Using R Studio version 1.1.453
When the "Check arguments to R function calls" option (Tools > Global Options > Code > Diagnostics) is checked, if a function is created in a list and named after another function, diagnostics will use the function in the list to check subsequent calls.
a <- list( paste = function(x) paste(x, collapse = ""), x = paste(letters, collapse = "") ) y <- paste(letters, collapse = "")
In this example, each flag says, "too many arguments in call to 'paste'". Of course, the code runs fine.