Fix vector/hashtable collection #483

Job	Run time
rust_ci (macos-latest, stable)	48s
rust_ci (macos-latest, beta)	57s
rust_ci (macos-latest, nightly)	55s
rust_ci (ubuntu-latest, stable)	1m 2s
rust_ci (ubuntu-latest, beta)	50s
rust_ci (ubuntu-latest, nightly)	1m 4s
rust_ci (windows-latest, stable)	1m 46s
rust_ci (windows-latest, beta)	1m 41s
rust_ci (windows-latest, nightly)	2m 35s
	11m 38s

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