Document bcp076

Author: mumian

articles/azure-resource-manager/bicep/diagnostics/bcp076.md

@@ -0,0 +1,58 @@
+---
+title: BCP076
+description: Can't index over expression of type <wrong-type>. Arrays or objects are required.
+ms.topic: reference
+ms.custom: devx-track-bicep
+ms.date: 05/20/2025
+---
+
+# Bicep diagnostic code - BCP076
+
+This diagnostic occurs when attempting to use the index operator ([] or [^index]) on an expression that is not an array or object. This happens when the expression being indexed is of an incompatible type, such as a string, integer, boolean, or null.
+
+## Description
+
+Can't index over expression of type \<wrong-type>. Arrays or objects are required.
+
+## Level
+
+Error
+
+## Examples
+
+The following code attempts to index a string, which triggers BCP076:
+
+```bicep
+var notAnArray = 'hello'
+var invalidAccess = notAnArray[0] // Error: BCP076 - Can't index over expression of type 'hello'. Arrays or objects are required.
+```
+
+This code tries to use the reverse index operator on an integer:
+
+```bicep
+var number = 42
+var invalidIndex = number[^1] // Error: BCP076 - Can't index over expression of type '42'. Arrays or objects are required.
+```
+
+To fix the error, ensure the expression is an array or object:
+
+```bicep
+var sizes = ['small', 'medium', 'large']
+var first = sizes[0] // Returns 'small'
+var last = sizes[^1] // Returns 'large'
+
+var settings = { key1: 'value1', key2: 'value2' }
+var value = settings['key1'] // Returns 'value1'
+```
+
+If you need to extract parts of a string, use string functions like [split](../bicep-functions-string.md#split) or [substring](../bicep-functions-string.md#substring):
+
+```bicep
+var text = 'hello'
+var chars = split(text, '') // Returns ['h', 'e', 'l', 'l', 'o']
+var firstChar = chars[0] // Returns 'h'
+```
+
+## Next steps
+
+For more information about Bicep diagnostics, see [Bicep core diagnostics](../bicep-core-diagnostics.md).