Report redundant str() and repr() for str.format args

[orsinium]

Rule request

Thesis

For most of the objects (for all objects and builtins, until redefined explicitly), the default result of __format__ is the same as __str__, so wrapping arguments of str.format into str() or repr() is redundant.

# bad
'{}'.format(str(1))

# good
'{}'.format(1)

# bad
'{}'.format(repr('a'))

# good
'{!r}'.format('a')

Reasoning

Simplification.