On March 16, the Tennessee House State & Local Government Committee amended HB 3060 to permit a candidate to file simultaneously as an independent candidate, and as a declared write-in candidate in a partisan primary for the same office.
If the candidate then lost the primary, he or she could still run as an independent candidate. See this story, which explains the motivation for the bill. The Speaker of the House is a Republican, but he is considered a traitor by his own party, because he became speaker with the votes of all the Democrats in the House, plus his own vote. As speaker, even though he is a Republican, he has appointed an equal number of committee chairs from each of the two major parties. The Republicans, in retaliation, had announced that he would not be allowed to file for re-election in the Republican primary this year. But if the bill is signed into law, he could be a write-in in the Republican primary. Since no other Republican has yet announced plans to run in his district, he could surely win a Republican primary as a write-in candidate. And if some other Republican does file for that primary, and defeat him, he can still run in that district as an independent.