Fix possible memory error. #444

Job	Run time
mmg-debug / ci (ubuntu-20.04, on, off, on, off, int32_t)	36m 45s
mmg-debug / ci (ubuntu-20.04, on, off, off, off, int32_t)	47m 58s
mmg-debug / ci (ubuntu-20.04, off, off, on, off, int32_t)	34m 11s
mmg-debug / ci (ubuntu-20.04, off, off, off, off, int32_t)	39m 31s
mmg-debug / ci (macos-12, on, off, on, off, int32_t)	49m 57s
mmg-debug / ci (macos-12, on, off, off, off, int32_t)	1h 6m 10s
mmg-debug / ci (macos-12, off, off, on, off, int32_t)	39m 58s
mmg-debug / ci (macos-12, off, off, off, off, int32_t)	44m 35s
mmg-debug / ci (ubuntu-20.04, off, off, off, on, int32_t)	5m 22s
mmg-debug / ci (macos-12, off, off, off, on, int32_t)	7m 7s
mmg-debug / ci (ubuntu-20.04, off, on, on, off, int32_t)	32m 55s
mmg-debug / ci (macos-12, off, on, on, off, int32_t)	34m 9s
mmg-debug / ci (windows-2022, off, off, off, off, int32_t)	51m 25s
mmg-debug / ci (windows-2022, on, off, off, off, int32_t)	50m 22s
mmg-debug / ci (windows-2022, off, on, off, off, int32_t)	52m 43s
mmg-debug / ci (ubuntu-20.04, on, on, on, on, int64_t)	6m 19s
mmg-debug / ci (ubuntu-20.04, off, off, off, off, int64_t)	3m 31s
mmg-debug / ci (macos-12, on, on, on, on, int64_t)	9m 4s
mmg-debug / ci (macos-12, off, off, off, off, int64_t)	4m 3s
mmg-debug / ci (windows-2022, on, on, off, off, int64_t)	5m 45s
mmg-debug / ci (windows-2022, off, off, off, off, int64_t)	6m 10s
	10h 28m 0s

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