/**

* @name Redundant call to recover

* @description Calling 'recover' in a function which isn't called using a defer

* statement has no effect. Also, putting 'recover' directly in a

* defer statement has no effect.

* @kind problem

* @problem.severity warning

* @id go/redundant-recover

* @tags quality

* reliability

* correctness

* external/cwe/cwe-248

* @precision high

*/

import go

predicate isDeferred(DataFlow::CallNode call) {

exists(DeferStmt defer | defer.getCall() = call.asExpr())

}

from DataFlow::CallNode recoverCall, FuncDef f, string msg

where

recoverCall.getTarget() = Builtin::recover() and

f = recoverCall.getRoot() and

(

isDeferred(recoverCall) and

msg = "Deferred calls to 'recover' have no effect."

or

not isDeferred(recoverCall) and

exists(f.getACall()) and

not isDeferred(f.getACall()) and

msg = "This call to 'recover' has no effect because $@ is never called using a defer statement."

)

select recoverCall, msg, f, "the enclosing function"