Bicep diagnostic code - BCP321

This diagnostic occurs when the compiler expects a value of one type but you provide something of a different type or null.

Description

Expected a value of type <expected-type> but the provided value is of type <actual-type> | null".

Level

Warning

Solutions

Use the expected type. If you're certain the value will never be null, use the null-forgiving operator to tell the compiler it's safe.

Examples

The following example raises the diagnostic because first(accounts) is possibly null if the array could be empty:

param storageCount int
param location string = resourceGroup().location

resource accounts 'Microsoft.Storage/storageAccounts@2023-05-01' = [for i in range(0, storageCount):{
  name: 'sa${i}'
  location: location
  sku: {
    name: 'Standard_LRS'
  }
  kind: 'StorageV2'
}]

output firstOne object = first(accounts)

You can fix the diagnostic by using the null-forgiving operator:

param storageCount int
param location string = resourceGroup().location

resource accounts 'Microsoft.Storage/storageAccounts@2023-05-01' = [for i in range(0, storageCount):{
  name: 'sa${i}'
  location: location
  sku: {
    name: 'Standard_LRS'
  }
  kind: 'StorageV2'
}]

output firstOne object = first(accounts)!

Next steps

For more information about Bicep diagnostics, see Bicep core diagnostics.