Retain HasDefaultParams flag on export. #14051

odersky · 2021-12-06T11:53:28Z

tests/run/i14020.scala

bishabosha

If a given has default parameters, then the user has to export named members as well as given members, when I would expect that they only need to export the given members:

class Dog {
  given bark(using msg: String = "Woof!"): String = s"bark: $msg"
}

class Wolf {
  private val dog = Dog()
  export dog.given // needs to be `export dog.{given, *}` to export the default arguments
}

val w = Wolf()
import w.given

summon[String] // error: I found: w.bark(/* missing */summon[String])

odersky · 2021-12-06T18:23:28Z

@bishabosha Fixing either of these things would create quite a big mess. I propose we wait until we have fixed the default parameter scheme to make default parameters inline expressions and not use default getters at all, then these things should become free. Even though fixing the default parameter scheme will be hard, it looks like a better investment of effort than fiddling with default getters here.

I propose we merge this now, after transferring your comment to the issue (which should be left open).

EDIT: I changed my mind. We can't have a discrepancy between named and unnamed here since default getters are not a visible language feature. So let me try to address the issues.

bishabosha · 2021-12-08T10:10:01Z

tests/run/i14020.scala

@@ -0,0 +1,35 @@
+class A:
+  def greeting(name: String = "you") = s"Hello $name"


I tried making greeting inline and now we get a crash when calling c.greeting(), (before this PR is just the standard missing argument error)

stack trace

scala> c.greeting() [error] (run-main-2) java.lang.IllegalArgumentException: Could not find proxy for name: String in List(val name, method greeting, class A, module class rs$line$1$, module class repl$, module class <root>), encl = package repl, owners = package repl, package <root>; enclosures = package repl, package <root> [error] java.lang.IllegalArgumentException: Could not find proxy for name: String in List(val name, method greeting, class A, module class rs$line$1$, module class repl$, module class <root>), encl = package repl, owners = package repl, package <root>; enclosures = package repl, package <root> [error] at dotty.tools.dotc.transform.LambdaLift$Lifter.searchIn$1(LambdaLift.scala:148) [error] at dotty.tools.dotc.transform.LambdaLift$Lifter.proxy(LambdaLift.scala:161) [error] at dotty.tools.dotc.transform.LambdaLift$Lifter.proxyRef(LambdaLift.scala:179) [error] at dotty.tools.dotc.transform.LambdaLift$Lifter.addFreeArgs$$anonfun$1(LambdaLift.scala:185) [error] at scala.collection.immutable.List.map(List.scala:246) [error] at dotty.tools.dotc.transform.LambdaLift$Lifter.addFreeArgs(LambdaLift.scala:185) [error] at dotty.tools.dotc.transform.LambdaLift.transformApply(LambdaLift.scala:322) [error] at dotty.tools.dotc.transform.LambdaLift.transformApply(LambdaLift.scala:321) [error] at dotty.tools.dotc.transform.MegaPhase.goApply(MegaPhase.scala:644) [error] at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:281) [error] at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:429) [error] at dotty.tools.dotc.transform.MegaPhase.mapValDef$1(MegaPhase.scala:235) [error] at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:240) [error] at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427) [error] at dotty.tools.dotc.transform.MegaPhase.transformStat$1(MegaPhase.scala:437) [error] at dotty.tools.dotc.transform.MegaPhase.recur$1(MegaPhase.scala:442) [error] at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:442) [error] at dotty.tools.dotc.transform.MegaPhase.mapPackage$1(MegaPhase.scala:382) [error] at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:385) [error] at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:429) [error] at dotty.tools.dotc.transform.MegaPhase.transformUnit(MegaPhase.scala:448) [error] at dotty.tools.dotc.transform.MegaPhase.run(MegaPhase.scala:460) [error] at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:308) [error] at scala.collection.immutable.List.map(List.scala:246) [error] at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:309) [error] at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:261) [error] at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15) [error] at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10) [error] at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323) [error] at dotty.tools.dotc.Run.runPhases$1(Run.scala:272) [error] at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:280) [error] at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18) [error] at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:68) [error] at dotty.tools.dotc.Run.compileUnits(Run.scala:289) [error] at dotty.tools.dotc.Run.compileUnits(Run.scala:228) [error] at dotty.tools.repl.ReplCompiler.runCompilationUnit(ReplCompiler.scala:167) [error] at dotty.tools.repl.ReplCompiler.compile(ReplCompiler.scala:178) [error] at dotty.tools.repl.ReplDriver.compile(ReplDriver.scala:251) [error] at dotty.tools.repl.ReplDriver.interpret(ReplDriver.scala:219) [error] at dotty.tools.repl.ReplDriver.loop$1(ReplDriver.scala:153) [error] at dotty.tools.repl.ReplDriver.runUntilQuit$$anonfun$1(ReplDriver.scala:156) [error] at dotty.tools.repl.ReplDriver.withRedirectedOutput(ReplDriver.scala:175) [error] at dotty.tools.repl.ReplDriver.runUntilQuit(ReplDriver.scala:156) [error] at xsbt.ConsoleInterface.run(ConsoleInterface.java:52) [error] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [error] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [error] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [error] at java.lang.reflect.Method.invoke(Method.java:498) [error] at sbt.internal.inc.AnalyzingCompiler.invoke(AnalyzingCompiler.scala:329) [error] at sbt.internal.inc.AnalyzingCompiler.console(AnalyzingCompiler.scala:233) [error] at sbt.Console.console0$1(Console.scala:64) [error] at sbt.Console.$anonfun$apply$5(Console.scala:74) [error] at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23) [error] at sbt.util.InterfaceUtil$$anon$1.get(InterfaceUtil.scala:17) [error] at sbt.TrapExit$App.run(TrapExit.scala:258) [error] at java.lang.Thread.run(Thread.java:748) [error] Nonzero exit code: 1 [error] (scala3-compiler-bootstrapped / Compile / console) Nonzero exit code: 1 [error] Total time: 32 s, completed Dec 8, 2021 11:09:44 AM

bishabosha

I don't think I can approve this before the issue with inline methods is resolved, maybe there is a separate underlying issue

Fixes scala#14020

Exported functions could be inline, but that did not work at all. This should be fixed by this commit.

bishabosha · 2021-12-13T10:22:02Z

tests/run/i14020.scala

+
+
+class Dog:
+  given bark(using msg: String = "Woof!"): String = s"bark: $msg"


I have found one last issue which is by making bark inline:

class Dog: inline given bark(using msg: String = "Woof!"): String = s"bark: $msg"

gives

-- Error: ---------------------------------------------------------------------- 31 |summon[String] | ^ |value dog cannot be accessed as a member of (Wolf_this : (w : Wolf)) from module class i14020$package$. | This location contains code that was inlined from i14020.scala:39 1 error found

you don't get the same error if you try to manually forward to dog.bark in Wolf:

class Wolf: private val dog = Dog() inline given bark(using msg: String = "Woof!"): String = dog.bark(using msg)

bishabosha

I found another issue which may be due to trying to access dog s default getter in the inlined code of w.bark

odersky · 2021-12-17T11:21:08Z

@bishabosha Can you open another issue for this? I don't have time to work on it, and I think as far as the original problem goes, everything is addressed. We should not let this fix wait indefinitely awaiting the resolution of the other issue.

bishabosha · 2021-12-17T20:02:40Z

@bishabosha Can you open another issue for this?

made issue #14131

odersky requested a review from bishabosha December 6, 2021 14:26

odersky assigned bishabosha Dec 6, 2021

bishabosha reviewed Dec 6, 2021

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odersky force-pushed the fix-14020 branch 2 times, most recently from 95457b2 to 57146f7 Compare December 7, 2021 12:27

bishabosha self-requested a review December 8, 2021 10:08

bishabosha reviewed Dec 8, 2021

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bishabosha self-requested a review December 8, 2021 10:10

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odersky added 5 commits December 10, 2021 18:13

Retain HasDefaultParams flag on export.

f4ce826

Fixes scala#14020

Make export of default getters work also with named and given exports

340a3b9

Simplify

4d87bb9

Fix flags of export forwarders

6fb3c53

Fix inline + export combination

cbff98d

Exported functions could be inline, but that did not work at all. This should be fixed by this commit.

odersky force-pushed the fix-14020 branch from 57146f7 to cbff98d Compare December 10, 2021 17:13

bishabosha self-requested a review December 13, 2021 08:41

bishabosha reviewed Dec 13, 2021

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bishabosha requested changes Dec 13, 2021

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bishabosha mentioned this pull request Dec 17, 2021

Exported inline does not generate inline accessors to exported path #14131

Closed

bishabosha self-requested a review December 17, 2021 20:02

bishabosha approved these changes Dec 17, 2021

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bishabosha merged commit b3ab102 into scala:master Dec 17, 2021

bishabosha deleted the fix-14020 branch December 17, 2021 20:03

smarter mentioned this pull request Dec 21, 2021

Exporting extension methods drops default arguments #14159

Closed

pikinier20 mentioned this pull request Apr 26, 2022

import exported function from another file lose default parameters #15031

Closed

WojciechMazur mentioned this pull request Dec 6, 2022

Child class cannot access exported inline methods from parent class #16469

Closed

Kordyjan added this to the 3.1.2 milestone Aug 2, 2023

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Retain HasDefaultParams flag on export. #14051

Retain HasDefaultParams flag on export. #14051

odersky commented Dec 6, 2021

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odersky commented Dec 17, 2021

bishabosha commented Dec 17, 2021

		@@ -0,0 +1,35 @@
		class A:
		def greeting(name: String = "you") = s"Hello $name"



		class Dog:
		given bark(using msg: String = "Woof!"): String = s"bark: $msg"

Retain HasDefaultParams flag on export. #14051

Retain HasDefaultParams flag on export. #14051

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