Before emitting a warning message, code should check that the usage in
question should be diagnosed by calling ShouldWarn(). A fair number of
sites in the code do not, and can emit portability warnings
unconditionally, which can confuse a user that hasn't asked for them
(-pedantic) and isn't terribly concerned about portability *to* other
compilers.
Add calls to ShouldWarn() or IsEnabled() around messages that need them,
and add -pedantic to tests that now require it to test their portability
messages, and add more expected message lines to those tests when
-pedantic causes other diagnostics to fire.
The index of an implied DO loop in a DATA statement or array
constructor is defined by Fortran 2018 to have scope over its
implied DO loop. This definition is unfortunate, because it
requires the implied DO loop's bounds expressions to be in the
scope of the index variable. Consequently, in code like
integer, parameter :: j = 5
real, save :: a(5) = [(j, j=1, j)]
the upper bound of the loop is a reference to the index variable,
not the parameter in the enclosing scope.
This patch limits the scope of the index variable to the "body"
of the implied DO loop as one would naturally expect, with a warning.
I would have preferred to make this a hard error, but most Fortran
compilers treat this case as f18 now does. If the standard
were to be fixed, the warning could be made optional.
Differential Revision: https://reviews.llvm.org/D108595
