Files
Nim/tests/effects/tfuncs_cannot_mutate.nim
2021-04-06 16:20:01 +02:00

40 lines
755 B
Nim

discard """
errormsg: "'mutate' can have side effects"
nimout: '''an object reachable from 'n' is potentially mutated
tfuncs_cannot_mutate.nim(39, 15) the mutation is here
tfuncs_cannot_mutate.nim(37, 7) is the statement that connected the mutation to the parameter
'''
"""
{.experimental: "strictFuncs".}
type
Node = ref object
le, ri: Node
data: string
func insert(x: var seq[Node]; yyy: Node) =
let L = x.len
x.setLen L + 1
x[L] = yyy
func len(n: Node): int =
var it = n
while it != nil:
inc result
it = it.ri
func doNotDistract(n: Node) =
var m = Node()
m.data = "abc"
func select(a, b: Node): Node = b
func mutate(n: Node) =
var it = n
let x = it
let y = x
let z = y
select(x, z).data = "tricky"