auto merge of rust-lang#18773 : subhashb/rust/convert_remaining_failures_to_panic, r=steveklabnik

I have also renamed `fail` to `panic` in some non-documentation comments, where I thought it mattered.
Fixes rust-lang#18677 

cc @steveklabnik

Author: bors

src/libcollections/slice.rs

@@ -424,7 +424,7 @@ fn merge_sort<T>(v: &mut [T], compare: |&T, &T| -> Ordering) {
     // allocate some memory to use as scratch memory, we keep the
     // length 0 so we can keep shallow copies of the contents of `v`
     // without risking the dtors running on an object twice if
-    // `compare` fails.
+    // `compare` panics.
     let mut working_space = Vec::with_capacity(2 * len);
     // these both are buffers of length `len`.
     let mut buf_dat = working_space.as_mut_ptr();

src/libcore/option.rs

@@ -303,7 +303,7 @@ impl<T> Option<T> {
     ///
     /// # Panics
     ///
-    /// Fails if the value is a `None` with a custom panic message provided by
+    /// Panics if the value is a `None` with a custom panic message provided by
     /// `msg`.
     ///
     /// # Example
@@ -315,7 +315,7 @@ impl<T> Option<T> {
     ///
     /// ```{.should_fail}
     /// let x: Option<&str> = None;
-    /// x.expect("the world is ending"); // fails with `world is ending`
+    /// x.expect("the world is ending"); // panics with `world is ending`
     /// ```
     #[inline]
     #[unstable = "waiting for conventions"]

src/libgetopts/lib.rs

@@ -569,7 +569,7 @@ impl fmt::Show for Fail_ {
 ///
 /// On success returns `Ok(Matches)`. Use methods such as `opt_present`
 /// `opt_str`, etc. to interrogate results.
-/// # Errors
+/// # Panics
 ///
 /// Returns `Err(Fail_)` on failure: use the `Show` implementation of `Fail_` to display
 /// information about it.
@@ -860,9 +860,9 @@ enum LengthLimit {
 /// Note: Function was moved here from `std::str` because this module is the only place that
 /// uses it, and because it was too specific for a general string function.
 ///
-/// #Failure:
+/// # Panics
 ///
-/// Fails during iteration if the string contains a non-whitespace
+/// Panics during iteration if the string contains a non-whitespace
 /// sequence longer than the limit.
 fn each_split_within<'a>(ss: &'a str, lim: uint, it: |&'a str| -> bool)
                      -> bool {

src/libgreen/stack.rs

@@ -42,7 +42,7 @@ impl Stack {
     pub fn new(size: uint) -> Stack {
         // Map in a stack. Eventually we might be able to handle stack
         // allocation failure, which would fail to spawn the task. But there's
-        // not many sensible things to do on OOM.  Failure seems fine (and is
+        // not many sensible things to do on OOM. Panic seems fine (and is
         // what the old stack allocation did).
         let stack = match MemoryMap::new(size, &[MapReadable, MapWritable,
                                                  MapNonStandardFlags(STACK_FLAGS)]) {

src/librand/distributions/exponential.rs

@@ -73,7 +73,7 @@ pub struct Exp {
 
 impl Exp {
     /// Construct a new `Exp` with the given shape parameter
-    /// `lambda`. Fails if `lambda <= 0`.
+    /// `lambda`. Panics if `lambda <= 0`.
     pub fn new(lambda: f64) -> Exp {
         assert!(lambda > 0.0, "Exp::new called with `lambda` <= 0");
         Exp { lambda_inverse: 1.0 / lambda }

src/librand/distributions/gamma.rs

@@ -95,7 +95,7 @@ impl Gamma {
     /// Construct an object representing the `Gamma(shape, scale)`
     /// distribution.
     ///
-    /// Fails if `shape <= 0` or `scale <= 0`.
+    /// Panics if `shape <= 0` or `scale <= 0`.
     pub fn new(shape: f64, scale: f64) -> Gamma {
         assert!(shape > 0.0, "Gamma::new called with shape <= 0");
         assert!(scale > 0.0, "Gamma::new called with scale <= 0");
@@ -208,7 +208,7 @@ enum ChiSquaredRepr {
 
 impl ChiSquared {
     /// Create a new chi-squared distribution with degrees-of-freedom
-    /// `k`. Fails if `k < 0`.
+    /// `k`. Panics if `k < 0`.
     pub fn new(k: f64) -> ChiSquared {
         let repr = if k == 1.0 {
             DoFExactlyOne
@@ -261,7 +261,7 @@ pub struct FisherF {
 
 impl FisherF {
     /// Create a new `FisherF` distribution, with the given
-    /// parameter. Fails if either `m` or `n` are not positive.
+    /// parameter. Panics if either `m` or `n` are not positive.
     pub fn new(m: f64, n: f64) -> FisherF {
         assert!(m > 0.0, "FisherF::new called with `m < 0`");
         assert!(n > 0.0, "FisherF::new called with `n < 0`");
@@ -302,7 +302,7 @@ pub struct StudentT {
 
 impl StudentT {
     /// Create a new Student t distribution with `n` degrees of
-    /// freedom. Fails if `n <= 0`.
+    /// freedom. Panics if `n <= 0`.
     pub fn new(n: f64) -> StudentT {
         assert!(n > 0.0, "StudentT::new called with `n <= 0`");
         StudentT {

src/librand/distributions/mod.rs

@@ -113,7 +113,7 @@ pub struct WeightedChoice<'a, T:'a> {
 impl<'a, T: Clone> WeightedChoice<'a, T> {
     /// Create a new `WeightedChoice`.
     ///
-    /// Fails if:
+    /// Panics if:
     /// - `v` is empty
     /// - the total weight is 0
     /// - the total weight is larger than a `uint` can contain.

src/librand/distributions/normal.rs

@@ -90,7 +90,11 @@ pub struct Normal {
 
 impl Normal {
     /// Construct a new `Normal` distribution with the given mean and
-    /// standard deviation. Fails if `std_dev < 0`.
+    /// standard deviation.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `std_dev < 0`.
     pub fn new(mean: f64, std_dev: f64) -> Normal {
         assert!(std_dev >= 0.0, "Normal::new called with `std_dev` < 0");
         Normal {
@@ -132,7 +136,11 @@ pub struct LogNormal {
 
 impl LogNormal {
     /// Construct a new `LogNormal` distribution with the given mean
-    /// and standard deviation. Fails if `std_dev < 0`.
+    /// and standard deviation.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `std_dev < 0`.
     pub fn new(mean: f64, std_dev: f64) -> LogNormal {
         assert!(std_dev >= 0.0, "LogNormal::new called with `std_dev` < 0");
         LogNormal { norm: Normal::new(mean, std_dev) }

src/librand/distributions/range.rs

@@ -55,7 +55,7 @@ pub struct Range<X> {
 
 impl<X: SampleRange + PartialOrd> Range<X> {
     /// Create a new `Range` instance that samples uniformly from
-    /// `[low, high)`. Fails if `low >= high`.
+    /// `[low, high)`. Panics if `low >= high`.
     pub fn new(low: X, high: X) -> Range<X> {
         assert!(low < high, "Range::new called with `low >= high`");
         SampleRange::construct_range(low, high)

src/librand/lib.rs

@@ -204,15 +204,18 @@ pub trait Rng {
         Generator { rng: self }
     }
 
-    /// Generate a random value in the range [`low`, `high`). Fails if
-    /// `low >= high`.
+    /// Generate a random value in the range [`low`, `high`).
     ///
     /// This is a convenience wrapper around
     /// `distributions::Range`. If this function will be called
     /// repeatedly with the same arguments, one should use `Range`, as
     /// that will amortize the computations that allow for perfect
     /// uniformity, as they only happen on initialization.
     ///
+    /// # Panics
+    ///
+    /// Panics if `low >= high`.
+    ///
     /// # Example
     ///
     /// ```rust