Fortran: This patch fixes comments 23 and 24 of PR96320.

2021-01-21  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/96320
	* decl.c (gfc_match_modproc): It is not an error to find a
	module procedure declaration within a contains block.
	* expr.c (gfc_check_vardef_context): Pure procedure result is
	assignable. Change 'own_scope' accordingly.
	* resolve.c (resolve_typebound_procedure): A procedure that
	has the module procedure attribute is almost certainly a
	module procedure, whatever its interface.

gcc/testsuite/
	PR fortran/96320
	* gfortran.dg/module_procedure_5.f90 : New test.
	* gfortran.dg/module_procedure_6.f90 : New test.

5 files changed, 89 insertions, 2 deletions

diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index 4771b59..7239158 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -9856,7 +9856,8 @@ gfc_match_modproc (void)
   gfc_namespace *module_ns;
   gfc_interface *old_interface_head, *interface;
 
-  if (gfc_state_stack->state != COMP_INTERFACE
+  if ((gfc_state_stack->state != COMP_INTERFACE
+       && gfc_state_stack->state != COMP_CONTAINS)
       || gfc_state_stack->previous == NULL
       || current_interface.type == INTERFACE_NAMELESS
       || current_interface.type == INTERFACE_ABSTRACT)
diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index 188e796..4f456fc 100644
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -6243,6 +6243,9 @@ gfc_check_vardef_context (gfc_expr* e, bool pointer, bool alloc_obj,
 
   /* Variable not assignable from a PURE procedure but appears in
      variable definition context.  */
+  own_scope = own_scope
+	      || (sym->attr.result && sym->ns->proc_name
+		  && sym == sym->ns->proc_name->result);
   if (!pointer && !own_scope && gfc_pure (NULL) && gfc_impure_variable (sym))
     {
       if (context)
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index bb069ef..c075d0f 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -14025,7 +14025,8 @@ resolve_typebound_procedure (gfc_symtree* stree)
       /* Check for F08:C465.  */
       if ((!proc->attr.subroutine && !proc->attr.function)
 	  || (proc->attr.proc != PROC_MODULE
-	      && proc->attr.if_source != IFSRC_IFBODY)
+	      && proc->attr.if_source != IFSRC_IFBODY
+	      && !proc->attr.module_procedure)
 	  || proc->attr.abstract)
 	{
 	  gfc_error ("%qs must be a module procedure or an external "
diff --git a/gcc/testsuite/gfortran.dg/module_procedure_5.f90 b/gcc/testsuite/gfortran.dg/module_procedure_5.f90
new file mode 100644
index 0000000..3dafa06
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/module_procedure_5.f90
@@ -0,0 +1,31 @@
+! { dg-do compile }
+!
+! Test the fix for the testcase in comment 23 of PR96320, which used to
+! fail with the message: Variable ‘new_foo’ cannot appear in a variable
+! definition context.
+!
+! Contributed by Damian Rouson  <damian@sourceryinstitute.org>
+!
+module foobar
+  implicit none
+
+  type foo
+    integer bar
+  end type
+
+  interface
+    pure module function create() result(new_foo)
+      implicit none
+      type(foo) new_foo
+    end function
+  end interface
+
+contains
+  module procedure create
+    new_foo%bar = 1  ! Error here
+  end procedure
+end module
+
+  use foobar
+  print *, create ()
+end
diff --git a/gcc/testsuite/gfortran.dg/module_procedure_6.f90 b/gcc/testsuite/gfortran.dg/module_procedure_6.f90
new file mode 100644
index 0000000..e642d52
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/module_procedure_6.f90
@@ -0,0 +1,51 @@
+! { dg-do run }
+!
+! Test the fix for the testcase in comment 24 of PR96320, which used to
+! fail with the message: ‘set_user_defined’ must be a module procedure or
+! an external procedure with an explicit interface at (1)
+!
+! Contributed by Damian Rouson  <damian@sourceryinstitute.org>
+!
+module hole_interface
+  type hole_t
+    integer :: user_defined
+    real :: hole_diameter
+  contains
+    procedure set_user_defined
+    procedure set_diameter
+  end type
+
+  interface
+    module subroutine set_diameter (this, diameter)
+      class(hole_t) :: this
+      real :: diameter
+    end subroutine
+
+    module subroutine set_user_defined(this, user_defined)
+      class(hole_t) :: this
+      integer :: user_defined
+    end subroutine
+  end interface
+
+contains
+  module procedure set_user_defined
+    this%user_defined = user_defined
+  end procedure
+
+  module procedure set_diameter
+    this%hole_diameter = diameter
+    if (this%user_defined .lt. 0) then
+      call this%set_user_defined (0)
+    end if
+  end procedure
+end module
+
+  use hole_interface ! Error was here
+  type (hole_t) :: ht = hole_t (-1, 0.0)
+  call ht%set_diameter(1.0)
+  if ((ht%user_defined .ne. 0) .and. (ht%hole_diameter .ne. 1.0)) stop 1
+  call ht%set_user_defined (5)
+  if ((ht%user_defined .ne. 5) .and. (ht%hole_diameter .ne. 1.0)) stop 2
+  call ht%set_diameter(2.0)
+  if ((ht%user_defined .ne. 5) .and. (ht%hole_diameter .ne. 2.0)) stop 3
+end