meta_programming_err.cairo

%builtins output

from starkware.cairo.common.alloc import alloc
from starkware.cairo.common.invoke import invoke
from starkware.cairo.common.registers import get_label_location


struct A:
    member a: felt
    member b: felt
end

func get_value(a: A, b: A) -> (f: felt):
    let res = a.a + b.b
    return (res)
end

func main{output_ptr : felt*}():
    tempvar a = new A(a=1, b=2)
    tempvar b = new A(a=3, b=4)
    let (ptr_arr: felt*) = alloc()

    assert ptr_arr[0] = cast(a, felt)
    assert ptr_arr[1] = cast(b, felt)

    let (func_pc) = get_label_location(get_value)
    invoke(func_pc, 2, ptr_arr)

    return ()
end

# Error: code:15:13: While expanding the reference 'res' in:
#     return (res)
#             ^
# code:14:13: Error at pc=0:32:
# Cannot add two relocatable values: 1:41 + 1:11.
#     let z = a.a + b.b
#             ^*******^
# Cairo traceback (most recent call last):
# code:26:5: (pc=0:61)
#     invoke(func_pc, 2, ptr_arr)
#     ^*************************^
# /var/task/starkware/cairo/common/invoke.cairo:6:5: (pc=0:13)
#     call abs func_ptr
#     ^***************^