Ensure result inputs always have an entry node.

Author: Max Schaefer

ql/src/semmle/go/dataflow/FunctionInputsAndOutputs.qll

@@ -116,7 +116,7 @@ private class ResultInput extends FunctionInput, TInResult {
     |
       // if the result is assigned to an SSA variable, we want to propagate mutations backwards
       // through that variable
-      exists(DataFlow::SsaNode ssa | ssa.getInit() = pred | result = ssa.(DataFlow::PostUpdateNode))
+      exists(DataFlow::SsaNode ssa | ssa.getInit() = pred | result = ssa)
       or
       // otherwise the entry node is simply the result
       not exists(DataFlow::SsaNode ssa | ssa.getInit() = pred) and

ql/test/library-tests/semmle/go/dataflow/FunctionInputsAndOutputs/FunctionInput_getEntryNode.expected

@@ -25,9 +25,15 @@
 | result | main.go:53:2:53:22 | call to op2 | main.go:53:2:53:22 | call to op2 |
 | result | main.go:53:14:53:21 | call to bump | main.go:53:14:53:21 | call to bump |
 | result | tst2.go:10:9:10:26 | call to NewEncoder | tst2.go:10:9:10:26 | call to NewEncoder |
+| result | tst2.go:10:9:10:39 | call to Encode | tst2.go:10:2:10:4 | definition of err |
 | result | tst.go:9:17:9:33 | call to new | tst.go:9:2:9:12 | definition of bytesBuffer |
 | result 0 | main.go:51:2:51:14 | call to op | main.go:51:2:51:14 | call to op |
 | result 0 | main.go:53:2:53:22 | call to op2 | main.go:53:2:53:22 | call to op2 |
 | result 0 | main.go:53:14:53:21 | call to bump | main.go:53:14:53:21 | call to bump |
+| result 0 | main.go:54:10:54:15 | call to test | main.go:54:2:54:2 | definition of x |
+| result 0 | main.go:56:9:56:15 | call to test2 | main.go:56:2:56:2 | definition of x |
 | result 0 | tst2.go:10:9:10:26 | call to NewEncoder | tst2.go:10:9:10:26 | call to NewEncoder |
+| result 0 | tst2.go:10:9:10:39 | call to Encode | tst2.go:10:2:10:4 | definition of err |
 | result 0 | tst.go:9:17:9:33 | call to new | tst.go:9:2:9:12 | definition of bytesBuffer |
+| result 1 | main.go:54:10:54:15 | call to test | main.go:54:5:54:5 | definition of y |
+| result 1 | main.go:56:9:56:15 | call to test2 | main.go:56:5:56:5 | definition of y |