const Z = 0 type Foo[T] = object when true: u: int else: v: int Foo1[T] = object when T is int: x: T elif true: z: char Foo2[x:static[int]] = object when (x and 1) == 1: x: array[x+1,int] else: x: array[x,int] Foo3 = Foo2[128] # #8417 Foo4[A: static[int]] = object when Z == 0: discard else: discard block: var x: Foo[int] = Foo[int](u: 42) doAssert x.u == 42 # Don't evaluate `when` branches before the type is instantiated block: var x: Foo1[bool] = Foo1[bool](z: 'o') doAssert x.z == 'o' block: var x: Foo2[3] doAssert x.x.len == 4 block: var x: Foo2[4] doAssert x.x.len == 4 block: var x: Foo3 doAssert x.x.len == 128 block: var x: Foo4[0] type MyObject = object x: int when (NimMajor, NimMinor) >= (1, 1): y: int discard MyObject(x: 100, y: 200) block: # Ensure when evaluates properly in objects type X[bits: static int] = object #22474 when bits >= 256: data32: byte else: data16: byte static: discard X[255]().data16 discard X[256]().data32 type ComplexExprObject[S: static string, I: static int, Y: static auto] = object when 'h' in S and I < 10 and Y isnot float: a: int elif I > 30: b: int elif typeof(Y) is float: c: int else: d: int static: discard ComplexExprObject["hello", 9, 300i32]().a discard ComplexExprObject["", 40, 30f]().b discard ComplexExprObject["", 20, float 30]().c discard ComplexExprObject["", 20, ""]().d