The following has evaluated to null or missing:
==> a[1] [in template "template" at line 144, column 14]
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Tip: It's the final [] step that caused this error, not those before it.
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Tip: If the failing expression is known to be legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present#elsewhen-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
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FTL stack trace ("~" means nesting-related):
- Failed at: ${a[1]} [in template "template" at line 144, column 12]