From c55cb36a6ad00996b5efb33c0c5357fc5fa9919c Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Mon, 6 May 2024 20:57:29 +0200
Subject: [PATCH] Fortran: improve attribute conflict checking [PR93635]

gcc/fortran/ChangeLog:

	PR fortran/93635
	* symbol.cc (gfc_check_conflict): Move some attribute conflict
	checks that depend on the selected version of the Fortran standard
	so that error reporting gets more consistent.

gcc/testsuite/ChangeLog:

	PR fortran/93635
	* gfortran.dg/pr93635.f90: New test.
---
 gcc/fortran/symbol.cc                 | 30 ++++++++++++---------------
 gcc/testsuite/gfortran.dg/pr93635.f90 | 19 +++++++++++++++++
 2 files changed, 32 insertions(+), 17 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr93635.f90

diff --git a/gcc/fortran/symbol.cc b/gcc/fortran/symbol.cc
index 8f7deac1d1e..ed17291c53e 100644
--- a/gcc/fortran/symbol.cc
+++ b/gcc/fortran/symbol.cc
@@ -459,22 +459,6 @@ gfc_check_conflict (symbol_attribute *attr, const char *name, locus *where)
   if (where == NULL)
     where = &gfc_current_locus;

-  if (attr->pointer && attr->intent != INTENT_UNKNOWN)
-    {
-      a1 = pointer;
-      a2 = intent;
-      standard = GFC_STD_F2003;
-      goto conflict_std;
-    }
-
-  if (attr->in_namelist && (attr->allocatable || attr->pointer))
-    {
-      a1 = in_namelist;
-      a2 = attr->allocatable ? allocatable : pointer;
-      standard = GFC_STD_F2003;
-      goto conflict_std;
-    }
-
   /* Check for attributes not allowed in a BLOCK DATA.  */
   if (gfc_current_state () == COMP_BLOCK_DATA)
     {
@@ -579,10 +563,12 @@ gfc_check_conflict (symbol_attribute *attr, const char *name, locus *where)
     return false;

   conf (allocatable, pointer);
+
+  /* Moving these checks past the function/subroutine conflict check may
+     cause trouble with minor variations of testcase pr87907.f90.  */
   conf_std (allocatable, dummy, GFC_STD_F2003);
   conf_std (allocatable, function, GFC_STD_F2003);
   conf_std (allocatable, result, GFC_STD_F2003);
-  conf_std (elemental, recursive, GFC_STD_F2018);

   conf (in_common, dummy);
   conf (in_common, allocatable);
@@ -911,6 +897,16 @@ gfc_check_conflict (symbol_attribute *attr, const char *name, locus *where)
       break;
     }

+  /* Conflict checks depending on the selected version of the Fortran
+     standard are preferably applied after standard-independent ones, so
+     that one gets more consistent error reporting and recovery.  */
+  if (attr->pointer && attr->intent != INTENT_UNKNOWN)
+    conf_std (pointer, intent, GFC_STD_F2003);
+
+  conf_std (in_namelist, allocatable, GFC_STD_F2003);
+  conf_std (in_namelist, pointer, GFC_STD_F2003);
+  conf_std (elemental, recursive, GFC_STD_F2018);
+
   return true;

 conflict:
diff --git a/gcc/testsuite/gfortran.dg/pr93635.f90 b/gcc/testsuite/gfortran.dg/pr93635.f90
new file mode 100644
index 00000000000..4ef33fecf2b
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr93635.f90
@@ -0,0 +1,19 @@
+! { dg-do compile }
+! PR fortran/93635
+!
+! Test that some attribute conflicts are properly diagnosed
+
+program p
+  implicit none
+  character(len=:),allocatable :: r,s
+  namelist /args/ r,s
+  equivalence(r,s) ! { dg-error "EQUIVALENCE attribute conflicts with ALLOCATABLE" }
+  allocate(character(len=1024) :: r)
+end
+
+subroutine sub (p, q)
+  implicit none
+  real, pointer, intent(inout) :: p(:), q(:)
+  namelist /nml/ p,q
+  equivalence(p,q) ! { dg-error "EQUIVALENCE attribute conflicts with DUMMY" }
+end
--
2.35.3