I was claiming that the sentence
The ice cream was so good, he ate all of it. ... (1)
is a run-on sentence. And somebody pointed out that
The ice cream was so good he ate all of it. ... (2)
sounds like it is not a run-on sentence. I think the reason is that it sounds very much like:
The ice cream was so good that he ate all of it. ... (3)
and this doesn't sound like a run-on sentence. Are they run-on sentences? If (3) is not, is it a particular proper grammatical construct that makes it not a run-on sentence? (because there are two clauses (with verbs) and not connected by a conjunction, semicolon, or separated by a period .)
The question was closed because a definition of run-on sentence was needed. The definition is:
A run-on sentence occurs when two or more independent clauses (also known as complete sentences) are connected improperly.