a bare infinitive or a verb root?

[Listenever]

What Frank did was wash his shirts yesterday.
(Bas Aarts, English Syntax and Argumentation)

It is said the highlighted part is a VP. And I think ‘was’ is the inflection and then ‘wash’ needs to be called not a bare infinitive but a verb root. Is this right?

 

[Keith Bradford]

Listenever, the two terms bare infinitive and verb root are the same. The bare infinitive is the verb root.

You only need to use the term verb root when you're talking about other forms (such as washing or washed or washerwoman), where you need to distinguish between root and suffix.

 

[AutumnOwl]

Listenever, the two terms bare infinitive and verb root are the same. The bare infinitive is the verb root.

When you are discussing the English language.