From 7805e4dbb7697bfe285dd8492c3ad0e6e7e2904b Mon Sep 17 00:00:00 2001
From: Tagir Valeev <tagir.valeev@jetbrains.com>
Date: Thu, 4 Aug 2022 13:10:04 +0200
Subject: [PATCH] [java-dfa] IDEA-299239 Pattern nullity handling for Java 19

GitOrigin-RevId: ded6dcdf0f6b1cca8aec4a223290fc231fb67483
---
 .../dataFlow/NullabilityProblemKind.java      |  8 +++--
 .../dataFlow/java/ControlFlowAnalyzer.java    |  4 ++-
 .../dataFlow/fixture/SwitchNullability.java   | 30 +++++++++++++++++++
 .../DataFlowInspection19Test.java             |  3 ++
 4 files changed, 42 insertions(+), 3 deletions(-)
 create mode 100644 java/java-tests/testData/inspection/dataFlow/fixture/SwitchNullability.java

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullabilityProblemKind.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullabilityProblemKind.java
index d95db6bca8f6..65aba581e9f0 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullabilityProblemKind.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullabilityProblemKind.java
@@ -7,6 +7,7 @@ import com.intellij.codeInspection.dataFlow.java.ControlFlowAnalyzer;
 import com.intellij.codeInspection.dataFlow.jvm.problems.JvmDfaProblem;
 import com.intellij.codeInspection.util.InspectionMessage;
 import com.intellij.java.analysis.JavaAnalysisBundle;
+import com.intellij.pom.java.LanguageLevel;
 import com.intellij.psi.*;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.JavaPsiPatternUtil;
@@ -350,8 +351,11 @@ public final class NullabilityProblemKind<T extends PsiElement> {
           if (labelElementList == null) continue;
           for (PsiCaseLabelElement element : labelElementList.getElements()) {
             if (element instanceof PsiExpression && TypeConversionUtil.isNullType(((PsiExpression)element).getType())) return null;
-            if (element instanceof PsiPattern && expressionType != null &&
-                JavaPsiPatternUtil.isTotalForType(element, expressionType)) return null;
+            if (PsiUtil.getLanguageLevel(element).isLessThan(LanguageLevel.JDK_19_PREVIEW) &&
+                element instanceof PsiPattern && expressionType != null &&
+                JavaPsiPatternUtil.isTotalForType(element, expressionType)) {
+              return null;
+            }
           }
         }
       }
diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/ControlFlowAnalyzer.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/ControlFlowAnalyzer.java
index 715d7304ae01..95d76fd08f40 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/ControlFlowAnalyzer.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/ControlFlowAnalyzer.java
@@ -36,6 +36,7 @@ import com.intellij.codeInspection.dataFlow.types.DfTypes;
 import com.intellij.codeInspection.dataFlow.value.*;
 import com.intellij.codeInspection.dataFlow.value.DfaControlTransferValue.Trap;
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.pom.java.LanguageLevel;
 import com.intellij.psi.*;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.InheritanceUtil;
@@ -1115,7 +1116,8 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
       addInstruction(new JvmPushInstruction(expressionValue, null));
 
       DeferredOffset condGotoOffset = null;
-      if (!JavaPsiPatternUtil.isTotalForType(sourcePattern, checkType)) {
+      if (!JavaPsiPatternUtil.isTotalForType(sourcePattern, checkType) ||
+          !PsiUtil.getLanguageLevel(myCodeFragment).isLessThan(LanguageLevel.JDK_19_PREVIEW)) {
         addInstruction(new DupInstruction());
         addInstruction(new PushValueInstruction(DfTypes.typedObject(JavaPsiPatternUtil.getPatternType(innerPattern), Nullability.NOT_NULL)));
 
diff --git a/java/java-tests/testData/inspection/dataFlow/fixture/SwitchNullability.java b/java/java-tests/testData/inspection/dataFlow/fixture/SwitchNullability.java
new file mode 100644
index 000000000000..5372d3cdf14e
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/fixture/SwitchNullability.java
@@ -0,0 +1,30 @@
+class Test {
+  void test(Object obj) {
+    switch (obj) {
+      case Object o -> {
+        if (<warning descr="Condition 'o == null' is always 'false'">o == null</warning>) {}
+      }
+    }
+    if (<warning descr="Condition 'obj == null' is always 'false'">obj == null</warning>) {}
+  }
+
+  void test2(Object obj) {
+    switch (obj) {
+      case null -> {}
+      case Object o -> {
+        if (<warning descr="Condition 'o == null' is always 'false'">o == null</warning>) {}
+      }
+    }
+    if (obj == null) {}
+  }
+
+  void test3(Object obj) {
+    switch (obj) {
+      case Object o -> {
+        if (<warning descr="Condition 'o == null' is always 'false'">o == null</warning>) {}
+      }
+      case null -> {}
+    }
+    if (obj == null) {}
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection19Test.java b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection19Test.java
index d796f6ebbf9b..cb9b08c87c0a 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection19Test.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection19Test.java
@@ -20,4 +20,7 @@ public class DataFlowInspection19Test extends DataFlowInspectionTestCase {
   public void testWhenPatterns() {
     doTest();
   }
+  public void testSwitchNullability() {
+    doTest();
+  }
 }
\ No newline at end of file