Function emit_non_null_assert 

pub fn emit_non_null_assert(
    emitter: &mut FunctionEmitter<'_>,
    ctx: &CodegenCtx<'_>,
    value: ExprId,
    target_ty: &Type,
) -> Result<(), CompilerFailure>

value!. Converts a runtime null into a catchable TypeError instead of relying on ref.as_non_null, which would trap.