duplicates:

• SR-8354 Runtime warning on failure to demangle type

Issue Description:

It seems that using lazy.map leads to a Swift demangling issue:

SWIFT RUNTIME BUG: unable to demangle type of field '_transform'. mangled type name is 'q_7ElementSTQzc'

Paste into a Playground:

let l = [1, 2, 3, 4, 5]
let a = l.lazy.map { i -> Int in
    return i
}
l

Using l.map instead of l.lazy.map alleviates the error.