Description of the problem:

According to the spec, a negative value for count in string.replace should be ignored and this is also what python and the Go implementation do.

# Current implementation
"abc".replace("a", "z", -1)    # "abc"

# Python/Go
"abc".replace("a", "z", -1)    # "zbc"

Side Note: The parameter count of string.replace is incorrectly named maxsplit in the definition of replace here.