byte-compiler bug

Hi,

I'm running into a case where byte-compilation changes
the semantic of a function. This is with R 3.4.0:

  foo <- function(x) { TRUE && x }

  foo(c(a=FALSE))
  # [1] FALSE          # OK

  foo(c(a=TRUE))
  # [1] TRUE           # OK

  foo(c(a=FALSE))
  #     a              # ????
  # FALSE

The 3rd call returned a result that it different from the 1st
call!

After scratching my head for a while, I found out that there
is a lot going on:

  1) When calling foo the first 2 times, the function is not
     byte-compiled so is behaving as expected.

  2) However after the 2nd call, the function gets automatically
     compiled. This seems to be a new feature in R 3.4.0 but
     you'll have to grep the NEWS file to find out (search for
     JIT). The man page for cmpfun/enableJIT nicely explains
     the JIT levels but I couldn't find anywhere that the level
     is set to 3 by default. I don't even know how one is
     supposed to get the current level. Calling enableJIT() to
     change the level returns a value, and this value might
     look like the previous level, but this is undocumented and
     it returns 0 instead of 3 the 1st time I call it anyway.

  3) There is some bug in the byte-compiler that seems to make it
     treat `&&` like if it were `&` when compiling foo.

Cheers,
H.

sessionInfo()

R version 3.4.0 (2017-04-21)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 16.04.2 LTS

Matrix products: default
BLAS: /home/biocbuild/bbs-3.5-bioc/R/lib/libRblas.so
LAPACK: /home/biocbuild/bbs-3.5-bioc/R/lib/libRlapack.so

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] compiler_3.4.0