re PR fortran/91942 (ICE in match_vtag, at fortran/io.c:1485)

2019-10-02  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/91942
	* io.c (match_vtag): Check for non-NULL result->symtree.
	(match_out_tag): Check for invalid constant due to inquiry parameter.
	(match_filepos): Instead of a syntax error, go to cleanup to get better
	error messages.

2019-10-02  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/91942
	* gfortran.dg/pr91587.f90: Update dg-error regex.
	* gfortran.dg/pr91942.f90: New test.

From-SVN: r276472

1 files changed, 31 insertions, 17 deletions

diff --git a/gcc/fortran/io.c b/gcc/fortran/io.c
index 9ae06b1f..b969a1a 100644
--- a/gcc/fortran/io.c
+++ b/gcc/fortran/io.c
@@ -1482,24 +1482,29 @@ match_vtag (const io_tag *tag, gfc_expr **v)
       return MATCH_ERROR;
     }
 
-  if (result->symtree->n.sym->attr.intent == INTENT_IN)
+  if (result->symtree)
     {
-      gfc_error ("Variable %s cannot be INTENT(IN) at %C", tag->name);
-      gfc_free_expr (result);
-      return MATCH_ERROR;
-    }
+      bool impure;
 
-  bool impure = gfc_impure_variable (result->symtree->n.sym);
-  if (impure && gfc_pure (NULL))
-    {
-      gfc_error ("Variable %s cannot be assigned in PURE procedure at %C",
-		 tag->name);
-      gfc_free_expr (result);
-      return MATCH_ERROR;
-    }
+      if (result->symtree->n.sym->attr.intent == INTENT_IN)
+	{
+	  gfc_error ("Variable %s cannot be INTENT(IN) at %C", tag->name);
+	  gfc_free_expr (result);
+	  return MATCH_ERROR;
+	}
+
+      impure = gfc_impure_variable (result->symtree->n.sym);
+      if (impure && gfc_pure (NULL))
+	{
+	  gfc_error ("Variable %s cannot be assigned in PURE procedure at %C",
+		     tag->name);
+	  gfc_free_expr (result);
+	  return MATCH_ERROR;
+	}
 
-  if (impure)
-    gfc_unset_implicit_pure (NULL);
+      if (impure)
+	gfc_unset_implicit_pure (NULL);
+    }
 
   *v = result;
   return MATCH_YES;
@@ -1515,7 +1520,16 @@ match_out_tag (const io_tag *tag, gfc_expr **result)
 
   m = match_vtag (tag, result);
   if (m == MATCH_YES)
-    gfc_check_do_variable ((*result)->symtree);
+    {
+      if ((*result)->symtree)
+	gfc_check_do_variable ((*result)->symtree);
+
+      if ((*result)->expr_type == EXPR_CONSTANT)
+	{
+	  gfc_error ("Expecting a variable at %L", &(*result)->where);
+	  return MATCH_ERROR;
+	}
+    }
 
   return m;
 }
@@ -2845,7 +2859,7 @@ match_filepos (gfc_statement st, gfc_exec_op op)
 
   m = match_file_element (fp);
   if (m == MATCH_ERROR)
-    goto syntax;
+    goto cleanup;
   if (m == MATCH_NO)
     {
       m = gfc_match_expr (&fp->unit);