Remove @RelevantJavaTypes annotation from SameLenChecker (#6256)

Author: mernst

checker/src/main/java/org/checkerframework/checker/index/samelen/SameLenChecker.java

@@ -1,7 +1,6 @@
 package org.checkerframework.checker.index.samelen;
 
 import org.checkerframework.common.basetype.BaseTypeChecker;
-import org.checkerframework.framework.qual.RelevantJavaTypes;
 import org.checkerframework.framework.source.SuppressWarningsPrefix;
 
 /**
@@ -10,7 +9,9 @@
  *
  * @checker_framework.manual #index-checker Index Checker
  */
-@RelevantJavaTypes({CharSequence.class, Object[].class, Object.class})
+// This @RelevantJavaTypes annotation is incorrect, because @SameLen can apply to an arbitrary
+// user-defined datatype: https://checkerframework.org/manual/#index-annotating-fixed-size .
+// @RelevantJavaTypes({CharSequence.class, Object[].class, Object.class})
 @SuppressWarningsPrefix({"index", "samelen"})
 public class SameLenChecker extends BaseTypeChecker {
   /** Create a new SameLenChecker. */

checker/tests/index/SameLenIrrelevant.java

@@ -1,20 +1,24 @@
 // Tests that adding an @SameLen annotation to a primitive type is still
 // an error.
 
+// All the errors in this test case are disabled.  They were issued when `@SameLen` was restricted
+// to arrays and CharSequence, but @SameLen can be written on an arbitrary user-defined type:
+// https://checkerframework.org/manual/#index-annotating-fixed-size .
+
 import org.checkerframework.checker.index.qual.SameLen;
 
 public class SameLenIrrelevant {
-  // :: error: (anno.on.irrelevant)
+  // NO :: error: (anno.on.irrelevant)
   public void test(@SameLen("#2") int x, int y) {
     // do nothing
   }
 
-  // :: error: (anno.on.irrelevant)
+  // NO :: error: (anno.on.irrelevant)
   public void test(@SameLen("#2") double x, double y) {
     // do nothing
   }
 
-  // :: error: (anno.on.irrelevant)
+  // NO :: error: (anno.on.irrelevant)
   public void test(@SameLen("#2") char x, char y) {
     // do nothing
   }