1 files changed, 5 insertions, 0 deletions
diff --git a/parse.y b/parse.y
index af81a897b7..d0a106b5f8 100644
--- a/parse.y
+++ b/parse.y
@@ -1731,6 +1731,11 @@ primary_value 	: primary
 
 then		: term
 		| ':'
+		    {
+		        rb_warn("colon will be obsoleted; use semicolon");
+			value_expr($1);
+			$$ = $1;
+		    }
 		| kTHEN
 		| term kTHEN
 		;