Merge branch 'false_warning' into blead

This branch regularizes the warnings and errors generated when a hex or
octal character constant contains an illegal character, and when such a
constant evaluates to something that won't fit into a 32 bit word.

It unifies where the text is generated, leading to a uniform syntax that
no longer has slight spelling variances.  And some messages previously
gave outright false information.  Some cases of a too-high code point
weren't caught immediately; this is fixed.

During pattern compilation, some messages could have become truncated or
garbled.  This is fixed.

This resolves GH #17340 False warning that character is ignored

1 files changed, 12 insertions, 2 deletions

diff --git a/numeric.c b/numeric.c
index ad75f63373..4c2f12b8cd 100644
--- a/numeric.c
+++ b/numeric.c
@@ -513,12 +513,16 @@ Perl_grok_bin_oct_hex(pTHX_ const char *start,
 
             if (! overflowed) {
                 overflowed = TRUE;
-                Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
+                if (   ! (input_flags & PERL_SCAN_SILENT_OVERFLOW)
+                    &&    ckWARN_d(WARN_OVERFLOW))
+                {
+                    Perl_warner(aTHX_ packWARN(WARN_OVERFLOW),
                                        "Integer overflow in %s number",
                                        (base == 16) ? "hexadecimal"
                                                     : (base == 2)
                                                       ? "binary"
                                                       : "octal");
+                }
             }
             continue;
         }
@@ -526,7 +530,13 @@ Perl_grok_bin_oct_hex(pTHX_ const char *start,
         if (   *s == '_'
             && len
             && allow_underscores
-            && _generic_isCC(s[1], class_bit))
+            && _generic_isCC(s[1], class_bit)
+
+                /* Don't allow a leading underscore if the only-medial bit is
+                 * set */
+            && (   LIKELY(s > s0)
+                || UNLIKELY((input_flags & PERL_SCAN_ALLOW_MEDIAL_UNDERSCORES)
+                                        != PERL_SCAN_ALLOW_MEDIAL_UNDERSCORES)))
         {
             --len;
             ++s;