[pull] master from shader-slang:master

source/slang/hlsl.meta.slang

@@ -533,6 +533,7 @@ interface ITexelElement
 {
     associatedtype Element : __BuiltinArithmeticType;
     static const int elementCount;
+    [OverloadRank(-1)]
     __init(Element x);
 }
 

source/slang/slang-check-decl.cpp

@@ -7545,7 +7545,9 @@ void SemanticsVisitor::checkExtensionConformance(ExtensionDecl* decl)
                        .as<ExtensionDecl>();
     auto targetType = getTargetType(m_astBuilder, declRef);
 
-    for (auto inheritanceDecl : decl->getMembersOfType<InheritanceDecl>())
+    // Make a copy of inhertanceDecls first since `checkConformance` may modify decl->members.
+    auto inheritanceDecls = decl->getMembersOfType<InheritanceDecl>().toList();
+    for (auto inheritanceDecl : inheritanceDecls)
     {
         checkConformance(targetType, inheritanceDecl, decl);
     }
@@ -7596,7 +7598,7 @@ void SemanticsVisitor::checkAggTypeConformance(AggTypeDecl* decl)
         // just with `abstract` methods that replicate things?
         // (That's what C# does).
 
-        // Make a copy of inhertanceDecls firstsince `checkConformance` may modify decl->members.
+        // Make a copy of inhertanceDecls first since `checkConformance` may modify decl->members.
         auto inheritanceDecls = decl->getMembersOfType<InheritanceDecl>().toList();
         for (auto inheritanceDecl : inheritanceDecls)
         {

source/slang/slang-check-inheritance.cpp

@@ -450,14 +450,15 @@ InheritanceInfo SharedSemanticsContext::_calcInheritanceInfo(
                 // then we need to add the extension itself as a facet.
                 //
                 auto extDeclRef =
-                    createDefaultSubstitutionsIfNeeded(astBuilder, &visitor, extensionDecl);
-                auto selfExtFacet = new (arena) Facet::Impl(
+                    createDefaultSubstitutionsIfNeeded(astBuilder, &visitor, extensionDecl)
+                        .as<ExtensionDecl>();
+                auto extInheritanceInfo = getInheritanceInfo(extDeclRef, circularityInfo);
+                addDirectBaseFacet(
                     Facet::Kind::Extension,
-                    Facet::Directness::Direct,
-                    extDeclRef,
                     selfType,
-                    astBuilder->getTypeEqualityWitness(selfType));
-                allFacets.add(selfExtFacet);
+                    selfIsSelf,
+                    extDeclRef,
+                    extInheritanceInfo);
             }
         }
 

source/slang/slang-check-overload.cpp

@@ -1321,6 +1321,34 @@ int SemanticsVisitor::CompareLookupResultItems(
     LookupResultItem const& left,
     LookupResultItem const& right)
 {
+    auto leftDeclRefParent = getParentDeclRef(left.declRef);
+    auto rightDeclRefParent = getParentDeclRef(right.declRef);
+
+    bool leftIsExtension = false;
+    bool rightIsExtension = false;
+    bool leftIsFreeFormExtension = false;
+    bool rightIsFreeFormExtension = false;
+
+    // Prefer declarations that are not in free-form generic extensions, i.e.
+    // `extension<T:IFoo> T { /* declaration here should have lower precedence. */ }
+    if (auto leftExt = as<ExtensionDecl>(leftDeclRefParent.getDecl()))
+    {
+        leftIsExtension = true;
+        if (isDeclRefTypeOf<GenericTypeParamDeclBase>(leftExt->targetType))
+            leftIsFreeFormExtension = true;
+    }
+    if (auto rightExt = as<ExtensionDecl>(rightDeclRefParent.getDecl()))
+    {
+        rightIsExtension = true;
+        if (isDeclRefTypeOf<GenericTypeParamDeclBase>(rightExt->targetType))
+            rightIsFreeFormExtension = true;
+    }
+
+    // If one of the candidates is a free-form extension, it is always worse than
+    // a non-free-form extension.
+    if (leftIsFreeFormExtension != rightIsFreeFormExtension)
+        return int(leftIsFreeFormExtension) - int(rightIsFreeFormExtension);
+
     // It is possible for lookup to return both an interface requirement
     // and the concrete function that satisfies that requirement.
     // We always want to favor a concrete method over an interface
@@ -1334,16 +1362,12 @@ int SemanticsVisitor::CompareLookupResultItems(
     // directly (it is only visible through the requirement witness
     // information for inheritance declarations).
     //
-    auto leftDeclRefParent = getParentDeclRef(left.declRef);
-    auto rightDeclRefParent = getParentDeclRef(right.declRef);
     bool leftIsInterfaceRequirement = isInterfaceRequirement(left.declRef.getDecl());
     bool rightIsInterfaceRequirement = isInterfaceRequirement(right.declRef.getDecl());
     if (leftIsInterfaceRequirement != rightIsInterfaceRequirement)
         return int(leftIsInterfaceRequirement) - int(rightIsInterfaceRequirement);
 
     // Prefer non-extension declarations over extension declarations.
-    bool leftIsExtension = as<ExtensionDecl>(leftDeclRefParent.getDecl()) != nullptr;
-    bool rightIsExtension = as<ExtensionDecl>(rightDeclRefParent.getDecl()) != nullptr;
     if (leftIsExtension != rightIsExtension)
     {
         // Add a special case for constructors, where we prefer the one that is not synthesized,

source/slang/slang-lower-to-ir.cpp

@@ -3094,9 +3094,10 @@ struct StmtLoweringVisitor;
 
 void maybeEmitDebugLine(
     IRGenContext* context,
-    StmtLoweringVisitor& visitor,
+    StmtLoweringVisitor* visitor,
     Stmt* stmt,
-    SourceLoc loc = SourceLoc());
+    SourceLoc loc = SourceLoc(),
+    bool allowNullStmt = false);
 
 // When lowering something callable (most commonly a function declaration),
 // we need to construct an appropriate parameter list for the IR function
@@ -5221,6 +5222,8 @@ struct ExprLoweringVisitorBase : public ExprVisitor<Derived, LoweredValInfo>
         auto afterBlock = builder->createBlock();
         auto irCond = getSimpleVal(context, lowerRValueExpr(context, expr->arguments[0]));
 
+        maybeEmitDebugLine(context, nullptr, nullptr, irCond->sourceLoc, true);
+
         // ifElse(<first param>, %true-block, %false-block, %after-block)
         builder->emitIfElse(irCond, thenBlock, elseBlock, afterBlock);
 
@@ -6211,6 +6214,8 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
 
         auto irCond = getSimpleVal(context, lowerRValueExpr(context, condExpr));
 
+        maybeEmitDebugLine(context, this, stmt, condExpr->loc);
+
         IRInst* ifInst = nullptr;
 
         if (elseStmt)
@@ -6323,7 +6328,7 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         // want to emit the expression for the loop condition:
         if (const auto condExpr = stmt->predicateExpression)
         {
-            maybeEmitDebugLine(context, *this, stmt, condExpr->loc);
+            maybeEmitDebugLine(context, this, stmt, condExpr->loc);
 
             auto irCondition =
                 getSimpleVal(context, lowerRValueExpr(context, stmt->predicateExpression));
@@ -6383,7 +6388,7 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         insertBlock(continueLabel);
         if (auto incrExpr = stmt->sideEffectExpression)
         {
-            maybeEmitDebugLine(context, *this, stmt, incrExpr->loc);
+            maybeEmitDebugLine(context, this, stmt, incrExpr->loc);
             lowerRValueExpr(context, incrExpr);
         }
 
@@ -6432,7 +6437,7 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         // want to emit the expression for the loop condition:
         if (auto condExpr = stmt->predicate)
         {
-            maybeEmitDebugLine(context, *this, stmt, condExpr->loc);
+            maybeEmitDebugLine(context, this, stmt, condExpr->loc);
 
             auto irCondition = getSimpleVal(context, lowerRValueExpr(context, condExpr));
 
@@ -6498,7 +6503,7 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         // want to emit the expression for the loop condition:
         if (auto condExpr = stmt->predicate)
         {
-            maybeEmitDebugLine(context, *this, stmt, stmt->predicate->loc);
+            maybeEmitDebugLine(context, this, stmt, stmt->predicate->loc);
 
             auto irCondition = getSimpleVal(context, lowerRValueExpr(context, condExpr));
 
@@ -7398,24 +7403,29 @@ IRInst* getOrEmitDebugSource(IRGenContext* context, PathInfo path)
 
 void maybeEmitDebugLine(
     IRGenContext* context,
-    StmtLoweringVisitor& visitor,
+    StmtLoweringVisitor* visitor,
     Stmt* stmt,
-    SourceLoc loc)
+    SourceLoc loc,
+    bool allowNullStmt)
 {
     if (!context->includeDebugInfo)
         return;
-    if (as<EmptyStmt>(stmt))
-        return;
-    if (!loc.isValid())
-        loc = stmt->loc;
+
+    if (!allowNullStmt)
+    {
+        if (as<EmptyStmt>(stmt))
+            return;
+        if (!loc.isValid())
+            loc = stmt->loc;
+    }
+
     auto sourceManager = context->getLinkage()->getSourceManager();
-    auto sourceView = context->getLinkage()->getSourceManager()->findSourceView(loc);
+    auto sourceView = sourceManager->findSourceView(loc);
     if (!sourceView)
         return;
 
     IRInst* debugSourceInst = nullptr;
-    auto humaneLoc =
-        context->getLinkage()->getSourceManager()->getHumaneLoc(loc, SourceLocType::Emit);
+    auto humaneLoc = sourceManager->getHumaneLoc(loc, SourceLocType::Emit);
 
     // Do a best-effort attempt to retrieve the nominal source file.
     auto pathInfo = sourceView->getPathInfo(loc, SourceLocType::Emit);
@@ -7434,7 +7444,8 @@ void maybeEmitDebugLine(
     {
         debugSourceInst = getOrEmitDebugSource(context, pathInfo);
     }
-    visitor.startBlockIfNeeded(stmt);
+    if (visitor)
+        visitor->startBlockIfNeeded(stmt);
     context->irBuilder->emitDebugLine(
         debugSourceInst,
         humaneLoc.line,
@@ -7471,7 +7482,7 @@ void lowerStmt(IRGenContext* context, Stmt* stmt)
 
     try
     {
-        maybeEmitDebugLine(context, visitor, stmt, stmt->loc);
+        maybeEmitDebugLine(context, &visitor, stmt, stmt->loc);
         visitor.dispatch(stmt);
     }
     // Don't emit any context message for an explicit `AbortCompilationException`

tests/language-feature/extensions/extension-override-2.slang

@@ -0,0 +1,41 @@
+//TEST:INTERPRET(filecheck=CHECK):
+interface IBar
+{}
+
+interface IFoo : IBar
+{
+    void execute();
+}
+
+struct Impl : IFoo
+{
+    void execute()
+    {
+        printf("Impl::execute();\n");
+    }
+}
+
+extension<T:IBar> T : IFoo
+{
+    void execute()
+    {
+        printf("Extension::execute();\n");
+    }
+}
+
+struct Base : IBar{}
+
+void test<T:IFoo>(T t)
+{
+    t.execute();
+}
+
+void main()
+{
+    // CHECK: Impl::execute();
+    Impl f;
+    test(f);
+    // CHECK: Extension::execute();
+    Base b;
+    test(b);
+}