Don't apply BanUnknownThis conformance rule to TS-originated files

PiperOrigin-RevId: 601702161

Author: Closure Team

src/com/google/javascript/jscomp/ConformanceRules.java

@@ -1631,6 +1631,12 @@ public BanUnknownThis(AbstractCompiler compiler, Requirement requirement)
       super(compiler, requirement);
     }
 
+    @Override
+    protected boolean tsIsAllowlisted() {
+      // We expect TypeScript to already check it.
+      return true;
+    }
+
     @Override
     protected ConformanceResult checkConformance(NodeTraversal t, Node n) {
       if (n.isThis()) {

test/com/google/javascript/jscomp/CheckConformanceTest.java

@@ -2384,6 +2384,18 @@ public void testCustomBanUnknownThis_allowsGoogAssert() {
     testNoWarning("function f() {goog.asserts.assertInstanceof(this, Error);}");
   }
 
+  @Test
+  public void testCustomBanUnknownThis_allowsTs() {
+    configuration =
+        "requirement: {\n"
+            + "  type: CUSTOM\n"
+            + "  java_class: 'com.google.javascript.jscomp.ConformanceRules$BanUnknownThis'\n"
+            + "  error_message: 'BanUnknownThis Message'\n"
+            + "}";
+
+    testNoWarning(srcs(SourceFile.fromCode("file.closure.js", "function f() {alert(this);}")));
+  }
+
   private static String config(String rule, String message, String... fields) {
     String result = "requirement: {\n" + "  type: CUSTOM\n" + "  java_class: '" + rule + "'\n";
     for (String field : fields) {