[Ur] Compiler Bug?

[Adam Chlipala]

Karn Kallio wrote:
> Here is an example of Ur/Web code which leads to generation of a webapp.c
> which does not compile ... maybe it is an urweb compiler bug?
>    

It was two separate bugs.

First, the compiler was still asking GCC to process generated C code, 
even when errors were encountered during the code generation process.

Second, the "Especialize" optimization wasn't removing some uses of 
higher-order functions.  This was responsible for the first two lines in 
the error output, which are the only two that should have been output in 
the first place.  I've tweaked the heuristic so that the appropriate 
simplifications are made.