incorrect ScopeException with -Xcheck-macros when few functions is generate slices inside common Quote

[rssh]

Compiler version

3.1.1-RC1

Minimized code

-Xcheck-macros should be in compiler flags.

file M.scala

package x

import scala.quoted._

object Macro:

   inline def genOp(inline f:Int): Int = ${
      genOpImpl('f)
   }

   def genOpImpl(f: Expr[Int])(using Quotes): Expr[Int] = {

      def firstOp(): Expr[Int] =
      '{
        var x=1
        ${secondOp('x,f)}
      }

      def secondOp(x:Expr[Int], y:Expr[Int]): Expr[Int] =
         '{ $x + $y }

      firstOp()
   }

file X.scala:

package x

object Main:

   def main(args: Array[String]):Unit =
      Macro.genOp(10)

Output

[info] welcome to sbt 1.5.5 (Homebrew Java 17)
[info] loading global plugins from /Users/rssh/.sbt/1.0/plugins
[info] loading project definition from /Users/rssh/tests/dotty/restricted-correct-scope/project
[info] loading settings for project root from build.sbt ...
[info] set current project to test (in build file:/Users/rssh/tests/dotty/restricted-correct-scope/)
[info] Executing in batch mode. For better performance use sbt's shell
[info] compiling 2 Scala sources to /Users/rssh/tests/dotty/restricted-correct-scope/target/scala-3.1.1-RC1/classes ...
[error] -- Error: /Users/rssh/tests/dotty/restricted-correct-scope/src/main/scala/x/X.scala:6:17 
[error] 6 |      Macro.genOp(10)
[error]   |      ^^^^^^^^^^^^^^^
[error]   |Exception occurred while executing macro expansion.
[error]   |scala.quoted.runtime.impl.ScopeException: Expression created in a splice was used outside of that splice.
[error]   |Created in: src/main/scala/x/M.scala:16 at column 9
[error]   |Used in: src/main/scala/x/M.scala:20 at column 13
[error]   |Expr: x
[error]   |
[error]   |
[error]   |Creation stack:
[error]   |	src/main/scala/x/M.scala:16 at column 9
[error]   |	/Users/rssh/tests/dotty/restricted-correct-scope/src/main/scala/x/M.scala:7 at column 42
[error]   |
[error]   |
[error]   |Use stack:
[error]   |	src/main/scala/x/M.scala:20 at column 13
[error]   |	/Users/rssh/tests/dotty/restricted-correct-scope/src/main/scala/x/M.scala:7 at column 42
[error]   |
[error]   |          
[error]   |	at scala.quoted.runtime.impl.ScopeException$.checkInCorrectScope(ScopeException.scala:35)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$.quotedExprToTree(PickledQuotes.scala:43)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$$anon$1.transform(PickledQuotes.scala:82)
[error]   |	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1430)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$$anon$1.transform(PickledQuotes.scala:106)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$$anon$1.transform(PickledQuotes.scala:96)
[error]   |	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1396)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$$anon$1.transform(PickledQuotes.scala:106)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$.spliceTerms(PickledQuotes.scala:121)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$.unpickleTerm(PickledQuotes.scala:60)
[error]   |	at scala.quoted.runtime.impl.QuotesImpl.unpickleExpr(QuotesImpl.scala:2973)
[error]   |	at x.Macro$.secondOp$1(M.scala:20)
[error]   |	at x.Macro$.firstOp$1$$anonfun$1(M.scala:16)
[error]   |	at x.Macro$.firstOp$1$$anonfun$adapted$1(M.scala:16)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$$anon$1.transform(PickledQuotes.scala:81)
[error]   |	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1430)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$$anon$1.transform(PickledQuotes.scala:106)
[error]   |	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1410)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$$anon$1.transform(PickledQuotes.scala:106)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$.spliceTerms(PickledQuotes.scala:121)
[error]   |	at dotty.tools.dotc.quoted.PickledQuotes$.unpickleTerm(PickledQuotes.scala:60)
[error]   |	at scala.quoted.runtime.impl.QuotesImpl.unpickleExpr(QuotesImpl.scala:2973)
[error]   |	at x.Macro$.firstOp$1(M.scala:16)
[error]   |	at x.Macro$.genOpImpl(M.scala:23)
[error]   |
[error]   | This location contains code that was inlined from X.scala:6
[error] one error found
[error] one error found

Expectation

should be compiled

[rssh]

(after thinking -- maybe exists way to add something like @nowarn annotation )

[cchantep]

Maybe related to #13926

[rssh]

Yes, I think this is duplicate

[nicolasstucki]

The error showed a quote that was created with the wrong Quotes instance. The code example be fixed by tracing the current Quotes in secondOp.

package x

import scala.quoted._

object Macro:

   inline def genOp(inline f:Int): Int = ${
      genOpImpl('f)
   }

   def genOpImpl(f: Expr[Int])(using Quotes): Expr[Int] = {


     def firstOp(): Expr[Int] =
      '{
        var x=1
        ${secondOp('x,f)}
      }
-     def secondOp(x:Expr[Int], y:Expr[Int]): Expr[Int] =
+     def secondOp(x:Expr[Int], y:Expr[Int])(using Quotes): Expr[Int] =
         '{ $x + $y }

      firstOp()
   }

The compiler can still detect and fix the mistake, but it will cost it some more circles to fix it. If this pattern is nested repeatedly it can have an exponential cost.

[nicolasstucki]

What we do need is a better way to hint at how to fix these errors in the error itself.