RecursionError on long elif

[thatch]

Given

def func(x):
    if x == "a":
        return "a"
    elif x == "a":
        return "a"
    elif x == "a":
        return "a"
    elif x == "a":
        return "a"
    elif x == "a":  # repeat elif/return 160 times total
        return "a"

We get the error when running flake8 on it:

ERROR:1:1: X002 File "flake8/main/cli.py", line 16, in main   
ERROR:1:1: X002 File "flake8/main/application.py", line 412, in run
ERROR:1:1: X002 File "flake8/main/application.py", line 400, in _run
ERROR:1:1: X002 File "flake8/main/application.py", line 318, in run_checks
ERROR:1:1: X002 File "flake8/checker.py", line 340, in run    
ERROR:1:1: X002 File "flake8/checker.py", line 324, in run_serial
ERROR:1:1: X002 File "flake8/checker.py", line 612, in run_checks
ERROR:1:1: X002 File "flake8/checker.py", line 520, in run_ast_checks
ERROR:1:1: X002 File "mccabe.py", line 266, in run            
ERROR:1:1: X002 File "mccabe.py", line 47, in preorder        
ERROR:1:1: X002 File "mccabe.py", line 41, in dispatch        
ERROR:1:1: X002 File "mccabe.py", line 167, in default        
ERROR:1:1: X002 File "mccabe.py", line 31, in default         
ERROR:1:1: X002 File "mccabe.py", line 41, in dispatch        
ERROR:1:1: X002 File "mccabe.py", line 135, in visitFunctionDef
ERROR:1:1: X002 File "mccabe.py", line 111, in dispatch_list       
ERROR:1:1: X002 File "mccabe.py", line 41, in dispatch
ERROR:1:1: X002 File "mccabe.py", line 177, in visitIf
ERROR:1:1: X002 File "mccabe.py", line 190, in _subgraph
ERROR:1:1: X002 File "mccabe.py", line 204, in _subgraph_parse
ERROR:1:1: X002 File "mccabe.py", line 111, in dispatch_list
...
ERROR:1:1: X002 File "mccabe.py", line 177, in visitIf
ERROR:1:1: X002 File "mccabe.py", line 190, in _subgraph
ERROR:1:1: X002 File "mccabe.py", line 204, in _subgraph_parse
ERROR:1:1: X002 File "mccabe.py", line 111, in dispatch_list
ERROR:1:1: X002 File "mccabe.py", line 41, in dispatch
ERROR:1:1: X002 File "mccabe.py", line 177, in visitIf
ERROR:1:1: X002 File "mccabe.py", line 190, in _subgraph
ERROR:1:1: X002 File "mccabe.py", line 204, in _subgraph_parse
ERROR:1:1: X002 File "mccabe.py", line 111, in dispatch_list
ERROR:1:1: X002 File "mccabe.py", line 41, in dispatch
ERROR:1:1: X002 File "mccabe.py", line 177, in visitIf
ERROR:1:1: X002 File "mccabe.py", line 190, in _subgraph
ERROR:1:1: X002 File "mccabe.py", line 196, in _subgraph_parse
ERROR:1:1: X002 File "mccabe.py", line 111, in dispatch_list
ERROR:1:1: X002 File "mccabe.py", line 41, in dispatch
ERROR:1:1: X002 RecursionError: maximum recursion depth exceeded