1 files changed, 26 insertions, 0 deletions
diff --git a/source/slang/syntax.h b/source/slang/syntax.h
index eb7cee40a..aa3944d0a 100644
--- a/source/slang/syntax.h
+++ b/source/slang/syntax.h
@@ -1104,6 +1104,32 @@ namespace Slang
 
     typedef Dictionary<unsigned int, RefPtr<RefObject>> AttributeArgumentValueDict;
 
+        /// Collects information about existential type parameters and their arguments.
+    struct ExistentialTypeSlots
+    {
+            /// For each type parameter, holds the interface/existential type that constrains it.
+        List<RefPtr<Type>> paramTypes;
+
+            /// An argument for an existential type parameter.
+            ///
+            /// Comprises a concrete type and a witness for its conformance to the desired
+            /// interface/existential type for the corresponding parameter.
+            ///
+        struct Arg
+        {
+            RefPtr<Type>    type;
+            RefPtr<Val>     witness;
+        };
+
+            /// Any arguments provided for the existential type parameters.
+            ///
+            /// It is possible for `args` to be empty even if `paramTypes` is non-empty;
+            /// that situation represents an unspecialized program or entry point.
+            ///
+        List<Arg> args;
+    };
+
+
     // Generate class definition for all syntax classes
 #define SYNTAX_FIELD(TYPE, NAME) TYPE NAME;
 #define FIELD(TYPE, NAME) TYPE NAME;