https://github.com/rust-lang/rfcs/pull/221
The current terminology of "task failure" often causes problems when
writing or speaking about code. You often want to talk about the
possibility of an operation that returns a Result "failing", but cannot
because of the ambiguity with task failure. Instead, you have to speak
of "the failing case" or "when the operation does not succeed" or other
circumlocutions.
Likewise, we use a "Failure" header in rustdoc to describe when
operations may fail the task, but it would often be helpful to separate
out a section describing the "Err-producing" case.
We have been steadily moving away from task failure and toward Result as
an error-handling mechanism, so we should optimize our terminology
accordingly: Result-producing functions should be easy to describe.
To update your code, rename any call to `fail!` to `panic!` instead.
Assuming you have not created your own macro named `panic!`, this
will work on UNIX based systems:
grep -lZR 'fail!' . | xargs -0 -l sed -i -e 's/fail!/panic!/g'
You can of course also do this by hand.
[breaking-change]
This commit shreds all remnants of libextra from the compiler and standard
distribution. Two modules, c_vec/tempfile, were moved into libstd after some
cleanup, and the other modules were moved to separate crates as seen fit.
Closes#8784Closes#12413Closes#12576
Previously, resolve was allowing impls, traits or classes that were
nested within a fn to refer to upvars, as well as referring to type
parameters bound by the fn. Fixing this required adding a new kind of
def: def_typaram_binder, which can refer to any of an impl, trait or
class that has bound ty params. resolve uses this to enforce that
methods can refer to their parent item's type parameters, but not to
outer items' type parameters; other stages ignore it. I also made
sure that impl, trait and class methods get checked inside a
MethodRibKind thing so as to forbid upvars, and changed the definition
of MethodRibKind so that its second argument is an optional node_id
(so that required trait method signatures can be checked with a
MethodRibKind as well).
