When a component of a "custom" type is a character, taking a substring of it triggers a warning about the variable being truncated (with -Wall). Maybe it is not the correct syntax to get a substring out of a character component (still, it works fine for printing, for example)?
$cat test.f90 PROGRAM test IMPLICIT NONE TYPE custom CHARACTER(LEN=10) :: nom END TYPE custom CHARACTER (LEN=10) :: a CHARACTER (LEN=2) :: b TYPE(custom) :: c a='1234567890' b=a(1:2) c%nom=a b=c%nom(1:2) END PROGRAM test $gfortran -Wall -c test.f90 test1.f90:13.14: b=c%nom(1:2) 1 Warning: rhs of CHARACTER assignment at (1) will be truncated (10/2) -- Summary: Spurious(?) warning about character truncation Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: minor Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jellby at yahoo dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31266