Support generic interfaces. (#3278)

* Initial support for generic interfaces.

* Cleanup.

* Add generic syntax for interfaces.

---------

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

1 files changed, 10 insertions, 0 deletions

diff --git a/source/slang/slang-ast-decl-ref.cpp b/source/slang/slang-ast-decl-ref.cpp
index c77cf72ed..c9511e4e7 100644
--- a/source/slang/slang-ast-decl-ref.cpp
+++ b/source/slang/slang-ast-decl-ref.cpp
@@ -150,6 +150,11 @@ Val* LookupDeclRef::_resolveImplOverride()
 
 DeclRefBase* LookupDeclRef::_getBaseOverride()
 {
+    auto supType = getWitness()->getSup();
+    if (auto declRefType = as<DeclRefType>(supType))
+    {
+        return declRefType->getDeclRef();
+    }
     return nullptr;
 }
 
@@ -432,10 +437,13 @@ DeclRef<Decl> createDefaultSubstitutionsIfNeeded(
     ShortList<GenericDecl*> genericParentDecls;
     auto lastSubstNode = SubstitutionSet(declRef).getInnerMostNodeWithSubstInfo();
     auto lastGenApp = as<GenericAppDeclRef>(lastSubstNode);
+    auto lastLookup = as<LookupDeclRef>(lastSubstNode);
     for (auto dd = declRef.getDecl()->parentDecl; dd; dd = dd->parentDecl)
     {
         if (lastGenApp && dd == lastGenApp->getGenericDecl())
             break;
+        if (lastLookup && lastLookup->getDecl()->isChildOf(dd))
+            break;
         if (auto gen = as<GenericDecl>(dd))
             genericParentDecls.add(gen);
     }
@@ -454,6 +462,8 @@ DeclRef<Decl> createDefaultSubstitutionsIfNeeded(
         }
         parentDeclRef = astBuilder->getGenericAppDeclRef(parentDeclRef.as<GenericDecl>(), args.getArrayView());
     }
+    if (!parentDeclRef)
+        return declRef;
     if (parentDeclRef.getDecl() == declRef.getDecl())
         return parentDeclRef;
     return astBuilder->getMemberDeclRef(parentDeclRef, declRef.getDecl());