Summary: public anonymous types have file:line in its name.
Since file is relative path, type name can have '/' in its name.
This is very fragile since we might create file wiht typename in its name (for example for methods).
Replacing '/' with '_' should make frontend more resilient to failure.
Translation of anonymous structs is still pretty fragile (due to relative path in its name),
but at least it doesn't crash frontend
Reviewed By: dulmarod
Differential Revision: D2559936
fb-gh-sync-id: 647fd7f
Andrzej Kotulski