From fbd8b70ca6253e021c14373e365966eadd6f150e Mon Sep 17 00:00:00 2001
From: Mikhail Pyltsin <Mikhail.Pyltsin@jetbrains.com>
Date: Tue, 19 Sep 2023 16:20:50 +0200
Subject: [PATCH] [java-inspections] IDEA-332812 Convert to old-style switch:
 produce incorrect code for null, default

GitOrigin-RevId: f0de0aee91d2b41e1ebb6e7a815851cbbf5b8447
---
 .../EnhancedSwitchBackwardMigrationInspection.java   |  6 +++++-
 .../afterCaseNullDefault.java                        | 12 ++++++++++++
 .../afterReturnCaseNullDefault.java                  | 11 +++++++++++
 .../beforeCaseNullDefault.java                       |  9 +++++++++
 .../beforeReturnCaseNullDefault.java                 |  9 +++++++++
 5 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterCaseNullDefault.java
 create mode 100644 java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterReturnCaseNullDefault.java
 create mode 100644 java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeCaseNullDefault.java
 create mode 100644 java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeReturnCaseNullDefault.java

diff --git a/java/java-impl-inspections/src/com/intellij/codeInspection/EnhancedSwitchBackwardMigrationInspection.java b/java/java-impl-inspections/src/com/intellij/codeInspection/EnhancedSwitchBackwardMigrationInspection.java
index ed491a010f02..d08299005e95 100644
--- a/java/java-impl-inspections/src/com/intellij/codeInspection/EnhancedSwitchBackwardMigrationInspection.java
+++ b/java/java-impl-inspections/src/com/intellij/codeInspection/EnhancedSwitchBackwardMigrationInspection.java
@@ -286,7 +286,11 @@ public final class EnhancedSwitchBackwardMigrationInspection extends AbstractBas
       }
       else {
         PsiCaseLabelElement[] labelElements = labelElementList.getElements();
-        caseExpressionsText = StreamEx.of(labelElements).map(e -> "case " + ct.text(e) + ":").joining("\n");
+        caseExpressionsText = StreamEx.of(labelElements)
+          .map(e -> e instanceof PsiDefaultCaseLabelElement ?
+                    (ct.text(e) + ":") :
+                    ("case " + ct.text(e) + ":"))
+          .joining("\n");
       }
       PsiStatement body = rule.getBody();
       String finalBody;
diff --git a/java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterCaseNullDefault.java b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterCaseNullDefault.java
new file mode 100644
index 000000000000..e2f50b74d329
--- /dev/null
+++ b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterCaseNullDefault.java
@@ -0,0 +1,12 @@
+// "Replace with old style 'switch' statement" "true"
+
+class CaseNullDefault {
+  void bar(Object o) {
+      switch (o) {
+          case null:
+          default:
+              System.out.println("1");
+              break;
+      }
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterReturnCaseNullDefault.java b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterReturnCaseNullDefault.java
new file mode 100644
index 000000000000..062d22f72a3c
--- /dev/null
+++ b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/afterReturnCaseNullDefault.java
@@ -0,0 +1,11 @@
+// "Replace with old style 'switch' statement" "true"
+
+class ReturnCaseNullDefault {
+  int bar(Object o) {
+      switch (o) {
+          case null:
+          default:
+              return 1;
+      }
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeCaseNullDefault.java b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeCaseNullDefault.java
new file mode 100644
index 000000000000..137e16780739
--- /dev/null
+++ b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeCaseNullDefault.java
@@ -0,0 +1,9 @@
+// "Replace with old style 'switch' statement" "true"
+
+class CaseNullDefault {
+  void bar(Object o) {
+    switc<caret>h (o) {
+      case null, default -> System.out.println("1");
+    }
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeReturnCaseNullDefault.java b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeReturnCaseNullDefault.java
new file mode 100644
index 000000000000..fdea31bd3e66
--- /dev/null
+++ b/java/java-tests/testData/inspection/switchExpressionBackwardMigration/beforeReturnCaseNullDefault.java
@@ -0,0 +1,9 @@
+// "Replace with old style 'switch' statement" "true"
+
+class ReturnCaseNullDefault {
+  int bar(Object o) {
+    return switc<caret>h (o) {
+      case null, default -> 1;
+    }
+  }
+}
\ No newline at end of file