add UNREACHABLE_RETURN

Not every compilers understand that rb_raise does not return.  When a
function does not end with a return statement, such compilers can issue
warnings.  We would better tell them about reachabilities.

1 files changed, 1 insertions, 0 deletions

diff --git a/time.c b/time.c
index 457fac9748..ca571c80cd 100644
--- a/time.c
+++ b/time.c
@@ -5434,6 +5434,7 @@ end_submicro: ;
 
   invalid_format:
     rb_raise(rb_eTypeError, "marshaled time format differ");
+    UNREACHABLE_RETURN(Qundef);
 }
 
 /* :nodoc: */