if (whenExpression != null) {
                    val subject = whenExpression.subjectExpression ?: return with(analysisSession) { builtinTypes.BOOLEAN }
                    val kotlinType = analysisContext.analyze(subject).getType(subject)
                    return kotlinType?.toKtNonErrorType(analysisContext)
                }
            }

        val whenExpression = (condition.parent as? KtWhenEntry)?.parent as? KtWhenExpression ?: return null
        val subject = whenExpression.subjectExpression ?: return with(analysisSession) { builtinTypes.BOOLEAN }
        return getKtExpressionNonErrorType(subject)
    }

    private fun getKtExpressionNonErrorType(expression: KtExpression): KtType? =
        getKtExpressionType(expression)?.nonErrorTypeOrNull()

            // Parentheses are ignored for this analysis.
            is KtParenthesizedExpression ->
                doesParentUseChild(parent.parent, parent)

            // When expressions use the subject expression _unless_ the first branch in the
            // when is an `else`.
            is KtWhenExpression ->
                parent.subjectExpression == child && parent.entries.firstOrNull()?.isElse == false