Can Be Non-nullable

ID

kotlin.can_be_nonnullable

Severity

info

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Kotlin

Tags

code-style, null-safety

Description

Reports val properties declared with a nullable type T? whose initialiser is a compile-time literal known to be non-null (string, numeric, boolean, or character constant). Because a val cannot be reassigned, the property is already guaranteed never to be null, and the type can be tightened from T? to T.

Rationale

val tag: String? = "alpha"   // FLAW — never null, drop the `?`
val explicit: String? = null // OK — initialiser is null
val derived: String? = compute()   // OK — call may return null
val plain: String = "alpha"  // OK — already non-nullable

A nullable type forces every consumer to handle the null branch — usually with ?., !!, or ?:. When the value can never be null, that ceremony adds reading cost without buying any safety.

Remediation

Drop the ? from the type so the compiler enforces the property’s real contract:

val tag: String = "alpha"

References