Those of you who suppose yourselves to insist on “grammatically correct English” might want to wrap your heads around this.
Notice that the periphrastic future with ‘go’ is used in the present progressive of ‘go’ with the main or lexical verb in the infinitive e.g. I’m going to buy a car tomorrow. In speech, this is normally reduced to I’m gonna buy a car tomorrow. Most mavens would interpret this as a contraction of ‘going’ and ‘to’ and announce that such speech is careless and slovenly.
But when we encounter the same sequence of sounds in I’m going to college next year, we will never hear *I’m gonna college next year. Why is that?…… mavens, why is that?
How about ‘used to’, as in I used to sing in the choir. No one who speaks English ever pronounces the sd of used any way other than st. Yet if we used the same sequence of sounds, e.g. I used two eggs in that recipe, ‘used’ is pronounced zd. Explain that, if you will, mavens.
Then how about ‘will’ as in ‘Will you go to the store with me?”. Future tense, right? The person wants to know if, in the future, someone WILL, in the future, accompany him. The reply is OK, I will or No, I won’t. Still future? Then the query from a 3rd party, Why won’t you go to the store with him? Is the concern here still the future or one of ‘wanting to’? Of course, the mavens will sidestep the issue by bringing up the old shibboleth of shall/will.