Python, 39 bytes

def f(a,x):print(a.index(x));f(a[1:],x)

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Finishes with an exception

-5 bytes thanks to AnttiP

Whython, 41 bytes

def f(a,x):print(a.index(x))+f(a[1:],x)?0

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No error

Python, 38 bytes

def f(a,x):f(a[1:print(a.index(x))],x)

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Finishes with an exception

-5 bytes thanks to AnttiP

-1 thanks to dingledooper

Whython, 40 bytes

def f(a,x):f(a[1:print(a.index(x))],x)?0

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No error

Python, 39 bytes

def f(a,x):print(a.index(x));f(a[1:],x)

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Finishes with an exception

-5 bytes thanks to AnttiP

Whython, 46 bytes

def f(a,x):
 while[print(a.index(x))]?0:_,*a=a

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No error

Python, 39 bytes

def f(a,x):print(a.index(x));f(a[1:],x)

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Finishes with an exception

-5 bytes thanks to AnttiP

Whython, 41 bytes

def f(a,x):print(a.index(x))+f(a[1:],x)?0

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No error

Python, 44 bytes

def f(a,x):
 while[print(a.index(x))]:_,*a=a

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Finishes with an exception. If not allowed:

Python, 49 bytes

def f(a,x):
 while x in a:yield a.index(x);_,*a=a

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Whython, 46 bytes

def f(a,x):
 while[print(a.index(x))]?0:_,*a=a

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Python, 39 bytes

def f(a,x):print(a.index(x));f(a[1:],x)

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Finishes with an exception

-5 bytes thanks to AnttiP

Whython, 46 bytes

def f(a,x):
 while[print(a.index(x))]?0:_,*a=a

Attempt This Online!

No error