From bf9726c4ed9e39e0662935d374a4fd9465fde0a9 Mon Sep 17 00:00:00 2001
From: Tagir Valeev <Tagir.Valeev@jetbrains.com>
Date: Tue, 26 Jan 2021 15:30:29 +0700
Subject: [PATCH] [java-dfa] Avoid extra unboxing in prefix inc/dec operation

Fixes IDEA-260267 Integer equality not properly evaluated after auto-increment

GitOrigin-RevId: 981901b35969c900ae17a362a74dd53884518295
---
 .../dataFlow/ControlFlowAnalyzer.java         | 28 ++++++++++---------
 .../dataFlow/fixture/BoxingIncrement.java     | 17 +++++++++++
 .../DataFlowInspectionTest.java               |  1 +
 3 files changed, 33 insertions(+), 13 deletions(-)
 create mode 100644 java/java-tests/testData/inspection/dataFlow/fixture/BoxingIncrement.java

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java
index 54edf6e294e8..3435ab637fb6 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java
@@ -1941,26 +1941,28 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
       }
       else {
         operand.accept(this);
-        PsiType type = expression.getType();
-        PsiPrimitiveType unboxed = PsiPrimitiveType.getUnboxedType(type);
-        generateBoxingUnboxingInstructionFor(operand, unboxed == null ? type : unboxed);
         if (PsiUtil.isIncrementDecrementOperation(expression)) {
           if (!processIncrementDecrement(expression, operand)) {
             pushUnknown();
             addInstruction(new AssignInstruction(operand, null, myFactory.createValue(operand)));
           }
         }
-        else if (expression.getOperationTokenType() == JavaTokenType.EXCL) {
-          addInstruction(new NotInstruction(expression));
-        }
-        else if (expression.getOperationTokenType() == JavaTokenType.MINUS && (PsiType.INT.equals(type) || PsiType.LONG.equals(type))) {
-          addInstruction(new PushValueInstruction(DfTypes.defaultValue(type)));
-          addInstruction(new SwapInstruction());
-          addInstruction(new BinopInstruction(expression.getOperationTokenType(), expression, type));
-        }
         else {
-          addInstruction(new PopInstruction());
-          pushUnknown();
+          PsiType type = expression.getType();
+          PsiPrimitiveType unboxed = PsiPrimitiveType.getUnboxedType(type);
+          generateBoxingUnboxingInstructionFor(operand, unboxed == null ? type : unboxed);
+          if (expression.getOperationTokenType() == JavaTokenType.EXCL) {
+            addInstruction(new NotInstruction(expression));
+          }
+          else if (expression.getOperationTokenType() == JavaTokenType.MINUS && (PsiType.INT.equals(type) || PsiType.LONG.equals(type))) {
+            addInstruction(new PushValueInstruction(DfTypes.defaultValue(type)));
+            addInstruction(new SwapInstruction());
+            addInstruction(new BinopInstruction(expression.getOperationTokenType(), expression, type));
+          }
+          else {
+            addInstruction(new PopInstruction());
+            pushUnknown();
+          }
         }
       }
     }
diff --git a/java/java-tests/testData/inspection/dataFlow/fixture/BoxingIncrement.java b/java/java-tests/testData/inspection/dataFlow/fixture/BoxingIncrement.java
new file mode 100644
index 000000000000..e2430bbbc5fe
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/fixture/BoxingIncrement.java
@@ -0,0 +1,17 @@
+class X {
+  void test() {
+    Integer integer = 0;
+    ++integer;
+    if (<warning descr="Condition 'integer == 1' is always 'true'">integer == 1</warning>) {
+      System.out.println("Line to be printed");
+    }
+  }
+
+  void test2() {
+    Integer integer = 0;
+    integer++;
+    if (<warning descr="Condition 'integer == 1' is always 'true'">integer == 1</warning>) {
+      System.out.println("Line to be printed");
+    }
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.java b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.java
index f6534018bbcc..5a47fdcc1cc4 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.java
@@ -679,6 +679,7 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testProtobufNotNullGetters() { doTest(); }
   public void testAIOOBETransfer() { doTest(); }
   public void testBoxingShortByte() { doTest(); }
+  public void testBoxingIncrement() { doTest(); }
   public void testUnboxingWithConversionCalls() { doTest(); }
   public void testNullableAliasing() { doTest(); }
   public void testReapplyTypeArguments() { doTest(); }