Regexp: don't return error when match fails at EOF

bytes/regexp_test.go

@@ -69,6 +69,13 @@ func TestRegexp(t *testing.T) {
 		must.True(t, succeeded)
 		must.EqOp(t, "", value)
 	})
+	t.Run("fails without an error at EOF", func(t *testing.T) {
+		p := pbytes.Regexp("a")
+		result, err := p(gigaparsec.MakeState(strings.NewReader("")))
+		succeeded, _, _ := result.Status()
+		must.NoError(t, err)
+		must.False(t, succeeded)
+	})
 }
 
 func TestRuneReader(t *testing.T) {