Macros crash in `Inlines.inlineCallTrace` after changes to `->` desugering

[WojciechMazur]

Based on the OpenCB failure in kalin-rudnicki/oxygen

Compiler version

Last good release: 3.10.0-RC1-bin-20260630-a8ae375-NIGHTLY
First bad release: 3.10.0-RC1-bin-20260701-14f4239-NIGHTLY
Bisect points to 4f67b39

Minimized code

// macro.scala 

import scala.quoted.*

object Macros:
  def impl(using Quotes): Expr[Int] =
    val inner: Expr[Int] = '{ 1 }
    val pair: (Int, Expr[Int]) = 0 -> '{ $inner + 1 }
    pair._2

  inline def trigger: Int = ${ impl }

//> using file macro.scala 

@main def run(): Unit =
  println(Macros.trigger)

Output (click arrow to expand)

Details

Exception in thread "main" java.lang.AssertionError: assertion failed
        at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:13)
        at dotty.tools.dotc.inlines.Inlines$.inlineCallTrace(Inlines.scala:344)
        at dotty.tools.dotc.transform.PickleQuotes$.pickleAsTasty$1(PickleQuotes.scala:306)
        at dotty.tools.dotc.transform.PickleQuotes$.pickle(PickleQuotes.scala:391)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:98)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1588)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:51)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform$$anonfun$1(Trees.scala:1660)
        at scala.collection.immutable.List.mapConserve(List.scala:470)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1660)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1554)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:51)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1562)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:51)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1588)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:51)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1617)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:42)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1315)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1315)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformBlock(tpd.scala:1320)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1568)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:51)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1620)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:42)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1315)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1315)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1317)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:49)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1622)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:42)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.loop$2(tpd.scala:1315)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1315)
        at dotty.tools.dotc.ast.tpd$TreeMapWithPreciseStatContexts.transformStats(tpd.scala:1317)
        at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1633)
        at dotty.tools.dotc.transform.MacroTransform$Transformer.transform(MacroTransform.scala:42)
        at dotty.tools.dotc.transform.PickleQuotes$$anon$1.transform(PickleQuotes.scala:102)
        at dotty.tools.dotc.transform.MacroTransform.run(MacroTransform.scala:20)
        at dotty.tools.dotc.transform.PickleQuotes.run(PickleQuotes.scala:89)
        at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:405)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:331)
        at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:397)
        at dotty.tools.dotc.Run.runPhases$1(Run.scala:414)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1$$anonfun$2(Run.scala:456)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1$$anonfun$adapted$1(Run.scala:456)
        at scala.Function0.apply$mcV$sp(Function0.scala:42)
        at dotty.tools.dotc.Run.showProgress(Run.scala:519)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:456)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:469)
        at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:469)
        at dotty.tools.dotc.Run.compileSources(Run.scala:342)
        at dotty.tools.dotc.Run.compile(Run.scala:327)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:36)
        at dotty.tools.dotc.Driver.process(Driver.scala:208)
        at dotty.tools.dotc.Driver.process(Driver.scala:176)
        at dotty.tools.dotc.Driver.process(Driver.scala:188)
        at dotty.tools.dotc.Driver.main(Driver.scala:214)
        at dotty.tools.dotc.Main.main(Main.scala)
Compilation failed