New feature: Recognize functions that modify the parent environment?

[jcrodriguez1989]

For example, when opt_constant_propagation finds a function call, it deletes the previously found constant-assigned values. This is mainly done to avoid having

x <- 1
assign("x", 3)
y <- x

Propagated to

x <- 1
assign("x", 3)
y <- 1

In R we can list which base functions modify the environment, for example, assign, rm, etc. However, this would not be a solution, as we can define new functions that wrap the base ones, for instance:

rm_all <- function() {
env <- .GlobalEnv
rm(list = ls(envir = env), envir = env)
}

A possible solution would be to let the user identify which functions edit the environment.

• in a roxygen2 way:

# o @edits_env rm_all
...

or

rm_all() # o @edits_env

• by parameter:

opt_constant_propagation(list(code), env_edit = c("rm_all", ...))