Warn that implicit should have explicit type [ci: last-only]

[som-snytt]

Implicit definitions are required to have an explicit type ascribed in Scala 3. Now Scala 2 warns if the type is missing (and therefore inferred). Under -Xsource:3, the warning becomes an error. (Local implicits are exempted because they are not available before they are defined.)

Fixes scala/bug#5265

[som-snytt]

-Werror FTW.

[error] /home/jenkins/workspace/scala-2.13.x-validate-main/src/reflect/scala/reflect/api/Internals.scala:1101:18: Implicit definition should have explicit type
[error]     implicit val token = new CompatToken
[error]                  ^
[error] one error found

[som-snytt]

Fields are not marked implicit, and can't access the accessor without cycles, so mark it and check when typing the getter.

[SethTisue]

/rebuild

(https://scala-ci.typesafe.com/job/scala-2.13.x-validate-main/16292 got stuck)

meanwhile, Travis-CI has failure information

[som-snytt]

I didn't switch to draft after handling val, and still doesn't handle val in traits. Plus cycle of test breakage.

[som-snytt]

Hung again. I don't see the red ex for canceling jenkins job.

Travis:

[info] + IndexScript.allPackages: OK, proved property.
[info] Elapsed time: 0.432 sec 
failing seed for mutable.TreeMapProjection.get, contains is WGrJJZh_6eL-dRMg_fX5Komy1UboU3eTd2SlGrJ3d9G=
[info] ! mutable.TreeMapProjection.get, contains: Exception raised on property evaluation.
[info] > ARG_0: HashMap( -> 0)
[info] > ARG_1: None
[info] > ARG_2: Some()
[info] > ARG_0_ORIGINAL: HashMap(պ -> -2147483648)
[info] > ARG_1_ORIGINAL: Some()
[info] > Exception: java.lang.NullPointerException: null
[info] scala.collection.mutable.TreeMap$TreeMapProjection.isInsideViewBounds(TreeMap.scala:193)
[info] scala.collection.mutable.TreeMap$TreeMapProjection.contains(TreeMap.scala:211)
[info] scala.collection.mutable.MutableTreeMapProjectionProperties$.$anonfun$new$125(MutableTreeMap.scala:238)
[info] scala.collection.mutable.MutableTreeMapProjectionProperties$.$anonfun$new$125$adapted(MutableTreeMap.scala:237)
[info] scala.collection.IterableOnceOps.forall(IterableOnce.scala:589)
[info] scala.collection.IterableOnceOps.forall$(IterableOnce.scala:586)
[info] scala.collection.AbstractIterable.forall(Iterable.scala:933)
[info] scala.collection.mutable.MutableTreeMapProjectionProperties$.$anonfun$new$124(MutableTreeMap.scala:237)
[info] scala.collection.mutable.MutableTreeMapProjectionProperties$.$anonfun$new$124$adapted(MutableTreeMap.scala:230)

Locally,

[info] + Range inclusiveByOne.foreach.visited.size: OK, passed 100 tests.
[info] Elapsed time: 0.002 sec
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007fad5f9c03fc, pid=30176, tid=30206
#
# JRE version: OpenJDK Runtime Environment (18.0.1.1+2) (build 18.0.1.1+2-6)
# Java VM: OpenJDK 64-Bit Server VM (18.0.1.1+2-6, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V  [libjvm.so+0xd263fc][info] + Range inclusiveByOne.sum: OK, passed 100 tests.
[info] Elapsed time: 0.002 sec
[info] + Range inclusiveByOne.sumCustomNumeric: OK, passed 100 tests.
[info] Elapsed time: 0.004 sec

Travis says both

export ADOPTOPENJDK=8
$ java -Xmx32m -version
openjdk version "11.0.2" 2019-01-15
OpenJDK Runtime Environment 18.9 (build 11.0.2+9)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.2+9, mixed mode)
$ javac -J-Xmx32m -version
javac 11.0.2

[som-snytt]

I should have @SethTisue about cancel culture.

[SethTisue]

canceled another stuck Jenkins job just now. signed, The Canceler

[som-snytt]

Oops sorry @SethTisue I forgot to diagnose the hang slash crash. I pushed so I could view diffs.

While I was mechanically adding inferred types, I didn't notice:

-  implicit val ord = implicitly[Ordering[K]]
+  private val ord = implicitly[Ordering[K]]

[som-snytt]

A clean repo crashes in scalacheck/test on latest 18. It would be nice if you could tell which test.

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007f87d3cd4acc, pid=1203, tid=1219
#
# JRE version: OpenJDK Runtime Environment (18.0.2.1+1) (build 18.0.2.1+1-1)
# Java VM: OpenJDK 64-Bit Server VM (18.0.2.1+1-1, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V  [libjvm.so+0xd27acc]  SubTypeCheckNode::sub(Type const*, Type const*) const+0x26c

Current thread (0x00007f87cc0d0830):  JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=1219, stack(0x00007f87a84ad000,0x00007f87a85ae000)]


Current CompileTask:
C2:   5155 9279       4       scala.collection.ArrayOps$::prepended$extension (48 bytes)

[som-snytt]

It's the old space after [ci:] gotcha!

I'll re-squash after @lrytz review.

[SethTisue]

A clean repo crashes in scalacheck/test on latest 18

mind opening a scala-dev ticket on that?

[som-snytt]

Could add a lint option if not -Xsource:3? Usually it's deprecation then error.

[SethTisue]

let's figure this out for ~2.13.10~ 2.13.11

[SethTisue]

@som-snytt mind resolving the merge conflict? where does this stand, do you believe it is ready for review?

[SethTisue]

@som-snytt /me turns on the machine that goes "ping!"

[SethTisue]

Note that this impacts macro authors too; see https://github.com/scala/bug/issues/12798