UnnecessaryLambda: keep the receiver of the method we're replacing _i…

…f one exists_. Not sure this is correct in 100% of cases, but it fixes the new test without breaking the old tests. :) PiperOrigin-RevId: 482201874
google · Oct 19, 2022 · 0087e31 · 0087e31
1 parent 6d82c80
commit 0087e31
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Showing 2 changed files with 43 additions and 4 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/UnnecessaryLambda.java b/core/src/main/java/com/google/errorprone/bugpatterns/UnnecessaryLambda.java
@@ -290,10 +290,13 @@ private static void replaceUseWithMethodReference(
           (receiver != null ? "." : "") + newName);
     } else {
       Symbol sym = getSymbol(node);
-      fix.replace(
-          node,
-          String.format(
-              "%s::%s", isStatic(sym) ? sym.owner.enclClass().getSimpleName() : "this", newName));
+      String receiverCode;
+      if (node instanceof MethodInvocationTree && getReceiver(node) != null) {
+        receiverCode = state.getSourceForNode(getReceiver(node));
+      } else {
+        receiverCode = isStatic(sym) ? sym.owner.enclClass().getSimpleName().toString() : "this";
+      }
+      fix.replace(node, String.format("%s::%s", receiverCode, newName));
     }
   }
 

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/UnnecessaryLambdaTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/UnnecessaryLambdaTest.java
@@ -352,4 +352,40 @@ public void producesIgnored() {
         .expectUnchanged()
         .doTest();
   }
+
+  @Test
+  public void e() {
+    testHelper
+        .addInputLines(
+            "Test.java",
+            "import java.util.function.Predicate;",
+            "class Test {",
+            "  private void foo(Predicate<Object> p) {}",
+            "  public void test() {",
+            "    foo(E.ELEM.pred());",
+            "  }",
+            "  private enum E {",
+            "    ELEM;",
+            "    Predicate<Object> pred() {",
+            "      return o -> true;",
+            "    }",
+            "  }",
+            "}")
+        .addOutputLines(
+            "Test.java",
+            "import java.util.function.Predicate;",
+            "class Test {",
+            "  private void foo(Predicate<Object> p) {}",
+            "  public void test() {",
+            "    foo(E.ELEM::pred);",
+            "  }",
+            "  private enum E {",
+            "    ELEM;",
+            "    boolean pred(Object o) {",
+            "      return true;",
+            "    }",
+            "  }",
+            "}")
+        .doTest();
+  }
 }