[fortran,4/4] C binding access to C_PTR type: main fix

diff --git a/gfortran.h b/gfortran.h
index 44d5c91..89f4f73 100644
--- a/gfortran.h
+++ b/gfortran.h
@@ -2626,7 +2626,8 @@  gfc_try gfc_verify_c_interop_param (gfc_symbol *);
 gfc_try verify_bind_c_sym (gfc_symbol *, gfc_typespec *, int, gfc_common_head *);
 gfc_try verify_bind_c_derived_type (gfc_symbol *);
 gfc_try verify_com_block_vars_c_interop (gfc_common_head *);
-void generate_isocbinding_symbol (const char *, iso_c_binding_symbol, const char *);
+void generate_isocbinding_symbol (const char *, iso_c_binding_symbol,
+				  const char *, bool);
 gfc_symbol *get_iso_c_sym (gfc_symbol *, char *, const char *, int);
 int gfc_get_sym_tree (const char *, gfc_namespace *, gfc_symtree **, bool);
 int gfc_get_ha_symbol (const char *, gfc_symbol **);
diff --git a/module.c b/module.c
index 1b38555..062cf81 100644
--- a/module.c
+++ b/module.c
@@ -5708,7 +5708,8 @@  import_iso_c_binding_module (void)
 		  generate_isocbinding_symbol (iso_c_module_name,
 					       (iso_c_binding_symbol) i,
 					       u->local_name[0] ? u->local_name
-								: u->use_name);
+								: u->use_name,
+					       false);
 	      }
 	  }
 
@@ -5763,7 +5764,8 @@  import_iso_c_binding_module (void)
 
 	      default:
 		generate_isocbinding_symbol (iso_c_module_name,
-					     (iso_c_binding_symbol) i, NULL);
+					     (iso_c_binding_symbol) i, NULL,
+					     false);
 	    }
 	}
    }
diff --git a/symbol.c b/symbol.c
index b03d572..4244fda 100644
--- a/symbol.c
+++ b/symbol.c
@@ -3837,7 +3837,7 @@  gen_special_c_interop_ptr (int ptr_id, gfc_symbol *tmp_sym,
 	 that has arg(s) of the missing type.  In this case, a
 	 regular version of the thing should have been put in the
 	 current ns.  */
-      generate_isocbinding_symbol (module_name, type_id, NULL);
+      generate_isocbinding_symbol (module_name, type_id, NULL, true);
       tmp_sym->ts.u.derived = get_iso_c_binding_dt (type_id);
     }
 
@@ -3945,7 +3945,7 @@  gen_cptr_param (gfc_formal_arglist **head,
     {
       /* This can happen if the user did not define c_ptr but they are
 	 trying to use one of the iso_c_binding functions that need it.  */
-      generate_isocbinding_symbol (module_name, c_ptr_id, NULL);
+      generate_isocbinding_symbol (module_name, c_ptr_id, NULL, true);
       c_ptr_sym = get_iso_c_binding_dt (c_ptr_id);
     }
 
@@ -4248,6 +4248,39 @@  std_for_isocbinding_symbol (int id)
     }
 }
 
+
+/* Tells whether symbol TMP_SYM is ISO_C_BINDING's symbol identified by SYM_ID.
+   If TMP_SYM is a generic, it uses the derived type in the list of interfaces
+   (if there is one).  Returns the symbol if it matches SYM_ID,
+   NULL otherwise.  */
+
+static gfc_symbol *
+check_iso_c_symbol (gfc_symbol *tmp_sym, iso_c_binding_symbol sym_id)
+{
+  if (tmp_sym->attr.generic)
+    tmp_sym = gfc_find_dt_in_generic (tmp_sym);
+
+  if (tmp_sym == NULL || tmp_sym->from_intmod != INTMOD_ISO_C_BINDING)
+    return NULL;
+
+  /* FIXME: This block is probably unnecessary. */
+  if (tmp_sym->attr.flavor == FL_DERIVED
+      && get_iso_c_binding_dt (tmp_sym->intmod_sym_id) == NULL)
+    {
+      gfc_dt_list *dt_list;
+      dt_list = gfc_get_dt_list ();
+      dt_list->derived = tmp_sym;
+      dt_list->next = gfc_derived_types;
+      gfc_derived_types = dt_list;
+    }
+
+  if (tmp_sym->intmod_sym_id != sym_id)
+    return NULL;
+
+  return tmp_sym;
+}
+
+
 /* Generate the given set of C interoperable kind objects, or all
    interoperable kinds.  This function will only be given kind objects
    for valid iso_c_binding defined types because this is verified when
@@ -4261,7 +4294,7 @@  std_for_isocbinding_symbol (int id)
 
 void
 generate_isocbinding_symbol (const char *mod_name, iso_c_binding_symbol s,
-			     const char *local_name)
+			     const char *local_name, bool hidden)
 {
   const char *const name = (local_name && local_name[0]) ? local_name
 					     : c_interop_kinds_table[s].name;
@@ -4272,34 +4305,47 @@  generate_isocbinding_symbol (const char *mod_name, iso_c_binding_symbol s,
   if (gfc_notification_std (std_for_isocbinding_symbol (s)) == ERROR)
     return;
 
-  tmp_symtree = gfc_find_symtree (gfc_current_ns->sym_root, name);
+  if (!hidden)
+    {
+      tmp_symtree = gfc_find_symtree (gfc_current_ns->sym_root, name);
+
+      /* Already exists in this scope so don't re-add it.  */
+      if (tmp_symtree != NULL)
+	{
+	  if (check_iso_c_symbol (tmp_symtree->n.sym, s) == NULL)
+	    tmp_symtree->ambiguous = 1;
+
+	  return;
+	}
+    }
 
-  /* Already exists in this scope so don't re-add it. */
-  if (tmp_symtree != NULL && (tmp_sym = tmp_symtree->n.sym) != NULL
-      && (!tmp_sym->attr.generic
-	  || (tmp_sym = gfc_find_dt_in_generic (tmp_sym)) != NULL)
-      && tmp_sym->from_intmod == INTMOD_ISO_C_BINDING)
+  tmp_symtree = gfc_find_symtree (gfc_current_ns->sym_root,
+				  c_interop_kinds_table[s].name);
+  if (tmp_symtree != NULL)
     {
-      if (tmp_sym->attr.flavor == FL_DERIVED
-	  && !get_iso_c_binding_dt (tmp_sym->intmod_sym_id))
+      tmp_sym = check_iso_c_symbol (tmp_symtree->n.sym, s);
+      if (tmp_sym != NULL)
 	{
-	  gfc_dt_list *dt_list;
-	  dt_list = gfc_get_dt_list ();
-	  dt_list->derived = tmp_sym;
-	  dt_list->next = gfc_derived_types;
-  	  gfc_derived_types = dt_list;
-        }
+	  if (hidden)
+	    return;
 
-      return;
+	  gcc_assert (strcmp (name, c_interop_kinds_table[s].name) != 0);
+	  tmp_symtree = gfc_new_symtree (&gfc_current_ns->sym_root, name);
+	  tmp_symtree->n.sym = tmp_sym;
+	  tmp_symtree->n.sym->refs++;
+	  return;
+	}
     }
 
   /* Create the sym tree in the current ns.  */
-  gfc_get_sym_tree (name, gfc_current_ns, &tmp_symtree, false);
-  if (tmp_symtree)
-    tmp_sym = tmp_symtree->n.sym;
+  if (!hidden)
+    tmp_symtree = gfc_new_symtree (&gfc_current_ns->sym_root, name);
   else
-    gfc_internal_error ("generate_isocbinding_symbol(): Unable to "
-			"create symbol");
+    tmp_symtree = gfc_get_unique_symtree (gfc_current_ns);
+
+  tmp_sym = gfc_new_symbol (c_interop_kinds_table[s].name, gfc_current_ns);
+  tmp_symtree->n.sym = tmp_sym;
+  tmp_sym->refs++;
 
   /* Say what module this symbol belongs to.  */
   tmp_sym->module = gfc_get_string (mod_name);
@@ -4392,21 +4438,26 @@  generate_isocbinding_symbol (const char *mod_name, iso_c_binding_symbol s,
 	  gfc_component *tmp_comp = NULL;
 	  char comp_name[(GFC_MAX_SYMBOL_LEN * 2) + 1];
 
-	  hidden_name = gfc_get_string ("%c%s",
-			    (char) TOUPPER ((unsigned char) tmp_sym->name[0]),
-                            &tmp_sym->name[1]);
+	  if (!hidden)
+	    {
+	      hidden_name = gfc_get_string ("%c%s",
+				(char) TOUPPER ((unsigned char) name[0]),
+				&name[1]);
 
-	  /* Generate real derived type.  */
-	  tmp_symtree = gfc_find_symtree (gfc_current_ns->sym_root,
-					  hidden_name);
-
-	  if (tmp_symtree != NULL)
-	    gcc_unreachable ();
-	  gfc_get_sym_tree (hidden_name, gfc_current_ns, &tmp_symtree, false);
-	  if (tmp_symtree)
-	    dt_sym = tmp_symtree->n.sym;
+	      gcc_assert (gfc_find_symtree (gfc_current_ns->sym_root,
+					    hidden_name) == NULL);
+
+	      tmp_symtree = gfc_new_symtree (&gfc_current_ns->sym_root,
+					     hidden_name);
+	    }
 	  else
-	    gcc_unreachable ();
+	    tmp_symtree = gfc_get_unique_symtree (gfc_current_ns);
+
+	  /* Generate real derived type.  */
+	  dt_sym = gfc_new_symbol (c_interop_kinds_table[s].name,
+				   gfc_current_ns);
+	  tmp_symtree->n.sym = dt_sym;
+	  tmp_symtree->n.sym->refs++;
 
 	  /* Generate an artificial generic function.  */
 	  dt_sym->name = gfc_get_string (tmp_sym->name);
@@ -4545,7 +4596,8 @@  generate_isocbinding_symbol (const char *mod_name, iso_c_binding_symbol s,
 		  {
 		    /* Create the necessary derived type so we can continue
 		       processing the file.  */
-		    generate_isocbinding_symbol (mod_name, c_ptr_id, NULL);
+		    generate_isocbinding_symbol (mod_name, c_ptr_id, NULL,
+						 true);
 		    tmp_sym->ts.u.derived = get_iso_c_binding_dt (c_ptr_id);
 		  }