Generic tuple types

gistfile1.nim

# compiles
type Foo = tuple[x, y: float]
proc foo(a, b: Foo): bool = (a.x == b.x) and (a.y == b.y)
var f = (1.0, 2.0)
check(foo(f, f))

# does not compile
type Bar[T] = tuple[x, y: T]
proc bar(a, b: Bar): bool = (a.x == b.x) and (a.y == b.y) # Error: undeclared identifier: 'x'
var b = (1.0, 2.0)
check(bar(b, b)) # Info: instantiation from here

Workaround:

var b: Bar[float] = (1.0, 2.0)