Macro expansion regression (Java 11)

[michelou]

Minimized code

object Main {
  val lifeOfPi = 3.14159
  val fInterpolator = f"The approximate value of pi is $lifeOfPi%4.2f"
  
  def main(args: Array[String]): Unit = {
    println(fInterpolator)
  }

}

Output (click arrow to expand)

Release 0.27.0-RC1 compiles (and runs) fine:

$ dotc -version
Dotty compiler version 0.27.0-RC1 -- Copyright 2002-2020, LAMP/EPFL

$ dotc -deprecation -feature -classpath "W:\examples\Interpolators\target\classes" -d "W:\examples\Interpolators\target\classes" W:\examples\Interpolators\src\main\scala\Main.scala

$ dotr -classpath W:\examples\Interpolators\target\classes Main
The approximate value of pi is 3,14

Nightly build 0.28.0-bin-20200908-ce48f5a-NIGHTLY crashes:

$ dotc -version
Dotty compiler version 0.28.0-bin-20200908-ce48f5a-NIGHTLY-git-ce48f5a -- Copyright 2002-2020, LAMP/EPFL

$ dotc -deprecation -feature -classpath "W:\examples\Interpolators\target\classes" -d "W:\examples\Interpolators\target\classes" W:\examples\Interpolators\src\main\scala\Main.scala
-- Error: W:\examples\Interpolators\src\main\scala\Main.scala:52:22 ------------
52 |  val fInterpolator = f"The approximate value of pi is $lifeOfPi%4.2f"
   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |Exception occurred while executing macro expansion.
   |java.lang.BootstrapMethodError: bootstrap method initialization exception
   |    at java.base/java.lang.invoke.BootstrapMethodInvoker.invoke(BootstrapMethodInvoker.java:194)
   |    at java.base/java.lang.invoke.CallSite.makeSite(CallSite.java:307)
   |    at java.base/java.lang.invoke.MethodHandleNatives.linkCallSiteImpl(MethodHandleNatives.java:258)
   |    at java.base/java.lang.invoke.MethodHandleNatives.linkCallSite(MethodHandleNatives.java:248)
   |    at dotty.internal.StringContextMacro$.interpolate(StringContextMacro.scala:709)
   |    at dotty.internal.StringContextMacro$.interpolate(StringContextMacro.scala:117)
   |    at dotty.internal.StringContextMacro$.inline$interpolate(StringContextMacro.scala:60)
   |Caused by: java.lang.invoke.LambdaConversionException: Type mismatch for instantiated parameter 0: int is not a subtype of class java.lang.Object
   |    at java.base/java.lang.invoke.AbstractValidatingLambdaMetafactory.checkDescriptor(AbstractValidatingLambdaMetafactory.java:308)
   |    at java.base/java.lang.invoke.AbstractValidatingLambdaMetafactory.validateMetafactoryArgs(AbstractValidatingLambdaMetafactory.java:294)
   |    at java.base/java.lang.invoke.LambdaMetafactory.altMetafactory(LambdaMetafactory.java:503)
   |    at java.base/java.lang.invoke.BootstrapMethodInvoker.invoke(BootstrapMethodInvoker.java:138)
   |    at java.base/java.lang.invoke.CallSite.makeSite(CallSite.java:307)
   |    at java.base/java.lang.invoke.MethodHandleNatives.linkCallSiteImpl(MethodHandleNatives.java:258)
   |    at java.base/java.lang.invoke.MethodHandleNatives.linkCallSite(MethodHandleNatives.java:248)
   |    at dotty.internal.StringContextMacro$.interpolate(StringContextMacro.scala:709)
   |    at dotty.internal.StringContextMacro$.interpolate(StringContextMacro.scala:117)
   |    at dotty.internal.StringContextMacro$.inline$interpolate(StringContextMacro.scala:60)
   |    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   |    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
   |    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   |    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
   |    at dotty.tools.dotc.transform.Splicer$Interpreter.interpretedStaticMethodCall$$anonfun$2$$anonfun$1(Splicer.scala:328)

   |    at dotty.tools.dotc.transform.Splicer$Interpreter.stopIfRuntimeException(Splicer.scala:388)
   |    at dotty.tools.dotc.transform.Splicer$Interpreter.interpretedStaticMethodCall$$anonfun$1(Splicer.scala:328)
   |    at dotty.tools.dotc.transform.Splicer$Interpreter.interpretTree(Splicer.scala:253)
   |    at dotty.tools.dotc.transform.Splicer$Interpreter.interpretTree$$anonfun$4(Splicer.scala:273)
   |    at dotty.tools.dotc.transform.Splicer$.$anonfun$2(Splicer.scala:53)
   |    at scala.Option.fold(Option.scala:263)
   |    at dotty.tools.dotc.transform.Splicer$.splice(Splicer.scala:53)
   |    at dotty.tools.dotc.typer.Inliner.dotty$tools$dotc$typer$Inliner$$expandMacro(Inliner.scala:1415)
   |    at dotty.tools.dotc.typer.Inliner$InlineTyper.typedApply(Inliner.scala:1242)
   |    at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2456)
   |    at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2517)
   |    at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2586)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2590)
   |    at dotty.tools.dotc.typer.ReTyper.typedTyped(ReTyper.scala:60)
   |    at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2461)
   |    at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2517)
   |    at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:122)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2586)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2583)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2590)
   |    at dotty.tools.dotc.typer.Inliner.inlined(Inliner.scala:738)
   |    at dotty.tools.dotc.typer.Inliner$.inlineCall(Inliner.scala:127)
   |    at dotty.tools.dotc.typer.Typer.adaptNoArgsOther$4(Typer.scala:3269)
   |    at dotty.tools.dotc.typer.Typer.adaptNoArgs$1(Typer.scala:3362)
   |    at dotty.tools.dotc.typer.Typer.adapt1(Typer.scala:3586)
   |    at dotty.tools.dotc.typer.Typer.adapt(Typer.scala:2917)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2586)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2590)
   |    at dotty.tools.dotc.typer.Namer.typedAheadExpr$$anonfun$1(Namer.scala:1228)
   |    at dotty.tools.dotc.typer.Namer.typedAhead(Namer.scala:1215)
   |    at dotty.tools.dotc.typer.Namer.typedAheadExpr(Namer.scala:1228)
   |    at dotty.tools.dotc.typer.Namer.rhsType$1$$anonfun$1(Namer.scala:1362)
   |    at dotty.tools.dotc.typer.PrepareInlineable$.dropInlineIfError(PrepareInlineable.scala:217)
   |    at dotty.tools.dotc.typer.Namer.rhsType$2(Namer.scala:1362)
   |    at dotty.tools.dotc.typer.Namer.cookedRhsType$1(Namer.scala:1373)
   |    at dotty.tools.dotc.typer.Namer.lhsType$1(Namer.scala:1374)
   |    at dotty.tools.dotc.typer.Namer.inferredType$1(Namer.scala:1385)
   |    at dotty.tools.dotc.typer.Namer.valOrDefDefSig(Namer.scala:1393)
   |    at dotty.tools.dotc.typer.Namer$Completer.typeSig(Namer.scala:680)
   |    at dotty.tools.dotc.typer.Namer$Completer.completeInCreationContext(Namer.scala:801)
   |    at dotty.tools.dotc.typer.Namer$Completer.complete(Namer.scala:712)
   |    at dotty.tools.dotc.core.SymDenotations$SymDenotation.completeFrom(SymDenotations.scala:166)
   |    at dotty.tools.dotc.core.Denotations$Denotation.completeInfo$1(Denotations.scala:188)
   |    at dotty.tools.dotc.core.Denotations$Denotation.info(Denotations.scala:190)
   |    at dotty.tools.dotc.core.SymDenotations$SymDenotation.ensureCompleted(SymDenotations.scala:364)
   |    at dotty.tools.dotc.typer.Typer.retrieveSym(Typer.scala:2398)
   |    at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2423)
   |    at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2516)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2586)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2590)
   |    at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2612)
   |    at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2661)
   |    at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:2118)
   |    at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$2(Typer.scala:2444)
   |    at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2448)
   |    at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2516)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2586)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2590)
   |    at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2612)
   |    at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2661)
   |    at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:2242)
   |    at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2488)
   |    at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2517)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2586)
   |    at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2590)
   |    at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2705)
   |    at dotty.tools.dotc.typer.FrontEnd.liftedTree1$1(FrontEnd.scala:79)
   |    at dotty.tools.dotc.typer.FrontEnd.typeCheck$$anonfun$1(FrontEnd.scala:84)
   |    at dotty.runtime.function.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
   |    at dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:43)
   |    at dotty.tools.dotc.typer.FrontEnd.typeCheck(FrontEnd.scala:85)
   |    at dotty.tools.dotc.typer.FrontEnd.runOn$$anonfun$3(FrontEnd.scala:120)
   |    at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15)
   |    at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10)
   |    at scala.collection.immutable.List.foreach(List.scala:333)
   |    at dotty.tools.dotc.typer.FrontEnd.runOn(FrontEnd.scala:120)
   |    at dotty.tools.dotc.Run.runPhases$4$$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:63)
   |    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)
   |
   | This location contains code that was inlined from Main.scala:52
1 error found

[smarter]

What's the output of java -version?

[nicolasstucki]

At that line we seem to be calling the funcion of a foreach

https://github.com/lampepfl/dotty/blob/760e50310e3913f704af369b8c0aaf1f254f0b14/library/src-bootstrapped/dotty/internal/StringContextMacro.scala#L709

[michelou]

@smarter Good point. I forgot to mention that I'm using Java 11.0.8+10.

$ java -version
openjdk version "11.0.8" 2020-07-14
OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.8+10)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.8+10, mixed mode, sharing)

The code example works fine with Java 1.8.0_262-b10 (i.e. JAVA_HOME=c:\opt\jdk-1.8.0_262-b10).

[smarter]

Caused by: java.lang.invoke.LambdaConversionException: Type mismatch for instantiated parameter 0: int is not a subtype of class java.lang.Object

Java 9+ is stricter about the type signature of methods used to implement lambdas which means we sometimes have to create a forwarder method with a different signature, this is supposed to be handled by Erasure when retyping Closures: https://github.com/lampepfl/dotty/blob/760e50310e3913f704af369b8c0aaf1f254f0b14/compiler/src/dotty/tools/dotc/transform/Erasure.scala#L372-L421, I'm not sure why it's not working here.

I think the first thing to do would be to try to reproduce the problem outside of a macro to simplify things, @nicolasstucki is this possible?

[smarter]

Also we should try to bisect this, @michelou can you check older nightlies of dotty 0.28 (https://repo1.maven.org/maven2/ch/epfl/lamp/dotty_0.28/) to find the first one where this problem occurs?

[michelou]

@smarter Ok, I'll try to bisect this from the Maven repository (between 20200827 and 20200908).

[michelou]

@smarter That was fast.
The issue appears between 0.27.0-RC1 and 0.28.0-bin-20200827-757e431-NIGHTLY, the first 0.28 nightly build.

$ dotc -version
Dotty compiler version 0.28.0-bin-20200827-757e431-NIGHTLY-git-757e431 -- Copyright 2002-2020, LAMP/EPFL

$ dotc -deprecation -feature -classpath "W:\examples\Interpolators\target\classes" -d "W:\examples\Interpolators\target\classes" W:\examples\Interpolators\src\main\scala\Main.scala
-- Error: W:\examples\Interpolators\src\main\scala\Main.scala:13:22 ------------
13 |  val fInterpolator = f"The approximate value of pi is $lifeOfPi%4.2f"
   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |Exception occurred while executing macro expansion.
   |java.lang.BootstrapMethodError: bootstrap method initialization exception
   ...
   |    at dotty.tools.dotc.Driver.main(Driver.scala:203)
   |    at dotty.tools.dotc.Main.main(Main.scala)
   |
   | This location contains code that was inlined from Main.scala:13
1 error found

[smarter]

That's very weird since there were no code changes between those: https://github.com/lampepfl/dotty/compare/f21775cb09e748091353fdb82eaeae32d2226dfe..757e4312b86e85832135f2cf2d8aeba598989e06

[smarter]

Are you cleaning the content of W:\examples\Interpolators\target\classes before every test?

[michelou]

Yes. In my initial post I did only retranscript the two comands dotc and dotr.

Here is the full output (using option -debug) of my batch file build.bat (subcommand clean --> rmdir on output line 5):

$ build -debug clean compile
[build] Options    : _DOTTY=1 _TASTY=0 _TIMER=0 _VERBOSE=0
[build] Subcommands: _CLEAN=1 _COMPILE=1 _DECOMPILE=0 _DOC=0 _LINT=0 _RUN=0 _TEST=0
[build] Variables  : JAVA_HOME="C:\opt\jdk-11.0.8+10" DOTTY_HOME="C:\opt\dotty-0.27.0-RC1"
[build] Variables  : _MAIN_CLASS=Main _MAIN_ARGS=
[build] rmdir /s /q "W:\examples\Interpolators\target"
[build] 00000000000000 'W:\examples\Interpolators\target\classes\.latest-build'
[build] 00000000000000 'W:\examples\Interpolators\src\main\java\*.java'
[build] _COMPILE_REQUIRED=0
[build] 00000000000000 'W:\examples\Interpolators\target\classes\.latest-build'
[build] 20200910202506 'W:\examples\Interpolators\src\main\scala\*.scala'
[build] _COMPILE_REQUIRED=1
[build] "C:\opt\dotty-0.27.0-RC1\bin\dotc.bat" "@W:\examples\Interpolators\target\scalac_opts.txt" "@W:\examples\Interpolators\target\scalac_sources.txt"
-- Error: W:\examples\Interpolators\src\main\scala\Main.scala:13:22 ------------
13 |  val fInterpolator = f"The approximate value of pi is $lifeOfPi%4.2f"
   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |Exception occurred while executing macro expansion.
   |java.lang.BootstrapMethodError: bootstrap method initialization exception
   ...
   |    at dotty.tools.dotc.Driver.main(Driver.scala:203)
   |    at dotty.tools.dotc.Main.main(Main.scala)
   |
   | This location contains code that was inlined from Main.scala:13
1 error found
Error: Compilation of 1 Scala source files failed
[build] _EXITCODE=1

$ C:\opt\dotty-0.27.0-RC1\bin\dotc.bat -version
Dotty compiler version 0.28.0-bin-20200827-757e431-NIGHTLY-git-757e431 -- Copyright 2002-2020, LAMP/EPFL

PS. In order to compare the behavior of the two versions 0.27.0-RC1 and 0.28.0-bin-20200827-757e431-NIGHTLY I simply switch their respective libraries. Do you have any concerns about that operation ?

$ dir /b c:\opt\dotty-0.27.0-RC1\lib\0.27.0-RC1
dist_0.27-0.27.0-RC1.jar
dotty-compiler_0.27-0.27.0-RC1.jar
dotty-doc_0.27-0.27.0-RC1.jar
dotty-interfaces-0.27.0-RC1.jar
dotty-library_0.27-0.27.0-RC1.jar
dotty-staging_0.27-0.27.0-RC1.jar
dotty-tasty-inspector_0.27-0.27.0-RC1.jar
tasty-core_0.27-0.27.0-RC1.jar

$ dir /b c:\opt\dotty-0.27.0-RC1\lib\0.28.0-bin-20200827-757e431-NIGHTLY
dotty-compiler_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-doc_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-interfaces-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-language-server_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-library_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-library_sjs1_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-sbt-bridge-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-staging_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-tasty-inspector_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-tastydoc-input_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty-tastydoc_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
dotty_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar
tasty-core_0.28-0.28.0-bin-20200827-757e431-NIGHTLY.jar