[Bug fortran/47660] New: Retain warning text of -Wconversion messages when -Wconversion-extra is in effect

[thenlich at users dot sourceforge.net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47660

           Summary: Retain warning text of -Wconversion messages when
                    -Wconversion-extra is in effect
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: thenlich@users.sourceforge.net


A warning for a construct which is printed for -Wconversion should be printed
with the same text when -Wconversion-extra is in effect.

In other words, when -Wconversion-extra is in effect, conversions which are
likely to change the expression's value should have a distinctly different
warning text than conversions which don't. This makes it easier for the user to
find the most relevant issues in the source code more quickly without running
the compiler two times with -Wconversion and -Wconversion-extra.

For example:
real(4) r1
real(8) r2
integer(4) i
r1 = r2
r1 = 0_8
i = 0._8
end

$ gfortran -Wconversion testconv2.f90
testconv2.f90:4.5:

r1 = r2
     1
Warning: Possible change of value in conversion from REAL(8) to REAL(4) at (1)
testconv2.f90:5.5:

r1 = 0_8
     1
Warning: Possible change of value in conversion from INTEGER(8) to REAL(4) at
(1
)
testconv2.f90:6.4:

i = 0._8
    1
Warning: Possible change of value in conversion from REAL(8) to INTEGER(4) at
(1
)

$ gfortran -Wconversion-extra testconv2.f90
testconv2.f90:4.5:

r1 = r2
     1
Warning: Conversion from REAL(8) to REAL(4) at (1)
testconv2.f90:5.5:

r1 = 0_8
     1
Warning: Conversion from INTEGER(8) to REAL(4) at (1)
testconv2.f90:6.4:

i = 0._8
    1
Warning: Possible change of value in conversion from REAL(8) to INTEGER(4) at
(1)


The first two warnings should have the same text in both runs.