code: public static ImmutableList<Fix> fixesByReplacingExpressionWithLocallyDeclaredField(
        ExpressionTree input, Predicate<JCVariableDecl> validFieldPredicate, VisitorState state) {
      Preconditions.checkState(input.getKind() == IDENTIFIER || input.getKind() == MEMBER_SELECT);
  
      ImmutableMultimap<Integer, JCVariableDecl> potentialReplacements =
          ASTHelpers.findEnclosingNode(state.getPath(), JCClassDecl.class).getMembers().stream()
              .filter(JCVariableDecl.class::isInstance)
              .map(JCVariableDecl.class::cast)
              .filter(validFieldPredicate)
              .collect(collectByEditDistanceTo(simpleNameOfIdentifierOrMemberAccess(input)));
  
      return buildValidReplacements(
          potentialReplacements, var -> SuggestedFix.replace(input, "this." + var.sym));
    }
docs: Suggest replacing {@code input} with a qualified reference to a locally declared field with a
  similar or the same name as the {@code input} expression.
  
  @param input a MEMBER_SELECT or IDENTIFIER expression which should be replaced.
  @param validFieldPredicate Predicate used to decide which locally declared fields are
  appropriate candidates for replacement (e.g.: is the appropriate type)