# ggplot() throws informative errors

    `mapping` must be created with `aes()`.
    x You've supplied a character vector.

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    `data` cannot be a function.
    i Have you misspelled the `data` argument in `ggplot()`

# construction have user friendly errors

    Cannot use `+` with a single argument.
    i Did you accidentally put `+` on a new line?

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    Cannot add <ggproto> objects together.
    i Did you forget to add this object to a <ggplot> object?

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    Can't add `1` to a <ggplot> object.

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    Can't add `geom_point` to a <ggplot> object
    i Did you forget to add parentheses, as in `geom_point()`?

