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Failing to summon given Type[T] instances with path-dependent types #16959

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pweisenburger opened this issue Feb 19, 2023 · 0 comments · Fixed by #17205
Closed

Failing to summon given Type[T] instances with path-dependent types #16959

pweisenburger opened this issue Feb 19, 2023 · 0 comments · Fixed by #17205
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@nicolasstucki
Labels
area:metaprogramming:quotes Issues related to quotes and splices itype:bug itype:crash
Milestone
3.3.1

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@pweisenburger
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pweisenburger commented Feb 19, 2023 •
edited by nicolasstucki
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Compiler version

3.3.1-RC1-bin-20230216-2507577-NIGHTLY

This report contains three slightly different versions, one behaves unexpectedly, one crashes the compiler and one with a confusing compiler error. Not sure if the underlying cause is the same or if these are different issues.

Version 1 (Unexpected Behavior)

Minimized code

import scala.quoted.*

inline def test = ${ testImpl }

def testImpl(using Quotes) =
  import quotes.reflect.*

  final class PackedType[T](using t: Type[T]):
    opaque type Type = T
    given quoted.Type[Type] = t

  val int = PackedType[Int]
  val string = PackedType[String]

  println(TypeRepr.of[int.Type].show)
  println(TypeRepr.of[string.Type].show)
  println(TypeRepr.of[(int.Type, string.Type)].show)

  '{ () }

Output

When expanding, the macro prints:

scala.Int
java.lang.String
scala.Tuple2[scala.Int, scala.Int]

Expectation

I would expect it to print:

scala.Int
java.lang.String
scala.Tuple2[scala.Int, java.lang.String]

int.Type and string.Type are clearly different types (by their path) and should use their respective givens. I could not easily reproduce this behavior using custom types, which makes me think the compiler magic to summon Type[T] instances might be involved.

Version 2 (Compiler Crash)

Another encoding (which I'm not really sure should actually compile) crashes the compiler (which, I suppose, should not happen):

inline def test = ${ testImpl }

def testImpl(using Quotes) =
  import quotes.reflect.*

  final class PackedType(using t: Type[?]):
    opaque type Type = t.Underlying
    given quoted.Type[Type] = t

  '{ () }
Stack Trace 
[error] java.util.NoSuchElementException: None.get
[error] scala.None$.get(Option.scala:627)
[error] scala.None$.get(Option.scala:626)
[error] dotty.tools.dotc.core.StagingContext$.getQuoteTypeTags(StagingContext.scala:43)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transformSpliceType(PCPCheckAndHeal.scala:158)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:126)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1483)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:73)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:149)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1240)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:64)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:145)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1483)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:73)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:149)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformBlock(tpd.scala:1243)
[error] dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1429)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:49)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:132)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:56)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:149)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1240)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:64)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:145)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1483)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:73)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:149)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1238)
[error] dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1240)
[error] dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1491)
[error] dotty.tools.dotc.ast.TreeMapWithImplicits.transform(TreeMapWithImplicits.scala:73)
[error] dotty.tools.dotc.transform.TreeMapWithStages.mapOverTree$1(TreeMapWithStages.scala:79)
[error] dotty.tools.dotc.transform.TreeMapWithStages.transform(TreeMapWithStages.scala:149)
[error] dotty.tools.dotc.transform.PCPCheckAndHeal.transform(PCPCheckAndHeal.scala:61)
[error] dotty.tools.dotc.transform.Staging$$anon$2.transform(Staging.scala:73)
[error] dotty.tools.dotc.transform.MacroTransform.run(MacroTransform.scala:18)
[error] dotty.tools.dotc.transform.Staging.run(Staging.scala:69)
[error] dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:324)
[error] scala.collection.immutable.List.map(List.scala:246)
[error] dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:328)
[error] dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:247)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1321)
[error] dotty.tools.dotc.Run.runPhases$1(Run.scala:263)
[error] dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:271)
[error] dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:280)
[error] dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:67)
[error] dotty.tools.dotc.Run.compileUnits(Run.scala:280)
[error] dotty.tools.dotc.Run.compileSources(Run.scala:195)
[error] dotty.tools.dotc.Run.compile(Run.scala:179)
[error] dotty.tools.dotc.Driver.doCompile(Driver.scala:35)
[error] dotty.tools.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:88)
[error] dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22)
[error] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:91)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:193)
[error] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[error] sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:248)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:183)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:163)
[error] sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:239)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:163)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:211)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5(Incremental.scala:179)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5$adapted(Incremental.scala:177)
[error] sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:463)
[error] sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:116)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52)
[error] sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:263)
[error] sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:418)
[error] sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:506)
[error] sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:405)
[error] sbt.internal.inc.Incremental$.apply(Incremental.scala:171)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:488)
[error] sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:425
[error] sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137)
[error] sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2363)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2313)
[error] sbt.internal.server.BspCompileTask$.$anonfun$compute$1(BspCompileTask.scala:30)
[error] sbt.internal.io.Retry$.apply(Retry.scala:46)
[error] sbt.internal.io.Retry$.apply(Retry.scala:28)
[error] sbt.internal.io.Retry$.apply(Retry.scala:23)
[error] sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:30)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2311)
[error] scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
[error] sbt.std.Transform$$anon$4.work(Transform.scala:68)
[error] sbt.Execute.$anonfun$submit$2(Execute.scala:282)
[error] sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:23)
[error] sbt.Execute.work(Execute.scala:291)
[error] sbt.Execute.$anonfun$submit$1(Execute.scala:282)
[error] sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
[error] sbt.CompletionService$$anon$2.call(CompletionService.scala:64)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
[error] java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
[error] java.base/java.lang.Thread.run(Thread.java:833)

Version 3 (Confusing Error Message)

Given the following code:

inline def test = ${ testImpl }

def testImpl(using Quotes) =
  import quotes.reflect.*

  given int: Type[?] = Type.of[Int]
  println(TypeRepr.of[(int.Underlying, String)].show)

  '{ () }

The compiler produces the following error:

[error] -- [E141] Type Error
[error]    |  println(TypeRepr.of[(int.Underlying, String)].show)
[error]    |                                               ^
[error]    |Missing type parameters for int.Underlying in subpart (int.Underlying, String) of inferred type (int.Underlying, String)
[error]    |
[error]    | longer explanation available when compiling with `-explain`
[error] -- [E141] Type Error
[error]    |  println(TypeRepr.of[(int.Underlying, String)].show)
[error]    |                       ^^^^^^^^^^^^^^
[error]    |                       Missing type parameters for int.Underlying
[error]    |
[error]    | longer explanation available when compiling with `-explain`

I'm not sure whether the code should compile, but the error message is not very helpful as it suggests missing type parameters for int.Underlying, which does not take type parameters.

EDIT: I assume now what the last error message wants to say is: int.Underlying is <: AnyKind, i.e., it may or may not take arguments; but the message is not very clear on this.
@pweisenburger pweisenburger added itype:bug itype:crash stat:needs triage Every issue needs to have an "area" and "itype" label labels Feb 19, 2023
@nicolasstucki nicolasstucki added area:metaprogramming:quotes Issues related to quotes and splices and removed stat:needs triage Every issue needs to have an "area" and "itype" label labels Feb 20, 2023
nicolasstucki added a commit to dotty-staging/dotty that referenced this issue Apr 4, 2023
@nicolasstucki
Use TermRef to distinguish distinct Type[T] instances
cbbae64 
We used the symbol before, but this ignored the specific path to the
instance of Type[T].

Fixes scala#16959
@nicolasstucki nicolasstucki mentioned this issue Apr 4, 2023
Merged
@nicolasstucki nicolasstucki self-assigned this Apr 4, 2023
nicolasstucki added a commit that referenced this issue Apr 17, 2023
@nicolasstucki
Use TermRef to distinguish distinct Type[T] instances (#17205)
7187e22 
We used the symbol before, but this ignored the specific path to the
instance of Type[T].

Fixes #16959
Dedelweiss pushed a commit to Dedelweiss/dotty that referenced this issue Apr 17, 2023
@nicolasstucki @Dedelweiss
Use TermRef to distinguish distinct Type[T] instances
fe73780 
We used the symbol before, but this ignored the specific path to the
instance of Type[T].

Fixes scala#16959
@Kordyjan Kordyjan added this to the 3.3.1 milestone Aug 1, 2023
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area:metaprogramming:quotes Issues related to quotes and splices itype:bug itype:crash
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Milestone
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Use TermRef to distinguish distinct Type[T] instances dotty-staging/dotty
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@pweisenburger @nicolasstucki @Kordyjan