Fix a false positive when comparing protos.

PiperOrigin-RevId: 384457967
google · Jul 13, 2021 · e08936b · e08936b
1 parent 960c32a
commit e08936b
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Showing 2 changed files with 34 additions and 2 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/TypeCompatibilityUtils.java b/core/src/main/java/com/google/errorprone/bugpatterns/TypeCompatibilityUtils.java
@@ -82,7 +82,8 @@ private TypeCompatibilityReport compatibilityOfTypes(
     }
 
     // If they're the exact same type, they are definitely compatible.
-    if (state.getTypes().isSameType(upperBound(leftType), upperBound(rightType))) {
+    Types types = state.getTypes();
+    if (types.isSameType(upperBound(leftType), upperBound(rightType))) {
       return TypeCompatibilityReport.compatible();
     }
 
@@ -103,7 +104,7 @@ private TypeCompatibilityReport compatibilityOfTypes(
     // class Bar extends Super<String>
     // class Foo extends Super<Integer>
     // Bar and Foo would least-upper-bound to Super, and we compare String and Integer to each-other
-    Type commonSupertype = state.getTypes().lub(rightType, leftType);
+    Type commonSupertype = types.lub(types.erasure(rightType), types.erasure(leftType));
     // primitives, etc. can't have a common superclass.
     if (commonSupertype.getTag().equals(TypeTag.BOT)
         || commonSupertype.getTag().equals(TypeTag.ERROR)) {

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/EqualsIncompatibleTypeTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/EqualsIncompatibleTypeTest.java
@@ -120,4 +120,35 @@ public void methodReference_comparableTypes_noFinding() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void wildcards_whenIncompatible() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            "",
+            "public class Test {",
+            "  public void test(Class<? extends Integer> a, Class<? extends String> b) {",
+            "    // BUG: Diagnostic contains:",
+            "    a.equals(b);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void unconstrainedWildcard_compatibleWithAnything() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
+            "",
+            "public class Test {",
+            "  public void test(java.lang.reflect.Method m, Class<?> c) {",
+            "    TestProtoMessage.class.equals(m.getParameterTypes()[0]);",
+            "    TestProtoMessage.class.equals(c);",
+            "  }",
+            "}")
+        .doTest();
+  }
 }