The standard does *not* require that a real or imaginary part of a complex
literal constant be a scalar if it is a named constant. Downgrade a
recently installed check to a portability warning, and document it.
Differential Revision: https://reviews.llvm.org/D139046
The common language extension that allows arbitary expressions
to be used as components in a complex constructor (x,y) -- not both
constant, since that would make it a complex literal constant --
still have to be scalar; it's not an elemental operation like the
CMPLX() intrinsic function is.
Differential Revision: https://reviews.llvm.org/D136978