fix: fix bug in WeakCacheSet

[AayushSabharwal]

No description provided.

[github-actions]

Benchmark Results

	master	86ac039...	master/86ac0395b37a39...
overhead/acrule/a+2	0.979 ± 0.026 μs	0.971 ± 0.025 μs	1.01
overhead/acrule/a+2+b	0.978 ± 0.053 μs	0.958 ± 0.26 μs	1.02
overhead/acrule/a+b	0.265 ± 0.0076 μs	0.269 ± 0.007 μs	0.984
overhead/acrule/noop:Int	1.56 ± 0.01 ns	1.56 ± 0.01 ns	0.999
overhead/acrule/noop:Sym	22 ± 4.6 ns	22.6 ± 6 ns	0.972
overhead/rule/noop:Int	0.0355 ± 0.0015 μs	0.0345 ± 0.0018 μs	1.03
overhead/rule/noop:Sym	0.0331 ± 0.0011 μs	0.0324 ± 0.0012 μs	1.02
overhead/rule/noop:Term	0.0331 ± 0.0011 μs	0.0325 ± 0.0015 μs	1.02
overhead/ruleset/noop:Int	0.118 ± 0.0025 μs	0.118 ± 0.0028 μs	1
overhead/ruleset/noop:Sym	0.131 ± 0.0028 μs	0.121 ± 0.0043 μs	1.08
overhead/ruleset/noop:Term	4.62 ± 0.093 μs	4.4 ± 0.11 μs	1.05
overhead/simplify/noop:Int	0.255 ± 0.0043 μs	0.22 ± 0.0065 μs	1.16
overhead/simplify/noop:Sym	0.244 ± 0.0041 μs	0.217 ± 0.003 μs	1.13
overhead/simplify/noop:Term	0.0477 ± 0.0016 ms	0.0465 ± 0.0012 ms	1.03
overhead/simplify/randterm (+, *):serial	0.12 ± 0.0024 s	0.119 ± 0.0035 s	1.01
overhead/simplify/randterm (+, *):thread	0.0828 ± 0.0033 s	0.0811 ± 0.0033 s	1.02
overhead/simplify/randterm (/, *):serial	0.223 ± 0.019 ms	0.219 ± 0.019 ms	1.01
overhead/simplify/randterm (/, *):thread	0.254 ± 0.017 ms	0.251 ± 0.017 ms	1.01
overhead/substitute/a	0.0994 ± 0.0059 ms	0.0937 ± 0.011 ms	1.06
overhead/substitute/a,b	0.0843 ± 0.0078 ms	0.0792 ± 0.0071 ms	1.06
overhead/substitute/a,b,c	20.6 ± 2.1 μs	19.1 ± 1.2 μs	1.08
polyform/easy_iszero	0.04 ± 0.00088 ms	0.039 ± 0.00088 ms	1.03
polyform/isone	2.79 ± 0.01 ns	3.1 ± 0.01 ns	0.903
polyform/iszero	1.35 ± 0.021 ms	1.33 ± 0.022 ms	1.02
polyform/simplify_fractions	1.92 ± 0.064 ms	1.81 ± 0.033 ms	1.07
time_to_load	1.12 ± 0.0039 s	1.13 ± 0.016 s	0.992

Benchmark Plots

A plot of the benchmark results have been uploaded as an artifact to the workflow run for this PR.
Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).