Well, they do say very clearly that they "solve" problems by
program synthesisand what they describe is perfectly legit program synthesis.
To clarify, program synthesis (or automatic programming) is the task of
generating programs from specifications. There are two kinds of program
synthesis: deductive program synthesis, from a complete specification of the
target program; and inductive program synthesis, or program induction, from an
incomplete specification (such as sets of program inputs and outputs, or
traces). An example of deductive program synthesis is the generation of
low-level code from a high-level language by a compiler.
What the paper describes is a kind of deductive program synthesis from a
complete specification in natural lanaguage. I suspect the true contribution of
the work is the demonstration of using natural language as a complete
specification, where earlier work generally only demonstrated the use of natural
language as incomplete specification (for example, comments describing intent
rather than implementation) and the combination of natural language with code;
as in the original Codex work [Edit: actually, now that I look again, the codex
paper also has examples of comments that fully specify the target program, e.g.
in Figure 2: https://arxiv.org/abs/2107.03374; so the work above is typically
incremental].
On the other hand it's clear to me that the training has made the model memorise
answers and all the work in prompt engineering, described under "Workflow"
serves to find the right prompts to retrieve the desired memorisations, much
like one must fire just the right SQL query to get back the right data.
Certainly interesting to see in action and useful for everyday work, but far
from "solving" anything in the gradniose way that it is announced by the authors
(e.g. "These astounding results..." in section "Conclusion", etc).