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, 18 insertions, 0 deletions

diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 1e3c6a361..8df5ae618 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -169,6 +169,8 @@ namespace Slang
 
         void visitInheritanceDecl(InheritanceDecl* inheritanceDecl);
 
+        void visitThisTypeConstraintDecl(ThisTypeConstraintDecl* thisTypeConstraintDecl);
+
             /// Validate that `decl` isn't illegally inheriting from a type in another module.
             ///
             /// This call checks a single `inheritanceDecl` to make sure that it either
@@ -1600,6 +1602,22 @@ namespace Slang
         // based on the declaration that is doing the inheriting.
     }
 
+    void SemanticsDeclBasesVisitor::visitThisTypeConstraintDecl(ThisTypeConstraintDecl* thisTypeConstraintDecl)
+    {
+        // Make sure IFoo<T>.This.ThisIsIFooConstraint.base.type is properly set
+        // to DeclRefType(IFoo<T>) with default generic arguments.
+        if (!thisTypeConstraintDecl->base.type)
+        {
+            auto parentTypeDecl = getParentDecl(getParentDecl(thisTypeConstraintDecl));
+            thisTypeConstraintDecl->base.type = DeclRefType::create(
+                m_astBuilder,
+                createDefaultSubstitutionsIfNeeded(
+                    m_astBuilder,
+                    this,
+                    getDefaultDeclRef(parentTypeDecl)));
+        }
+    }
+
         // Concretize interface conformances so that we have witnesses as required for lookup.
         // for lookup.
     struct SemanticsDeclConformancesVisitor