Fix #3067: Flag missing parent type of implicit object as error #3770
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Implicit objects should not allow parent types to be computed from argument expressions of an application. This is analogous to demanding an explicit type for implicit vals and defs.
i3067b.scala exhibited a scenario where errors were swallowed because they were produced during completion in a typer state that was later reset during a typerState#test. I.e the sequence was start test --> complete --> reset typerstate We avoid that now by marking completer typer state to be shared and disabling re-using of shared typer states.
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@nicolasstucki Can you check why i3067 fails the fromTasty test? |
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Could we instead restrict the implicit scope used when typing the parents of an |
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I minimized the failure of i3067 from TASTY. class Test(f: List[String] => List[String])
object o extends Test(_.map(x => x))The bug is that when we compile from TASTY not all @scala.annotation.internal.SourceFile("tests/pos/i3067.scala") final module
class
o$ extends Test {
def <init>(): Unit =
{
super(o$#o$$superArg$1())
()
}
private <static> def o$$superArg$1(): Function1 =
{
closure(this.o$$superArg$1$$anonfun$1)
}
private <static> def o$$superArg$1$$anonfun$1$$anonfun$1(x: String): String
=
x
private <static> def o$$superArg$1$$anonfun$1(
_$1: scala.collection.immutable.List
): scala.collection.immutable.List =
_$1.map(
{
closure(this.o$$superArg$1$$anonfun$1$$anonfun$1)
}
, scala.collection.immutable.List.canBuildFrom()).asInstanceOf[
scala.collection.immutable.List
]
} @scala.annotation.internal.SourceFile("tests/pos/i3067.scala") final module
class
o$ extends Test {
def <init>(): Unit =
{
super(o$#o$$superArg$1())
()
}
private <static> def o$$superArg$1(): Function1 =
{
closure(this.o$$superArg$1$$anonfun$1)
}
private <static> def o$$superArg$1$$anonfun$1(
_$1: scala.collection.immutable.List
): scala.collection.immutable.List =
_$1.map(
{
def $anonfun(x: String): String = x
closure(o.$anonfun)
}
, scala.collection.immutable.List.canBuildFrom()).asInstanceOf[
scala.collection.immutable.List
]
} |
And what to do about indirect recursions? Since we decided on demanding full types elsewhere I think it makes sense to not make an exception for objects. |
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@nicolastucki What is a simple command to compile from Tasty that does not involve composing a classpath manually? |
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Not really. I will create a way to test from TASTY compilation directly from the sources. For now, you can replace |
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#3786 will add a way to debug from Tasty directly from the sources. |
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The markShared scheme seems fragile. It's hard to know for sure all the situations where it could be necessary. I can think of at least FunProto (whose peculiar use of Context is already causing problems: #2412) |
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Implicit objects should not allow parent types to be computed from argument
expressions of an application. This is analogous to demanding an explicit type
for implicit vals and defs.
This fix was straightfoward, however it exhibited another problem: Some errors issued
during completion were never reported because the completion happened inside a
TyperState#testthat reset the reporter subsequently. The fix for this one was a bitmore involved.