Leo Liu <sdl.web@gmail.com> writes:

> Due to a typo in my code, I got a bug report on ggtags
> https://github.com/leoliu/ggtags/issues/17. I was fooled by the elisp
> compiler which warns mal-formed let forms without lexical-binding.
>
> To reproduce
> 1. Download the file in the attachment
> 2. byte-compile it
> 3. remove the first line and byte-compile it
>
> step 2 produces no warnings while step 3 does.

Under lexical binding, the malformed `let' is correctly reformed in
`cconv-convert' before it gets passed to the optimizer.  In other words,
it's assumed to be properly formed.  This looks like a bug.

On first thought, it seems that cconv-convert should check for proper
form and signal an _error_ if the check fails.  On the other hand, this
would be inconsistent with what happens under dynamic binding.  (On that
note, under dynamic binding, why is this considered a warning and not an
error?)

Patch attached.