[BUG] Incorrect calculation of expressions with contains()

[dmgonch]

Existing rule

No response

Description of the issue

An expression that includes contains() seems to always returns true (at least in the repro below). See as well the correct result produced by az deployment group create --what-if ... command.

Error messages

The result of running repro steps below is incorrect - doesNotContain must be false

        "properties": {
            "doesNotContain": true,
            "doesContain": true,
            "indexOfSubstring": 1,
            "stringToCheck": "abcd",
            "stringToFind": "bc",

Reproduction

Create bug.bicep:

var stringToCheck = 'abcd'
var stringToFind = 'bc'
var doesNotContain = !(contains(stringToCheck, stringToFind))
var doesContain = contains(stringToCheck, stringToFind)
var indexOfSubstring = indexOf(stringToCheck, stringToFind)

#disable-next-line BCP081 no-deployments-resources
resource taskDeployment 'Microsoft.Resources/deployments@2020-10-01' = {
  name: 'name'
  properties: {
    mode: 'Incremental'
    template: {
      '$schema': 'https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#'
      contentVersion: '1.0.0.0'
      resources: [
        {
          apiVersion: '2019-12-01'
          type: 'Microsoft.ManagedIdentity/userAssignedIdentities'
          name: 'test'
          properties: {
            doesNotContain: doesNotContain
            doesContain: doesContain
            indexOfSubstring: indexOfSubstring
            stringToCheck: stringToCheck
            stringToFind: stringToFind
          }
        }
      ]
    }
  }
}

Running az deployment group create --what-if -x Ignore --subscription <SUB-ID> -g <RG-NAME> -f bug.bicep produces the correct result:

      properties.doesContain:      true
      properties.doesNotContain:   false
      properties.indexOfSubstring: 1
      properties.stringToCheck:    "abcd"
      properties.stringToFind:     "bc"

Version of PSRule

2.9.0

Version of PSRule for Azure

1.31.0

Additional context

$PSVersionTable

Name                           Value
----                           -----
PSVersion                      7.3.4
PSEdition                      Core
GitCommitId                    7.3.4
OS                             Linux 5.10.102.1-microsoft-standard-WSL2 #1 SMP Wed Mar 2 00:30:59 UTC 2022
Platform                       Unix
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

[BernieWhite]

@dmgonch Thanks for reporting the issue.