Inlining issue for named tuples hidden behind opaque types

[hamzaremmal]

Compiler version

3.6.2

Minimized code

//> using scala 3.6.2
//> using options -experimental

import scala.language.experimental.namedTuples

opaque type System = (wires: Any)

extension (system: System)
  inline def foo = system.wires
end extension

val simulation: System = ???
val _ = simulation.foo

Output

-- Error: solution.scala:12:19 -------------------------------------------------
 12 |val _ = simulation.foo
    |        ^^^^^^^^^^^^^^
    |undefined: tup.productElement # -1: TermRef(TermRef(NoPrefix,val tup),productElement) at inlining
    |---------------------------------------------------------------------------
    |Inline stack trace
    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    |This location contains code that was inlined from NamedTuple.scala:144
    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    |This location contains code that was inlined from NamedTuple.scala:144
    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    |This location contains code that was inlined from NamedTuple.scala:144
  9 |  inline def foo = system.wires
    |                   ^^^^^^^^^^^^
     ---------------------------------------------------------------------------
1 error found

Expectation

Compiles without any issue

Notes

• The soft keyword opaque in System is important to reproduce the issue
• The soft keyword inline in foo is important to reproduce the issue

[EugeneFlesselle]

Potentially related to #14653, #20427