Inline as a soft keyword

[allanrenucci]

You can currently define a variable whose name is inline, but you can't reference it

class Test {
  def foo(x: Int): Int = {
    val inline = 3
    inline
  }
}

-- [E103] Syntax Error: tests/allan/Test.scala:4:4 -----------------------------
4 |    inline
  |    ^^^^^^
  |    Illegal start of statement: no modifiers allowed here

longer explanation available when compiling with `-explain`

[odersky]

Not sure what should be done about it? inline can be used if it can't be confused with a modifier.
We interpret that as "can't appear where a statement could start". I don't see why we should enter into more contortions than this.

[allanrenucci]

In one of the previous meetings, we said that if inline is a valid val/def name, then one should be able to refer to it. And that we already have the infrastructure in the parser (arbitrary number of lookahead) to disambiguate between an identifier and a modifier.

[allanrenucci]

a soft keyword is a keyword if it is followed (skipping new inlines, and other soft keyword) by def, val, class, trait (start of definition, see Tokens.defIntroTokens), implicit...