diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index d28889ed865..e0f057fc37b 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -17235,6 +17236,17 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
       cp_apply_type_quals_to_decl (cp_type_quals (restype), resdecl);
     }
 
+  /* Set the result decl source location to the location of the typespec.  */
+  if (DECL_RESULT (decl1)
+      && DECL_TEMPLATE_INSTANTIATION (decl1)
+      && DECL_TEMPLATE_INFO (decl1)
+      && DECL_TI_TEMPLATE (decl1)
+      && DECL_TEMPLATE_RESULT (DECL_TI_TEMPLATE (decl1))
+      && DECL_RESULT (DECL_TEMPLATE_RESULT (DECL_TI_TEMPLATE (decl1))))
+      DECL_SOURCE_LOCATION (DECL_RESULT (decl1))
+	= DECL_SOURCE_LOCATION (
+	    DECL_RESULT (DECL_TEMPLATE_RESULT (DECL_TI_TEMPLATE (decl1))));
+
   /* Record the decl so that the function name is defined.
      If we already have a decl for this name, and it is a FUNCTION_DECL,
      use the old decl.  */
@@ -17532,7 +17544,19 @@ start_function (cp_decl_specifier_seq *declspecs,
     gcc_assert (same_type_p (TREE_TYPE (TREE_TYPE (decl1)),
 			     integer_type_node));
 
-  return start_preparsed_function (decl1, attrs, /*flags=*/SF_DEFAULT);
+  bool ret = start_preparsed_function (decl1, attrs, /*flags=*/SF_DEFAULT);
+
+  /* decl1 might be ggc_freed here.  */
+  decl1 = current_function_decl;
+
+  tree result;
+  /* Set the result decl source location to the location of the typespec.  */
+  if (TREE_CODE (decl1) == FUNCTION_DECL
+      && declspecs->locations[ds_type_spec] != UNKNOWN_LOCATION
+      && (result = DECL_RESULT (decl1)) != NULL_TREE
+      && DECL_SOURCE_LOCATION (result) == input_location)
+    DECL_SOURCE_LOCATION (result) = declspecs->locations[ds_type_spec];
+  return ret;
 }
 
 /* Returns true iff an EH_SPEC_BLOCK should be created in the body of
@@ -18063,6 +18087,14 @@ finish_function (bool inline_p)
 	suppress_warning (fndecl, OPT_Wreturn_type);
     }
 
+    if (getenv("XXX") != NULL)
+      {
+	location_t result_loc = DECL_SOURCE_LOCATION (DECL_RESULT (fndecl));
+	gcc_rich_location richloc (result_loc);
+	richloc.add_fixit_replace (result_loc, "the return type");
+	warning_at (&richloc, 0, "result dec%c locus sample", 'l');
+      }
+
   /* Lambda closure members are implicitly constexpr if possible.  */
   if (cxx_dialect >= cxx17
       && LAMBDA_TYPE_P (CP_DECL_CONTEXT (fndecl)))