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MonadError, monads that can be thrown to and caught from
- Either - IO - Try - Maybe
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15 files changed

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-91
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‎CHANGELOG.md‎

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@@ -22,6 +22,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
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- `IO#pin`, for pinning an `IO` to an `Executor` without yet executing it
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- `IO#fuse`, for fusing the fork opportunities of a given `IO` into a single linearized `IO`
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- `IO#exceptionallyIO`, like `exceptionally` but recover inside another `IO`
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- `MonadError`, monads that can be thrown to and caught from
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## [4.0.0] - 2019-05-20
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### Changed

‎pom.xml‎

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@@ -1,5 +1,6 @@
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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<parent>
@@ -60,6 +61,12 @@
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</properties>
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<dependencies>
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<dependency>
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<groupId>io.jaegertracing</groupId>
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<artifactId>jaeger-client</artifactId>
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<version>0.35.5</version>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>junit</groupId>
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<artifactId>junit</artifactId>

‎src/main/java/com/jnape/palatable/lambda/adt/Either.java‎

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@@ -13,6 +13,7 @@
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import com.jnape.palatable.lambda.functor.builtin.Lazy;
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import com.jnape.palatable.lambda.io.IO;
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import com.jnape.palatable.lambda.monad.Monad;
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import com.jnape.palatable.lambda.monad.MonadError;
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import com.jnape.palatable.lambda.traversable.Traversable;
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import java.util.Objects;
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*/
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public abstract class Either<L, R> implements
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CoProduct2<L, R, Either<L, R>>,
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Monad<R, Either<L, ?>>,
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MonadError<L, R, Either<L, ?>>,
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Traversable<R, Either<L, ?>>,
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Bifunctor<L, R, Either<?, ?>> {
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@@ -206,7 +207,7 @@ public <C> Choice3<L, R, C> diverge() {
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*/
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@Override
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public final <R2> Either<L, R2> fmap(Fn1<? super R, ? extends R2> fn) {
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return Monad.super.<R2>fmap(fn).coerce();
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return MonadError.super.<R2>fmap(fn).coerce();
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}
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/**
@@ -247,7 +248,7 @@ public final <R2> Either<L, R2> pure(R2 r2) {
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*/
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@Override
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public final <R2> Either<L, R2> zip(Applicative<Fn1<? super R, ? extends R2>, Either<L, ?>> appFn) {
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return Monad.super.zip(appFn).coerce();
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return MonadError.super.zip(appFn).coerce();
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}
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/**
@@ -265,15 +266,31 @@ public <R2> Lazy<Either<L, R2>> lazyZip(
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*/
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@Override
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public final <R2> Either<L, R2> discardL(Applicative<R2, Either<L, ?>> appB) {
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return Monad.super.discardL(appB).coerce();
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return MonadError.super.discardL(appB).coerce();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public final <R2> Either<L, R> discardR(Applicative<R2, Either<L, ?>> appB) {
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return Monad.super.discardR(appB).coerce();
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return MonadError.super.discardR(appB).coerce();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public Either<L, R> throwError(L l) {
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return left(l);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public Either<L, R> catchError(Fn1<? super L, ? extends Monad<R, Either<L, ?>>> recoveryFn) {
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return match(recoveryFn.fmap(Monad::coerce), Either::right);
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}
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/**

‎src/main/java/com/jnape/palatable/lambda/adt/Maybe.java‎

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@@ -13,6 +13,7 @@
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import com.jnape.palatable.lambda.functor.builtin.Lazy;
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import com.jnape.palatable.lambda.io.IO;
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import com.jnape.palatable.lambda.monad.Monad;
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import com.jnape.palatable.lambda.monad.MonadError;
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import com.jnape.palatable.lambda.traversable.Traversable;
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import java.util.Objects;
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*/
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public abstract class Maybe<A> implements
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CoProduct2<Unit, A, Maybe<A>>,
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Monad<A, Maybe<?>>,
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MonadError<Unit, A, Maybe<?>>,
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Traversable<A, Maybe<?>> {
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private Maybe() {
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return flatMap(a -> predicate.apply(a) ? just(a) : nothing());
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public Maybe<A> throwError(Unit unit) {
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return nothing();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public Maybe<A> catchError(Fn1<? super Unit, ? extends Monad<A, Maybe<?>>> recoveryFn) {
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return match(recoveryFn, Maybe::just).coerce();
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}
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/**
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* If this value is absent, return the value supplied by <code>lSupplier</code> wrapped in <code>Either.left</code>.
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* Otherwise, wrap the value in <code>Either.right</code> and return it.
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*/
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@Override
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public final <B> Maybe<B> fmap(Fn1<? super A, ? extends B> fn) {
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return Monad.super.<B>fmap(fn).coerce();
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return MonadError.super.<B>fmap(fn).coerce();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public final <B> Maybe<B> zip(Applicative<Fn1<? super A, ? extends B>, Maybe<?>> appFn) {
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return Monad.super.zip(appFn).coerce();
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return MonadError.super.zip(appFn).coerce();
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}
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/**
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*/
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@Override
158175
public final <B> Maybe<B> discardL(Applicative<B, Maybe<?>> appB) {
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return Monad.super.discardL(appB).coerce();
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return MonadError.super.discardL(appB).coerce();
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}
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162179
/**
163180
* {@inheritDoc}
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*/
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@Override
166183
public final <B> Maybe<A> discardR(Applicative<B, Maybe<?>> appB) {
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return Monad.super.discardR(appB).coerce();
184+
return MonadError.super.discardR(appB).coerce();
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}
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/**

‎src/main/java/com/jnape/palatable/lambda/adt/Try.java‎

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@@ -8,6 +8,7 @@
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import com.jnape.palatable.lambda.functor.builtin.Lazy;
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import com.jnape.palatable.lambda.io.IO;
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import com.jnape.palatable.lambda.monad.Monad;
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import com.jnape.palatable.lambda.monad.MonadError;
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import com.jnape.palatable.lambda.traversable.Traversable;
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import java.util.Objects;
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* @param <A> the possibly successful expression result
2829
* @see Either
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*/
30-
public abstract class Try<A> implements Monad<A, Try<?>>, Traversable<A, Try<?>>, CoProduct2<Throwable, A, Try<A>> {
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public abstract class Try<A> implements
32+
MonadError<Throwable, A, Try<?>>,
33+
Traversable<A, Try<?>>,
34+
CoProduct2<Throwable, A, Try<A>> {
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private Try() {
3337
}
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return match(fn.fmap(Either::left), Either::right);
163167
}
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169+
/**
170+
* {@inheritDoc}
171+
*/
172+
@Override
173+
public Try<A> throwError(Throwable throwable) {
174+
return failure(throwable);
175+
}
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/**
178+
* {@inheritDoc}
179+
*/
180+
@Override
181+
public Try<A> catchError(Fn1<? super Throwable, ? extends Monad<A, Try<?>>> recoveryFn) {
182+
return match(t -> recoveryFn.apply(t).coerce(), Try::success);
183+
}
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/**
166186
* {@inheritDoc}
167187
*/
168188
@Override
169189
public <B> Try<B> fmap(Fn1<? super A, ? extends B> fn) {
170-
return Monad.super.<B>fmap(fn).coerce();
190+
return MonadError.super.<B>fmap(fn).coerce();
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}
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/**
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*/
192212
@Override
193213
public <B> Try<B> zip(Applicative<Fn1<? super A, ? extends B>, Try<?>> appFn) {
194-
return Monad.super.zip(appFn).coerce();
214+
return MonadError.super.zip(appFn).coerce();
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}
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/**
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208228
*/
209229
@Override
210230
public <B> Try<B> discardL(Applicative<B, Try<?>> appB) {
211-
return Monad.super.discardL(appB).coerce();
231+
return MonadError.super.discardL(appB).coerce();
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}
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214234
/**
215235
* {@inheritDoc}
216236
*/
217237
@Override
218238
public <B> Try<A> discardR(Applicative<B, Try<?>> appB) {
219-
return Monad.super.discardR(appB).coerce();
239+
return MonadError.super.discardR(appB).coerce();
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}
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/**

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