a ConstError is a prototype for a certain type of error

Err holds a description of an error along with information about where the error was created. It may be embedded in custom error types to add extra i

Locationer is an interface that represents a certain class of errors that contain the location information from where they were raised.

containsChecker is a copy of the containsChecker from juju/testing

errWithType is an Err bundled with its error type (a ConstError)

errorInfo holds information about a single error type: its type and name, wrapping and variable arguments constructors and message suffix.

This is an uncomparable error type, as it is a struct that supports the error interface (as opposed to a pointer type).

fmtNoop provides an internal type for wrapping errors so they won't be printed in fmt type commands. As this type is used by the Hide function it's ex

locationError is the internal implementation of the Locationer interface.

satisfiesChecker is a copy of the satisfiesChecker from juju/testing

The testError is a value type error for ease of seeing results when the test fails.

helper for Format