fix compilation error if Repeated is included in Diagrams assertion

[taisukeoe]

I'd like to report a bug with the latest combination, Scala 3.0.0, ScalaTest 3.2.9 and sbt 1.5.2, and fix the bug by this PR.

About the bug:

Test/compile fails in Diagrams assert which takes an expression including varargs in Scala 3.0.0. It compiles in Scala 2.13.6.

[error] -- [E007] Type Mismatch Error: /home/taisukeoe/workspace/Sandbox/scala3-scalatest/src/test/scala/DiagramTest.scala:7:4 
[error] 7 |    assert(Seq("a", "b") == Seq("a"))
[error]   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]   |    Found:    String*
[error]   |    Required: String
[error]   |
[error]   |    The following import might make progress towards fixing the problem:
[error]   |
[error]   |      import org.scalactic.Prettifier.default
[error]   |
[error]   | This location contains code that was inlined from DiagramTest.scala:9
[error] -- [E007] Type Mismatch Error: /home/taisukeoe/workspace/Sandbox/scala3-scalatest/src/test/scala/DiagramTest.scala:7:4 
[error] 7 |    assert(Seq("a", "b") == Seq("a"))
[error]   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]   |    Found:    (11 : Int)
[error]   |    Required: String
[error]   |
[error]   |    The following import might make progress towards fixing the problem:
[error]   |
[error]   |      import org.scalactic.Prettifier.default
[error]   |
[error]   | This location contains code that was inlined from DiagramTest.scala:9

Minimal Reproducible project

https://github.com/taisukeoe/scala3-scalatest/tree/aba74a99d00cd42b1215147f62d094a2ce628488

About This PR

This PR fixes the above compilation error, and make Diagrams assertion works with varargs, which is represented by Typed(Repeated(_, _), _) term.

Note

There is still a Diagrams assertion error message corruption in Scala 3.0.0, as follows.

[info]   org.scalatest.diagrams.Diagrams.assert(Seq(a, b) != Seq(3, 5))
[info]                                        | |   |  |  || |   |  |
[info]                                        | |   3  5  || |   3  5
[info]                                        | |         || scala.collection.immutable.Seq$@2c58b1c9
[info]                                        | |         |List(3, 5)
[info]                                        | |         false
[info]                                        | scala.collection.immutable.Seq$@2c58b1c9
[info]                                        List(3, 5) (DirectDiagrammedAssertionsSpec.scala:527)

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[cheeseng]

@taisukeoe Sorry for getting back late to this and thanks for the fix! The fix looks good and worked great for Scala 3, but the added test for vararg seems working only under Scala 3, when built with Scala 2:

[error] /home/cheeseng/git/scalatest/jvm/diagrams-test/src/test/scala/org/scalatest/diagrams/DirectDiagrammedAssertionsSpec.scala:601:47: exception during macro expansion: 
[error] scala.MatchError: varargs (of class scala.reflect.internal.Trees$Ident)
[error] 	at org.scalatest.diagrams.DiagrammedExprMacro.traverseApply(DiagrammedExprMacro.scala:110)
[error] 	at org.scalatest.diagrams.DiagrammedExprMacro.applyExpr(DiagrammedExprMacro.scala:202)
[error] 	at org.scalatest.diagrams.DiagrammedExprMacro.transformAst(DiagrammedExprMacro.scala:387)
[error] 	at org.scalatest.diagrams.DiagrammedExprMacro.applyExpr(DiagrammedExprMacro.scala:205)
[error] 	at org.scalatest.diagrams.DiagrammedExprMacro.transformAst(DiagrammedExprMacro.scala:387)
[error] 	at org.scalatest.diagrams.DiagrammedExprMacro.genMacro(DiagrammedExprMacro.scala:421)
[error] 	at org.scalatest.diagrams.DiagramsMacro$.macroImpl(DiagramsMacro.scala:101)
[error] 	at org.scalatest.diagrams.DiagramsMacro$.assert(DiagramsMacro.scala:125)
[error] 	at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
[error] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[error] 	at java.lang.reflect.Method.invoke(Method.java:498)
[error] 	at scala.reflect.macros.runtime.JavaReflectionRuntimes$JavaReflectionResolvers.$anonfun$resolveJavaReflectionRuntime$6(JavaReflectionRuntimes.scala:51)
[error] 	at scala.tools.nsc.typechecker.Macros.macroExpandWithRuntime(Macros.scala:770)
[error]         org.scalatest.diagrams.Diagrams.assert(varargs(1, "y", "z") == 1 -> Seq("y", "z"))
[error]                                               ^

From the error message may be we can enhance our Scala 2 macro to support it, if not perhaps the test can be added under dotty/diagrams-test instead?

[taisukeoe]

@cheeseng
Thank you for confirmation!

From the error message may be we can enhance our Scala 2 macro to support it, if not perhaps the test can be added under dotty/diagrams-test instead?

As long as I quickly checked, this error is occurred only when varargs is defined as local method inside of describe method, and there seems to be a rare case if a method needs to be defined inside of describe.
So I'd move varargs method to outside of describe, because it's nicer not to have Scala 3 specific test file if possible.

---

Oops, this change seems to break Scala 3 side test. I'm checking this.

[error] -- Error: /home/taisukeoe/workspace/OSS/scalatest/dotty/diagrams-test/target/scala-3/src_managed/test/org/scalatest/diagrams/DirectDiagrammedAssertionsSpec.scala:541:8 
[error] 541 |        org.scalatest.diagrams.Diagrams.assert(varargs(1, "y", "z") == 1 -> Seq("y", "z"))
[error]     |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]     |wrong number of arguments at pickler for (x: Int, y: String*): (Int, Seq[String]): (x.value.varargs : (x: Int, y: String*): (Int, Seq[String])), expected: 2, found: 3
[error]     | This location contains code that was inlined from DirectDiagrammedAssertionsSpec.scala:541

[taisukeoe]

Oops, this change seems to break Scala 3 side test. I'm checking this.

It is fixed now. Would you please review this again? @cheeseng

[cheeseng]

@taisukeoe Thanks for the latest version! The changes works great! One last thing you may want to add the tests into DiagrammedAssertionsSpec.scala also, which is a sibling tests for DiagrammedAssertions that calls the assert function through mixed in trait, instead of directly through Diagrams companion object.

@bvenners I have tested this with Scala 2.10, 2.13, 3.0, js and native.

[taisukeoe]

@cheeseng
Thank you for confirmation. I have added tests to DiagramsSpec as well.