Default parameter values should be avoided in favor of method overloading. Why?
def add(a: Int, b: Int = 2) = a + b
List(1).map(add) // Compile error
def add2(a: Int) = add2(a, b = 2)
def add2(a: Int, b: Int) = a + b
Ólafur Páll Geirsson olafurpg
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| diff --git a/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala b/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala | |
| index d78f809..a13c972 100644 | |
| --- a/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala | |
| +++ b/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala | |
| @@ -17,6 +17,9 @@ import akka.util.Switch | |
| import scala.concurrent.duration.Duration | |
| import scala.util.control.NonFatal | |
| import java.util.concurrent.TimeUnit | |
| +import akka.actor.ActorSystem | |
| +import akka.event.LoggingAdapter |
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| diff --git a/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala b/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala | |
| index d78f809..a13c972 100644 | |
| --- a/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala | |
| +++ b/akka-testkit/src/main/scala/akka/testkit/CallingThreadDispatcher.scala | |
| @@ -17,6 +17,9 @@ import akka.util.Switch | |
| import scala.concurrent.duration.Duration | |
| import scala.util.control.NonFatal | |
| import java.util.concurrent.TimeUnit | |
| +import akka.actor.ActorSystem | |
| +import akka.event.LoggingAdapter |
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| commit c6a47ed6c2f5a91fb7394ea7e9a3695af029aa0c | |
| Author: Ólafur Páll Geirsson <[email protected]> | |
| Date: Wed Sep 6 11:29:51 2017 +0200 | |
| Undo manual fixes. | |
| diff --git a/akka-actor/src/main/scala/akka/event/EventBus.scala b/akka-actor/src/main/scala/akka/event/EventBus.scala | |
| index ff76b3c..d61fce4 100644 | |
| --- a/akka-actor/src/main/scala/akka/event/EventBus.scala | |
| +++ b/akka-actor/src/main/scala/akka/event/EventBus.scala |
olafurpg
/ NoDefaultParams.md
Created
September 8, 2017 11:45
Default parameter values are bad, let me explain why
olafurpg
/ NoDefaultParameters.scala
Last active
September 8, 2017 15:56
Scalafix linter rule to disallow default parameter values
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| import scalafix._ | |
| import scala.meta._ | |
| case object NoDefaultParams extends Rule("NoDefaultParams") { | |
| val error = LintCategory.error( | |
| "Default parameter values should be avoided, use method overloading instead. " + | |
| "Details: https://gist.github.com/olafurpg/38699f591329c3bcff52b7412dcb696b" | |
| ) | |
| override def check(ctx: RuleCtx): List[LintMessage] = ctx.tree.collect { | |
| case param"..$_ $_: $_ = ${Some(default)}" => | |
| error.at(s"default parameter values are not allowed.", default.pos) |
olafurpg
/ NoDefaultParamsTest.scala
Created
September 8, 2017 12:27
Test case for NoDefaultParams rule
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| /* | |
| rule = "https://gist.githubusercontent.com/olafurpg/7b022c7120156716def282028b091e8b/raw/2a83cfc22462804c53a9fb67d0c0220b8b82f124/NoDefaultParameters.scala" | |
| */ | |
| package test | |
| class NoDefaultParams { | |
| def foo(e: Int = 2) = e // assert: NoDefaultParams | |
| def bar(e: Int) = e | |
| } |
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
1: tests/src/test-2.11/scala/records/test/[email protected]
2: _root_.spire.math.FpFilterExact#`===`(Lspire/math/FpFilter;Lspire/algebra/Signed;Lalgebra/ring/Rng;)Z.
2: _root_.records.test.Typecheck.typed(Ljava/lang/String;)V.
2: _root_.sourcecode.Text.apply(Ljava/lang/Object;)Lsourcecode/Text;.
2: _root_.spire.syntax.IsRealOps#isWhole()Z.
2: _root_.monix.types.Functor.Ops#map(Lscala/Function1;)Ljava/lang/Object;.
2: _root_.spire.syntax.BitStringOps#bitCount()I.
2: _root_.com.typesafe.scalalogging.Logger#debug(Ljava/lang/String;Ljava/lang/Throwable;)V.