https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70529
Bug ID: 70529
Summary: Unhelpful diagnostic for hex float literals,
inconsistent parsing
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: g...@axel-naumann.de
Target Milestone: ---
auto d = 0x123p-2;
with g++ prog.cc -Wall -Wextra -std=c++14 -fsyntax-only
produces
prog.cc:1:10: error: exponent has no digits
auto d = 0x123p-2;
^~~~~~
That's a gross misrepresentation of the source code ;-) IIUC
https://github.com/gcc-mirror/gcc/commit/14c36b1402b82304739e865a27cb1aed0d87ec73
removed hex float literal support for c++ std <= 14, making this code
ill-formed.
OTOH this behavior is inconsistent, in that hex float literals with positive
exponents remain valid, even for above invocation.
A more helpful diagnostic (similar to "use of C++1z hexadecimal floating
constant") would be really good to have for people upgrading to GCC 6 without
also upgrading to c++1z. At least for those people with hex floats with
negative exponents :-)
Thanks for considering!
Axel.
