Migrate back to generic type parameter

README.md

@@ -156,9 +156,7 @@ struct MyEqMatcher<T> {
     expected: T,
 }
 
-impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
-    type ActualT = T;
-
+impl<T: PartialEq + Debug> Matcher<T> for MyEqMatcher<T> {
     fn matches(&self, actual: &Self::ActualT) -> MatcherResult {
          (self.expected == *actual).into()
     }
@@ -179,7 +177,7 @@ impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
 It is recommended to expose a function which constructs the matcher:
 
 ```rust
-pub fn eq_my_way<T: PartialEq + Debug>(expected: T) -> impl Matcher<ActualT = T> {
+pub fn eq_my_way<T: PartialEq + Debug>(expected: T) -> impl Matcher<T> {
     MyEqMatcher { expected }
 }
 ```

googletest/crate_docs.md

@@ -216,10 +216,8 @@ struct MyEqMatcher<T> {
     expected: T,
 }
 
-impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
-    type ActualT = T;
-
-    fn matches(&self, actual: &Self::ActualT) -> MatcherResult {
+impl<T: PartialEq + Debug> Matcher<T> for MyEqMatcher<T> {
+    fn matches<'a>(&self, actual: &'a T) -> MatcherResult where T: 'a{
         if self.expected == *actual {
             MatcherResult::Match
         } else {
@@ -250,10 +248,8 @@ impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
  #    expected: T,
  # }
  #
- # impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
- #    type ActualT = T;
- #
- #    fn matches(&self, actual: &Self::ActualT) -> MatcherResult {
+ # impl<T: PartialEq + Debug> Matcher<T> for MyEqMatcher<T> {
+ #    fn matches<'a>(&self, actual: &'a T) -> MatcherResult where T: 'a{
  #        if self.expected == *actual {
  #            MatcherResult::Match
  #        } else {
@@ -273,7 +269,7 @@ impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
  #    }
  # }
  #
- pub fn eq_my_way<T: PartialEq + Debug>(expected: T) -> impl Matcher<ActualT = T> {
+ pub fn eq_my_way<T: PartialEq + Debug>(expected: T) -> impl Matcher<T> {
     MyEqMatcher { expected }
  }
  ```
@@ -289,10 +285,8 @@ impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
 #    expected: T,
 # }
 #
-# impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
-#    type ActualT = T;
-#
-#    fn matches(&self, actual: &Self::ActualT) -> MatcherResult {
+# impl<T: PartialEq + Debug> Matcher<T> for MyEqMatcher<T> {
+#    fn matches<'a>(&self, actual: &'a T) -> MatcherResult where T: 'a{
 #        if self.expected == *actual {
 #            MatcherResult::Match
 #        } else {
@@ -312,7 +306,7 @@ impl<T: PartialEq + Debug> Matcher for MyEqMatcher<T> {
 #    }
 # }
 #
-# pub fn eq_my_way<T: PartialEq + Debug>(expected: T) -> impl Matcher<ActualT = T> {
+# pub fn eq_my_way<T: PartialEq + Debug>(expected: T) -> impl Matcher<T> {
 #    MyEqMatcher { expected }
 # }
 # /* The attribute macro would prevent the function from being compiled in a doctest.

googletest/src/assertions.rs

@@ -499,7 +499,7 @@ pub mod internal {
     #[must_use = "The assertion result must be evaluated to affect the test result."]
     pub fn check_matcher<T: Debug + ?Sized>(
         actual: &T,
-        expected: impl Matcher<ActualT = T>,
+        expected: impl Matcher<T>,
         actual_expr: &'static str,
         source_location: SourceLocation,
     ) -> Result<(), TestAssertionFailure> {

googletest/src/matcher.rs

@@ -21,17 +21,16 @@ use crate::matchers::__internal_unstable_do_not_depend_on_these::DisjunctionMatc
 use std::fmt::Debug;
 
 /// An interface for checking an arbitrary condition on a datum.
-pub trait Matcher {
-    /// The type against which this matcher matches.
-    type ActualT: Debug + ?Sized;
-
+pub trait Matcher<ActualT: Debug + ?Sized> {
     /// Returns whether the condition matches the datum `actual`.
     ///
     /// The trait implementation defines what it means to "match". Often the
     /// matching condition is based on data stored in the matcher. For example,
     /// `eq` matches when its stored expected value is equal (in the sense of
     /// the `==` operator) to the value `actual`.
-    fn matches(&self, actual: &Self::ActualT) -> MatcherResult;
+    fn matches<'a>(&self, actual: &'a ActualT) -> MatcherResult
+    where
+        ActualT: 'a;
 
     /// Returns a description of `self` or a negative description if
     /// `matcher_result` is `DoesNotMatch`.
@@ -128,7 +127,10 @@ pub trait Matcher {
     ///     format!("which points to a value {}", self.expected.explain_match(actual.deref()))
     /// }
     /// ```
-    fn explain_match(&self, actual: &Self::ActualT) -> String {
+    fn explain_match<'a>(&self, actual: &'a ActualT) -> String
+    where
+        ActualT: 'a,
+    {
         format!("which {}", self.describe(self.matches(actual)))
     }
 
@@ -155,10 +157,7 @@ pub trait Matcher {
     // TODO(b/264518763): Replace the return type with impl Matcher and reduce
     // visibility of ConjunctionMatcher once impl in return position in trait
     // methods is stable.
-    fn and<Right: Matcher<ActualT = Self::ActualT>>(
-        self,
-        right: Right,
-    ) -> ConjunctionMatcher<Self, Right>
+    fn and<Right: Matcher<ActualT>>(self, right: Right) -> ConjunctionMatcher<Self, Right>
     where
         Self: Sized,
     {
@@ -185,10 +184,7 @@ pub trait Matcher {
     // TODO(b/264518763): Replace the return type with impl Matcher and reduce
     // visibility of DisjunctionMatcher once impl in return position in trait
     // methods is stable.
-    fn or<Right: Matcher<ActualT = Self::ActualT>>(
-        self,
-        right: Right,
-    ) -> DisjunctionMatcher<Self, Right>
+    fn or<Right: Matcher<ActualT>>(self, right: Right) -> DisjunctionMatcher<Self, Right>
     where
         Self: Sized,
     {
@@ -206,7 +202,7 @@ const PRETTY_PRINT_LENGTH_THRESHOLD: usize = 60;
 /// The parameter `actual_expr` contains the expression which was evaluated to
 /// obtain `actual`.
 pub(crate) fn create_assertion_failure<T: Debug + ?Sized>(
-    matcher: &impl Matcher<ActualT = T>,
+    matcher: &impl Matcher<T>,
     actual: &T,
     actual_expr: &'static str,
     source_location: SourceLocation,
@@ -240,7 +236,11 @@ pub enum MatcherResult {
 
 impl From<bool> for MatcherResult {
     fn from(b: bool) -> Self {
-        if b { MatcherResult::Match } else { MatcherResult::NoMatch }
+        if b {
+            MatcherResult::Match
+        } else {
+            MatcherResult::NoMatch
+        }
     }
 }
 

googletest/src/matcher_support/edit_distance.rs

@@ -430,8 +430,8 @@ mod tests {
     }
 
     #[test]
-    fn returns_common_part_plus_difference_plus_common_part_when_there_is_common_prefix_and_suffix()
-    -> Result<()> {
+    fn returns_common_part_plus_difference_plus_common_part_when_there_is_common_prefix_and_suffix(
+    ) -> Result<()> {
         let result = edit_list(
             ["Common part (1)", "Actual only", "Common part (2)"],
             ["Common part (1)", "Expected only", "Common part (2)"],
@@ -449,8 +449,8 @@ mod tests {
     }
 
     #[test]
-    fn returns_common_part_plus_extra_actual_plus_common_part_when_there_is_common_prefix_and_suffix()
-    -> Result<()> {
+    fn returns_common_part_plus_extra_actual_plus_common_part_when_there_is_common_prefix_and_suffix(
+    ) -> Result<()> {
         let result = edit_list(
             ["Common part (1)", "Actual only", "Common part (2)"],
             ["Common part (1)", "Common part (2)"],
@@ -467,8 +467,8 @@ mod tests {
     }
 
     #[test]
-    fn returns_common_part_plus_extra_expected_plus_common_part_when_there_is_common_prefix_and_suffix()
-    -> Result<()> {
+    fn returns_common_part_plus_extra_expected_plus_common_part_when_there_is_common_prefix_and_suffix(
+    ) -> Result<()> {
         let result = edit_list(
             ["Common part (1)", "Common part (2)"],
             ["Common part (1)", "Expected only", "Common part (2)"],
@@ -500,8 +500,8 @@ mod tests {
     }
 
     #[test]
-    fn does_not_skip_extra_parts_on_actual_in_prefix_mode_at_end_when_they_are_in_common()
-    -> Result<()> {
+    fn does_not_skip_extra_parts_on_actual_in_prefix_mode_at_end_when_they_are_in_common(
+    ) -> Result<()> {
         let result = edit_list(
             ["Actual only", "Common part"],
             ["Expected only", "Common part"],
@@ -518,8 +518,8 @@ mod tests {
     }
 
     #[test]
-    fn does_not_skip_corresponding_line_on_actual_when_actual_and_expected_differ_in_prefix_mode()
-    -> Result<()> {
+    fn does_not_skip_corresponding_line_on_actual_when_actual_and_expected_differ_in_prefix_mode(
+    ) -> Result<()> {
         let result = edit_list(["Actual only"], ["Expected only"], Mode::Prefix);
         verify_that!(
             result,

googletest/src/matchers/all_matcher.rs

@@ -75,22 +75,23 @@ pub mod internal {
     /// For internal use only. API stablility is not guaranteed!
     #[doc(hidden)]
     pub struct AllMatcher<'a, T: Debug + ?Sized, const N: usize> {
-        components: [Box<dyn Matcher<ActualT = T> + 'a>; N],
+        components: [Box<dyn Matcher<T> + 'a>; N],
     }
 
     impl<'a, T: Debug + ?Sized, const N: usize> AllMatcher<'a, T, N> {
         /// Constructs an [`AllMatcher`] with the given component matchers.
         ///
         /// Intended for use only by the [`all`] macro.
-        pub fn new(components: [Box<dyn Matcher<ActualT = T> + 'a>; N]) -> Self {
+        pub fn new(components: [Box<dyn Matcher<T> + 'a>; N]) -> Self {
             Self { components }
         }
     }
 
-    impl<'a, T: Debug + ?Sized, const N: usize> Matcher for AllMatcher<'a, T, N> {
-        type ActualT = T;
-
-        fn matches(&self, actual: &Self::ActualT) -> MatcherResult {
+    impl<'a, T: Debug + ?Sized, const N: usize> Matcher<T> for AllMatcher<'a, T, N> {
+        fn matches<'b>(&self, actual: &'b T) -> MatcherResult
+        where
+            T: 'b,
+        {
             for component in &self.components {
                 match component.matches(actual) {
                     MatcherResult::NoMatch => {
@@ -102,7 +103,10 @@ pub mod internal {
             MatcherResult::Match
         }
 
-        fn explain_match(&self, actual: &Self::ActualT) -> String {
+        fn explain_match<'b>(&self, actual: &'b T) -> String
+        where
+            T: 'b,
+        {
             match N {
                 0 => anything::<T>().explain_match(actual),
                 1 => self.components[0].explain_match(actual),

googletest/src/matchers/any_matcher.rs

@@ -77,26 +77,30 @@ pub mod internal {
     /// For internal use only. API stablility is not guaranteed!
     #[doc(hidden)]
     pub struct AnyMatcher<'a, T: Debug + ?Sized, const N: usize> {
-        components: [Box<dyn Matcher<ActualT = T> + 'a>; N],
+        components: [Box<dyn Matcher<T> + 'a>; N],
     }
 
     impl<'a, T: Debug + ?Sized, const N: usize> AnyMatcher<'a, T, N> {
         /// Constructs an [`AnyMatcher`] with the given component matchers.
         ///
         /// Intended for use only by the [`all`] macro.
-        pub fn new(components: [Box<dyn Matcher<ActualT = T> + 'a>; N]) -> Self {
+        pub fn new(components: [Box<dyn Matcher<T> + 'a>; N]) -> Self {
             Self { components }
         }
     }
 
-    impl<'a, T: Debug + ?Sized, const N: usize> Matcher for AnyMatcher<'a, T, N> {
-        type ActualT = T;
-
-        fn matches(&self, actual: &Self::ActualT) -> MatcherResult {
+    impl<'a, T: Debug + ?Sized, const N: usize> Matcher<T> for AnyMatcher<'a, T, N> {
+        fn matches<'b>(&self, actual: &'b T) -> MatcherResult
+        where
+            T: 'b,
+        {
             MatcherResult::from(self.components.iter().any(|c| c.matches(actual).is_match()))
         }
 
-        fn explain_match(&self, actual: &Self::ActualT) -> String {
+        fn explain_match<'b>(&self, actual: &'b T) -> String
+        where
+            T: 'b,
+        {
             match N {
                 0 => format!("which {}", anything::<T>().describe(MatcherResult::NoMatch)),
                 1 => self.components[0].explain_match(actual),

googletest/src/matchers/anything_matcher.rs

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 use crate::matcher::{Matcher, MatcherResult};
-use std::{fmt::Debug, marker::PhantomData};
+use std::fmt::Debug;
 
 /// Matches anything. This matcher always succeeds.
 ///
@@ -29,16 +29,17 @@ use std::{fmt::Debug, marker::PhantomData};
 /// # }
 /// # should_pass().unwrap();
 /// ```
-pub fn anything<T: Debug + ?Sized>() -> impl Matcher<ActualT = T> {
-    Anything::<T>(Default::default())
+pub fn anything<T: Debug + ?Sized>() -> impl Matcher<T> {
+    Anything
 }
 
-struct Anything<T: ?Sized>(PhantomData<T>);
+struct Anything;
 
-impl<T: Debug + ?Sized> Matcher for Anything<T> {
-    type ActualT = T;
-
-    fn matches(&self, _: &T) -> MatcherResult {
+impl<T: Debug + ?Sized> Matcher<T> for Anything {
+    fn matches<'a>(&self, _: &'a T) -> MatcherResult
+    where
+        T: 'a,
+    {
         MatcherResult::Match
     }