Hotfix/remove null this work around (#831)

* Re-enable warnings around null this.

* Remove testing for nullptr in Substitution::Equals tests

* Fix ref counting problem in vulkan render.

* * Remove SLANG_ASSERT(this) in mthods
* Place asserts conservatively at method call sites where appropriate.

1 files changed, 1 insertions, 1 deletions

diff --git a/source/slang/syntax.h b/source/slang/syntax.h
index 344e94ff9..6a404214e 100644
--- a/source/slang/syntax.h
+++ b/source/slang/syntax.h
@@ -417,7 +417,7 @@ namespace Slang
             : substitutions(subst)
         {
         }
-        bool Equals(SubstitutionSet substSet) const;
+        bool Equals(const SubstitutionSet& substSet) const;
         int GetHashCode() const;
     };