Feature/as refactor review (#821)

* Replace dynamicCast with as where does not change behavior (ie not Type derived).
Use free function where scoping is clear.

* Replace uses of dynamicCast with as when there is no difference in behavior.

* Remove the IsXXXX methods from Type.

* Don't have separate smart pointer to store canonicalType on Type.

* Simplify Slang.FilteredMemberRefList.Adjust, such does the cast directly.

* Use free as where appropriate.

* Use free function version of casts where appropriate.

* Fix text in casting.md

* Fix typos in decl-refs.md

* Remove the uses of free function as on RefDecl.
Add 'canAs' to RefDecl as a way to test if a cast is possible.
Moved 'as' into RefDeclBase.

* Use 'is' to test for as cast on smart pointers.
Fix small scope issue.

* * Cache stringType and enumTypeType on the Session
* Make DeclRefType::Create return a RefPtr
* Make casting of result use the *method* .as  (cos using free function would mean objects being wrongly destroyed)
* Make results from createInstance ref'd to avoid possible leaks.

* Fix typo in template parameter for is on RefPtr.

1 files changed, 7 insertions, 12 deletions

diff --git a/source/slang/syntax-base-defs.h b/source/slang/syntax-base-defs.h
index 7f49bb607..93fe687fd 100644
--- a/source/slang/syntax-base-defs.h
+++ b/source/slang/syntax-base-defs.h
@@ -80,27 +80,22 @@ public:
     Session* getSession() { return this->session; }
     void setSession(Session* s) { this->session = s; }
 
-    bool Equals(Type * type);
-    bool Equals(RefPtr<Type> type);
-
-    bool IsTextureOrSampler();
-    bool IsTexture() { return as<TextureType>(this) != nullptr; }
-    bool IsSampler() { return as<SamplerStateType>(this) != nullptr; }
-    bool IsStruct();
-    //bool IsClass();
-
+    bool Equals(Type* type);
+    
     Type* GetCanonicalType();
 
     virtual RefPtr<Val> SubstituteImpl(SubstitutionSet subst, int* ioDiff) override;
 
     virtual bool EqualsVal(Val* val) override;
+
+    ~Type();
+
 protected:
-    virtual bool EqualsImpl(Type * type) = 0;
+    virtual bool EqualsImpl(Type* type) = 0;
 
     virtual RefPtr<Type> CreateCanonicalType() = 0;
     Type* canonicalType = nullptr;
-    RefPtr<Type> canonicalTypeRefPtr;
-
+    
     Session* session = nullptr;
     )
 END_SYNTAX_CLASS()