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