Kotlin supports two types of equality: structural equality and referential equality. While there are use cases for both, checking for referential equality for some types (such as String or List) is likely not intentional and may case unexpected results.

Noncompliant Code

val areEqual = "aString" === otherString
val areNotEqual = "aString" !== otherString

Compliant Code

val areEqual = "aString" == otherString
val areNotEqual = "aString" != otherString

Options

• forbiddenTypePatterns (default: ['kotlin.string'])

  Specifies those types for which referential equality checks are considered a rule violation. The types are defined by a list of simple glob patterns (supporting * and ? wildcards) that match the fully qualified type name.