Decide upon approach to structural types

[felixmulder]

No description provided.

[olafurpg]

Related discussion #1175.

[sirinath]

Perhaps it might be worthwhile to look into other languages like OCaml which uses structural types and also make this an opportunity to improve on structural types.

[olafurpg]

Here is a summary of structural types containing defs in the wild: olafurpg/scala-experiments#2

The sample is taken from these projects: https://github.com/olafurpg/scala-repos/tree/master/repos

Seems like many of them are in scala/scala jetbrains/intellij-scala

[edmundnoble]

Have we considered removing structural types? From your analysis @olafurpg it looks like structural types with defs are used more in Scala's compiler tests than anywhere else, and if we came up with a story for first-class type projections I don't think they'd have any uses at all.

[smarter]

The latest status of structural types is the new implementation (which is not tied to Java reflection, although it can support it to) at: #1881

[odersky]

Superseded by #1886 and #1881.