Array.cs performs an Unsafe.As cast that is an undefined behaviour

[MichalPetryka]

Array.cs uses Unsafe.As to cast arrays to other array types which is UB in case types don't match, it should be changed to casting the ref returned from GetArrayDataReference instead:

runtime/src/libraries/System.Private.CoreLib/src/System/Array.cs

Line 1603 in fcff857

ref Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(Unsafe.As<int[]>(array)), endIndex),

runtime/src/libraries/System.Private.CoreLib/src/System/Array.cs

Line 1613 in fcff857

ref Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(Unsafe.As<long[]>(array)), endIndex),

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Issue Details

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Array.cs uses Unsafe.As to cast arrays to other array types which is UB in case types don't match, it should be changed to casting the ref returned from GetArrayDataReference instead:

runtime/src/libraries/System.Private.CoreLib/src/System/Array.cs

Line 1603 in fcff857

ref Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(Unsafe.As<int[]>(array)), endIndex),

runtime/src/libraries/System.Private.CoreLib/src/System/Array.cs

Line 1613 in fcff857

ref Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(Unsafe.As<long[]>(array)), endIndex),

Author:	MichalPetryka
Assignees:	-
Labels:	area-System.Runtime, untriaged, in-pr
Milestone:	-