Datapack function error

In a datapack, when someone uses the "function" command, there is a particular issue, when this command is run through the "execute" command. In the execute command you can execute something at an entity or as an entity. If I write a loop function that just executes a function as all players, for example:

execute as @a at @s run function datapack:effects

and if i place code in the effects function like this it will not run at all:

execute if block ~ ~-1 ~ ice run effect give @s speed 1 2 true

(note ~ ~ ~ will run, but will be considered 0 0 0)