Incur l-value conversion cost during overload resolution. (#3195)

* Incur l-value conversion cost during overload resolution.

* Fix compile error.

* cleanup.

---------

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

1 files changed, 10 insertions, 0 deletions

diff --git a/source/slang/slang-ast-support-types.h b/source/slang/slang-ast-support-types.h
index 5d7ca49cb..0b4e9cab2 100644
--- a/source/slang/slang-ast-support-types.h
+++ b/source/slang/slang-ast-support-types.h
@@ -140,6 +140,9 @@ namespace Slang
         // the element type of the vector)
         kConversionCost_ScalarToVector = 1,
 
+        // Additional cost when casting an LValue.
+        kConversionCost_LValueCast = 800,
+
         // Conversion is impossible
         kConversionCost_Impossible = 0xFFFFFFFF,
     };
@@ -521,6 +524,13 @@ namespace Slang
 
         QualType(Type* type);
 
+        QualType(Type* type, bool isLVal)
+            : QualType(type)
+        {
+            isLeftValue = isLVal;
+        }
+
+
         Type* Ptr() { return type; }
 
         operator Type*() { return type; }