From 049aac1b80143753b4b3449e529024bafe2250be Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Tue, 12 Jul 2022 22:45:05 -0700
Subject: Support `class` types. (#2321)

* Support `class` types.

* Ignore class-keyword test

* Fix codereview comments and warnings.

Co-authored-by: Yong He <yhe@nvidia.com>
---
 source/slang/slang-check-overload.cpp | 37 +++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

(limited to 'source/slang/slang-check-overload.cpp')

diff --git a/source/slang/slang-check-overload.cpp b/source/slang/slang-check-overload.cpp
index bd27c7df2..be351a78f 100644
--- a/source/slang/slang-check-overload.cpp
+++ b/source/slang/slang-check-overload.cpp
@@ -60,6 +60,40 @@ namespace Slang
         return counts;
     }
 
+    bool SemanticsVisitor::TryCheckOverloadCandidateClassNewMatchUp(OverloadResolveContext& context, OverloadCandidate const& candidate)
+    {
+        // Check that a constructor call to a class type must be in a `new` expr, and a `new` expr
+        // is only used to construct a class.
+        bool isClassType = false;
+        bool isNewExpr = false;
+        if (auto ctorDeclRef = candidate.item.declRef.as<ConstructorDecl>())
+        {
+            if (auto resultType = as<DeclRefType>(candidate.resultType))
+            {
+                if (resultType->declRef.as<ClassDecl>())
+                {
+                    isClassType = true;
+                }
+            }
+        }
+        if (as<NewExpr>(context.originalExpr))
+        {
+            isNewExpr = true;
+        }
+
+        if (isNewExpr && !isClassType)
+        {
+            getSink()->diagnose(context.originalExpr, Diagnostics::newCanOnlyBeUsedToInitializeAClass);
+            return false;
+        }
+        if (!isNewExpr && isClassType)
+        {
+            getSink()->diagnose(context.originalExpr, Diagnostics::classCanOnlyBeInitializedWithNew);
+            return false;
+        }
+        return true;
+    }
+
     bool SemanticsVisitor::TryCheckOverloadCandidateArity(
         OverloadResolveContext&		context,
         OverloadCandidate const&	candidate)
@@ -572,6 +606,9 @@ namespace Slang
 
         context.mode = OverloadResolveContext::Mode::ForReal;
 
+        if (!TryCheckOverloadCandidateClassNewMatchUp(context, candidate))
+            goto error;
+
         if (!TryCheckOverloadCandidateArity(context, candidate))
             goto error;
 
-- 
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