Fix an incorrect UnnecessaryAnonymousClass refactoring

don't refactor anonymous classes that implement the FI via a superclass. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=250349768
google · Jun 6, 2019 · c775984 · c775984
1 parent be8c5e9
commit c775984
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diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/UnnecessaryAnonymousClass.java b/core/src/main/java/com/google/errorprone/bugpatterns/UnnecessaryAnonymousClass.java
@@ -44,6 +44,7 @@
 import com.sun.source.tree.VariableTree;
 import com.sun.source.util.TreePathScanner;
 import com.sun.tools.javac.code.Symbol;
+import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import com.sun.tools.javac.code.Type;
 import com.sun.tools.javac.tree.JCTree;
 import java.util.Objects;
@@ -99,6 +100,18 @@ public Description matchVariable(VariableTree tree, VisitorState state) {
     if (type == null || !state.getTypes().isFunctionalInterface(type)) {
       return NO_MATCH;
     }
+    MethodSymbol methodSymbol = getSymbol(implementation);
+    if (methodSymbol == null) {
+      return NO_MATCH;
+    }
+    Symbol descriptorSymbol = state.getTypes().findDescriptorSymbol(type.tsym);
+    if (!methodSymbol.getSimpleName().contentEquals(descriptorSymbol.getSimpleName())) {
+      return NO_MATCH;
+    }
+    if (!methodSymbol.overrides(
+        descriptorSymbol, methodSymbol.owner.enclClass(), state.getTypes(), false)) {
+      return NO_MATCH;
+    }
     if (state.isAndroidCompatible()) {
       return NO_MATCH;
     }

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/UnnecessaryAnonymousClassTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/UnnecessaryAnonymousClassTest.java
@@ -91,4 +91,29 @@ public void variable_static() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void abstractClass() {
+    testHelper
+        .addInputLines(
+            "Test.java",
+            "import java.util.function.Function;",
+            "class Test {",
+            "  static abstract class Impl implements Function<String, String> {",
+            "    public String apply(String input) {",
+            "      return input;",
+            "    }",
+            "    public abstract void f(String input);",
+            "  }",
+            "  private final Function<String, String> camelCase = new Impl() {",
+            "    public void f(String input) {}",
+            "  };",
+            "  void g() {",
+            "    Function<String, String> f = camelCase;",
+            "    System.err.println(camelCase.apply(\"world\"));",
+            "  }",
+            "}")
+        .expectUnchanged()
+        .doTest();
+  }
 }