NearbyCallers: scan the body of expression lambdas.

PiperOrigin-RevId: 624922054

core/src/main/java/com/google/errorprone/bugpatterns/time/NearbyCallers.java

@@ -167,8 +167,7 @@ private static ImmutableList<Tree> getNearbyTreesToScan(VisitorState state) {
           return ImmutableList.of(parent);
 
         case LAMBDA_EXPRESSION:
-          // if we reach a lambda tree, then don't scan anything since we don't know where/when that
-          // lambda will actually be executed.
+          // if we reach a lambda tree, just scan the lambda body itself
           // TODO(glorioso): for simple expression lambdas, consider looking for use sites and scan
           // *those* sites, but binding the lambda variable to its use site might be rough :(
 
@@ -179,7 +178,7 @@ private static ImmutableList<Tree> getNearbyTreesToScan(VisitorState state) {
           //   long nanos = NANOS.apply(myDuration) + SECONDS.apply(myDuration) * 1_000_000L;
           //
           // how do we track myDuration through both layers?
-          return ImmutableList.of();
+          return ImmutableList.of(((LambdaExpressionTree) parent).getBody());
 
         case CLASS:
           // if we get all the way up to the class tree, then _only_ scan the other class-level

core/src/test/java/com/google/errorprone/bugpatterns/time/JavaDurationGetSecondsGetNanoTest.java

@@ -324,4 +324,22 @@ public void getNanoInLambda() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void bothUsedWithinALambda() {
+    compilationHelper
+        .addSourceLines(
+            "test/TestCase.java",
+            "package test;",
+            "import com.google.common.collect.ImmutableMap;",
+            "import java.time.Duration;",
+            "import java.util.function.Supplier;",
+            "public class TestCase {",
+            "  public static Supplier<ImmutableMap<String, Object>> foo(Duration duration) {",
+            "    return () -> ImmutableMap.of(",
+            "        \"seconds\", duration.getSeconds(), \"nanos\", duration.getNano());",
+            "  }",
+            "}")
+        .doTest();
+  }
 }