Allow extension on interface (#369)

This completes item 5 in issue #361.

The interesting change is that when checking for interface conformance, we include the requirements (include transitive interfaces) defined in extensions as well. (check.cpp line 1946)

All the other changes are for one thing: reoder the semantic checkings to two explicit stages: check header and check body. In check header phase, we check everything except function bodies, register all extensions with their target decls, then check interface conformances for all concrete types. In body checking phase, we look inside the function bodies and check concrete statements/expressions. This change ensures that we take extension into consideration in all places where it should be.

1 files changed, 28 insertions, 8 deletions

diff --git a/source/slang/syntax.h b/source/slang/syntax.h
index ab26b1f6d..93e421977 100644
--- a/source/slang/syntax.h
+++ b/source/slang/syntax.h
@@ -1098,32 +1098,52 @@ namespace Slang
     // Declarations
     //
 
+    inline ExtensionDecl* GetCandidateExtensions(DeclRef<AggTypeDecl> const& declRef)
+    {
+        return declRef.getDecl()->candidateExtensions;
+    }
+
     inline FilteredMemberRefList<Decl> getMembers(DeclRef<ContainerDecl> const& declRef)
     {
         return FilteredMemberRefList<Decl>(declRef.getDecl()->Members, declRef.substitutions);
     }
 
-    template<typename T>
-    inline FilteredMemberRefList<T> getMembersOfType(DeclRef<ContainerDecl> const& declRef)
+    // TODO: change this to return a lazy list instead of constructing actual list
+    inline List<DeclRef<Decl>> getMembersWithExt(DeclRef<ContainerDecl> const& declRef)
     {
-        return FilteredMemberRefList<T>(declRef.getDecl()->Members, declRef.substitutions);
+        List<DeclRef<Decl>> rs;
+        for (auto d : FilteredMemberRefList<Decl>(declRef.getDecl()->Members, declRef.substitutions))
+            rs.Add(d);
+        if (auto aggDeclRef = declRef.As<AggTypeDecl>())
+        {
+            for (auto ext = GetCandidateExtensions(aggDeclRef); ext; ext = ext->nextCandidateExtension)
+            {
+                for (auto mbr : getMembers(DeclRef<ContainerDecl>(ext, declRef.substitutions)))
+                    rs.Add(mbr);
+            }
+        }
+        return rs;
     }
 
-    inline ExtensionDecl* GetCandidateExtensions(DeclRef<AggTypeDecl> const& declRef)
+    template<typename T>
+    inline FilteredMemberRefList<T> getMembersOfType(DeclRef<ContainerDecl> const& declRef)
     {
-        return declRef.getDecl()->candidateExtensions;
+        return FilteredMemberRefList<T>(declRef.getDecl()->Members, declRef.substitutions);
     }
 
     template<typename T>
-    inline FilteredMemberRefList<T> getMembersOfTypeWithExt(DeclRef<ContainerDecl> const& declRef)
+    inline List<DeclRef<T>> getMembersOfTypeWithExt(DeclRef<ContainerDecl> const& declRef)
     {
-        auto rs = getMembersOfType<T>(declRef);
+        List<DeclRef<T>> rs;
+        for (auto d : getMembersOfType<T>(declRef))
+            rs.Add(d);
         if (auto aggDeclRef = declRef.As<AggTypeDecl>())
         {
             for (auto ext = GetCandidateExtensions(aggDeclRef); ext; ext = ext->nextCandidateExtension)
             {
                 auto extMembers = getMembersOfType<T>(DeclRef<ContainerDecl>(ext, declRef.substitutions));
-                const_cast<List<RefPtr<Decl>>&>(rs.decls).AddRange(extMembers.decls);
+                for (auto mbr : extMembers)
+                    rs.Add(mbr);
             }
         }
         return rs;