From 4f060e1ff140874e1d7424a08c6d23e9c9d50d13 Mon Sep 17 00:00:00 2001
From: Kurt Alfred Kluever <kak@google.com>
Date: Wed, 14 Feb 2024 13:32:20 -0800
Subject: [PATCH] Add a test case demonstrating a
 `CanIgnoreReturnValueSuggester` bug.

PiperOrigin-RevId: 607088772
---
 .../CanIgnoreReturnValueSuggesterTest.java    | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/checkreturnvalue/CanIgnoreReturnValueSuggesterTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/checkreturnvalue/CanIgnoreReturnValueSuggesterTest.java
index 7b1e6f27c0a..6062ed46b27 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/checkreturnvalue/CanIgnoreReturnValueSuggesterTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/checkreturnvalue/CanIgnoreReturnValueSuggesterTest.java
@@ -924,4 +924,49 @@ public void anonymous() {
         .expectUnchanged()
         .doTest();
   }
+
+  @Test
+  public void returningANewInstance() {
+    helper
+        .addInputLines(
+            "MyBuilder.java",
+            "public final class MyBuilder {",
+            "  MyBuilder() { }",
+            "  MyBuilder(String name) { }",
+            "  MyBuilder(MyBuilder builder) { }",
+            "  public MyBuilder passingParam(String name) {",
+            "    return new MyBuilder(name);",
+            "  }",
+            "  public MyBuilder passingThis() {",
+            "    return new MyBuilder(this);",
+            "  }",
+            "  public MyBuilder notPassing() {",
+            "    return new MyBuilder();",
+            "  }",
+            "}")
+        .addOutputLines(
+            "MyBuilder.java",
+            "import com.google.errorprone.annotations.CanIgnoreReturnValue;",
+            "public final class MyBuilder {",
+            "  MyBuilder() { }",
+            "  MyBuilder(String name) { }",
+            "  MyBuilder(MyBuilder builder) { }",
+            // TODO(b/325282579): this is a bug! we should not recommend @CIRV here!
+            "  @CanIgnoreReturnValue",
+            "  public MyBuilder passingParam(String name) {",
+            "    return new MyBuilder(name);",
+            "  }",
+            // TODO(b/325282579): this is a bug! we should not recommend @CIRV here!
+            "  @CanIgnoreReturnValue",
+            "  public MyBuilder passingThis() {",
+            "    return new MyBuilder(this);",
+            "  }",
+            // TODO(b/325282579): this is a bug! we should not recommend @CIRV here!
+            "  @CanIgnoreReturnValue",
+            "  public MyBuilder notPassing() {",
+            "    return new MyBuilder();",
+            "  }",
+            "}")
+        .doTest();
+  }
 }