Initialization error in Scanner

[liufengyun]

minimized code

    class LookaheadScanner(indent: Boolean = false) extends Scanner(source, offset) {
      override val indentSyntax = indent
      /// ...
    }

Trace that leads to the violation:

[warn] -- Warning: dotty/compiler/src/dotty/tools/dotc/parsing/Scanners.scala:885:34
[warn] 885 |      override val indentSyntax = indent
[warn]     |                                  ^
[warn]     |Access non-initialized field LookaheadScanner.this.indentSyntax. Calling trace:
[warn]     | -> class LookaheadScanner(indent: Boolean = false) extends Scanner(source, offset) {	[Scanners.scala:884 ]
[warn]     |  -> nextToken()	[Scanners.scala:1323 ]
[warn]     |   -> if (isAfterLineEnd) handleNewLine(lastToken)	[Scanners.scala:311 ]
[warn]     |    -> indentIsSignificant = indentSyntax	[ Scanners.scala:484]

expectation

The field indentSyntax should only be used after it is initialized.