diff --git a/tests/verilog/constparser_f.ys b/tests/verilog/constparser_f.ys
index 3dd3f1323..4c5eff46f 100644
--- a/tests/verilog/constparser_f.ys
+++ b/tests/verilog/constparser_f.ys
@@ -1,6 +1,7 @@
+logger -expect prefix-error "<<EOT:2: ERROR: Digit larger than 1 used in in base-2 constant." 1
 read_verilog <<EOT
 module test (y);
-    output signed [2:0] y = 1'b1;
+    output signed [2:0] y = 1'bf;
 endmodule
 EOT
 dump