diff --git a/src/common/scripting/core/types.h b/src/common/scripting/core/types.h
index 380ae88d44..e68612fcff 100644
--- a/src/common/scripting/core/types.h
+++ b/src/common/scripting/core/types.h
@@ -110,7 +110,7 @@ public:
 	EScopeFlags ScopeFlags = (EScopeFlags)0;
 	bool            SizeKnown = true;
 
-	bool			TypeInternal = false;
+	bool			VMInternalStruct = false;
 	bool			TypeDeprecated = false; // mVersion is deprecation version, not minimum version
 	FString			mDeprecationMessage;
 
diff --git a/src/common/scripting/frontend/zcc-parse.lemon b/src/common/scripting/frontend/zcc-parse.lemon
index 85e3a762b4..2affe274b4 100644
--- a/src/common/scripting/frontend/zcc-parse.lemon
+++ b/src/common/scripting/frontend/zcc-parse.lemon
@@ -442,12 +442,12 @@ struct_def(X) ::= EXTEND STRUCT(T) IDENTIFIER(A) LBRACE opt_struct_body(B) RBRAC
 }
 
 %type struct_flags{ClassFlagsBlock}
-struct_flags(X) ::= .										{ X.Flags = 0; X.Version = {0, 0}; X.DeprecationMessage = NULL; }
-struct_flags(X) ::= struct_flags(A) UI.						{ X.Flags = A.Flags | ZCC_UIFlag; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
-struct_flags(X) ::= struct_flags(A) PLAY.					{ X.Flags = A.Flags | ZCC_Play; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
-struct_flags(X) ::= struct_flags(A) CLEARSCOPE.				{ X.Flags = A.Flags | ZCC_ClearScope; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
-struct_flags(X) ::= struct_flags(A) NATIVE.					{ X.Flags = A.Flags | ZCC_Native; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
-struct_flags(X) ::= struct_flags(A) INTERNAL.				{ X.Flags = A.Flags | ZCC_Internal; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
+struct_flags(X) ::= .													{ X.Flags = 0; X.Version = {0, 0}; X.DeprecationMessage = NULL; }
+struct_flags(X) ::= struct_flags(A) UI.									{ X.Flags = A.Flags | ZCC_UIFlag; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
+struct_flags(X) ::= struct_flags(A) PLAY.								{ X.Flags = A.Flags | ZCC_Play; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
+struct_flags(X) ::= struct_flags(A) CLEARSCOPE.							{ X.Flags = A.Flags | ZCC_ClearScope; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
+struct_flags(X) ::= struct_flags(A) NATIVE.								{ X.Flags = A.Flags | ZCC_Native; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
+struct_flags(X) ::= struct_flags(A) UNSAFE LPAREN INTERNAL RPAREN.		{ X.Flags = A.Flags | ZCC_VMInternalStruct; X.Version = A.Version; X.DeprecationMessage = A.DeprecationMessage; }
 struct_flags(X) ::= struct_flags(A) VERSION LPAREN STRCONST(C) RPAREN.	{ X.Flags = A.Flags | ZCC_Version; X.Version = C.String->GetChars(); X.DeprecationMessage = A.DeprecationMessage; }
 
 struct_flags(X) ::= struct_flags(A) DEPRECATED LPAREN STRCONST(C) opt_deprecation_message(D) RPAREN.
diff --git a/src/common/scripting/frontend/zcc_compile.cpp b/src/common/scripting/frontend/zcc_compile.cpp
index 492498f4b5..006219d0e5 100644
--- a/src/common/scripting/frontend/zcc_compile.cpp
+++ b/src/common/scripting/frontend/zcc_compile.cpp
@@ -758,11 +758,11 @@ void ZCCCompiler::CreateStructTypes()
 			s->strct->Type->mDeprecationMessage = s->strct->DeprecationMessage ? *s->strct->DeprecationMessage : "";
 		}
 
-		if (s->strct->Flags & ZCC_Internal)
+		if (s->strct->Flags & ZCC_VMInternalStruct)
 		{
 			if(fileSystem.GetFileContainer(Lump) == 0)
 			{
-				s->strct->Type->TypeInternal = true;
+				s->strct->Type->VMInternalStruct = true;
 			}
 			else
 			{
@@ -2214,7 +2214,7 @@ PType *ZCCCompiler::ResolveUserType(PType *outertype, ZCC_BasicType *type, ZCC_I
 		}
 
 		//only allow references to internal types inside internal types
-		if (ptype->TypeInternal && !outertype->TypeInternal)
+		if (ptype->VMInternalStruct && !outertype->VMInternalStruct)
 		{
 			Error(type, "Type %s not accessible", FName(type->UserType->Id).GetChars());
 			return TypeError;
diff --git a/src/common/scripting/frontend/zcc_parser.h b/src/common/scripting/frontend/zcc_parser.h
index d12d7b87e1..7596553a58 100644
--- a/src/common/scripting/frontend/zcc_parser.h
+++ b/src/common/scripting/frontend/zcc_parser.h
@@ -67,6 +67,7 @@ enum
 	ZCC_Sealed				= 1 << 23,
 	ZCC_FuncConstUnsafe		= 1 << 24,
 	ZCC_UnsafeClearScope	= 1 << 25,
+	ZCC_VMInternalStruct	= 1 << 26,
 };
 
 // Function parameter modifiers
diff --git a/wadsrc/static/zscript/engine/base.zs b/wadsrc/static/zscript/engine/base.zs
index 14cedaed4e..33c14eef6e 100644
--- a/wadsrc/static/zscript/engine/base.zs
+++ b/wadsrc/static/zscript/engine/base.zs
@@ -189,7 +189,7 @@ struct Vector3
 }
 */
 
-struct _ native internal	// These are the global variables, the struct is only here to avoid extending the parser for this.
+struct _ native unsafe(internal)	// These are the global variables, the struct is only here to avoid extending the parser for this.
 {
 	native readonly Array<class> AllClasses;
     native internal readonly Map<Name , Service> AllServices;
@@ -903,7 +903,7 @@ enum EmptyTokenType
 
 // Although String is a builtin type, this is a convenient way to attach methods to it.
 // All of these methods are available on strings
-struct StringStruct native internal
+struct StringStruct native unsafe(internal)
 {
 	native static vararg String Format(String fmt, ...);
 	native vararg void AppendFormat(String fmt, ...);
@@ -952,7 +952,7 @@ struct Translation version("2.4")
 }
 
 // Convenient way to attach functions to Quat
-struct QuatStruct native internal
+struct QuatStruct native unsafe(internal)
 {
 	native static Quat SLerp(Quat from, Quat to, double t);
 	native static Quat NLerp(Quat from, Quat to, double t);
diff --git a/wadsrc/static/zscript/engine/dynarrays.zs b/wadsrc/static/zscript/engine/dynarrays.zs
index 28f36b313c..d21c70e1a1 100644
--- a/wadsrc/static/zscript/engine/dynarrays.zs
+++ b/wadsrc/static/zscript/engine/dynarrays.zs
@@ -1,7 +1,7 @@
 // The VM uses 7 integral data types, so for dynamic array support we need one specific set of functions for each of these types.
 // Do not use these structs directly, they are incomplete and only needed to create prototypes for the needed functions.
 
-struct DynArray_I8 native internal
+struct DynArray_I8 native unsafe(internal)
 {
 	native readonly int Size;
 	
@@ -21,7 +21,7 @@ struct DynArray_I8 native internal
 	native void Clear ();
 }
 
-struct DynArray_I16 native internal
+struct DynArray_I16 native unsafe(internal)
 {
 	native readonly int Size;
 
@@ -41,7 +41,7 @@ struct DynArray_I16 native internal
 	native void Clear ();
 }
 
-struct DynArray_I32 native internal
+struct DynArray_I32 native unsafe(internal)
 {
 	native readonly int Size;
 
@@ -62,7 +62,7 @@ struct DynArray_I32 native internal
 	native void Clear ();
 }
 
-struct DynArray_F32 native internal
+struct DynArray_F32 native unsafe(internal)
 {
 	native readonly int Size;
 	
@@ -82,7 +82,7 @@ struct DynArray_F32 native internal
 	native void Clear ();
 }
 
-struct DynArray_F64 native internal
+struct DynArray_F64 native unsafe(internal)
 {
 	native readonly int Size;
 	
@@ -102,7 +102,7 @@ struct DynArray_F64 native internal
 	native void Clear ();
 }
 
-struct DynArray_Ptr native internal
+struct DynArray_Ptr native unsafe(internal)
 {
 	native readonly int Size;
 	
@@ -122,7 +122,7 @@ struct DynArray_Ptr native internal
 	native void Clear ();
 }
 
-struct DynArray_Obj native internal
+struct DynArray_Obj native unsafe(internal)
 {
 	native readonly int Size;
 	
@@ -142,7 +142,7 @@ struct DynArray_Obj native internal
 	native void Clear ();
 }
 
-struct DynArray_String native internal
+struct DynArray_String native unsafe(internal)
 {
 	native readonly int Size;
 
diff --git a/wadsrc/static/zscript/engine/maps.zs b/wadsrc/static/zscript/engine/maps.zs
index 0e71c3b05f..dbc2f4dadc 100644
--- a/wadsrc/static/zscript/engine/maps.zs
+++ b/wadsrc/static/zscript/engine/maps.zs
@@ -1,5 +1,5 @@
 
-struct Map_I32_I8 native internal
+struct Map_I32_I8 native unsafe(internal)
 {
     native void Copy(Map_I32_I8 other);
     native void Move(Map_I32_I8 other);
@@ -18,7 +18,7 @@ struct Map_I32_I8 native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_I8 native internal
+struct MapIterator_I32_I8 native unsafe(internal)
 {
     native bool Init(Map_I32_I8 other);
     native bool ReInit();
@@ -31,7 +31,7 @@ struct MapIterator_I32_I8 native internal
     native void SetValue(int value);
 }
 
-struct Map_I32_I16 native internal
+struct Map_I32_I16 native unsafe(internal)
 {
     native void Copy(Map_I32_I16 other);
     native void Move(Map_I32_I16 other);
@@ -50,7 +50,7 @@ struct Map_I32_I16 native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_I16 native internal
+struct MapIterator_I32_I16 native unsafe(internal)
 {
     native bool Init(Map_I32_I16 other);
     native bool ReInit();
@@ -63,7 +63,7 @@ struct MapIterator_I32_I16 native internal
     native void SetValue(int value);
 }
 
-struct Map_I32_I32 native internal
+struct Map_I32_I32 native unsafe(internal)
 {
     native void Copy(Map_I32_I32 other);
     native void Move(Map_I32_I32 other);
@@ -82,7 +82,7 @@ struct Map_I32_I32 native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_I32 native internal
+struct MapIterator_I32_I32 native unsafe(internal)
 {
     native bool Init(Map_I32_I32 other);
     native bool ReInit();
@@ -95,7 +95,7 @@ struct MapIterator_I32_I32 native internal
     native void SetValue(int value);
 }
 
-struct Map_I32_F32 native internal
+struct Map_I32_F32 native unsafe(internal)
 {
     native void Copy(Map_I32_F32 other);
     native void Move(Map_I32_F32 other);
@@ -114,7 +114,7 @@ struct Map_I32_F32 native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_F32 native internal
+struct MapIterator_I32_F32 native unsafe(internal)
 {
     native bool Init(Map_I32_F32 other);
     native bool ReInit();
@@ -127,7 +127,7 @@ struct MapIterator_I32_F32 native internal
     native void SetValue(double value);
 }
 
-struct Map_I32_F64 native internal
+struct Map_I32_F64 native unsafe(internal)
 {
     native void Copy(Map_I32_F64 other);
     native void Move(Map_I32_F64 other);
@@ -146,7 +146,7 @@ struct Map_I32_F64 native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_F64 native internal
+struct MapIterator_I32_F64 native unsafe(internal)
 {
     native bool Init(Map_I32_F64 other);
     native bool ReInit();
@@ -159,7 +159,7 @@ struct MapIterator_I32_F64 native internal
     native void SetValue(double value);
 }
 
-struct Map_I32_Obj native internal
+struct Map_I32_Obj native unsafe(internal)
 {
     native void Copy(Map_I32_Obj other);
     native void Move(Map_I32_Obj other);
@@ -178,7 +178,7 @@ struct Map_I32_Obj native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_Obj native internal
+struct MapIterator_I32_Obj native unsafe(internal)
 {
     native bool Init(Map_I32_Obj other);
     native bool ReInit();
@@ -191,7 +191,7 @@ struct MapIterator_I32_Obj native internal
     native void SetValue(Object value);
 }
 
-struct Map_I32_Ptr native internal
+struct Map_I32_Ptr native unsafe(internal)
 {
     native void Copy(Map_I32_Ptr other);
     native void Move(Map_I32_Ptr other);
@@ -210,7 +210,7 @@ struct Map_I32_Ptr native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_Ptr native internal
+struct MapIterator_I32_Ptr native unsafe(internal)
 {
     native bool Init(Map_I32_Ptr other);
     native bool Next();
@@ -220,7 +220,7 @@ struct MapIterator_I32_Ptr native internal
     native void SetValue(voidptr value);
 }
 
-struct Map_I32_Str native internal
+struct Map_I32_Str native unsafe(internal)
 {
     native void Copy(Map_I32_Str other);
     native void Move(Map_I32_Str other);
@@ -239,7 +239,7 @@ struct Map_I32_Str native internal
     native void Remove(int key);
 }
 
-struct MapIterator_I32_Str native internal
+struct MapIterator_I32_Str native unsafe(internal)
 {
     native bool Init(Map_I32_Str other);
     native bool ReInit();
@@ -254,7 +254,7 @@ struct MapIterator_I32_Str native internal
 
 // ---------------
 
-struct Map_Str_I8 native internal
+struct Map_Str_I8 native unsafe(internal)
 {
     native void Copy(Map_Str_I8 other);
     native void Move(Map_Str_I8 other);
@@ -273,7 +273,7 @@ struct Map_Str_I8 native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_I8 native internal
+struct MapIterator_Str_I8 native unsafe(internal)
 {
     native bool Init(Map_Str_I8 other);
     native bool ReInit();
@@ -286,7 +286,7 @@ struct MapIterator_Str_I8 native internal
     native void SetValue(int value);
 }
 
-struct Map_Str_I16 native internal
+struct Map_Str_I16 native unsafe(internal)
 {
     native void Copy(Map_Str_I16 other);
     native void Move(Map_Str_I16 other);
@@ -305,7 +305,7 @@ struct Map_Str_I16 native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_I16 native internal
+struct MapIterator_Str_I16 native unsafe(internal)
 {
     native bool Init(Map_Str_I16 other);
     native bool ReInit();
@@ -318,7 +318,7 @@ struct MapIterator_Str_I16 native internal
     native void SetValue(int value);
 }
 
-struct Map_Str_I32 native internal
+struct Map_Str_I32 native unsafe(internal)
 {
     native void Copy(Map_Str_I32 other);
     native void Move(Map_Str_I32 other);
@@ -337,7 +337,7 @@ struct Map_Str_I32 native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_I32 native internal
+struct MapIterator_Str_I32 native unsafe(internal)
 {
     native bool Init(Map_Str_I32 other);
     native bool ReInit();
@@ -350,7 +350,7 @@ struct MapIterator_Str_I32 native internal
     native void SetValue(int value);
 }
 
-struct Map_Str_F32 native internal
+struct Map_Str_F32 native unsafe(internal)
 {
     native void Copy(Map_Str_F32 other);
     native void Move(Map_Str_F32 other);
@@ -369,7 +369,7 @@ struct Map_Str_F32 native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_F32 native internal
+struct MapIterator_Str_F32 native unsafe(internal)
 {
     native bool Init(Map_Str_F32 other);
     native bool ReInit();
@@ -382,7 +382,7 @@ struct MapIterator_Str_F32 native internal
     native void SetValue(double value);
 }
 
-struct Map_Str_F64 native internal
+struct Map_Str_F64 native unsafe(internal)
 {
     native void Copy(Map_Str_F64 other);
     native void Move(Map_Str_F64 other);
@@ -401,7 +401,7 @@ struct Map_Str_F64 native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_F64 native internal
+struct MapIterator_Str_F64 native unsafe(internal)
 {
     native bool Init(Map_Str_F64 other);
     native bool ReInit();
@@ -414,7 +414,7 @@ struct MapIterator_Str_F64 native internal
     native void SetValue(double value);
 }
 
-struct Map_Str_Obj native internal
+struct Map_Str_Obj native unsafe(internal)
 {
     native void Copy(Map_Str_Obj other);
     native void Move(Map_Str_Obj other);
@@ -433,7 +433,7 @@ struct Map_Str_Obj native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_Obj native internal
+struct MapIterator_Str_Obj native unsafe(internal)
 {
     native bool Init(Map_Str_Obj other);
     native bool ReInit();
@@ -446,7 +446,7 @@ struct MapIterator_Str_Obj native internal
     native void SetValue(Object value);
 }
 
-struct Map_Str_Ptr native internal
+struct Map_Str_Ptr native unsafe(internal)
 {
     native void Copy(Map_Str_Ptr other);
     native void Move(Map_Str_Ptr other);
@@ -465,7 +465,7 @@ struct Map_Str_Ptr native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_Ptr native internal
+struct MapIterator_Str_Ptr native unsafe(internal)
 {
     native bool Init(Map_Str_Ptr other);
     native bool ReInit();
@@ -478,7 +478,7 @@ struct MapIterator_Str_Ptr native internal
     native void SetValue(voidptr value);
 }
 
-struct Map_Str_Str native internal
+struct Map_Str_Str native unsafe(internal)
 {
     native void Copy(Map_Str_Str other);
     native void Move(Map_Str_Str other);
@@ -497,7 +497,7 @@ struct Map_Str_Str native internal
     native void Remove(String key);
 }
 
-struct MapIterator_Str_Str native internal
+struct MapIterator_Str_Str native unsafe(internal)
 {
     native bool Init(Map_Str_Str other);
     native bool ReInit();