Rust

Add warning to custom memory types #6095

Job	Run time
Integration Test (AArch64)	1m 42s
Build (stable MSRV)	29s
Lints	1m 7s
Unit + Doc Tests	1m 33s
Integration Test (IA-32)	1m 31s
Integration Test (x86_64)	1m 27s
Integration Test (x86_64 Windows)	4m 35s
Build (feature permutations)	3m 30s
Build Standard Binary (nightly)	29s
Test Coverage	32s
Unit + Doc Tests (Miri)	1m 40s
Nightly (build, test, doc)	2m 27s
	21m 2s

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