[PATCH] Fortran: Fix diagnostic for ambiguous pointer function assignment [PR80012]

From: Gonzalo Silvalde Blanco <[email protected]>

The error message for an ambiguous pointer function assignment contained a
FIXME and an embedded newline that the diagnostics printer does not handle.
Split the single gfc_error call into a gfc_error for the main diagnostic
and an inform note for the F2008 explanation.

	PR fortran/80012

gcc/fortran/ChangeLog:

	* symbol.cc (gfc_add_procedure): Split error into gfc_error and
	inform.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr80012.f90: New test.

Signed-off-by: Gonzalo Silvalde Blanco <[email protected]>
---
Hi Harald,

I investigated the regression caused by my previous commit and I
believe I found the root cause.

The problem was the use of auto_diagnostic_group in gfc_add_procedure.
When that object is created, it increments the diagnostic group nesting
counter. Then, when gfc_error internally calls set_diagnostic_buffer,
it hits this assert in diagnostics/buffering.cc:50:

    gcc_assert (m_diagnostic_groups.m_group_nesting_depth == 0);

...which I think causes the ICE, since the nesting depth is no longer
0 at that point.

Looking at other uses of inform() in the Fortran frontend, none of them
wrap the call in an auto_diagnostic_group, and they work fine. So I
simply removed the auto_diagnostic_group wrapper.

I ran make check-fortran on both my patched version and a clean
mainline checkout. Both now give identical results in my PC.

Best regards,
Gonzalo

 gcc/fortran/symbol.cc                 | 22 +++++++++++-----------
 gcc/testsuite/gfortran.dg/pr80012.f90 | 14 ++++++++++++++
 2 files changed, 25 insertions(+), 11 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr80012.f90

diff --git a/gcc/fortran/symbol.cc b/gcc/fortran/symbol.cc
index 5ff14e27b94..9edfb8e9eeb 100644
--- a/gcc/fortran/symbol.cc
+++ b/gcc/fortran/symbol.cc
@@ -24,6 +24,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "options.h"
 #include "gfortran.h"
+#include "diagnostic-core.h"
 #include "parse.h"
 #include "match.h"
 #include "constructor.h"
@@ -1887,19 +1888,18 @@ gfc_add_procedure (symbol_attribute *attr, procedure_type t,
   if (attr->proc != PROC_UNKNOWN && !attr->module_procedure
       && attr->access == ACCESS_UNKNOWN)
     {
-      if (attr->proc == PROC_ST_FUNCTION && t == PROC_INTERNAL
-	  && !gfc_notification_std (GFC_STD_F2008))
-	gfc_error ("%s procedure at %L is already declared as %s "
-		   "procedure. \nF2008: A pointer function assignment "
-		   "is ambiguous if it is the first executable statement "
-		   "after the specification block. Please add any other "
-		   "kind of executable statement before it. FIXME",
+      gfc_error ("%s procedure at %L is already declared as %s procedure",
 		 gfc_code2string (procedures, t), where,
 		 gfc_code2string (procedures, attr->proc));
-      else
-	gfc_error ("%s procedure at %L is already declared as %s "
-		   "procedure", gfc_code2string (procedures, t), where,
-		   gfc_code2string (procedures, attr->proc));
+      if (attr->proc == PROC_ST_FUNCTION && t == PROC_INTERNAL
+	  && !gfc_notification_std (GFC_STD_F2008))
+	{
+	  inform (gfc_get_location (where),
+		  "F2008: A pointer function assignment is ambiguous if it is "
+		  "the first executable statement after the specification "
+		  "block.  Please add any other kind of executable "
+		  "statement before it");
+	}
 
       return false;
     }
diff --git a/gcc/testsuite/gfortran.dg/pr80012.f90 b/gcc/testsuite/gfortran.dg/pr80012.f90
new file mode 100644
index 00000000000..da626d565d8
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr80012.f90
@@ -0,0 +1,14 @@
+! { dg-do compile }
+! { dg-options "-std=gnu" }
+! PR fortran/80012
+! Test that the error message for ambiguous pointer function assignment
+! is split into an error and an informational note, without FIXME.
+
+two() = 7
+contains
+  function two () ! { dg-error "INTERNAL-PROC procedure at .1. is already declared as STATEMENT-PROC procedure" }
+! { dg-message "F2008: A pointer function assignment is ambiguous" "" { target *-*-* } 9 }
+    integer, pointer  :: two
+    allocate(two)
+  end function two
+end
-- 
2.47.3