StatementSwitchToExpressionSwitch - remove // fall out comments in switches

PiperOrigin-RevId: 696930118

Author: cushon

core/src/main/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitch.java

@@ -95,7 +95,7 @@ public final class StatementSwitchToExpressionSwitch extends BugChecker
       ImmutableSet.of(THROW, EXPRESSION_STATEMENT);
   private static final ImmutableSet<Kind> KINDS_RETURN_OR_THROW = ImmutableSet.of(THROW, RETURN);
   private static final Pattern FALL_THROUGH_PATTERN =
-      Pattern.compile("\\bfalls?.?through\\b", Pattern.CASE_INSENSITIVE);
+      Pattern.compile("\\bfalls?.?(through|out)\\b", Pattern.CASE_INSENSITIVE);
   // Default (negative) result for assignment switch conversion analysis. Note that the value is
   // immutable.
   private static final AssignmentSwitchAnalysisResult DEFAULT_ASSIGNMENT_SWITCH_ANALYSIS_RESULT =

core/src/test/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitchTest.java

@@ -4705,4 +4705,42 @@ String f(int x) {
             "-XepOpt:StatementSwitchToExpressionSwitch:EnableReturnSwitchConversion=true")
         .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
   }
+
+  @Test
+  public void fallOutComment() {
+    refactoringHelper
+        .addInputLines(
+            "Test.java",
+            """
+            public class Test {
+              String f(int x) {
+                switch (x) {
+                  case 0:
+                    return "ZERO";
+                  default: // fall out
+                }
+                return "";
+              }
+            }
+            """)
+        .addOutputLines(
+            "Test.java",
+            """
+            public class Test {
+              String f(int x) {
+                switch (x) {
+                  case 0 -> {
+                    return "ZERO";
+                  }
+                  default -> {}
+                }
+                return "";
+              }
+            }
+            """)
+        .setArgs(
+            "-XepOpt:StatementSwitchToExpressionSwitch:EnableDirectConversion=true",
+            "-XepOpt:StatementSwitchToExpressionSwitch:EnableReturnSwitchConversion=true")
+        .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
+  }
 }