C417 fix introduces a syntax error for `yield` in lambda expression

[dscorbett]

Summary

The fix for unnecessary-map (C417) introduces a syntax error when the lambda expression contains a yield expression. The fix, and possibly the rule, should be suppressed in that case. Example:

$ cat >c417.py <<'# EOF'
base = 0
gens = map(lambda x: (yield base + x), [1, 2, 3])
for gen in gens:
    print(*[*gen])
    base += 20
# EOF

$ python c417.py
1
22
43

$ ruff --isolated check c417.py --select C417 --unsafe-fixes --fix
Found 1 error (1 fixed, 0 remaining).

$ python c417.py 2>&1 | tail -n 3
    gens = ((yield base + x) for x in [1, 2, 3])
             ^^^^^^^^^^^^^^
SyntaxError: 'yield' inside generator expression

Version

ruff 0.12.11 (c2bc15b 2025-08-28)