st: Temporary variables saved by accident

[Adrian Sayers <Adrian.Sayers@bristol.ac.uk>]

Hi All,

I have come across some strange behaviour. After saving a file which uses 
temporary variables, the temporary variables are also saved, and converted 
to permanent variables. I had assumed this would not happen?
If i run all the code together i have no problems.
But if i run part 1 , then part 2 i get an error message of "__000002 
already defined"
I am running version 21.1

// Part 1
clear
	set obs 100
		gen age_1 = 10

tempvar P n
	gen `P' = uniform()
		sort `P'
			gen `n' = _n

save error_test.dta , replace


// Part 2
	use  error_test.dta  , clear
de
	hist age

so the work around is

drop __00*

But why does this happen?

Many thanks

Adrian

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