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stan-dev / stanc3

The Stan transpiler (from Stan to C++ and beyond).
BSD 3-Clause "New" or "Revised" License
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False positive on integer division warning #429

Closed bgoodri closed 4 years ago

bgoodri commented 4 years ago

When I do

./stanc.exe --allow_undefined --include_paths ~/stan-dev/rstanarm/src/stan_files/ --print-cpp ~/stan-dev/rstanarm/src/stan_files/mvmer.stan

I get an int division warning:

Info: Found int division at '/home/ben/stan-dev/rstanarm/src/stan_files///functions/mvmer_functions.stan', line 422, column 11, included from '/home/ben/stan-dev/rstanarm/src/stan_files/mvmer.stan', line 12, column 0: mean_PPD / N Positive values rounded down, negative values rounded up or down in platform-dependent way.

The line in question is

https://github.com/stan-dev/rstanarm/blob/master/src/stan_files/functions/mvmer_functions.stan#L428

but mean_PPD is declared as real up above, so this is a double divided by int operation rather than integer division.

adamhaber commented 4 years ago

This comes from | UReal, UInt, Divide here:

https://github.com/stan-dev/stanc3/blob/c63095d306f45b97364d985950b8cfd62509a7c9/src/frontend/Semantic_check.ml#L593-L605

which (probably) shouldn't be there. Should this be changed to | UInt, UInt, Divide?

seantalts commented 4 years ago

Woops, yep. That might have been my bad in the initial spec.

seantalts commented 4 years ago

This was fixed by #429.