All keys in an orddict must be unique. sys_core_fold:sub_sub_scope/1 broke that rule. It was probably harmless, but it is better to avoid such rule violations.
* hasse/unicode_atoms/OTP-14285: compiler: Handle (bad) Unicode parse transform module names kernel: Improve handling of Unicode filenames stdlib: Handle Unicode atoms in ms_transform stdlib: Improve Unicode handling of the Erlang parser stdlib: Handle unknown compiler options with Unicode stdlib: Handle Unicode macro names stdlib: Correct Unicode handling in escript dialyzer: Improve handling of Unicode parsetools: Improve handling of Unicode atoms stdlib: Handle Unicode atoms when formatting stacktraces stdlib: Add more checks of module names to the linter stdlib: Handle Unicode atoms better in io_lib_format stdlib: Handle Unicode atoms in c.erl
As part of sys_core_fold, variables involved in bit syntax matching would be annotated when it would be safe for a later pass to do the delayed sub-binary creation optimization. An implicit assumption regarding the annotation was that the code must not be further optimized. That assumption was broken in 05130e48555891, which introduced a fixpoint iteration (applying the optimizations until there were no more changes). That means that a variable could be annotated as safe for reusing the match context in one iteration, but a later iteration could rewrite the code in a way that would make the optimization unsafe. One way to fix this would be to clear all reuse_for_context annotations before each iteration. But that would be wasteful. Instead I chose to fix the problem by moving out the annotation code to a separate pass (sys_core_bsm) that is run later after all major optimizations of Core Erlang has been done.
compile:forms/1,2 is documented to return:
{ok,ModuleName,BinaryOrCode}
However, if one of the options 'from_core', 'from_asm', or
'from_beam' is given, ModuleName will be returned as [].
A worse problem is that is that if one those options are
combined with the 'native' option, compilation will crash.
Correct compile:forms/1,2 to pick up the module name from
the forms provided (either Core Erlang, Beam assembly code,
or a Beam file).
Reported here: https://bugs.erlang.org/browse/ERL-417
Make it clear that is_tagged_tuple/4 was added in OTP 20 (not R17).
Functions that can are known be pure can be evaluated at compile-time if the arguments are literals and if the result is expressible as a literal. list_to_ref/1 and list_to_port/1 returns terms that cannot be expressed as literals, so the optimization is not possible. The argument for port_to_list/1 is never a literal, so there is no way to evaluate it at compile-time. Therefore, marking those functions as pure serves no useful purpose. Note: list_to_pid/1 *is* marked as pure, but only so that we can test the code in sys_core_fold that rejects pure functions that evaluate to at term that is not possible to express as a literal. It is sufficient to have one pure function of that kind.
erlang:hash/2 was removed in c5d9b970fb5b3a71.