Default value of inline parameter is not inlined when the path involves a pattern match against null.

[readren]

Compiler version

3.7.0 with no scala options

Minimized code

class Something

transparent inline def test(inline oNio: Something | Null = null, inline offset: Int = 0): Int = {
	inline val index = inline oNio match {
		case null => offset
		case nio: Something => -1
	}
	index
}

@main def check(): Unit = {
	test(Something(), 0) // compiles
	test(Something()) // compiles
	test(null, 0) // compiles
	test(null) // complains with: inline value must have a literal constant type 
}

Output

[error] 19 |            test(null) // complains with: inline value must have a literal constant type
[error]    |            ^^^^^^^^^^
[error]    |            inline value must have a literal constant type
[error]    |----------------------------------------------------------------------------
[error]    |Inline stack trace
[error]    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]    |This location contains code that was inlined from Borrame.scala:9
[error]  9 |                    case null => offset
[error]    |                                 ^^^^^^
[error]     ----------------------------------------------------------------------------

Expectation

The call to test(null) should compile.

[som-snytt]

null does not matter. (Switch the RHS of the cases. It fails on the branch exercising the default.)

Deleting index works, so that the RHS is just the match.

Changing index to def complains about nested inline def.

It doesn't help to define the default as zero where inline def zero: 0 = 0.

Defining the default as inline offset: 0 = 0 does work, so it must be widened somewhere. Maybe defaults are always def.

          {
            inline val index: (test$default$2 : => Int) =
              i23177$package.test$default$2
            index:Int
          }