Bad parameter reference for inlined given definition

[nicolasstucki]

Minimized code

class D[T]

class C {
  def f() = {
    locally {
      given d[T] as D[T]
      g[D[Int]](d[Int])
    }
  }

  inline def locally[T](inline body: T): T = body

  def g[T](x: T): T = x
}

Output (click arrow to expand)

checking tests/pos/inlined-given.scala after phase typer
exception while typing this.g[D[Int]](d[Int]) of class class dotty.tools.dotc.ast.Trees$Apply # -1
exception while typing {
  class d[T >: Nothing <: Any]() extends D[d.this.T]() {
    T
  }
  final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
  this.g[D[Int]](d[Int])
} of class class dotty.tools.dotc.ast.Trees$Block # -1
exception while typing {
  class d[T >: Nothing <: Any]() extends D[d.this.T]() {
    T
  }
  final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
  this.g[D[Int]](d[Int])
} of class class dotty.tools.dotc.ast.Trees$Inlined # -1
exception while typing {
  class d[T >: Nothing <: Any]() extends D[d.this.T]() {
    T
  }
  final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
  this.g[D[Int]](d[Int])
}:D[Int] of class class dotty.tools.dotc.ast.Trees$Typed # -1
exception while typing {
  class d[T >: Nothing <: Any]() extends D[d.this.T]() {
    T
  }
  final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
  this.g[D[Int]](d[Int])
}:D[Int] of class class dotty.tools.dotc.ast.Trees$Inlined # -1
exception while typing {
  {
    class d[T >: Nothing <: Any]() extends D[d.this.T]() {
      T
    }
    final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
    this.g[D[Int]](d[Int])
  }:D[Int]
} of class class dotty.tools.dotc.ast.Trees$Block # -1
exception while typing def f(): D[Int] = 
  {
    {
      class d[T >: Nothing <: Any]() extends D[d.this.T]() {
        T
      }
      final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
      this.g[D[Int]](d[Int])
    }:D[Int]
  } of class class dotty.tools.dotc.ast.Trees$DefDef # -1
exception while typing class C() extends Object() {
  def f(): D[Int] = 
    {
      {
        class d[T >: Nothing <: Any]() extends D[d.this.T]() {
          T
        }
        final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
        this.g[D[Int]](d[Int])
      }:D[Int]
    }
  inline def locally[T >: Nothing <: Any](inline body: T): T = body:T
  def g[T >: Nothing <: Any](x: T): T = x
} of class class dotty.tools.dotc.ast.Trees$TypeDef # -1
exception while typing package <empty> {
  class D[T >: Nothing <: Any]() extends Object() {
    T
  }
  class C() extends Object() {
    def f(): D[Int] = 
      {
        {
          class d[T >: Nothing <: Any]() extends D[d.this.T]() {
            T
          }
          final given def d[T >: Nothing <: Any]: d[T] = new d[T]()
          this.g[D[Int]](d[Int])
        }:D[Int]
      }
    inline def locally[T >: Nothing <: Any](inline body: T): T = body:T
    def g[T >: Nothing <: Any](x: T): T = x
  }
} of class class dotty.tools.dotc.ast.Trees$PackageDef # -1
*** error while checking tests/pos/inlined-given.scala after phase typer ***
exception occurred while compiling tests/pos/inlined-given.scala
class dotty.tools.dotc.reporting.Diagnostic$StickyError at tests/pos/inlined-given.scala:<90..90>: bad parameter reference d.this.T at Ycheck
the parameter is type T in class d but the prefix (d.this : d)
does not define any corresponding arguments. while compiling tests/pos/inlined-given.scala
Exception in thread "main" class dotty.tools.dotc.reporting.Diagnostic$StickyError at tests/pos/inlined-given.scala:<90..90>: bad parameter reference d.this.T at Ycheck
the parameter is type T in class d but the prefix (d.this : d)
does not define any corresponding arguments.
        at dotty.tools.dotc.report$.error(report.scala:71)
        at dotty.tools.dotc.report$.error(report.scala:75)
        at dotty.tools.dotc.typer.ErrorReporting$.errorType(ErrorReporting.scala:34)
        at dotty.tools.dotc.typer.ErrorReporting$.errorTree(ErrorReporting.scala:26)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2523)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2708)
        at dotty.tools.dotc.typer.Typer.typedBlock(Typer.scala:903)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedBlock$$anonfun$2$$anonfun$1(TreeChecker.scala:503)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withDefinedSyms(TreeChecker.scala:199)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedBlock$$anonfun$1(TreeChecker.scala:503)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withBlock(TreeChecker.scala:227)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedBlock(TreeChecker.scala:503)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2467)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2520)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.typedInlined(Typer.scala:1630)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedInlined$$anonfun$1(TreeChecker.scala:506)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withDefinedSyms(TreeChecker.scala:199)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedInlined(TreeChecker.scala:506)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2480)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2520)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.ReTyper.typedTyped(ReTyper.scala:60)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2464)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2520)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.typedInlined(Typer.scala:1630)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedInlined$$anonfun$1(TreeChecker.scala:506)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withDefinedSyms(TreeChecker.scala:199)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedInlined(TreeChecker.scala:506)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2480)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2520)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2708)
        at dotty.tools.dotc.typer.Typer.typedBlock(Typer.scala:903)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedBlock$$anonfun$2$$anonfun$1(TreeChecker.scala:503)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withDefinedSyms(TreeChecker.scala:199)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedBlock$$anonfun$1(TreeChecker.scala:503)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withBlock(TreeChecker.scala:227)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedBlock(TreeChecker.scala:503)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2467)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2520)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2708)
        at dotty.tools.dotc.typer.Typer.$anonfun$34(Typer.scala:1982)
        at dotty.tools.dotc.typer.PrepareInlineable$.dropInlineIfError(PrepareInlineable.scala:217)
        at dotty.tools.dotc.typer.Typer.typedDefDef(Typer.scala:1982)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedDefDef$$anonfun$2$$anonfun$1(TreeChecker.scala:477)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withDefinedSyms(TreeChecker.scala:199)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedDefDef$$anonfun$1(TreeChecker.scala:480)
        at dotty.tools.dotc.transform.TreeChecker$Checker.withDefinedSyms(TreeChecker.scala:199)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedDefDef(TreeChecker.scala:481)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2436)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2519)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2615)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2664)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedStats(TreeChecker.scala:521)
        at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:2120)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedClassDef(TreeChecker.scala:453)
        at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$2(Typer.scala:2447)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2451)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2519)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2615)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2664)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedStats(TreeChecker.scala:521)
        at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:2245)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2491)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2520)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typedUnadapted(TreeChecker.scala:333)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2589)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2593)
        at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:317)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2708)
        at dotty.tools.dotc.transform.TreeChecker.check(TreeChecker.scala:151)
        at dotty.tools.dotc.transform.TreeChecker.run(TreeChecker.scala:120)
        at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:296)
        at scala.collection.immutable.List.map(List.scala:246)
        at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:297)
        at dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:185)
        at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
        at dotty.tools.dotc.Run.runPhases$5(Run.scala:195)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:203)
        at dotty.runtime.function.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
        at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:67)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:210)
        at dotty.tools.dotc.Run.compileSources(Run.scala:147)
        at dotty.tools.dotc.Run.compile(Run.scala:129)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:38)
        at dotty.tools.dotc.Driver.process(Driver.scala:195)
        at dotty.tools.dotc.Driver.process(Driver.scala:164)
        at dotty.tools.dotc.Driver.process(Driver.scala:176)
        at dotty.tools.dotc.Driver.main(Driver.scala:203)
        at dotty.tools.dotc.Main.main(Main.scala)

[odersky]

#9965 is unfortunately really hard to fix. Essentially, we have to copy a symbol graph which in the case of emebedded classes can become quite complicated. We manage with monomorphic classes, but cannot handle type parameters or children annotations (there's another issue for that). Essentially, whereever we have hidden Symbol->Symbol references, we fail.