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Adds the crate:: prefix to paths where appropriate.

Force us to name impls with just the filename/line number. We normally try to use types. But at some points, notably while printing cycle errors, this can result in extra or suboptimal error output, so this variable disables that check.

Avoids running any queries during any prints that occur during the closure. This may alter the appearance of some types (e.g. forcing verbose printing for opaque types). This method is used during some queries (e.g. explicit_item_bounds for opaque types), to ensure that any debug printing that occurs during the query computation does not end up recursively calling the same query.

Prevent path trimming if it is turned on. Path trimming affects Display impl of various rustc types, for example std::vec::Vec would be trimmed to Vec, if no other Vec is found.

Prevent selection of visible paths. Display impl of DefId will prefer visible (public) reexports of types as paths.


Folds through bound vars and placeholders, naming them

The “region highlights” are used to control region printing during specific error messages. When a “region highlight” is enabled, it gives an alternate way to print specific regions. For now, we always print those regions using a number, so something like “'0”.

Wrapper type for ty::TraitRef which opts-in to pretty printing only the trait name. That is, it will print Trait instead of <T as Trait<U>>.

Wrapper type for ty::TraitRef which opts-in to pretty printing only the trait path. That is, it will print Trait<U> instead of <T as Trait<U>>.



Trait for printers that pretty-print using fmt::Write to the printer.


The purpose of this function is to collect public symbols names that are unique across all crates in the build. Later, when printing about types we can use those names instead of the full exported path to them.