Fully separate positional arguments and keyword arguments

This removes the warnings added in 2.7, and changes the behavior
so that a final positional hash is not treated as keywords or
vice-versa.

To handle the arg_setup_block splat case correctly with keyword
arguments, we need to check if we are taking a keyword hash.
That case didn't have a test, but it affects real-world code,
so add a test for it.

This removes rb_empty_keyword_given_p() and related code, as
that is not needed in Ruby 3.  The empty keyword case is the
same as the no keyword case in Ruby 3.

This changes rb_scan_args to implement keyword argument
separation for C functions when the : character is used.
For backwards compatibility, it returns a duped hash.
This is a bad idea for performance, but not duping the hash
breaks at least Enumerator::ArithmeticSequence#inspect.

Instead of having RB_PASS_CALLED_KEYWORDS be a number,
simplify the code by just making it be rb_keyword_given_p().

1 files changed, 2 insertions, 10 deletions

diff --git a/vm_core.h b/vm_core.h
index 8807c23b6f..70575fa66b 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -1159,11 +1159,11 @@ typedef rb_control_frame_t *
 
 enum {
     /* Frame/Environment flag bits:
-     *   MMMM MMMM MMMM MMMM ____ FFFF FFFF EEEX (LSB)
+     *   MMMM MMMM MMMM MMMM ____ _FFF FFFF EEEX (LSB)
      *
      * X   : tag for GC marking (It seems as Fixnum)
      * EEE : 3 bits Env flags
-     * FF..: 8 bits Frame flags
+     * FF..: 7 bits Frame flags
      * MM..: 15 bits frame magic (to check frame corruption)
      */
 
@@ -1188,7 +1188,6 @@ enum {
     VM_FRAME_FLAG_LAMBDA    = 0x0100,
     VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM = 0x0200,
     VM_FRAME_FLAG_CFRAME_KW = 0x0400,
-    VM_FRAME_FLAG_CFRAME_EMPTY_KW = 0x0800, /* -- Remove In 3.0 -- */
 
     /* env flag */
     VM_ENV_FLAG_LOCAL       = 0x0002,
@@ -1249,13 +1248,6 @@ VM_FRAME_CFRAME_KW_P(const rb_control_frame_t *cfp)
     return VM_ENV_FLAGS(cfp->ep, VM_FRAME_FLAG_CFRAME_KW) != 0;
 }
 
-/* -- Remove In 3.0 -- */
-static inline int
-VM_FRAME_CFRAME_EMPTY_KW_P(const rb_control_frame_t *cfp)
-{
-    return VM_ENV_FLAGS(cfp->ep, VM_FRAME_FLAG_CFRAME_EMPTY_KW) != 0;
-}
-
 static inline int
 VM_FRAME_FINISHED_P(const rb_control_frame_t *cfp)
 {