Handle yield in Reachability

cushon · Error Prone Team · commit 1ad73c255ade · 2025-03-17T11:04:14.000-07:00
PiperOrigin-RevId: 737678874
diff --git a/check_api/src/main/java/com/google/errorprone/util/Reachability.java b/check_api/src/main/java/com/google/errorprone/util/Reachability.java
@@ -50,6 +50,7 @@
 import com.sun.source.tree.TryTree;
 import com.sun.source.tree.VariableTree;
 import com.sun.source.tree.WhileLoopTree;
+import com.sun.source.tree.YieldTree;
 import com.sun.source.util.SimpleTreeVisitor;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import com.sun.tools.javac.tree.JCTree;
@@ -419,6 +420,12 @@ public Boolean visitReturn(ReturnTree tree, Void unused) {
       return false;
     }
 
+    /* A yield statement cannot complete normally. */
+    @Override
+    public Boolean visitYield(YieldTree tree, Void unused) {
+      return false;
+    }
+
     /* A throw statement cannot complete normally. */
     @Override
     public Boolean visitThrow(ThrowTree tree, Void unused) {
@@ -459,5 +466,10 @@ public Boolean visitTry(TryTree that, Void unused) {
       }
       return completes;
     }
+
+    @Override
+    protected Boolean defaultAction(Tree tree, Void unused) {
+      throw new IllegalStateException(tree.getKind().toString());
+    }
   }
 }
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/PatternMatchingInstanceofTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/PatternMatchingInstanceofTest.java
@@ -698,4 +698,33 @@ public Class stringify(Object o) {
             """)
         .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
   }
+
+  @Test
+  public void switchExpression() {
+    assume().that(Runtime.version().feature()).isAtLeast(21);
+    helper
+        .addInputLines(
+            "Test.java",
+            """
+            class T {
+              interface Filter {
+                Object child();
+              }
+
+              int f(Object o) {
+                return switch (o) {
+                  case Filter filter -> {
+                    if (!(filter.child() instanceof Integer)) {
+                      yield 0;
+                    }
+                    yield 1;
+                  }
+                  default -> 2;
+                };
+              }
+            }
+            """)
+        .expectUnchanged()
+        .doTest();
+  }
 }

Original file line number	Diff line number	Diff line change
`@@ -50,6 +50,7 @@`
`50`	`50`	`import com.sun.source.tree.TryTree;`
`51`	`51`	`import com.sun.source.tree.VariableTree;`
`52`	`52`	`import com.sun.source.tree.WhileLoopTree;`
	`53`	`+import com.sun.source.tree.YieldTree;`
`53`	`54`	`import com.sun.source.util.SimpleTreeVisitor;`
`54`	`55`	`import com.sun.tools.javac.code.Symbol.MethodSymbol;`
`55`	`56`	`import com.sun.tools.javac.tree.JCTree;`
`@@ -419,6 +420,12 @@ public Boolean visitReturn(ReturnTree tree, Void unused) {`
`419`	`420`	`return false;`
`420`	`421`	`}`
`421`	`422`
	`423`	`+ /* A yield statement cannot complete normally. */`
	`424`	`+ @Override`
	`425`	`+ public Boolean visitYield(YieldTree tree, Void unused) {`
	`426`	`+ return false;`
	`427`	`+ }`
	`428`	`+`
`422`	`429`	`/* A throw statement cannot complete normally. */`
`423`	`430`	`@Override`
`424`	`431`	`public Boolean visitThrow(ThrowTree tree, Void unused) {`
`@@ -459,5 +466,10 @@ public Boolean visitTry(TryTree that, Void unused) {`
`459`	`466`	`}`
`460`	`467`	`return completes;`
`461`	`468`	`}`
	`469`	`+`
	`470`	`+ @Override`
	`471`	`+ protected Boolean defaultAction(Tree tree, Void unused) {`
	`472`	`+ throw new IllegalStateException(tree.getKind().toString());`
	`473`	`+ }`
`462`	`474`	`}`
`463`	`475`	`}`