(F) You tried to unshift an "unreal" array that can't be unshifted, such
as the main Perl stack.
-=item Can't upgrade that kind of scalar
+=item Can't upgrade %s (%d) to %d
(P) The internal sv_upgrade routine adds "members" to an SV, making it
into a more specialized kind of SV. The top several SV types are so
specialized, however, that they cannot be interconverted. This message
indicates that such a conversion was attempted.
-=item Can't upgrade to undef
-
-(P) The undefined SV is the bottom of the totem pole, in the scheme of
-upgradability. Upgrading to undef indicates an error in the code
-calling sv_upgrade.
-
=item Can't use anonymous symbol table for method lookup
(F) The internal routine that does method lookup was handed a symbol
internally--subject to loss of precision errors in subsequent
operations.
+=item Integer overflow in division
+
+(F) In the scope of the C<use integer;> pragma, division would have overflowed.
+This will happen if you attempt to divide the largest negative integer by -1,
+since the result cannot be represented as a signed integer on a two's complement
+system. This division is trapped as a Perl-level exception because on some
+architectures the integer divide operation will trigger a CPU exception
+causing program exit, rather than merely returning a mathematically wrong
+answer.
+
=item Integer overflow in format string for %s
-(F) The indexes and widths specified in the format string of printf()
-or sprintf() are too large. The numbers must not overflow the size of
+(F) The indexes and widths specified in the format string of C<printf()>
+or C<sprintf()> are too large. The numbers must not overflow the size of
integers for your architecture.
=item Integer overflow in version