IStructuralEquatable.Equals on array throws for multidimensional arrays

[roji]

Description

Array implements IStructuralEquatable, but its Equals implementation throws if a multi-dimensional array is passed.

Reproduction Steps

var arr1 = new int[2,2];
var arr2 = new int[2,2];

Console.WriteLine(typeof(IStructuralEquatable).IsAssignableFrom(arr1.GetType())); // True
Console.WriteLine(StructuralComparisons.StructuralEqualityComparer.Equals(arr1, arr2)); // throws

Expected behavior

The method is expected to return true or false.

Actual behavior

Exception:

Unhandled exception. System.ArgumentException: Array was not a one-dimensional array.
   at System.Array.GetValue(Int32 index)
   at System.Array.System.Collections.IStructuralEquatable.Equals(Object other, IEqualityComparer comparer)
   at System.Collections.StructuralEqualityComparer.Equals(Object x, Object y)
   at Program.<Main>$(String[] args) in /home/roji/projects/test/Program.cs:line 20

Regression?

No response

Known Workarounds

One can avoid using IStructuralEquatable or StructuralComparisons.StructuralEqualityComparer specifically for multidimensional arrays.

Configuration

.NET 6, Ubuntu impish, x64.

Other information

No response

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Issue Details

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### Description Array implements IStructuralEquatable, but its Equals implementation throws if a multi-dimensional array is passed. ### Reproduction Steps ```c# var arr1 = new int[2,2]; var arr2 = new int[2,2]; Console.WriteLine(typeof(IStructuralEquatable).IsAssignableFrom(arr1.GetType())); // True Console.WriteLine(StructuralComparisons.StructuralEqualityComparer.Equals(arr1, arr2)); // throws ``` ### Expected behavior The method is expected to return true or false. ### Actual behavior Exception: ``` Unhandled exception. System.ArgumentException: Array was not a one-dimensional array. at System.Array.GetValue(Int32 index) at System.Array.System.Collections.IStructuralEquatable.Equals(Object other, IEqualityComparer comparer) at System.Collections.StructuralEqualityComparer.Equals(Object x, Object y) at Program.

$(String[] args) in /home/roji/projects/test/Program.cs:line 20 ``` ### Regression? _No response_ ### Known Workarounds One can avoid using IStructuralEquatable or StructuralComparisons.StructuralEqualityComparer specifically for multidimensional arrays. ### Configuration .NET 6, Ubuntu impish, x64. ### Other information _No response_

Author:	roji
Assignees:	-
Labels:	`area-System.Runtime`, `untriaged`
Milestone:	-

[tannergooding]

This impacts CC. @dotnet/area-system-collections since it flows through StructuralEqualityComparer

CC. @jkotas, @stephentoub on if there are any known limitations that might prevent this from being handled.