Bicep diagnostic code - BCP144

This diagnostic occurs when you try to reference a resource or module collection (for example, one defined using a for-loop) without specifying an index. Bicep requires that such references explicitly indicate which resource or module in the collection you're referring to using an array index.

Description

Directly referencing a resource or module collection isn't currently supported here. Apply an array indexer to the expression.

Level

Error

Solutions

To resolve BCP144, use an array index to access each specific resource or module in the collection. Instead of looping over the collection directly, loop over the input array and use the index to reference the corresponding item.

Examples

The following example raises the diagnostic because it references a resource collection without specifying an index.

param names array = [
  'one'
  'two'
]

resource demo 'Microsoft.Storage/storageAccounts@2022-09-01' = [for name in names: {
  name: 'demo${name}'
  location: resourceGroup().location
  sku: {
    name: 'Standard_LRS'
  }
  kind: 'StorageV2'
  properties: {}
}]

// ❌ This line triggers BCP144.
output storageNames array = [for r in demo: r.name]

To resolve BCP144, use an array index to access each specific resource in the collection.

param names array = [
  'one'
  'two'
]

resource demo 'Microsoft.Storage/storageAccounts@2022-09-01' = [for name in names: {
  name: 'demo${name}'
  location: resourceGroup().location
  sku: {
    name: 'Standard_LRS'
  }
  kind: 'StorageV2'
  properties: {}
}]

// ✅ Correct usage with indexing.
output storageNames array = [for (name, i) in names: demo[i].name]

The following example shows the error code with a module collection.

param locations array = [
  'eastus'
  'westus'
]

module storageModule 'storage.bicep' = [for loc in locations: {
  name: 'storage-${loc}'
  params: {
    location: loc
  }
}]

// ❌ This line triggers BCP144.
output moduleOutputs array = [for m in storageModule: m.outputs.storageAccountName]

To resolve BCP144, use an array index to access each specific module in the collection.

param locations array = [
  'eastus'
  'westus'
]

module storageModule 'storage.bicep' = [for loc in locations: {
  name: 'storage-${loc}'
  params: {
    location: loc
  }
}]

// ✅ Correct usage with indexing.
output moduleOutputs array = [for (loc, i) in locations: storageModule[i].outputs.storageAccountName]

Next steps

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