`var T` return value can be uninitialized

[alaviss]

Example

type Foo* = object
  s: string

func leak*(A: var Foo): var Foo = discard

proc main() =
  var a: Foo
  echo a.leak().s

main()

Actual Output

Traceback (most recent call last)
test.nim(10)        test
test.nim(8)         main
SIGSEGV: Illegal storage access. (Attempt to read from nil?)

Expected Output

An uninitialized view should be a compile-time error

[alaviss]

Oh there's a warning for this that I missed: test.nim(4, 35) Warning: Cannot prove that 'result' is initialized. This will become a compile time error in the future. [ProveInit]