Support dependent generic constraints. (#4870)

* Support dependent generic constraints.

* Fix warning.

* Update comment.

* Fix.

* Add a test case to verify fix of #3804.

* Address review.

1 files changed, 5 insertions, 1 deletions

diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 58fbb4689..c27e0c6f0 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -2520,18 +2520,22 @@ namespace Slang
         // and likely a crash.
         // 
         // Accessing the members via index side steps the issue.
+
+        Index parameterIndex = 0;
         const auto& members = genericDecl->members;
         for (Index i = 0; i < members.getCount(); ++i)
         {
             Decl* m = members[i];
 
-            if (auto typeParam = as<GenericTypeParamDecl>(m))
+            if (auto typeParam = as<GenericTypeParamDeclBase>(m))
             {
                 ensureDecl(typeParam, DeclCheckState::ReadyForReference);
+                typeParam->parameterIndex = parameterIndex++;
             }
             else if (auto valParam = as<GenericValueParamDecl>(m))
             {
                 ensureDecl(valParam, DeclCheckState::ReadyForReference);
+                valParam->parameterIndex = parameterIndex++;
             }
             else if (auto constraint = as<GenericTypeConstraintDecl>(m))
             {