Make main methods invisible #11546

odersky · 2021-02-26T14:38:31Z

Add a new flag Invisible that gets set for compiler-generated main methods.
Invisible symbols are skipped when resolving members during typechecking.
They become visible after typechecking.

With that mechanism, we can accept main methods that are themselves called main.

Add a new flag Invisible that gets set for compiler-generated main methods. Invisible symbols are skipped when resolving members during typechecking. They become visible after typechecking. With that mechanism, we can accept main methods that are themselves called `main`.

Load bean properties in TreeUnpickler but make them invisible to Typer. This looks like the safer choice.

tasty/src/dotty/tools/tasty/TastyFormat.scala

bishabosha

this approval is to acknowledge the changes to the Tasty version, I have not checked the rest

odersky · 2021-02-28T14:13:33Z

@smarter Do you want to take a look?

smarter · 2021-02-28T17:52:30Z

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

      val isScala2MacroDefinedInScala3 = flags.is(Macro, butNot = Inline) && flags.is(Erased)
      ctx.owner match {
-        case cls: ClassSymbol if (!isScala2MacroDefinedInScala3 || cls == defn.StringContextClass) && !isSyntheticBeanAccessor  =>
+        case cls: ClassSymbol if !isScala2MacroDefinedInScala3 || cls == defn.StringContextClass =>
          // Enter all members of classes that are not Scala 2 macros or synthetic bean accessors.


Suggested change

// Enter all members of classes that are not Scala 2 macros or synthetic bean accessors.

// Enter all members of classes that are not Scala 2 macros

smarter · 2021-02-28T17:53:17Z

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -670,6 +668,7 @@ class TreeUnpickler(reader: TastyReader,
          case PARAMalias => addFlag(SuperParamAlias)
          case EXPORTED => addFlag(Exported)
          case OPEN => addFlag(Open)
+          case INVISIBLE => addFlag(Invisible)


This flag should be visible in tasty-reflect too /cc @nicolasstucki

smarter · 2021-02-28T17:55:13Z

tasty/src/dotty/tools/tasty/TastyFormat.scala

  final val SPLITCLAUSE = 45
+  final val INVISIBLE = 46


isLegalTag in this file still says:

firstSimpleTreeTag <= tag && tag <= SPLITCLAUSE ||

presumably that should be replaced with INVISIBLE (we should really add something like final val LAST_SIMPLE_TAG = INVISIBLE to avoid having to update multiple places like this).

japgolly · 2021-02-28T22:17:22Z

tasty/src/dotty/tools/tasty/TastyFormat.scala

@@ -211,7 +211,8 @@ Standard-Section: "ASTs" TopLevelStat*
                  PARAMsetter                                                      -- The setter part `x_=` of a var parameter `x` which itself is pickled as a PARAM
                  PARAMalias                                                       -- Parameter is alias of a superclass parameter
                  EXPORTED                                                         -- An export forwarder
-                  OPEN                                                             -- an open class
+                  OPEN
+                  INVISIBLE                                                            -- an open class


Comment on wrong line (and inconsistently indented).

Jasper-M · 2021-03-01T11:26:11Z

Does it make the generated class invisible? Or also the annotated method?

julienrf · 2021-03-02T10:48:49Z

I’ve noticed that when using the REPL I can’t call methods annotated with @main:

package example

def foo(): Unit = println("foo")

@main def run(): Unit = println("run")

Then, in the REPL,

scala> example.foo()
foo

scala> example.run()
1 |example.run()
  |^
  |Toplevel definition run is defined in
  |  /home/julien/example/target/scala-3.0.0-RC1/classes/example/Main$package.class
  |and also in
  |  /home/julien/example/target/scala-3.0.0-RC1/classes/example/run.class
  |One of these files should be removed from the classpath.

Would this PR solve the issue? Or should I open a new issue?

julienrf · 2021-03-02T10:52:40Z

BTW, it also makes the completion crash:

INFO: Error while finding completion candidates
dotty.tools.dotc.core.TypeError: Toplevel definition run is defined in
  /home/julien/example/target/scala-3.0.0-RC1/classes/example/Main$package.class
and also in
  /home/julien/example/target/scala-3.0.0-RC1/classes/example/run.class
One of these files should be removed from the classpath.
        at dotty.tools.dotc.core.SymDenotations$PackageClassDenotation.dropStale$1(SymDenotations.scala:2330)
        at dotty.tools.dotc.core.SymDenotations$PackageClassDenotation.recur$1(SymDenotations.scala:2294)
        at dotty.tools.dotc.core.SymDenotations$PackageClassDenotation.computeMembersNamed(SymDenotations.scala:2350)
        at dotty.tools.dotc.core.SymDenotations$ClassDenotation.membersNamed(SymDenotations.scala:1914)
        at dotty.tools.dotc.core.SymDenotations$ClassDenotation.findMember(SymDenotations.scala:1965)
        at dotty.tools.dotc.core.Types$Type.go$1(Types.scala:655)
        at dotty.tools.dotc.core.Types$Type.findMember(Types.scala:843)
        at dotty.tools.dotc.core.Types$Type.memberBasedOnFlags(Types.scala:638)
        at dotty.tools.dotc.core.Types$Type.member(Types.scala:622)
        at dotty.tools.dotc.interactive.Completion$CompletionBuffer.addMember(Completion.scala:292)
        at dotty.tools.dotc.interactive.Completion$CompletionBuffer.addAccessibleMembers$$anonfun$1(Completion.scala:345)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:333)
        at dotty.tools.dotc.interactive.Completion$CompletionBuffer.addAccessibleMembers(Completion.scala:345)
        at dotty.tools.dotc.interactive.Completion$CompletionBuffer.addMemberCompletions(Completion.scala:210)
        at dotty.tools.dotc.interactive.Completion$CompletionBuffer.addSelectionCompletions(Completion.scala:276)
        at dotty.tools.dotc.interactive.Completion$.computeCompletions(Completion.scala:122)
        at dotty.tools.dotc.interactive.Completion$.completions(Completion.scala:48)
        at dotty.tools.repl.ReplDriver.completions$$anonfun$1(ReplDriver.scala:188)
        at scala.util.Either.map(Either.scala:382)
        at dotty.tools.repl.ReplDriver.completions(ReplDriver.scala:189)
        at dotty.tools.repl.ReplDriver.$anonfun$3(ReplDriver.scala:113)
        at org.jline.reader.impl.LineReaderImpl.doComplete(LineReaderImpl.java:4397)
        at org.jline.reader.impl.LineReaderImpl.doComplete(LineReaderImpl.java:4363)
        at org.jline.reader.impl.LineReaderImpl.expandOrComplete(LineReaderImpl.java:4302)
        at org.jline.reader.impl.LineReaderImpl$1.apply(LineReaderImpl.java:3797)
        at org.jline.reader.impl.LineReaderImpl.readLine(LineReaderImpl.java:665)
        at org.jline.reader.impl.LineReaderImpl.readLine(LineReaderImpl.java:454)
        at dotty.tools.repl.JLineTerminal.readLine(JLineTerminal.scala:71)
        at dotty.tools.repl.ReplDriver.readLine$1(ReplDriver.scala:118)
        at dotty.tools.repl.ReplDriver.loop$1(ReplDriver.scala:128)
        at dotty.tools.repl.ReplDriver.runUntilQuit$$anonfun$1(ReplDriver.scala:133)
        at dotty.tools.repl.ReplDriver.withRedirectedOutput(ReplDriver.scala:152)
        at dotty.tools.repl.ReplDriver.runUntilQuit(ReplDriver.scala:133)
        at xsbt.ConsoleInterface.run(ConsoleInterface.java:52)

bishabosha · 2021-03-02T11:42:53Z

I’ve noticed that when using the REPL I can’t call methods annotated with @main:
Would this PR solve the issue? Or should I open a new issue?

I just tried it out and yes, with this PR the repl does call the method run and not error (I compiled the source separately and added the results to the classpath before I ran the repl)

odersky · 2021-03-05T15:43:35Z

@nicolasstucki Can you check the last commit please?

bishabosha · 2021-03-05T15:49:38Z

tasty/src/dotty/tools/tasty/TastyFormat.scala

-  final val EMPTYCLAUSE = 44
-  final val SPLITCLAUSE = 45
-  final val INVISIBLE = 46
+  final val INVISIBLE = 44


normally this would require a MajorVersion bump, but as we have not yet had a stable ExperimentalVersion this is fine

odersky · 2021-03-09T09:44:16Z

@nicolasstucki Could you have a quick review of the last commit, then we can merge this.

nicolasstucki

The changes in the reflection interface look good

nicolasstucki · 2021-03-09T11:16:03Z

@smarter are all the requested changes Ok? Can we merge?

BarkingBad · 2021-03-12T17:43:49Z

I think this PR brought some regression. Having this branch BarkingBad:scaladoc/scala3-docs-in-jar rebased on top of 86e8fb7174e2cfca42067e8be1ccd7dcc9250cd1 commit and executing task tasty-core-bootstrapped/Compile/doc is successful, but rebasing onto e6be077a56aac88c6e714243e153e58b52eb0445 or any subsequent commit fails with given error message:

[error] error while loading package$,
[error] class file dotty/tools/package.class is broken, reading aborted with class dotty.tools.tasty.UnpickleException
[error] TASTy signature has wrong version.
[error]  expected: {majorVersion: 28, minorVersion: 0 [unstable release: 2]}
[error]  found   : {majorVersion: 28, minorVersion: 0 [unstable release: 1]}
[error] 
[error] This TASTy file was produced by an unstable release.
[error] To read this TASTy file, your tooling must be at the same version.
[error] The TASTy file was produced by Scala (unknown).
[error] Note that your tooling is currently using an unstable TASTy version.
[error] one error found
[error] (tasty-core-bootstrapped / Compile / doc) DottyDoc Compilation Failed
[error] Total time: 127 s (02:07), completed 12 mar 2021, 18:35:34

You can find more details in CI actions at this PR (rebased on the newest master) #11578

smarter · 2021-03-12T17:52:00Z

@BarkingBad This doesn't sound like a bug in this PR, it sounds like the scaladoc task is doing something wrong and trying to use tasty files generated by the reference compiler with the current compiler, but those are intentionally incompatible.

odersky added 3 commits February 26, 2021 15:35

Make bean properties invisible

789ceb1

Load bean properties in TreeUnpickler but make them invisible to Typer. This looks like the safer choice.

Don't create constructor proxies for invisible classes

4f2e6a4

bishabosha requested changes Feb 26, 2021

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tasty/src/dotty/tools/tasty/TastyFormat.scala Outdated Show resolved Hide resolved

Bump experimental instead of minor version

b4dfb6b

odersky assigned bishabosha Feb 27, 2021

bishabosha approved these changes Feb 28, 2021

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bishabosha removed their assignment Feb 28, 2021

odersky assigned smarter Feb 28, 2021

smarter requested changes Feb 28, 2021

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japgolly reviewed Feb 28, 2021

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odersky added 2 commits March 5, 2021 16:42

Address review comments

a7a97b4

Expose Invisible flag in Tasty reflect

54495b6

odersky assigned nicolasstucki Mar 5, 2021

odersky requested a review from nicolasstucki March 5, 2021 15:43

bishabosha reviewed Mar 5, 2021

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valencik mentioned this pull request Mar 7, 2021

sbt console tab completion broken after importing io.kjaer.compiletime._ EmergentOrder/onnx-scala#182

Closed

nicolasstucki approved these changes Mar 9, 2021

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nicolasstucki removed their assignment Mar 9, 2021

smarter approved these changes Mar 9, 2021

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smarter merged commit e6be077 into scala:master Mar 9, 2021

smarter deleted the fix-main-shadowing branch March 9, 2021 12:31

Kordyjan added this to the 3.0.0 milestone Aug 2, 2023

	// Enter all members of classes that are not Scala 2 macros or synthetic bean accessors.
	// Enter all members of classes that are not Scala 2 macros

Make main methods invisible #11546

Make main methods invisible #11546

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