newruntime and unused generics: compiler crash

[mratsim]

Compile this with nim c --newruntime --d:newruntime

type CustSeq = object
  data: seq[int]


proc newCustSeq(len: Natural): CustSeq =
  result.data = newSeq[int](len)

when defined(newruntime):
  echo "Using Nim new runtime"

  proc `=sink`[T](a: var CustSeq, b: CustSeq) =
    echo "Value sinked"
    shallowCopy(a, b)

  proc `=move`[T](a, b: var CustSeq) =
    echo "Value moved"
    shallowCopy(a, b)


proc main() =
  let a = newCustSeq(10)
  let b = a
  echo b

main()

Error: internal error: (filename: ccgexprs.nim, line: 972)
No stack traceback available
To create a stacktrace, rerun compilation with ./koch temp c <file>

Removing the [T] to the sink and move solves the issue

[Yardanico]

Gives better error now:

Hint: used config file '/home/yardanico/Nim/config/nim.cfg' [Conf]
Hint: system [Processing]
Hint: test [Processing]
injecting into
## generic ``$`` operator for tuples that is lifted from the components
## of `x`. Example:
##
## .. code-block:: nim
##   $(23, 45) == "(23, 45)"
##   $() == "()"
result = "("
var firstElement = true
if not firstElement: add(result, ", ")
add(result, "data")
add(result, ": ")
if isNil(x.data): add(result, "nil")
else: add(result, $x.data)
firstElement = false
add(result, ")")
injecting into
let a = newCustSeq(10)
let b = a
echo [b]
test.nim(21, 7) Error: internal error: '=sink' operator is generic

[Yardanico]

@mratsim now prints:

tata.nim(21, 7) Error: internal error: '=sink' operator is generic

[narimiran]

Gives better error now:

Gives worse error now:

SIGSEGV: Illegal storage access. (Attempt to read from nil?)

[narimiran]

Gives worse error now:

...and better once again:

Error: unhandled exception: ..../compiler/liftdestructors.nim(583, 12) `typ.typeInst != nil` [AssertionError]