Nullability (PsiFunctionalExpression lambda, int parameterIndex) { PsiElement expression = lambda; PsiElement expressionParent = lambda.getParent(); while(expressionParent instanceof PsiConditionalExpression || expressionParent instanceof PsiParenthesizedExpression) { expression = expressionParent; expressionParent = expressionParent.getParent(); } if (expressionParent instanceof PsiExpressionList list && list.getParent() instanceof PsiMethodCallExpression call) { PsiMethod method = call.resolveMethod(); if (method != null) { int expressionIndex = ArrayUtil.find(list.getExpressions(), expression); return getLambdaParameterNullability(method, expressionIndex, parameterIndex); } } return Nullability.UNKNOWN; }