Support `constref` parameters passing. (#3249)

* Support `constref` parameters passing.

* Fix.

* Fix.

* Add test and diagnostic on mix use of __constref and no_diff.

* check for [constref] on differentiable member method.

---------

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/source/slang/slang-check-expr.cpp b/source/slang/slang-check-expr.cpp
index 5ea897448..abdd89b01 100644
--- a/source/slang/slang-check-expr.cpp
+++ b/source/slang/slang-check-expr.cpp
@@ -214,11 +214,11 @@ namespace Slang
     {
         auto exprType = expr->type.type;
 
-        if (auto refType = as<RefType>(exprType))
+        if (auto refType = as<RefTypeBase>(exprType))
         {
             auto openRef = m_astBuilder->create<OpenRefExpr>();
             openRef->innerExpr = expr;
-            openRef->type.isLeftValue = true;
+            openRef->type.isLeftValue = (as<RefType>(exprType) != nullptr);
             openRef->type.type = refType->getValueType();
             return openRef;
         }