Disallow statics of spans and class instance members of span

src/dlls/mscorrc/mscorrc.rc

@@ -1230,6 +1230,9 @@ BEGIN
     IDS_CLASSLOAD_NOTINTERFACE              "Could not load type '%1' from assembly '%2' because it attempts to implement a class as an interface."
     IDS_CLASSLOAD_VALUEINSTANCEFIELD        "Could not load the value type '%1' from assembly '%2' because it has an instance field of itself."
 
+    IDS_CLASSLOAD_BYREFLIKE_STATICFIELD     "A value type containing a by-ref instance field, such as Span<T>, cannot be used as the type for a static field."
+    IDS_CLASSLOAD_BYREFLIKE_NOTVALUECLASSFIELD "A value type containing a by-ref instance field, such as Span<T>, cannot be used as the type for a class instance field."
+
     IDS_CLASSLOAD_BAD_NAME                  "Type name '%1' from assembly '%2' is invalid."
     IDS_CLASSLOAD_RANK_TOOLARGE             "'%1' from assembly '%2' has too many dimensions."
     IDS_CLASSLOAD_BAD_MANAGED_RVA           "Managed method '%3' on type '%1' from assembly '%2' is not supported."

src/dlls/mscorrc/resource.h

@@ -947,4 +947,5 @@
 
 #define IDS_NATIVE_IMAGE_CANNOT_BE_LOADED_MULTIPLE_TIMES                               0x263a
 
-
+#define IDS_CLASSLOAD_BYREFLIKE_STATICFIELD        0x263b
+#define IDS_CLASSLOAD_BYREFLIKE_NOTVALUECLASSFIELD 0x263c

src/vm/methodtablebuilder.cpp

@@ -4222,6 +4222,17 @@ VOID    MethodTableBuilder::InitializeFieldDescs(FieldDesc *pFieldDescList,
                 // Inherit IsByRefLike characteristic from fields
                 if (!IsSelfRef(pByValueClass) && pByValueClass->IsByRefLike())
                 {
+                    if (fIsStatic)
+                    {
+                        // By-ref-like types cannot be used for static fields
+                        BuildMethodTableThrowException(IDS_CLASSLOAD_BYREFLIKE_STATICFIELD);
+                    }
+                    if (!IsValueClass())
+                    {
+                        // Non-value-classes cannot contain by-ref-like instance fields
+                        BuildMethodTableThrowException(IDS_CLASSLOAD_BYREFLIKE_NOTVALUECLASSFIELD);
+                    }
+
                     bmtFP->fIsByRefLikeType = true;
                 }