instructions when generating code.
"you will be given a section of code wrapped in ``` your task is analysis this code for any possible issues. You should list any issues you find and why you believe it's an issue. Then explain how to correct it"