Suggestions

check_api/src/main/java/com/google/errorprone/util/ASTHelpers.java

@@ -809,16 +809,26 @@ private static boolean isFinal(Symbol symbol) {
   }
 
   /**
-   * Flag for a record class and its canonical constructor. Can be replaced by {@code
-   * com.sun.tools.javac.code.Flags.RECORD} once the minimum JDK version is 14.
+   * Flag for record types, canonical record constructors and type members that are part of a
+   * record's state vector. Can be replaced by {@code com.sun.tools.javac.code.Flags.RECORD} once
+   * the minimum JDK version is 14.
    */
   private static final long RECORD_FLAG = 1L << 61;
 
   /**
-   * Returns true if the given {@link Symbol} is a record or the canonical constructor of a record.
+   * Returns true if the given {@link Tree} is a record, a record's canonical constructor or a
+   * member that is part of a record's state vector.
+   */
+  public static boolean isRecord(Tree tree) {
+    return isRecord(getSymbol(tree));
+  }
+
+  /**
+   * Returns true if the given {@link Symbol} is a record, a record's canonical constructor or a
+   * member that is part of a record's state vector.
    */
   public static boolean isRecord(Symbol symbol) {
-    return (symbol.flags() & RECORD_FLAG) == RECORD_FLAG;
+    return symbol != null && (symbol.flags() & RECORD_FLAG) == RECORD_FLAG;
   }
 
   /**

core/src/main/java/com/google/errorprone/bugpatterns/javadoc/InvalidParam.java

@@ -17,6 +17,7 @@
 package com.google.errorprone.bugpatterns.javadoc;
 
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.common.collect.MoreCollectors.onlyElement;
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.bugpatterns.javadoc.Utils.diagnosticPosition;
 import static com.google.errorprone.bugpatterns.javadoc.Utils.getBestMatch;
@@ -26,6 +27,7 @@
 import static com.google.errorprone.names.LevenshteinEditDistance.getEditDistance;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.MoreCollectors;
 import com.google.common.collect.Sets;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
@@ -75,11 +77,10 @@ public final class InvalidParam extends BugChecker implements ClassTreeMatcher,
   public Description matchClass(ClassTree classTree, VisitorState state) {
     DocTreePath path = getDocTreePath(state);
     if (path != null) {
-      // XXX: `isRecord`... should it also be able to handle `Tree`s?
       ImmutableSet<String> parameters =
-          ASTHelpers.isRecord(ASTHelpers.getSymbol(classTree))
-              ? getGeneratedConstructor(classTree).getParameters().stream()
-                  .map(v -> v.getName().toString())
+          ASTHelpers.isRecord(classTree)
+              ? getCanonicalRecordConstructor(classTree).getParameters().stream()
+                  .map(p -> p.getName().toString())
                   .collect(toImmutableSet())
               : ImmutableSet.of();
 
@@ -110,13 +111,12 @@ public Description matchMethod(MethodTree methodTree, VisitorState state) {
     return Description.NO_MATCH;
   }
 
-  private static MethodTree getGeneratedConstructor(ClassTree classTree) {
+  private static MethodTree getCanonicalRecordConstructor(ClassTree classTree) {
     return classTree.getMembers().stream()
         .filter(MethodTree.class::isInstance)
         .map(MethodTree.class::cast)
-        .findFirst()
-        .filter(tree -> tree.getName().contentEquals("<init>"))
-        .orElseThrow(() -> new IllegalStateException("Records must have a generated ctor"));
+        .filter(ASTHelpers::isRecord)
+        .collect(onlyElement());
   }
 
   /** Checks that documented parameters match the method's parameter list. */