Fortran: Avoid var initialization in interfaces [PR54753]

Intent(out) implies deallocation/default initialization; however, it is
pointless to do this for dummy-arguments symbols of procedures which are
inside an INTERFACE block. – This also fixes a bogus error for the attached
included testcase, but fixing the non-interface version still has to be done.

	PR fortran/54753

gcc/fortran/ChangeLog:

	* resolve.c (can_generate_init, resolve_fl_variable_derived,
	resolve_symbol): Only do initialization with intent(out) if not
	inside of an interface block.

gcc/testsuite/ChangeLog:

	* gfortran.dg/assumed_rank_23.f90: New test.

 gcc/fortran/resolve.c                         | 11 ++++++++---
 gcc/testsuite/gfortran.dg/assumed_rank_23.f90 | 16 ++++++++++++++++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 30b96b2f597..511fe3a5e55 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -12676,7 +12676,8 @@ can_generate_init (gfc_symbol *sym)
     || a->cray_pointer
     || sym->assoc
     || (!a->referenced && !a->result)
-    || (a->dummy && a->intent != INTENT_OUT)
+    || (a->dummy && (a->intent != INTENT_OUT
+		     || sym->ns->proc_name->attr.if_source == IFSRC_IFBODY))
     || (a->function && sym != sym->result)
   );
 }
@@ -12913,7 +12914,9 @@ resolve_fl_variable_derived (gfc_symbol *sym, int no_init_flag)
 
   /* Assign default initializer.  */
   if (!(sym->value || sym->attr.pointer || sym->attr.allocatable)
-      && (!no_init_flag || sym->attr.intent == INTENT_OUT))
+      && (!no_init_flag
+	  || (sym->attr.intent == INTENT_OUT
+	      && sym->ns->proc_name->attr.if_source != IFSRC_IFBODY)))
     sym->value = gfc_generate_initializer (&sym->ts, can_generate_init (sym));
 
   return true;
@@ -16154,7 +16157,8 @@ resolve_symbol (gfc_symbol *sym)
 		    || sym->ts.u.derived->attr.alloc_comp
 		    || sym->ts.u.derived->attr.pointer_comp))
 	   && !(a->function && sym != sym->result))
-	  || (a->dummy && a->intent == INTENT_OUT && !a->pointer))
+	  || (a->dummy && !a->pointer && a->intent == INTENT_OUT
+	      && sym->ns->proc_name->attr.if_source != IFSRC_IFBODY))
 	apply_default_init (sym);
       else if (a->function && sym->result && a->access != ACCESS_PRIVATE
 	       && (sym->ts.u.derived->attr.alloc_comp
@@ -16166,6 +16170,7 @@ resolve_symbol (gfc_symbol *sym)
 
   if (sym->ts.type == BT_CLASS && sym->ns == gfc_current_ns
       && sym->attr.dummy && sym->attr.intent == INTENT_OUT
+      && sym->ns->proc_name->attr.if_source != IFSRC_IFBODY
       && !CLASS_DATA (sym)->attr.class_pointer
       && !CLASS_DATA (sym)->attr.allocatable)
     apply_default_init (sym);
diff --git a/gcc/testsuite/gfortran.dg/assumed_rank_23.f90 b/gcc/testsuite/gfortran.dg/assumed_rank_23.f90
new file mode 100644
index 00000000000..c83aa7de1a3
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/assumed_rank_23.f90
@@ -0,0 +1,16 @@
+! { dg-do compile }
+!
+! PR fortran/54753
+! TS29113:C535c
+! F2018:C839
+!
+module m
+
+  interface
+    subroutine s1 (x, y)
+      class(*) :: x(..)
+      class(*), intent (out) :: y(..)
+    end subroutine
+  end interface
+
+end module