Meaning of option "Enable diagnostics within R function calls"

Enable diagnosis in R function call makes me confused and I found its explanation in Code Diagnostics in the RStudio IDE – Posit Support. I check or uncheck this option when all other diagnostic options are checked, the diagnostic information of the example (dplyr::select(mtcars, mpg, cyl)) did not change. There is only a warning about undefined variables, but in fact this warning is provided by option " Warn if variable used has no definition in scope"
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I wonder if anyone can provide relevant pictures or dynamic diagrams to illustrate the function of this option. Thanks in advance.