* fenollp/treewide_remove_unexpected_0xff/OTP-11323:
  Remove ^L characters hidden randomly in the code. Not those used in text files as delimiters.

While working on a tool that processes Erlang code and testing it against this repo,
I found out about those little sneaky 0xff. I thought it may be of help to other
people build such tools to remove non-conforming-to-standard characters.

When reporting a field redefinition in a record, erl_lint can forget
about some old unused variables.

f() -> X = 1, #r{a=foo,a=bar,a=qux}.

Variables used in the body of a try expression were marked as unsafe
*and* used, which makes no sense as an unsafe variable can't be used.

Function vtsubtract/2 is used to forget usage of such unsafe variables.

Reported-by: Paul Davis

When analyzing complex expressions (i.e. comprehensions, cases, tries,
ifs and receives), erl_lint does not forget about old unused variables
when returning the updated variable table. This causes a bug where old
unused variables are not recorded as such:

t(X, Y) ->
  #r{a=[ K || K <- Y ],b=[ K || K <- Y ]}.

As erl_lint uses vtmerge_pat/2 to merge the results of the analysis of
the two list comprehensions, X is marked as used and the warning is not
emitted.

The function vtmerge_pat/2 is used instead of the similar vtmerge/2
which does not mark multiple occurrences of a variable as usage to
handle cases like the following one:

t(X, Y) ->
  #r{a=A=X,b=A=Y}.

Other simpler expressions like conses, tuples and external fun
references do not correctly follow this behaviour, e.g. A is not marked
as used in the following code:

t(X, Y) ->
  {A=X,A=Y}.

This commit fixes both issues and makes erl_lint not return old unused
variables in updated tables and makes all compound expressions use
vtmerge_pat/2.

Reported-by: Anders Ramsell

* hb/stdlib/dets_bugfix/OTP-11245:
  Fix a Dets bug concerning traversal of tables

If the fun M:F/A construct was used erroneously the linter could
crash.

Thanks to Mikhail Sobolev for reporting the bug.

The bug was introduced in R16B.

Thanks to Manuel Durán Aguete.