Rename fail! to panic!

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]

1 files changed, 7 insertions, 7 deletions

diff --git a/src/libstd/num/strconv.rs b/src/libstd/num/strconv.rs
index af66e6ca934..6e0d81a63c9 100644
--- a/src/libstd/num/strconv.rs
+++ b/src/libstd/num/strconv.rs
@@ -264,10 +264,10 @@ pub fn float_to_str_bytes_common<T:NumCast+Zero+One+PartialEq+PartialOrd+Float+
     assert!(2 <= radix && radix <= 36);
     match exp_format {
         ExpDec if radix >= DIGIT_E_RADIX       // decimal exponent 'e'
-          => fail!("float_to_str_bytes_common: radix {} incompatible with \
+          => panic!("float_to_str_bytes_common: radix {} incompatible with \
                     use of 'e' as decimal exponent", radix),
         ExpBin if radix >= DIGIT_P_RADIX       // binary exponent 'p'
-          => fail!("float_to_str_bytes_common: radix {} incompatible with \
+          => panic!("float_to_str_bytes_common: radix {} incompatible with \
                     use of 'p' as binary exponent", radix),
         _ => ()
     }
@@ -553,19 +553,19 @@ pub fn from_str_bytes_common<T:NumCast+Zero+One+PartialEq+PartialOrd+Div<T,T>+
         ) -> Option<T> {
     match exponent {
         ExpDec if radix >= DIGIT_E_RADIX       // decimal exponent 'e'
-          => fail!("from_str_bytes_common: radix {} incompatible with \
+          => panic!("from_str_bytes_common: radix {} incompatible with \
                     use of 'e' as decimal exponent", radix),
         ExpBin if radix >= DIGIT_P_RADIX       // binary exponent 'p'
-          => fail!("from_str_bytes_common: radix {} incompatible with \
+          => panic!("from_str_bytes_common: radix {} incompatible with \
                     use of 'p' as binary exponent", radix),
         _ if special && radix >= DIGIT_I_RADIX // first digit of 'inf'
-          => fail!("from_str_bytes_common: radix {} incompatible with \
+          => panic!("from_str_bytes_common: radix {} incompatible with \
                     special values 'inf' and 'NaN'", radix),
         _ if (radix as int) < 2
-          => fail!("from_str_bytes_common: radix {} to low, \
+          => panic!("from_str_bytes_common: radix {} to low, \
                     must lie in the range [2, 36]", radix),
         _ if (radix as int) > 36
-          => fail!("from_str_bytes_common: radix {} to high, \
+          => panic!("from_str_bytes_common: radix {} to high, \
                     must lie in the range [2, 36]", radix),
         _ => ()
     }