If 'search' was called outside of the parser, note. might be called, which would fail if no lexer was set

core/parser/parser-tests.factor

@@ -496,3 +496,5 @@ DEFER: blah
 
 [ "IN: parser.tests USE: kernel TUPLE: blah < tuple ; : blah ; TUPLE: blah < tuple ; : blah ;" eval ]
 [ error>> error>> def>> \ blah eq? ] must-fail-with
+
+[ ] [ f lexer set f file set "Hello world" note. ] unit-test

core/parser/parser.factor

@@ -25,7 +25,7 @@ t parser-notes set-global
 : note. ( str -- )
     parser-notes? [
         file get [ path>> write ":" write ] when* 
-        lexer get line>> number>string write ": " write
+        lexer get [ line>> number>string write ": " write ] when*
         "Note: " write dup print
     ] when drop ;