https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80829
Bug ID: 80829
Summary: Use of constexpr constructors with base type
instantiation fails compilation
Product: gcc
Version: 7.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: aaron.wood at verizon dot com
Target Milestone: ---
Created attachment 41389
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41389&action=edit
Small reproducer
GCC 7.1 fails to compile programs where a type extends another type, both types
have constexpr constructors, and instantiating is done like so: constexpr A a =
B(10);
This produces: error: 'B(10).B::<anonymous>' is not a constant expression
because it refers to an incompletely initialized variable
constexpr A a = B(10);
The fix/workaround is to not use the base type: constexpr B b = B(10);
I've attached a small program that shows the A and B types I'm using here and
easily reproduces this issue on 7.1.
