hadley/ggplot2 — comment on commit 173094a923eb2ece8c57887755eca4e45df7b67d
File: R/geom-dotplot.r line 26
By briandk:

I suspect it's related to where you [set the default and required aesthetics][1]; y has a default aes of `..count..`, but x doesn't have a default:

```r
default_aes <- (function (.) aes(y=..count.., colour="black", fill = "black", alpha = 1))
```

Source: https://github.com/hadley/ggplot2/blob/df1a3e75037d300057193821068a4b2b036b6cf1/R/geom-dotplot.r#L248

[1]: https://github.com/hadley/ggplot2/blob/df1a3e75037d300057193821068a4b2b036b6cf1/R/geom-dotplot.r#L248