AssertionFailed: assertion failed: (2, 1)

[kubukoz]

Describe the bug

I don't know how to reproduce this, but I randomly saw this in my logs:

[Error - 23:56:46] Request textDocument/completion failed.
  Message: Internal error.
  Code: -32603 
java.util.concurrent.CompletionException: java.util.concurrent.ExecutionException: Boxed Exception
	at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:332)
	at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:347)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:708)
	at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:510)
	at java.base/java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:2194)
	at scala.meta.internal.metals.CancelTokens$.$anonfun$future$1(CancelTokens.scala:40)
	at scala.meta.internal.metals.CancelTokens$.$anonfun$future$1$adapted(CancelTokens.scala:38)
	at scala.concurrent.impl.Promise$Transformation.run(Promise.scala:484)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.util.concurrent.ExecutionException: Boxed Exception
	at scala.concurrent.impl.Promise$.scala$concurrent$impl$Promise$$resolve(Promise.scala:99)
	at scala.concurrent.impl.Promise$Transformation.handleFailure(Promise.scala:444)
	at scala.concurrent.impl.Promise$Transformation.run(Promise.scala:506)
	... 3 more
Caused by: java.lang.AssertionError: assertion failed: (2,1)
	at scala.reflect.internal.SymbolTable.throwAssertionError(SymbolTable.scala:185)
	at scala.reflect.internal.Symbols$Symbol.updateInfo(Symbols.scala:1593)
	at scala.meta.internal.pc.MetalsGlobal.shortSymbol$1(MetalsGlobal.scala:327)
	at scala.meta.internal.pc.MetalsGlobal.loop$1(MetalsGlobal.scala:409)
	at scala.meta.internal.pc.MetalsGlobal.shortType(MetalsGlobal.scala:538)
	at scala.meta.internal.pc.Signatures$SignaturePrinter.<init>(Signatures.scala:309)
	at scala.meta.internal.pc.completions.Completions.infoString(Completions.scala:288)
	at scala.meta.internal.pc.completions.Completions.infoString$(Completions.scala:285)
	at scala.meta.internal.pc.MetalsGlobal.infoString(MetalsGlobal.scala:36)
	at scala.meta.internal.pc.completions.Completions.detailString(Completions.scala:321)
	at scala.meta.internal.pc.completions.Completions.detailString$(Completions.scala:315)
	at scala.meta.internal.pc.MetalsGlobal.detailString(MetalsGlobal.scala:36)
	at scala.meta.internal.pc.CompletionProvider.$anonfun$completions$2(CompletionProvider.scala:110)
	at scala.collection.Iterator$$anon$10.next(Iterator.scala:461)
	at scala.collection.Iterator.toStream(Iterator.scala:1417)
	at scala.collection.Iterator.toStream$(Iterator.scala:1416)
	at scala.collection.AbstractIterator.toStream(Iterator.scala:1431)
	at scala.collection.Iterator.$anonfun$toStream$1(Iterator.scala:1417)
	at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1173)
	at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1163)
	at scala.collection.immutable.StreamIterator.$anonfun$next$1(Stream.scala:1061)
	at scala.collection.immutable.StreamIterator$LazyCell.v$lzycompute(Stream.scala:1050)
	at scala.collection.immutable.StreamIterator$LazyCell.v(Stream.scala:1050)
	at scala.collection.immutable.StreamIterator.hasNext(Stream.scala:1055)
	at scala.collection.convert.Wrappers$IteratorWrapper.hasNext(Wrappers.scala:32)
	at scala.collection.convert.JavaCollectionWrappers$JIteratorWrapper.hasNext(JavaCollectionWrappers.scala:46)
	at scala.collection.IterableOnceOps.foreach(IterableOnce.scala:619)
	at scala.collection.IterableOnceOps.foreach$(IterableOnce.scala:617)
	at scala.collection.AbstractIterable.foreach(Iterable.scala:935)
	at scala.meta.internal.metals.AdjustLspData.adjustCompletionListInPlace(AdjustLspData.scala:93)
	at scala.meta.internal.metals.AdjustLspData.adjustCompletionListInPlace$(AdjustLspData.scala:92)
	at scala.meta.internal.metals.AdjustedLspData.adjustCompletionListInPlace(AdjustLspData.scala:110)
	at scala.meta.internal.metals.Compilers.$anonfun$completions$2(Compilers.scala:673)
	at scala.concurrent.impl.Promise$Transformation.run(Promise.scala:467)
	... 3 more

Expected behavior

No response

Operating system

macOS

Editor/Extension

VS Code

Version of Metals

v.1.42

Extra context or search terms

No response