# Troubleshooting AWS CloudFormation Guard
Troubleshooting Guard

If you encounter issues while working with AWS CloudFormation Guard, consult the topics in this section.

**Topics**
+ [

## Clause fails when no resources of the selected type are present
](#troubleshooting-when-conditions-filters)
+ [

## Guard does not evaluate CloudFormation template with short-form Fn::GetAtt references
](#troubleshooting-cfn-intrinsic-functions)
+ [

## General troubleshooting topics
](#troubleshooting-general)

## Clause fails when no resources of the selected type are present
Clause fails when no resources of the selected type are present

When a query uses a filter like `Resources.*[ Type == 'AWS::ApiGateway::RestApi' ]`, if there are no `AWS::ApiGateway::RestApi` resources in the input, the clause evaluates to `FAIL`.

```
%api_gws.Properties.EndpointConfiguration.Types[*] == "PRIVATE"
```

To avoid this outcome, assign filters to variables and use the `when` condition check.

```
let api_gws = Resources.*[ Type == 'AWS::ApiGateway::RestApi' ]
    when %api_gws !empty { ...}
```

## Guard does not evaluate CloudFormation template with short-form Fn::GetAtt references
Guard does not evaluate CloudFormation template

Guard doesn't support the short forms of intrinsic functions. For example, using `!Join`, `!Sub` in a YAML-formatted CloudFormation template isn't supported. Instead, use the expanded forms of CloudFormation intrinsic functions. For example, use `Fn::Join`, `Fn::Sub` in YAML-formatted CloudFormation templates when evaluating them against Guard rules.

For more information about intrinsic functions, see the [intrinsic function reference](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference.html) in the *AWS CloudFormation User Guide*.

## General troubleshooting topics
General troubleshooting topics
+ Verify that `string` literals don't contain embedded escaped strings. Guard doesn't support embedded escape strings in `string` literals. If your intent is to parse inline JSON strings, use the `json_parse()` function available in Guard 3.0.0 and later. For more information, see [Using built-in functions](writing-rules.md#built-in-functions).
+ Verify that your `!=` comparisons compare compatible data types. For example, a `string` and an `int` are not compatible data types for comparison. When performing `!=` comparison, if the values are incompatible, an error occurs internally. Currently, the error is suppressed and converted to `false` to satisfy the [PartialEq](https://doc.rust-lang.org/std/cmp/trait.PartialEq.html) trait in Rust.