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Severity: error
Category: null-safety
Stage: Stage 0 (prototype)

Description

Accessing a property or calling a method on a value of type T? without first narrowing away the null case is a type error. SJS does not support optional chaining as a suppressor — narrow explicitly.

Example

// ✗ error
function getLength(s: string?): number {
  return s.length    // SJS-E003: s might be null
}

Fix

Narrow with a null check first:

// ✓ correct
function getLength(s: string?): number {
  if (s === null) return 0
  return s.length    // s: string here
}

Or use optional chaining only as an expression (not as a suppressor of the error — narrow the result):

const len: number = s?.length ?? 0   // ✓

Related codes

  • SJS-E001 — null assigned to non-nullable type
  • SJS-E011 — non-null assertion (!) is banned
Documentation