https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102240
Bug ID: 102240
Summary: [F03] derived type parameter does not shadow variable
name in enclosing scope
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: roland_wirth at web dot de
Target Milestone: ---
Consider the following module definition:
MODULE mo
IMPLICIT NONE
INTEGER :: n
TYPE t(n)
INTEGER, LEN :: n
INTEGER :: a(n)
END TYPE t
END MODULE
gfortran 9.1.0 produces the following error when trying to compile:
8 | INTEGER :: a(n)
| 1
Error: Variable 'n' at (1) in this context must be constant
Upon renaming the INTEGER variable to some other name `nn` the unit compiles
fine.
The Fortran 2003 standard (N1601) says in the Host association section
[16.4.1.3] that "A name that appears in the scoping unit as [...] (3) A
type-param-name in a derived-type-stmt [...] is a local identifier in the
scoping unit and any entity of the host that has this as its nongeneric name is
inaccessible by that name by host association." If I read that correctly the
type parameter `n` shadows the variable `n`, and the module definition should
be valid Fortran.
