1 files changed, 9 insertions, 0 deletions
diff --git a/toke.c b/toke.c
index efb834862a..8a84a5a48a 100644
--- a/toke.c
+++ b/toke.c
@@ -7807,6 +7807,15 @@ Perl_yylex(pTHX)
 		    yyerror_pv(tmpbuf, UTF ? SVf_UTF8 : 0);
 		}
 	    }
+	    else if (*s == '\\') {
+		if (!FEATURE_MYREF_IS_ENABLED)
+		    Perl_croak(aTHX_ "The experimental declared_refs "
+				     "feature is not enabled");
+		Perl_ck_warner_d(aTHX_
+		     packWARN(WARN_EXPERIMENTAL__DECLARED_REFS),
+		    "Reference constructors after declarators are "
+		    "experimental");
+	    }
 	    OPERATOR(MY);
 
 	case KEY_next: