Call pushExpressionResult after field flushing so CommonDataflow (and other clients) has flushed result

Fixes IDEA-230116 Incorrect "Redundant operation on empty container" inspection result

GitOrigin-RevId: d764150c114bca699202dc39160efc084c077036

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/StandardInstructionVisitor.java

@@ -233,7 +233,11 @@ public class StandardInstructionVisitor extends InstructionVisitor {
     DfaValue defaultResult = runner.getFactory().getObjectType(returnType, DfaPsiUtil.getElementNullability(returnType, method));
     Set<DfaCallState> currentStates = Collections.singleton(new DfaCallState(state.createClosureState(), callArguments));
     for (MethodContract contract : contracts) {
-      currentStates = addContractResults(contract, currentStates, runner.getFactory(), new HashSet<>(), defaultResult, methodRef);
+      Set<DfaMemoryState> results = new HashSet<>();
+      currentStates = addContractResults(contract, currentStates, runner.getFactory(), results, defaultResult, methodRef);
+      for (DfaMemoryState result : results) {
+        pushExpressionResult(result.pop(), new ResultOfInstruction(methodRef), result);
+      }
     }
     for (DfaCallState currentState: currentStates) {
       pushExpressionResult(defaultResult, new ResultOfInstruction(methodRef), currentState.myMemoryState);
@@ -366,7 +370,7 @@ public class StandardInstructionVisitor extends InstructionVisitor {
       }
     }
     for (DfaCallState callState : currentStates) {
-      pushExpressionResult(defaultResult, instruction, callState.myMemoryState);
+      callState.myMemoryState.push(defaultResult);
       finalStates.add(callState.myMemoryState);
     }
 
@@ -376,6 +380,7 @@ public class StandardInstructionVisitor extends InstructionVisitor {
       if (instruction.shouldFlushFields()) {
         state.flushFields();
       }
+      pushExpressionResult(state.pop(), instruction, state);
       result[i++] = new DfaInstructionState(runner.getInstruction(instruction.getIndex() + 1), state);
     }
     return result;
@@ -507,7 +512,7 @@ public class StandardInstructionVisitor extends InstructionVisitor {
       }
       if(state != null) {
         DfaValue result = contract.getReturnValue().getDfaValue(factory, defaultResult, new DfaCallState(state, arguments));
-        pushExpressionResult(result, new ResultOfInstruction(expression), state);
+        state.push(result);
         finalStates.add(state);
       }
     }

plugins/InspectionGadgets/test/com/siyeh/igtest/redundancy/redundant_operation_on_empty_container/EmptyCollectionReturnThis.java

@@ -0,0 +1,24 @@
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.stream.Stream;
+class TestInspection
+{
+  public static Stream<String> foo2(Object o)
+  {
+    HashSet<String> set = new HashSet<>();
+    return collect(o, set).stream();
+  }
+  public static Stream<String> foo(Object o)
+  {
+    return collect(o, new HashSet<>()).stream();
+  }
+  private static Collection<String> collect(Object o, Collection<String> result)
+  {
+    collectAll(o, result);
+    return result;
+  }
+  private static void collectAll(Object o, Collection<String> result)
+  {
+    result.add("foo");
+  }
+}

plugins/InspectionGadgets/testsrc/com/siyeh/ig/redundancy/RedundantOperationOnEmptyContainerInspectionTest.java

@@ -23,6 +23,9 @@ public class RedundantOperationOnEmptyContainerInspectionTest extends LightJavaI
   public void testStaticInitializer() {
     doTest();
   }
+  public void testEmptyCollectionReturnThis() { 
+    doTest();
+  }
 
   @Nullable
   @Override