Rename Rejection to Reason.

Since it's also on the `Fail` case, the old name doesn't really make
sense.

CHANGELOG.md

@@ -2,17 +2,18 @@
 
 ### Potential Breaking Changes
 
-- Instead of returning `-> Result<Self::Value, String>`, strategies are expected
-  to return `-> Result<Self::Value, Rejection>` instead. `Rejection` reduces
-  the amount of heap allocations, especially for `.prop_filter(..)` where
-  you may now also pass in `&'static str` as well as `Rc<str>`.
-  You will only experience breaks if you've written your own strategy types
-  or if you've used `TestCaseError::Reject` or `TestCaseError::Fail` expliclty.
+- Instead of returning `-> Result<Self::Value, String>`, strategies are
+  expected to return `-> Result<Self::Value, Reason>` instead. `Reason` reduces
+  the amount of heap allocations, especially for `.prop_filter(..)` where you
+  may now also pass in `&'static str`. You will only experience breaks if
+  you've written your own strategy types or if you've used
+  `TestCaseError::Reject` or `TestCaseError::Fail` explicitly.
 
 ### New Additions
 
-- Added `proptest::test_runner::Rejection` which allows you to avoid heap
-  allocation in some places or share allocation with string-interning.
+- Added `proptest::test_runner::Reason` which allows you to avoid heap
+  allocation in some places and may be used to make the API richer in the
+  future without incurring more breaking changes.
 
 - Added a type alias `proptest::strategy::NewTree<S>` where `S: Strategy`
   defined as: `type NewTree<S> = Result<<S as Strategy>::Value, Rejection>`.

src/strategy/filter.rs

@@ -18,12 +18,12 @@ use test_runner::*;
 /// See `Strategy::prop_filter()`.
 pub struct Filter<S, F> {
     pub(super) source: S,
-    pub(super) whence: Rejection,
+    pub(super) whence: Reason,
     pub(super) fun: Arc<F>,
 }
 
 impl<S, F> Filter<S, F> {
-    pub (super) fn new(source: S, whence: Rejection, fun: F) -> Self {
+    pub (super) fn new(source: S, whence: Reason, fun: F) -> Self {
         Self { source, whence, fun: Arc::new(fun) }
     }
 }

src/strategy/flatten.rs

@@ -91,7 +91,7 @@ where S::Value : Strategy,
 }
 
 impl<S : ValueTree> FlattenValueTree<S> where S::Value : Strategy {
-    fn new(runner: &mut TestRunner, meta: S) -> Result<Self, Rejection> {
+    fn new(runner: &mut TestRunner, meta: S) -> Result<Self, Reason> {
         let current = meta.current().new_value(runner)?;
         Ok(FlattenValueTree {
             meta: Fuse::new(meta),

src/strategy/statics.rs

@@ -39,15 +39,15 @@ pub trait FilterFn<T> {
 #[derive(Clone)]
 pub struct Filter<S, F> {
     source: S,
-    whence: Rejection,
+    whence: Reason,
     fun: F,
 }
 
 impl<S, F> Filter<S, F> {
     /// Adapt strategy `source` to reject values which do not pass `filter`,
     /// using `whence` as the reported reason/location.
-    pub fn new(source: S, whence: Rejection, filter: F) -> Self {
-        // NOTE: We don't use universal quantification R: Into<Rejection>
+    pub fn new(source: S, whence: Reason, filter: F) -> Self {
+        // NOTE: We don't use universal quantification R: Into<Reason>
         // since the module is not conviniently exposed.
         Filter { source, whence, fun: filter }
     }

src/strategy/traits.rs

@@ -25,7 +25,7 @@ use test_runner::*;
 /// [`ValueTree`]: trait.ValueTree.html
 /// [`Ok`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#variant.Ok
 /// [`Err`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#variant.Err
-pub type NewTree<S> = Result<<S as Strategy>::Value, Rejection>;
+pub type NewTree<S> = Result<<S as Strategy>::Value, Reason>;
 
 /// The value that functions under test use for a particular `Strategy`.
 pub type ValueFor<S> = <<S as Strategy>::Value as ValueTree>::Value;
@@ -259,7 +259,7 @@ pub trait Strategy : fmt::Debug {
     /// whole-input rejections.
     ///
     /// `whence` is used to record where and why the rejection occurred.
-    fn prop_filter<R: Into<Rejection>, F : Fn (&ValueFor<Self>) -> bool>
+    fn prop_filter<R: Into<Reason>, F : Fn (&ValueFor<Self>) -> bool>
         (self, whence: R, fun: F) -> Filter<Self, F>
     where Self : Sized {
         Filter::new(self, whence.into(), fun)

src/test_runner.rs

@@ -287,40 +287,40 @@ impl FailurePersistence {
 
 /// The reason for why something, such as a generated value, was rejected.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Rejection(Cow<'static, str>);
+pub struct Reason(Cow<'static, str>);
 
-impl From<&'static str> for Rejection {
+impl From<&'static str> for Reason {
     fn from(s: &'static str) -> Self {
-        Rejection(s.into())
+        Reason(s.into())
     }
 }
 
-impl From<String> for Rejection {
+impl From<String> for Reason {
     fn from(s: String) -> Self {
-        Rejection(s.into())
+        Reason(s.into())
     }
 }
 
-impl From<Box<str>> for Rejection {
+impl From<Box<str>> for Reason {
     fn from(s: Box<str>) -> Self {
-        Rejection(String::from(s).into())
+        Reason(String::from(s).into())
     }
 }
 
-impl ops::Deref for Rejection {
+impl ops::Deref for Reason {
     type Target = str;
     fn deref(&self) -> &Self::Target { self.0.deref() }
 }
 
-impl AsRef<str> for Rejection {
+impl AsRef<str> for Reason {
     fn as_ref(&self) -> &str { &*self }
 }
 
-impl Borrow<str> for Rejection {
+impl Borrow<str> for Reason {
     fn borrow(&self) -> &str { &*self }
 }
 
-impl fmt::Display for Rejection {
+impl fmt::Display for Reason {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fmt::Display::fmt(self.as_ref(), f)
     }
@@ -343,12 +343,12 @@ pub enum TestCaseError {
     ///
     /// The string gives the location and context of the rejection, and
     /// should be suitable for formatting like `Foo did X at {whence}`.
-    Reject(Rejection),
+    Reject(Reason),
     /// The code under test failed the test.
     ///
     /// The string should indicate the location of the failure, but may
     /// generally be any string.
-    Fail(Rejection),
+    Fail(Reason),
 }
 
 /// Convenience for the type returned by test cases.
@@ -361,15 +361,15 @@ impl TestCaseError {
     ///
     /// The string gives the location and context of the rejection, and
     /// should be suitable for formatting like `Foo did X at {whence}`.
-    pub fn reject<R: Into<Rejection>>(reason: R) -> Self {
+    pub fn reject<R: Into<Reason>>(reason: R) -> Self {
         TestCaseError::Reject(reason.into())
     }
 
     /// The code under test failed the test.
     ///
     /// The string should indicate the location of the failure, but may
     /// generally be any string.
-    pub fn fail<R: Into<Rejection>>(reason: R) -> Self {
+    pub fn fail<R: Into<Reason>>(reason: R) -> Self {
         TestCaseError::Fail(reason.into())
     }
 }
@@ -396,11 +396,11 @@ impl<E : ::std::error::Error> From<E> for TestCaseError {
 pub enum TestError<T> {
     /// The test was aborted for the given reason, for example, due to too many
     /// inputs having been rejected.
-    Abort(Rejection),
+    Abort(Reason),
     /// A failing test case was found. The string indicates where and/or why
     /// the test failed. The `T` is the minimal input found to reproduce the
     /// failure.
-    Fail(Rejection, T),
+    Fail(Reason, T),
 }
 
 impl<T : fmt::Debug> fmt::Display for TestError<T> {
@@ -424,7 +424,7 @@ impl<T : fmt::Debug> ::std::error::Error for TestError<T> {
     }
 }
 
-type RejectionDetail = BTreeMap<Rejection, u32>;
+type RejectionDetail = BTreeMap<Reason, u32>;
 
 /// State used when running a proptest test.
 #[derive(Clone)]
@@ -856,9 +856,9 @@ impl TestRunner {
 
     /// Update the state to account for a local rejection from `whence`, and
     /// return `Ok` if the caller should keep going or `Err` to abort.
-    pub fn reject_local<R>(&mut self, whence: R) -> Result<(), Rejection>
+    pub fn reject_local<R>(&mut self, whence: R) -> Result<(), Reason>
     where
-        R: Into<Rejection>
+        R: Into<Reason>
     {
         if self.local_rejects >= self.config.max_local_rejects {
             Err("Too many local rejects".into())
@@ -872,7 +872,7 @@ impl TestRunner {
 
     /// Update the state to account for a global rejection from `whence`, and
     /// return `Ok` if the caller should keep going or `Err` to abort.
-    fn reject_global<T>(&mut self, whence: Rejection) -> Result<(),TestError<T>> {
+    fn reject_global<T>(&mut self, whence: Reason) -> Result<(),TestError<T>> {
         if self.global_rejects >= self.config.max_global_rejects {
             Err(TestError::Abort("Too many global rejects".into()))
         } else {
@@ -883,7 +883,7 @@ impl TestRunner {
     }
 
     /// Insert 1 or increment the rejection detail at key for whence.
-    fn insert_or_increment(into: &mut RejectionDetail, whence: Rejection) {
+    fn insert_or_increment(into: &mut RejectionDetail, whence: Reason) {
         use std::collections::btree_map::Entry::*;
         match into.entry(whence) {
             Occupied(oe) => { *oe.into_mut() += 1; },