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discard """
action: compile
target: "c"
"""
# Covariance is not type safe:
# Note: `nim cpp` makes it a compile error (after codegen), even with:
# `var f = cast[proc (x: var TA) {.nimcall.}](cast[pointer](bp))`, which
# currently removes all the `cast` in cgen'd code, hence the compile error.
type
TA = object of RootObj
a: int
TB = object of TA
b: array[0..5000_000, int]
proc ap(x: var TA) = x.a = -1
proc bp(x: var TB) = x.b[high(x.b)] = -1
# in Nim proc (x: TB) is compatible to proc (x: TA),
# but this is not type safe:
var f = cast[proc (x: var TA) {.nimcall.}](bp)
var a: TA
f(a) # bp expects a TB, but gets a TA
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