Warnings and errors are negatives not positive. So if it generates a warning that is OK, it’s a false negative.
Just so you know, if your doctor calls and tells you that your HIV test is positive, you probably shouldn’t run out and celebrate.
That’s why I said false negative. The medical test is testing for the presence of a disease. So if they find the disease is considered a positive test (it found what it was looking for). For static analysis on code, its the opposite. Its testing if your code is free of issues that it can detect. If it finds no issues, then the test was positive. If does find issues, the test failed and each issue is a negative that contributed to the test failing.