Opaque type aliases not working as top level statements in repl

[Kordyjan]

Trying to define opaque type as a top-level statement in the repl is causing a parser error. It is also not working if opaque type definition is loaded from the file that is normally passing the compilation, using :l. Wrapping opaque type in object solves the problem.

Compiler version

master branch as of commit d7d4a9f

Minimized code

Any opaque type definition for example:

opaque type L = Int

Output

1 |opaque type L = Int
  |^^^^^^
  |Illegal start of statement: this modifier is not allowed here

Expectation

Opaque type is defined without errors

[tgodzik]

This looks like an issue in the Parsers:

https://github.com/lampepfl/dotty/blob/master/compiler/src/dotty/tools/dotc/parsing/Parsers.scala#L3829

Seems that somehow isDefIntro(modifierTokens) is false despite there being an explicit check for soft modifiers. Does the REPL wrap the code somehow, that might be causing this issue?

[bishabosha]

duplicate of #9879