Define equals manually for Swift JitInterface InlineArray types.

src/coreclr/tools/Common/JitInterface/CorInfoTypes.cs

@@ -1500,7 +1500,7 @@ public unsafe struct CORINFO_TYPE_LAYOUT_NODE
         public bool hasSignificantPadding { get => _hasSignificantPadding != 0; set => _hasSignificantPadding = value ? (byte)1 : (byte)0; }
     }
 
-    public struct CORINFO_SWIFT_LOWERING
+    public struct CORINFO_SWIFT_LOWERING : IEquatable<CORINFO_SWIFT_LOWERING>
     {
         private byte _byReference;
         public bool byReference { get => _byReference != 0; set => _byReference = value ? (byte)1 : (byte)0; }
@@ -1529,6 +1529,47 @@ private struct LoweredOffsets
 
         public nint numLoweredElements;
 
+        public override bool Equals(object obj)
+        {
+            return obj is CORINFO_SWIFT_LOWERING other && Equals(other);
+        }
+
+        public bool Equals(CORINFO_SWIFT_LOWERING other)
+        {
+            if (byReference != other.byReference)
+            {
+                return false;
+            }
+
+            // If both are by-ref, the rest of the bits mean nothing.
+            if (byReference)
+            {
+                return true;
+            }
+
+            return LoweredElements.Slice(0, (int)numLoweredElements).SequenceEqual(other.LoweredElements.Slice(0, (int)other.numLoweredElements))
+                && Offsets.Slice(0, (int)numLoweredElements).SequenceEqual(other.Offsets.Slice(0, (int)other.numLoweredElements));
+        }
+
+        public override int GetHashCode()
+        {
+            HashCode code = default;
+            code.Add(byReference);
+
+            if (byReference)
+            {
+                return code.ToHashCode();
+            }
+
+            for (int i = 0; i < numLoweredElements; i++)
+            {
+                code.Add(LoweredElements[i]);
+                code.Add(Offsets[i]);
+            }
+
+            return code.ToHashCode();
+        }
+
         // Override for a better unit test experience
         public override string ToString()
         {

src/coreclr/tools/aot/ILCompiler.Compiler.Tests/SwiftLoweringTests.cs

@@ -88,6 +88,10 @@ public static IEnumerable<object[]> DiscoverSwiftTypes()
                                 {
                                     expected.Offsets[i] = (uint)naturalOffset.AlignUp(size);
                                 }
+                                else
+                                {
+                                    expected.Offsets[i] = (uint)naturalOffset;
+                                }
                                 naturalOffset += size;
                             }
                         }