/**

* @name Unnecessary delete statement in function

* @description Using a 'delete' statement to delete a local variable is

* unnecessary, because the variable is deleted automatically when

* the function exits.

* @kind problem

* @tags maintainability

* useless-code

* @problem.severity warning

* @sub-severity low

* @precision high

* @id py/unnecessary-delete

*/

import python

predicate isInsideLoop(AstNode node) {

}

from Delete del, Expr e, Function f

where

f.getLastStatement() = del and

e = del.getATarget() and

f.containsInScope(e) and

not e instanceof Subscript and

not e instanceof Attribute and

not isInsideLoop(del) and

// False positive: calling `sys.exc_info` within a function results in a

// reference cycle, and an explicit call to `del` helps break this cycle.

not exists(FunctionValue ex |

ex = Value::named("sys.exc_info") and

ex.getACall().getScope() = f

)

select del, "Unnecessary deletion of local variable $@ in function $@.", e, e.toString(), f,

f.getName()